Term
| how volunteer peanuts can be weeds |
|
Definition
| volunteer peanuts from the previous season are serious weed problems in rotational crops in Georgia |
|
|
Term
|
Definition
| plant that interferes with human activity |
|
|
Term
|
Definition
-Weeds are dynamic and constantly change
-Of 250,000 plants species, 1% (2,500 species) are considered weeds
+Many of our most noxious weeds are not native |
|
|
Term
| how many plants are considered weeds? |
|
Definition
| Of 250,000 plants species, 1% (2,500 species) are considered weeds |
|
|
Term
|
Definition
| inhabit disturbed habitats |
|
|
Term
| what the ability to inhabit disturbed habitats allows weeds to do |
|
Definition
-germinate in poor conditions
-grow under poor soil fertility
-grow rapidly |
|
|
Term
| Physiology of Successful Weeds |
|
Definition
| -Morphology – Roots, Stem
-Physiology – C3, C4
-Genetic Diversity
-Seedbank and Dormancy |
|
|
Term
| diagram of current integrated weed management |
|
Definition
|
|
Term
| diagram of "ideal" integrated weed management |
|
Definition
|
|
Term
| Evolution of Row Crop Weed Management |
|
Definition
|
|
Term
| some things to consider in weed control |
|
Definition
-Herbicide Development
-Biological control
-Cover crops
-Tillage
-Herbicide decision aids
-Competitive crops |
|
|
Term
| some things to consider in weed science |
|
Definition
-Propagule dormancy
-Seed production
-Population genetics
-Emergence dynamics
-Weed/crop principles
-Population shifts |
|
|
Term
| how weed IPM differs from insect IPM regarding IPM tools |
|
Definition
|
|
Term
| how weed IPM differs from insect IPM regarding characters |
|
Definition
|
|
Term
| something the weed scientist and the farmer need to communicate |
|
Definition
| How to align the farmer’s time and labor constraints with site-specific “biological time constraints” of weeds? |
|
|
Term
| biological time constraints |
|
Definition
| time-dependent properties that influence weed management |
|
|
Term
| biological time constraints would include... |
|
Definition
-Periodicity of weed emergence
-Rate of weed and crop growth
-Crop sensitivity to early season weed competition |
|
|
Term
| HOW RESIDUAL HERBICIDES CAN ADDRESS “HIDDEN COSTS” OF EARLY-SEASON WEED COMPETITION |
|
Definition
| reducing timeliness issues associated with postemergence weed control |
|
|
Term
| some risks of residual herbicides |
|
Definition
-Rainfall to activate the herbicide
-Potential for early season crop injury (e.g. cold and wet weather)
-Can limit crop rotations |
|
|
Term
| some preventive (indirect) measures in IWM |
|
Definition
-farm equipment
-crop choice
-sanitation
-cropping techniques
-preventative measures
-soil cultivation
-damage thresholds |
|
|
Term
| some curative (direct) measures in IWM |
|
Definition
-mechanical control
-thermal control
-biocontrol
-chemical control |
|
|
Term
| some farm equipment measures in IWM |
|
Definition
-mechanization
-standardization
-equipment sharing
-contractors |
|
|
Term
| some crop choice measures in IWM |
|
Definition
-rotation
-competitiveness
-cover crops
-allelopathy |
|
|
Term
| some sanitation techniques in IWM |
|
Definition
-organic manures
-machinery
-volunteer crops |
|
|
Term
| some cropping techniques used in IWM |
|
Definition
-row-crops
-ridge-till
-transplanting
-crop density
-planting time
-nutrient management |
|
|
Term
| some preventative measures in IWM |
|
Definition
-mulching techniques
-solarization
-soil steaming |
|
|
Term
| some soil cultivation techniques in IWM |
|
Definition
-ploughing
-non-inverse tillage
-seedbed preparation
-false seedbed |
|
|
Term
| some damage thresholds of IWM |
|
Definition
-number/density thresholds
-period thresholds |
|
|
Term
| some mechanical control techniques in IWM |
|
Definition
-harrowing
-hoeing
-roll-cultivation
-finger-weeder
-torsion-weeder |
|
|
Term
| some thermal control techniques in IWM |
|
Definition
-flaming/IR
-steaming
-hot water |
|
|
Term
| some biocontrol techniques in IWM |
|
Definition
-beneficials
-bioherbicides |
|
|
Term
| some chemical control techniques in IWM |
|
Definition
-pre-emergence
-post-emergence
-application techniques |
|
|
Term
| the weed control practice of Prevention, soil solarization, weed control corresponds to this ecological principle |
|
Definition
| Reduce deposits to seedbank |
|
|
Term
| the weed control practice of Early cultivation, plant date corresponds to this ecological principle |
|
Definition
| Allow crop earlier resource capture |
|
|
Term
| the weed control practice of Cultivation, mowing, mulching corresponds to this ecological principle |
|
Definition
|
|
Term
| the weed control practice of Choice crop variety, early planting corresponds to this ecological principle |
|
Definition
|
|
Term
| the weed control practice of Choice seeding rate, row spacing corresponds to this ecological principle |
|
Definition
| Minimize intraspecific crop competition |
|
|
Term
| the weed control practice of Planting cover crop corresponds to this ecological principle |
|
Definition
| Maximize crop effect on weed |
|
|
Term
| the weed control practice of Rotation crop, control methods corresponds to this ecological principle |
|
Definition
| Modify environment to reduce weed growth |
|
|
Term
| the weed control practice of Intercropping corresponds to this ecological principle |
|
Definition
| Maximize crop use of resources |
|
|
Term
| the ecological principle of Reduce deposits to seedbank corresponds to this weed control practice |
|
Definition
| Prevention, soil solarization, weed control |
|
|
Term
| the ecological principle of Allow crop earlier resource capture corresponds to this weed control practice |
|
Definition
| Early cultivation, plant date |
|
|
Term
| the ecological principle of Reduce weed growth corresponds to this weed control practice |
|
Definition
| Cultivation, mowing, mulching |
|
|
Term
| the ecological principle of Maximize crop growth corresponds to this weed control practice |
|
Definition
| Choice crop variety, early planting |
|
|
Term
| the ecological principle of Minimize intraspecific crop competition corresponds to this weed control practice |
|
Definition
| Choice seeding rate, row spacing |
|
|
Term
| the ecological principle of Maximize crop effect on weed corresponds to this weed control practice |
|
Definition
|
|
Term
| the ecological principle of Modify environment to reduce weed growth corresponds to this weed control practice |
|
Definition
| Rotation crop, control methods |
|
|
Term
| the ecological principle of Maximize crop use of resources corresponds to this weed control practice |
|
Definition
|
|
Term
| the big hammer in current weed management |
|
Definition
|
|
Term
| the many little hammers in IWM |
|
Definition
-herbicide
-pathogens
-crop density
-cover crop
-harvester
-microbes
-tillage
-crop rotation |
|
|
Term
| flowchart of the big hammer in current weed management |
|
Definition
|
|
Term
| flowchart of the many little hammers in weed management |
|
Definition
|
|
Term
|
Definition
| Mature plants break loose from the root system and disperse seed as they tumble across the landscape. |
|
|
Term
| weed science vs. entomology in terms of how far along it is |
|
Definition
| weed science is behind entomology |
|
|
Term
| the main pigweed in the Midwest |
|
Definition
|
|
Term
| some weeds from the Midwest |
|
Definition
-giant ragweed
-lambsquarters
-common ragweed
-waterhemp |
|
|
Term
| how time of emergence can be used |
|
Definition
| to set up warning systems |
|
|
Term
| how length of germination makes some weed management decisions difficult |
|
Definition
| short means all at once and prolonged means emerging over long period of time |
|
|
Term
| short length of germination |
|
Definition
| all germinate at same time |
|
|
Term
| prolonged length of germination |
|
Definition
| weeds emerge over long period of time; not all at once |
|
|
Term
|
Definition
-Palmer amaranth
-Benghal Dayflower
-tall morning glory
-Texas millet |
|
|
Term
| What makes our weeds harder to manage? |
|
Definition
| the prolonged and moderate emergence |
|
|
Term
| Palmer amaranth seed production allows for... |
|
Definition
|
|
Term
| we need to scout weeds for... |
|
Definition
|
|
Term
| regarding weeds, you gotta counteract... |
|
Definition
|
|
Term
| A Weed’s mechanism for long-term survival |
|
Definition
|
|
Term
|
Definition
| seeds and fruits containing seeds on or in the soil |
|
|
Term
| you gotta manage ______ to make weed management easier |
|
Definition
|
|
Term
| why you gotta manage the seed bank... |
|
Definition
| to make weed management easier |
|
|
Term
|
Definition
| basically a vegetative means of propagation |
|
|
Term
| Seed vs Propagules: advantages of seeds |
|
Definition
-Seed more resistant to loss of viability
-Seed more numerous
-Seeds are not killed by herbicides |
|
|
Term
| Seed vs Propagules: advantages of propagules |
|
Definition
-Propagules emerge with greater vigor
-Propagules are more difficult to control because the control agent must kill the entire propagule |
|
|
Term
| Germination can be defined as... |
|
Definition
| the resumption of growth of a seed or a vegetative part |
|
|
Term
| some things that happen in germination |
|
Definition
-Imbibition of water
-Increased respiration
-Mobilization of food reserves
-Digestion of reserved foods |
|
|
Term
|
Definition
| the act or action of imbibing; especially : the taking up of fluid by a colloidal system resulting in swelling |
|
|
Term
| how germination occurs in our crops |
|
Definition
| begins promptly after planting and proceeds in an orderly fashion to the seedling emergence |
|
|
Term
| the principal means by which weed species perpetuate themselves and invade new areas |
|
Definition
|
|
Term
|
Definition
| embryonic life to exist in suspended animation for years---to preserve, protect, and ensure survival of the species |
|
|
Term
| when do seeds survive longer? shallowly buried in the soil or if left on the surface? |
|
Definition
| often if shallowly buried in soil |
|
|
Term
| what tillage does to seed bank |
|
Definition
| evidence suggests that it hastens depletion of the seed bank |
|
|
Term
| Seed longevity is increased if... |
|
Definition
| seeds are mixed in the soil rather than left on the surface |
|
|
Term
| Importance of soil-seed germination |
|
Definition
-Not the level or magnitude, but the fact that it does occur.
-Evidence exists that tillage hastens depletion of the seed bank.
+Now we promote reduced tillage
-Seed longevity is increased if seed are mixed in the soil rather than left on the surface. Seems to conflict with statement above.
-Can affect resistance development |
|
|
Term
|
Definition
| to prevent seed production |
|
|
Term
| cutting of weeds mostly used for... |
|
Definition
| annual and biennial plants |
|
|
Term
| how to do mowing regarding seeds |
|
Definition
| Mowing must be timely. Several weeds can have their flowers, pods, or berries separated from the plant and still make mature and viable seed. |
|
|
Term
| Environmental Factors that Impact Germination |
|
Definition
-Depth of Burial – the most consistent
-Light |
|
|
Term
| the most consistent factor affecting germination |
|
Definition
|
|
Term
| factors of light that affect germination |
|
Definition
-Light intensity
-Spectral composition – red vs. far-red/near infrared
-Duration |
|
|
Term
| this in the seed interacts with light quality |
|
Definition
|
|
Term
| this light primotes germination |
|
Definition
|
|
Term
| this light inhibits germination |
|
Definition
|
|
Term
| very few seeds will go deeper than... |
|
Definition
|
|
Term
| Environmental Factors that Impact Germination |
|
Definition
-Depth of Burial – the most consistent
-Light
-Red Light Contacting Soil Surface
-amount of canopy
-temp
-water
-soil
-chemicals
-gas exchange |
|
|
Term
| amount of red light reaching soil surface vs. germination |
|
Definition
| the more red light reaches the soil surface, the more germination |
|
|
Term
| how temp can affect plants |
|
Definition
-some plants require cold period and some require hot period
-some plants require specific variation between hot and cold temperature |
|
|
Term
| how the effect of water on a seed can vary by species |
|
Definition
-A certain level may need to be maintained
-Only a rainfall event required
-Too much may cause dormancy (induced)
+Rice production |
|
|
Term
| soil factors that impact germination |
|
Definition
-Crust on soil surface
+Impacts emergence more than germination
-Compaction
+Goosegrass does well in compacted soil
-Soil Structure |
|
|
Term
| Crust on soil surface impacts this more than germination |
|
Definition
|
|
Term
| some chemicals that can affect germination |
|
Definition
-chemicals contained in seed/fruit
-nitrate
-gibberellec acid
-ethylene
-herbicide, such as EPTC, Vernam, Zorial
-acscissic acid (plant hormone) |
|
|
Term
| how nitrate impacts germination |
|
Definition
|
|
Term
| what gibberellic acid does in plant |
|
Definition
| stimulates inactive form of phytochrome (but species dependent) |
|
|
Term
| how ethylene impacts germination |
|
Definition
|
|
Term
| something ethylene has been used for |
|
Definition
| Has been used on field scale to stimulate witchweed germ. |
|
|
Term
| how herbicides, such as EPTC, Vernam, and Zorial affect germination |
|
Definition
|
|
Term
| what Abscissic acid (plant hormone) does in seed |
|
Definition
| promotes dormancy in seed |
|
|
Term
| how oxygen can impact germination |
|
Definition
| restriction of oxygen from seed will inhibit germination |
|
|
Term
| why we would not expect pitted morningglory populations to be high in flooded soils or if there had been an excessive amount of rain |
|
Definition
| soil oxygen has a great influence on pitted morningglory germination |
|
|
Term
| Requirements for Germination |
|
Definition
-water
-oxygen
-temp
-light
-favorable pH |
|
|
Term
| why water is required for germination |
|
Definition
| because it's the solvent for food reserves |
|
|
Term
| why oxygen is required for germination |
|
Definition
|
|
Term
| how temp affects cell division |
|
Definition
| because it affects enzyme activity and cell division; very species specific |
|
|
Term
| how many plants require light to germinate? |
|
Definition
|
|
Term
| some plants that have a germination response to light favored by light |
|
Definition
-Bluegrass
-Lettuce
-Eclipta
-Tobacco
-Dock |
|
|
Term
| some plants that have a germination response to light favored by darkness |
|
Definition
|
|
Term
| some plants that have a germination response to light favored by light or darkness |
|
Definition
-Wheat
-Clover
-Bean
-Most plants |
|
|
Term
| size of seed vs. longevity |
|
Definition
| Seed size has very little to do with the ability of the seed to remain in the soil for extended periods of time and still remain viable. |
|
|
Term
| Some of the longest lived seeds in soil are also... |
|
Definition
| some of the smallest seed |
|
|
Term
| grass seed longevity vs. broadleaf weed seed longevity |
|
Definition
| GENERALLY, grass seeds do not survive in the soil as long as broadleaf weeds |
|
|
Term
| Effect of Soil Tillage on Weed Seed |
|
Definition
| Soil tillage is beneficial for weed seed germination. |
|
|
Term
| If you don’t have weeds and are not preparing a seedbed, don’t till the soil, except... |
|
Definition
| sometimes will help with water infiltration and wind erosion |
|
|
Term
| The improvement of weed seed germination following tillage is generally due to... |
|
Definition
| weed seed being exposed to light (just a flash is needed) or bringing the seed closer to the soil surface so that it can emerge |
|
|
Term
| how the influence of light on germination can be used |
|
Definition
as a management tool
example: Some researchers are showing that if tillage is done on a moonless night with no synthetic light source, some weed species can be reduced a great deal |
|
|
Term
| factors in depletion of the soil-seed bank |
|
Definition
-Natural ageing, respiration, enzyme activity
-Germination
-Microorganisms
-Other soil organisms
-Birds and animals
-Climate/environment
-Fire |
|
|
Term
| some info about Recovery of the Soil Seed Bank |
|
Definition
-Little definitive data on this subject
+Difficult to do and takes many years
+Scientists are impatient, must publish |
|
|
Term
| how to model seed depletion in soil |
|
Definition
| Negative exponential decay curve |
|
|
Term
| Negative exponential decay curve |
|
Definition
| S = S0 e-gt or loge S = loge S0 - gt
where S is the number of surviving seeds from an initial population S0 after t years. g is the annual rate of depletion. |
|
|
Term
| the Negative exponential decay curve is only valid on... |
|
Definition
-a year-to-year basis, and
-in the absence of seed influx. |
|
|
Term
| if the Negative exponential decay curve is true, implications include that seed banks have... |
|
Definition
-a constant half life, and
-a constant annual probability of depletion |
|
|
Term
| what gibberellic acid does in plant |
|
Definition
| stimulates inactive form of phytochrome (but species dependent) |
|
|
Term
| how ethylene impacts germination |
|
Definition
|
|
Term
| something ethylene has been used for |
|
Definition
| Has been used on field scale to stimulate witchweed germ. |
|
|
Term
| how herbicides, such as EPTC, Vernam, and Zorial affect germination |
|
Definition
|
|
Term
| what Abscissic acid (plant hormone) does in seed |
|
Definition
| promotes dormancy in seed |
|
|
Term
| how oxygen can impact germination |
|
Definition
| restriction of oxygen from seed will inhibit germination |
|
|
Term
| why we would not expect pitted morningglory populations to be high in flooded soils or if there had been an excessive amount of rain |
|
Definition
| soil oxygen has a great influence on pitted morningglory germination |
|
|
Term
| Requirements for Germination |
|
Definition
-water
-oxygen
-temp
-light
-favorable pH |
|
|
Term
| why water is required for germination |
|
Definition
| because it's the solvent for food reserves |
|
|
Term
| why oxygen is required for germination |
|
Definition
|
|
Term
| how temp affects cell division |
|
Definition
| because it affects enzyme activity and cell division; very species specific |
|
|
Term
| how many plants require light to germinate? |
|
Definition
|
|
Term
| some plants that have a germination response to light favored by light |
|
Definition
-Bluegrass
-Lettuce
-Eclipta
-Tobacco
-Dock |
|
|
Term
| some plants that have a germination response to light favored by darkness |
|
Definition
|
|
Term
| some plants that have a germination response to light favored by light or darkness |
|
Definition
-Wheat
-Clover
-Bean
-Most plants |
|
|
Term
| size of seed vs. longevity |
|
Definition
| Seed size has very little to do with the ability of the seed to remain in the soil for extended periods of time and still remain viable. |
|
|
Term
| Some of the longest lived seeds in soil are also... |
|
Definition
| some of the smallest seed |
|
|
Term
| grass seed longevity vs. broadleaf weed seed longevity |
|
Definition
| GENERALLY, grass seeds do not survive in the soil as long as broadleaf weeds |
|
|
Term
| Effect of Soil Tillage on Weed Seed |
|
Definition
| Soil tillage is beneficial for weed seed germination. |
|
|
Term
| If you don’t have weeds and are not preparing a seedbed, don’t till the soil, except... |
|
Definition
| sometimes will help with water infiltration and wind erosion |
|
|
Term
| The improvement of weed seed germination following tillage is generally due to... |
|
Definition
| weed seed being exposed to light (just a flash is needed) or bringing the seed closer to the soil surface so that it can emerge |
|
|
Term
| how the influence of light on germination can be used |
|
Definition
as a management tool
example: Some researchers are showing that if tillage is done on a moonless night with no synthetic light source, some weed species can be reduced a great deal |
|
|
Term
| factors in depletion of the soil-seed bank |
|
Definition
-Natural ageing, respiration, enzyme activity
-Germination
-Microorganisms
-Other soil organisms
-Birds and animals
-Climate/environment
-Fire |
|
|
Term
| some info about Recovery of the Soil Seed Bank |
|
Definition
-Little definitive data on this subject
+Difficult to do and takes many years
+Scientists are impatient, must publish |
|
|
Term
| how to model seed depletion in soil |
|
Definition
| Negative exponential decay curve |
|
|
Term
| Negative exponential decay curve |
|
Definition
| S = S0 e-gt or loge S = loge S0 - gt
where S is the number of surviving seeds from an initial population S0 after t years. g is the annual rate of depletion. |
|
|
Term
| the Negative exponential decay curve is only valid on... |
|
Definition
-a year-to-year basis, and
-in the absence of seed influx. |
|
|
Term
| if the Negative exponential decay curve is true, implications include that seed banks have... |
|
Definition
-a constant half life, and
-a constant annual probability of depletion |
|
|
Term
| this differentiates weeds from other pests |
|
Definition
|
|
Term
| how weeds can be an issue |
|
Definition
| because they can be toxic to livestock |
|
|
Term
| some characteristics of weeds |
|
Definition
-Weeds are dynamic and constantly change
-Many of our most noxious weeds are non native |
|
|
Term
| how many plants are considered weeds? |
|
Definition
|
|
Term
| how weeds can be classified |
|
Definition
| can be classified by crop and can be classed botanically |
|
|
Term
| most of our crops come from... |
|
Definition
|
|
Term
| for any given crop, the worst weed is usually... |
|
Definition
| something botanically similar |
|
|
Term
| characteristics of successful weeds |
|
Definition
| Genetic variability; allows them to adapt to changing environment |
|
|
Term
| Some weeds are obligate outcrossers, which means... |
|
Definition
| they can’t self pollinate |
|
|
Term
| the weeds that can develop resistance quickly |
|
Definition
|
|
Term
| the type of p'synth that's in some of our worst weeds |
|
Definition
|
|
Term
| the most efficient form of p'synth |
|
Definition
|
|
Term
| take advantage of the weed’s... |
|
Definition
|
|
Term
| why it's helpful to learn the biology of the weed |
|
Definition
| because the more you learn about the biology of the weed, the more you can combat it |
|
|
Term
|
Definition
| to reduce the workload on the herbicide as long as possible |
|
|
Term
| we need to have herbicides in balance with... |
|
Definition
| cultural and mechanical practices |
|
|
Term
|
Definition
| basically what you can do to make the crop more competitive with the weed |
|
|
Term
| until the ______, the only weed control we had was cultural and mechanical practices |
|
Definition
|
|
Term
| in this time frame, weed control has been mostly chemical |
|
Definition
|
|
Term
| in the future, we’ll probably have ______ practices to go along with cultural, mechanical, and chemical practices |
|
Definition
|
|
Term
| the reason our soil got so degraded |
|
Definition
| such bad tillage practices |
|
|
Term
| weed ______ is reactive and weed ______ is proactive |
|
Definition
|
|
Term
| weed control is ______ and weed science is ______ |
|
Definition
|
|
Term
| what living mulch does to weeds |
|
Definition
|
|
Term
| in weed science, the best you can do is... |
|
Definition
|
|
Term
| which yield loss is less predictable: that from weeds or that from insects? |
|
Definition
that from weeds
loss from weeds varies greatly |
|
|
Term
| why you have to rotate peanut out |
|
Definition
| because they’re so susceptible to disease |
|
|
Term
| biological time constraints have these costs |
|
Definition
|
|
Term
| what equipment can do with weed seeds |
|
Definition
|
|
Term
| you need to align the farmer’s ______ with ______ of weeds |
|
Definition
time and labor constraints
site specific “biological time constraints” |
|
|
Term
| biological time constraints |
|
Definition
| time dependent properties that influence weed management |
|
|
Term
| what residual herbicides do to weeds |
|
Definition
| residual herbicides mask to the grower some of the biological things of the weeds |
|
|
Term
| residual herbicides require ______ and have the risk of ______ |
|
Definition
|
|
Term
| integrated weed management (IWM) |
|
Definition
|
|
Term
| categories of methods of control for IWM |
|
Definition
-preventative (indirect)
-curative (direct) |
|
|
Term
| some weeds are so damaging that... |
|
Definition
| the threshold should be zero |
|
|
Term
| minimize this for seeds you allow |
|
Definition
|
|
Term
| the many little hammers for weed management are based on... |
|
Definition
|
|
Term
| how tumbleweed disperses seeds |
|
Definition
| tumbleweed tumbles across the land spreading seeds |
|
|
Term
| we need to scout weeds for... |
|
Definition
|
|
Term
| far red light vs. infrared |
|
Definition
| far red is close to infrared |
|
|
Term
| the more negative the numbers on the PEG axis,... |
|
Definition
|
|
Term
|
Definition
| soil filters out light from reaching the seed |
|
|
Term
| if you have more red light getting to the soil surface, you have (more or less) germination |
|
Definition
|
|
Term
| weed seeds can be more adaptable than... |
|
Definition
|
|
Term
| every time you get a rainfall, you get a... |
|
Definition
|
|
Term
| lotta weed seeds are set with... |
|
Definition
|
|
Term
| this thing in the soil mechanically breaks down that seed coat |
|
Definition
| the constant movement of the sandy particles in the soil over time |
|
|
Term
| making these in the soil can reduce the problem of soil compaction |
|
Definition
|
|
Term
| most of our crop plants are bred to thrive at this pH |
|
Definition
|
|
Term
| when we look at germination, we also need to look at... |
|
Definition
|
|
Term
| fertilize this, not the weed |
|
Definition
|
|
Term
| some seed coats are so thick that there’s no gas exchange until... |
|
Definition
| you scarify that seed coat |
|
|
Term
| how flooding can make it hard for some weeds to germinate |
|
Definition
| flooding reduces the oxygen level such that some weed seeds won’t germinate |
|
|
Term
| you can grow rice without flooding if... |
|
Definition
|
|
Term
| grass seeds usually don’t have as hard of a... |
|
Definition
|
|
Term
| turns out that tillage at this time reduces seed germination |
|
Definition
|
|
Term
| amount of soil organisms vs. organisms that will chew at that weed seed |
|
Definition
| the more soil organisms, the more organisms that will chew at that weed seed |
|
|
Term
|
Definition
| how hot it gets and how long it burns |
|
|
Term
| intensity of management vs. number of weeds |
|
Definition
| more intensive management corresponds with fewer weeds |
|
|
Term
| the variability of the morphology and physiology of seeds |
|
Definition
| the morphology and physiology of seeds can vary even from one mother plant |
|
|
Term
| some variation that can occur in seeds from the same plant |
|
Definition
| seeds from the same plant can have seed coats that are different colors and different thicknesses |
|
|
Term
| seeds in Palmer Amaranth that have longer dormancy |
|
Definition
| in Palmer amaranth, seeds from the bottom of the plant have longer dormancy than seeds from the top of the plant |
|
|
Term
| why Palmer amaranth seeds from the bottom of the plant have longer dormancy than seeds from the top of the plant |
|
Definition
| partly as a result of amount of sunlight |
|
|
Term
| how environmental conditions can affect brown and black seeds (I think this is in Palmer amaranth) |
|
Definition
| environmental conditions can affect proportion of brown vs. black seeds (I think this is in Palmer amaranth) |
|
|
Term
| weed emergence vs. environmental conditions |
|
Definition
| the different species of weeds will always come in the same sequence, but environmental conditions can make this sequence start earlier or later |
|
|
Term
|
Definition
| the weed and crop aren’t germinating together |
|
|
Term
| why the Harrington seed destructor is effective |
|
Definition
| because what comes out is ground up weed seed comes out as a powder that can’t germinate |
|
|
Term
| relying solely on herbicides gets you on a... |
|
Definition
|
|
Term
| this stuff must work together to control weeds |
|
Definition
| pre emergence stuff, seed destruction, and post emergence stuff |
|
|
Term
| focus on this to manage weeds effectively in an IWM program |
|
Definition
|
|
Term
| which thresholds are more sophisticated? those for weeds or those for insects? |
|
Definition
|
|
Term
| this weed control is essential for most crops |
|
Definition
|
|
Term
| weeds can have impact on... |
|
Definition
|
|
Term
| why wild mustard seed is bad for canola oil |
|
Definition
| chemicals from wild mustard seeds can contaminate canola oil, making it unsellable |
|
|
Term
| why some crops have no tolerance for weeds |
|
Definition
| some crops, such as Vidalia onions, are so uncompetitive that they have no tolerance for weeds |
|
|
Term
| if you put all the work on 1 big hammer,... |
|
Definition
|
|
Term
| when herbicides have to be applied |
|
Definition
| at the right time of plant growth |
|
|
Term
| when you’re doing pre season planning, always know the... |
|
Definition
|
|
Term
| cover crops (do or do not) do the work by themselves |
|
Definition
|
|
Term
| plant at this time to maximize effect |
|
Definition
|
|
Term
| if you do this, weeds will develop resistance to it |
|
Definition
| the same thing over and over again |
|
|
Term
| a lot of the BMP’s are part of... |
|
Definition
|
|
Term
| when cleaning equipment, you gotta... |
|
Definition
| pressure wash it and get the weed seeds off of there |
|
|
Term
|
Definition
| herbicide resistant cultivars |
|
|
Term
|
Definition
|
|
Term
| are organic growers using a lot of prevention? |
|
Definition
|
|
Term
|
Definition
|
|
Term
| how you gotta think about it in IPM |
|
Definition
| in IPM, you can’t just think about one thing; you gotta consider everything and think about it holistically |
|
|
Term
| why strip till peanut into rye? |
|
Definition
| because rye holds in water |
|
|
Term
|
Definition
|
|
Term
|
Definition
| erosion and loss of organic matter |
|
|
Term
| cover crop does this to weeds |
|
Definition
| cover crop can help suppress weeds |
|
|
Term
| this is a good rate of mulch |
|
Definition
|
|
Term
|
Definition
| when the peanut cotyledons are breaking the surface |
|
|
Term
|
Definition
| pre planting incorporated; this is herbicides that have to be incorporated into the soil |
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
| gotta do this to break up the weed seedlings |
|
Definition
|
|
Term
| optimum thing to do with peanuts |
|
Definition
|
|
Term
| Elimination is therefore an unrealistic outcome for invasive plant management unless... |
|
Definition
| the depletion rate is very high. Say > 90% per annum |
|
|
Term
| Seed dormancy varies with ... |
|
Definition
|
|
Term
| quantitative variation in behavior in populations tends to be... |
|
Definition
|
|
Term
| there can be these differences in seed populations |
|
Definition
|
|
Term
| this is correlated with "non-dormancy" |
|
Definition
| Optimum constant temperature for germination |
|
|
Term
| Optimum constant temperature is correlated with... |
|
Definition
|
|
Term
| Optimum constant temperature for germination is not correlated with... |
|
Definition
|
|
Term
| this is not correlated with latitude of origin |
|
Definition
| optimum constant temperature for germination |
|
|
Term
| part of Palmer amaranth with the greatest seed dormancy |
|
Definition
|
|
Term
| part of Palmer amaranth with the least seed dormancy |
|
Definition
|
|
Term
| Impact of Shade on Palmer Amaranth |
|
Definition
| the higher the fractional light interception, the higher the cumulative # of flowering plants |
|
|
Term
| Impact of Palmer Amaranth density on reproduction |
|
Definition
| the denser the population of Palmer amaranth, the greater the cumulative number of flowering plants |
|
|
Term
| this seed is above the harvester cutting height |
|
Definition
|
|
Term
| weed with the most retained seed |
|
Definition
|
|
Term
| depiction of how a Harrington Seed Destructor works |
|
Definition
|
|
Term
| cage mill speed of Harrington seed destructor vs. amount of seed destroyed |
|
Definition
| the faster it goes, the more seed gets destroyed |
|
|
Term
| Some concluding outcomes for weed management |
|
Definition
-Predicting population dynamics
-Mitigate risk of sudden expansion of infestation
-Have rational expectations of control of invasions |
|
|
Term
| Some concluding outcomes for weed management in terms of Predicting population dynamics |
|
Definition
-Quantify the life cycle
-Quantify seed-to-seed variation in population |
|
|
Term
| Some concluding outcomes for weed management in terms of Mitigating risk of sudden expansion of infestation |
|
Definition
-Explore options for control at various stages of the life cycle
-Manage the crop to suppress weeds
-Consider the overall farming system
-Rarely find magic bullets!
-Integrate diverse options is a best |
|
|
Term
| Some concluding outcomes for weed management in terms of Having rational expectations of control of invasions |
|
Definition
| -Understand factors affecting seed germination, dormancy and longevity |
|
|
Term
| the key to Palmer amaranth |
|
Definition
|
|
Term
| the critical time to control weeds |
|
Definition
| the time between harvesting of one crop and planting of the other crop |
|
|
Term
| the heart of all good weed control |
|
Definition
|
|
Term
| assume this about herbicide resistance |
|
Definition
|
|
Term
|
Definition
| number of weeds in a given area |
|
|
Term
|
Definition
| the lowest level of stimulus to which there is a reaction |
|
|
Term
|
Definition
| as weed density decreases, there is a level below which there is no further loss |
|
|
Term
| statistical threshold (damage threshold in entomology) |
|
Definition
| point at which statistically valid yield losses can be determined |
|
|
Term
|
Definition
(usually not discussed in weed science) – lowest population density which can cause economic losses
-In weed science, this is called damage threshold |
|
|
Term
|
Definition
| economic injury level in the context of weed science |
|
|
Term
| relationship between crop yield and how long you keep the weeds out |
|
Definition
| the longer you keep the weeds out, the higher the crop yield |
|
|
Term
| relationship between crop yield and how long you wait to get the weeds out |
|
Definition
| the longer you wait to get the weeds out, the lower the crop yield |
|
|
Term
| As weed densities increase, this becomes very critical |
|
Definition
| early season weed control |
|
|
Term
| size of weeds vs. POST herbicide effectiveness |
|
Definition
| As weeds get larger POST herbicide effectiveness decreases |
|
|
Term
| Ineffective control with POST herbicides increases the probability of selecting for... |
|
Definition
|
|
Term
| TIME OF POSTEMERGENCE WEED CONTROL IS A FUNCTION OF... |
|
Definition
| TIMING THE DIFFERENCE OF 2 DAYS! |
|
|
Term
|
Definition
| specific point where irreversable yield loss occurs |
|
|
Term
| effect of weed density on yield |
|
Definition
| the higher the weed density, the lower the yield |
|
|
Term
| effect of row spacing on weed biomass |
|
Definition
| the wider the rows, the greater the weed biomass |
|
|
Term
| effect of row spacing on crop yield |
|
Definition
| the wider the row spacing, the lower the crop yield |
|
|
Term
| more seedlings emerge on (bare or shaded) soil |
|
Definition
|
|
Term
| the best times to apply RoundUp |
|
Definition
| early (to remove early season weeds) and late (to remove late season weeds) |
|
|
Term
| how many applications of RoundUp are needed in the South? |
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
| you must give a crop this for it to be competitive with weeds |
|
Definition
|
|
Term
| In cropland, you need to reduce the ______ of the weed |
|
Definition
|
|
Term
| when the weed gets in the crop vs. the competitiveness of that weed |
|
Definition
| The earlier the weed gets in the crop, the more competitive it is |
|
|
Term
| you must give a crop this to reduce weed related losses |
|
Definition
|
|
Term
| the effect of pre emergence herbicide on crop health |
|
Definition
| pre emergence herbicide leads to healthier crops due to no weed competition |
|
|
Term
|
Definition
| herbicide application decision support system |
|
|
Term
|
Definition
| some things that can make you money and some things that can cost you money |
|
|
Term
| the most troublesome weed in the South |
|
Definition
|
|
Term
|
Definition
| knowledge and more inputs |
|
|
Term
| one thing you can do to reduce weed seed bank |
|
Definition
|
|
Term
| why there's some different versions of WeedCast |
|
Definition
| because there's some variability among populations of weeds from state to state |
|
|
Term
| some types of Prevention and Elimination Strategies |
|
Definition
-Cultural
-Mechanical
-Biological
-Chemical |
|
|
Term
| the most effective way to maintain adequate weed control |
|
Definition
| Employing various strategies or “many hammers” |
|
|
Term
|
Definition
| System by which all available tools are used to reduce weed seedbank, prevent weed emergence with crops, and minimize competition from weeds |
|
|
Term
| this can make it necessary to hand weed |
|
Definition
| limitation of herbicide options |
|
|
Term
| effect of tillage on weeds |
|
Definition
| Kills growing weeds; damages perennial roots & rhizomes; buries seeds too deeply to emerge; brings weed seeds to surface. |
|
|
Term
| effect of post-planting cultivation on weeds |
|
Definition
| Removes weeds from the crop. |
|
|
Term
| effect of stale seedbed on weeds |
|
Definition
| Flushes weeds from the soil before planting. |
|
|
Term
| effect of organic fertility sources on weeds |
|
Definition
| Favor crops over faster-growing weeds due to slow release of nutrients. |
|
|
Term
| effect of drip irrigation on weeds |
|
Definition
| Directs water to the crops rather than to weeds. |
|
|
Term
|
Definition
| Smothers weeds: delays emergence of weeds |
|
|
Term
| effect of using transplants on weeds |
|
Definition
| Competitive advantage to crop |
|
|
Term
| effect of competitive cultivars on weeds |
|
Definition
| Improves competitive ability of crop against weeds. |
|
|
Term
| effect of increasing plant density on weeds |
|
Definition
| Suppress weeds by shading |
|
|
Term
| effect of rapid cleanup after harvest on weeds |
|
Definition
| Prevents seed set by residual weeds. |
|
|
Term
| effect of cover crops on weeds |
|
Definition
| Suppress weeds, improves soil health |
|
|
Term
| some physical and mechanical practices of weed management |
|
Definition
-mowing
-Soil solarization (part of a plasticulture system)
-Hand weeding
-Cultivation
-Flaming |
|
|
Term
| how mowing helps manage weeds |
|
Definition
-Prevents seeding
-Depletes storage reserves
-Better control for broadleaves |
|
|
Term
| how soil solarization helps manage weeds |
|
Definition
-Effective control of winter annuals
-Limited control of perennials
-Cost prohibitive on large acreages
-Avoid tillage deeper than 3” after solarization |
|
|
Term
| keys to good solarization |
|
Definition
-work up soil to an even level surface removing big clods and rocks
-lay thin plastic sheeting <3mm as close to the ground as possible, burying edges of plastic
-use irrigation – wet soil conducts heat better than dry soil, field should remain at 70% field capacity
-leave in place for 4-8 weeks
-avoid anything more than shallow tilling to avoid bringing up weed seeds from lower depths that were not killed by the heat. |
|
|
Term
| the biggest challenge in organic veggie production |
|
Definition
|
|
Term
| some methods to weed between rows |
|
Definition
-hilling
-harrowing
-finger weeder
-hand hoeing or hand weeding
-robovator
-star cultivator
-ridge cultivator
-flex tine harrow, which uproots weeds
-torsion weeder
-computer-controlled cultivator
-camera controlled goosefoot cultivator
-brush hoe
-duo-parallelogramm
-bed-disc weeder
-multi-row rototiller |
|
|
Term
| a method of creating a false seedbed |
|
Definition
|
|
Term
| mowing height vs. weed spread |
|
Definition
| Mowing height has a direct impact on weed spread; the closer you mow, the more you reduce the nutsedge spread |
|
|
Term
| throwing soil on the crop increases the chance of... |
|
Definition
|
|
Term
| mechanical weed control works best for... |
|
Definition
|
|
Term
|
Definition
| it selects for the shorter weeds |
|
|
Term
| the influence of mowing on yellow nutsedge |
|
Definition
| the closer you mow, the less yellow nutsedge you have |
|
|
Term
| what cutting the top off does to yellow nutsedge |
|
Definition
| cutting the top off of nutsedge starves the tubers of carbohydrates and such |
|
|
Term
| mowing height vs. competitiveness of tall weeds |
|
Definition
| the higher the mowing height, the more competitive the tall weeds |
|
|
Term
| height of mowing vs. crabgrass control |
|
Definition
| the higher you mow, the less crabgrass |
|
|
Term
| why higher mowing height decreases the amount of crabgrass |
|
Definition
| because a higher mowing height makes the turf more competitive with the crabgrass |
|
|
Term
| fescue is bunchy such that... |
|
Definition
| if you let it get too tall, it’ll intercept all the light |
|
|
Term
| why the effect of mowing height is not as great on crabgrass in bermudagrass |
|
Definition
| because bermudagrass is much more competitive than tall fescue |
|
|
Term
| difference in distribution of fescue and bermuda grass |
|
Definition
| because Bermuda grass is more of a spreading grass and fescue is more of a clumpy grass |
|
|
Term
| some details about cultivation to reduce weeds |
|
Definition
-Should be shallow to lessen disturbance to weed seed bank
-Better for perennial and biennial control than annual weed control
+Exhaust root system by depleting storage reserves
+Requires 6-8 timely treatments in yr 1, then 3-5 the following year |
|
|
Term
| Exhaust root system by... |
|
Definition
| depleting storage reserves |
|
|
Term
| how often you need to control weeds using cultivation |
|
Definition
| 6-8 timely treatments in yr 1, then 3-5 the following year |
|
|
Term
| why you must thoroughly clean equipment before moving it between fields |
|
Definition
| to prevent weed transport |
|
|
Term
| Cultivation is good for... |
|
Definition
|
|
Term
| Potential Downsides of Cultivation |
|
Definition
-Exposes bare ground:
-Major cause of soil compaction
-Cost: expensive equipment, fuel
-Should not be done in wet conditions |
|
|
Term
| some bad things that result from exposing bare ground |
|
Definition
-increased erosion
-decreased biodiversity
-speeds decomposition of OM
-increases water run-off |
|
|
Term
| Dr. Vencill says sustainability is... |
|
Definition
|
|
Term
|
Definition
Environmental impact quotient
it was developed at Cornell |
|
|
Term
|
Definition
| impact as far as toxicology and human effects and such |
|
|
Term
|
Definition
|
|
Term
| this tillage has higher reliance on herbicides |
|
Definition
|
|
Term
| how mulch prevents seeds from germinating |
|
Definition
| by blocking light, can smother out some weeds |
|
|
Term
|
Definition
-Conserve water, minimal soil disruption
-Use local resources: straw, fabric, wood, newspaper, plastic |
|
|
Term
| be careful of this when using mulch |
|
Definition
| weed seeds in straw or hay |
|
|
Term
| when using mulch, avoid hay, unless... |
|
Definition
| you know its free of weeds |
|
|
Term
| mulch is especially good for... |
|
Definition
| perennial systems: blueberries, blackberries, flowers, trees |
|
|
Term
|
Definition
-wood chips
-shredded paper
-leaves
-straw |
|
|
Term
| how mulches control weeds |
|
Definition
|
|
Term
|
Definition
| small areas or high value crops |
|
|
Term
| mulch is limited mostly to... |
|
Definition
| emerged, established or transplanted crops |
|
|
Term
|
Definition
| Mulches are primarily used in high value areas such as landscaping and vegetables. |
|
|
Term
| what mulch doesn't control well |
|
Definition
| Perennial weeds with vigorous underground root systems |
|
|
Term
| this weed observed to emerge through 6 inches of rolled asphalt |
|
Definition
|
|
Term
| Regardless of what mulch, you gotta consider... |
|
Definition
| the thickness of the mulch; thicker seems to be better |
|
|
Term
| relationship of rye grass to a number of species |
|
Definition
|
|
Term
| the purpose of rye cover crop |
|
Definition
| to inhibit the establishment of Palmer amaranth |
|
|
Term
| why the use of rye grass is discouraged |
|
Definition
| because it could develop resistance to herbicides |
|
|
Term
| the greatest challenge in managing Palmer amaranth today |
|
Definition
| planting into fields with emerged weeds |
|
|
Term
| some details about flaming |
|
Definition
-Intense heat sears the leaf, causing the cell sap to expand and disrupt cell walls
-seedlings are most susceptible
-Broadleaf weeds are more susceptible than grasses
-May be used in wet soil conditions |
|
|
Term
| these plants are most susceptible to flaming |
|
Definition
-seedlings
-broadleaf weeds |
|
|
Term
| The idea of the stale seedbed technique... |
|
Definition
| to remove the weed from the soil surface |
|
|
Term
| stale seedbed technique of flaming |
|
Definition
-Planting delayed after seed bed preparation (tillage, irrigation, etc)
-Flaming knockdowns flush of weed seedlings prior to planting |
|
|
Term
| peak emergence technique of flaming |
|
Definition
-Crop seeded promptly after seedbed preparation
-Just before crop germinates, flaming used to kill weed seedlings
-Good method for direct-seeded, slow-germinating crops
-Glass or plastic can be used as a crop-germination indicator: crop grown under cover germinates 2-3 days before uncovered crop; flaming should occur when crop germinates under cover |
|
|
Term
|
Definition
-Emerged crops protected by: directing flame away from crops, shielding the crop, or flaming at a time when crop stems are resistant to heat
-Older plants able to recover from heat damage, while young seedlings are killed |
|
|
Term
| these weeds are harder to kill with flaming |
|
Definition
| bigger weeds and wet weeds |
|
|
Term
| this leads to maximum impact of flaming |
|
Definition
| Hot days and drying winds that further dry out weeds |
|
|
Term
| do you want to burn weeds while flaming? |
|
Definition
|
|
Term
| what it means when weeds are black when you're flaming |
|
Definition
| this means you're using too much fuel |
|
|
Term
| the questions to ask when burning |
|
Definition
|
|
Term
| This method of burning results in much hotter and longer burn that kills more weeds |
|
Definition
|
|
Term
| what flooding is used for in rice |
|
Definition
|
|
Term
| 2 weeds that survive flooding |
|
Definition
| Barnyardgrass and arrowhead survive |
|
|
Term
| flooding shifts this spectrum |
|
Definition
|
|
Term
| how flooding controls weeds |
|
Definition
| Flooding works by depleting weed roots of oxygen since less oxygen is dissolved in water than air. Rice roots can survive low oxygen conditions. |
|
|
Term
| some cultural strategies to control weeds |
|
Definition
-Buy quality crop seed with low/no weed seeds present
-Do not allow weeds to form seed
-Thoroughly compost (>130°F for ≥15 days) all manure and plant residues to ensure destruction of weed seed
-Stale seedbed technique |
|
|
Term
|
Definition
| Prepare soil for planting and bring weed seeds to the surface; allow weeds to germinate, kill weeds with light tillage/minimal soil disruption. May be repeated. Plant main crop. |
|
|
Term
| some cultural practices to improve crop competitiveness |
|
Definition
-Improve soil tilth, aeration, and fertility to optimize crop growth
-Increase crop density through narrow row spacing and increased seeding rate
-Use transplants, rather than seed, when possible
-Plant at optimal soil temperatures to prevent slow germination of crop
-Choose competitive crop cultivars
-Manage fertility according to crop needs; avoid excess application |
|
|
Term
| some cultural practices to reduce weed numbers |
|
Definition
-Mulch (wood chips, mow and blow, paper, living, plastic, etc)
-Use weed-suppressive cover crops
-Crop rotations
-Intercrop |
|
|
Term
|
Definition
-wood chips
-mow and blow
-paper
-living
-plastic
-etc |
|
|
Term
| some details about the cultural practice of using weed-suppressive cover crops |
|
Definition
-Quick germinating, high biomass
-Field with high weed pressure may warrant full year of cover cropping and fallow to reduce weeds |
|
|
Term
| some details about the cultural practice of using crop rotations |
|
Definition
| altering narrowly spaced crops with closely spaced crops, shallow rooted/deep rooted crops, cold/warm season crops |
|
|
Term
| example of the cultural practice of using intercropping |
|
Definition
| Clover underseeded in sweetcorn |
|
|
Term
| Crop rotations mix up the... |
|
Definition
|
|
Term
| Crop rotations prevent... |
|
Definition
| severe infestations of one or a few weeds |
|
|
Term
| how crop rotations prevent severe infestations of one or a few weeds |
|
Definition
| due to differing planting & harvest dates, competitive ability, fertility and other cultural practices; this makes weeds more manageable |
|
|
Term
| Cultural weed control refers to... |
|
Definition
| anything we can do with the agronomics to give the crop an advantage over the weed. |
|
|
Term
| mixing it up does this to weeds |
|
Definition
| does a number on the seed bank; reduces emergence of weeds |
|
|
Term
| This is critical to crop vigor and competitive ability |
|
Definition
|
|
Term
| Rapid and even emergence is critical to... |
|
Definition
| crop vigor and competitive ability |
|
|
Term
| Planting cotton when soil temp too low leads to... |
|
Definition
|
|
Term
| Reduced row crop spacing favors... |
|
Definition
| competitive ability of many crops |
|
|
Term
| how narrower rows can help control weeds |
|
Definition
Narrowing the row spacing speeds time to canopy closure and the time to which the crop has the competitive advantage for light.
the more light interceltion by the crop, the more far red light, reducing weed growth |
|
|
Term
| why narrower row spacings lead to greater yield |
|
Definition
| primarily due to better light competition |
|
|
Term
| area in leaf vs. crop competitiveness |
|
Definition
| Less area in leaf means crop is more competitive |
|
|
Term
| Less light gets to soil on north-south or east-west? |
|
Definition
|
|
Term
| crop population vs. competitiveness of crop |
|
Definition
| Increased crop population can often improve competitive ability of crop |
|
|
Term
| why you gotta be careful with row spacing for some crops like cotton |
|
Definition
| because changing the row spacing completely changes the architecture of the crop; from picker cotton to stripper cotton; yield goes down; gotta have different equipment to pick it |
|
|
Term
| Increased crop population in some crops leads to... |
|
Definition
| too much disease and insect incidence |
|
|
Term
| % wheat yield loss vs. wild mustard population density |
|
Definition
| the higher the wild mustard population density, the greater the % wheat yield loss |
|
|
Term
| seeding rate vs. work load on herbicide |
|
Definition
| the higher the seeding rate, the less the work load on herbicide |
|
|
Term
| the effect of crop rotation on weeds |
|
Definition
| crop rotation limits the weeds |
|
|
Term
| seeding rate vs. competitiveness of wheat |
|
Definition
| Wheat more competitive at higher seeding rate |
|
|
Term
| how the competitiveness of corn can vary by cultivar |
|
Definition
| Late maturing varieties less competitive than early ones; those that mature faster are more competitive |
|
|
Term
| how the competitiveness of wheat can vary by cultivar |
|
Definition
| Normal height varieties more competitive with weeds than semi-dwarf varieties, but the normal height varieties have lower yield potential because more mass is going into stem as oppose to grain; semi dwarf has higher yield, but needs more herbicides |
|
|
Term
| the pros and cons of normal and semi-dwarf varieties of wheat |
|
Definition
| Normal height varieties more competitive with weeds than semi-dwarf varieties, but the normal height varieties have lower yield potential because more mass is going into stem as oppose to grain; semi dwarf has higher yield, but needs more herbicides |
|
|
Term
| why most wheat varieties are semi-dwarf |
|
Definition
| so that lodging can be reduced |
|
|
Term
| why you gotta be careful of whether you put out a slow release or quick release N fertilizer on wheat |
|
Definition
| because wild oat can take advantage of N earlier than wheat |
|
|
Term
| these amendments can increase grass weed infestations |
|
Definition
|
|
Term
| Low N in turf can increase... |
|
Definition
|
|
Term
| High N in turf can increase... |
|
Definition
-annual bluegrass
-chickweed |
|
|
Term
| this can determine what the weed spectrum is |
|
Definition
|
|
Term
| what lime does to wild radish |
|
Definition
|
|
Term
| what lime does for barley |
|
Definition
| gives barley competitive advantage over rye grass |
|
|
Term
| what cover crops do to weeds |
|
Definition
-Smother weeds by out-competing for light, water, nutrients
-Release allelopathic chemicals that suppress weed germination
-May reduce weed emergence by 75-90% |
|
|
Term
| some examples of cover crops |
|
Definition
-Sudan grass
-buckwheat
-annual rye grass
-sesbania
-many more |
|
|
Term
| some examples of intercropping |
|
Definition
-Cotton and watermelons
-Cotton and clover
-Corn and clover |
|
|
Term
|
Definition
-watermelon
-canteloupe
-squash |
|
|
Term
|
Definition
|
|
Term
| the types of crops weeds tend to infest |
|
Definition
| crops with similar life cycles |
|
|
Term
| some things to consider when changing crop ecology |
|
Definition
-shallow/deep roots
-cold/warm season
-row/drilled crops
-foliage density
-heavy/light feeders |
|
|
Term
| some cultural practices that can be altered to manage weeds |
|
Definition
-cultivation
-mowing
-fertilization
-herbicide application
-planting/harvest dates |
|
|
Term
| 12 Steps to Sustainable Weed Management according to Schonbeck |
|
Definition
Step 1. Know the weeds on your farm.
Step 2. Plan cropping systems to minimize open niches for weeds.
Step 3. Keep the weeds guessing.
Step 4. Design the cropping system and select tools for effective weed control.
Step 5. Grow vigorous, competitive crops.
Step 6. Put the weeds out of work – grow cover crops.
Step 7. Manage the weed seedbank: minimize deposits and maximize withdrawls.
Step 8. Knock the weeds out at critical times.
Step 9. Utilize biological processes to enhance weed control.
Step 10. Bring existing weeds under control before planting weed-sensitive crops and long-term perennial crops.
Step 11. Keep observing the weeds and adapt practices accordingly.
Step 12. Experiment and stay educated. Keep up on new developments and practices. |
|
|
Term
| steps to pre-season planning for sustainable weed management according to Schonbeck |
|
Definition
Step 1. Know the weeds on your farm.
Step 2. Plan cropping systems to minimize open niches for weeds.
Step 3. Keep the weeds guessing.
Step 4. Design the cropping system and select tools for effective weed control. |
|
|
Term
| some Preventive (Cultural) Practices for sustainable weed management according to Schonbeck |
|
Definition
| Step 5. Grow vigorous, competitive crops. Step 6. Put the weeds out of work – grow cover crops. Step 7. Manage the weed seedbank: minimize deposits and maximize withdrawals. |
|
|
Term
| some control tactics for sustainable weed management according to Schonbeck |
|
Definition
Step 8. Knock the weeds out at critical times.
Step 9. Utilize biological processes to enhance weed control.
Step 10. Bring existing weeds under control before planting weed-sensitive crops and long-term perennial crops. |
|
|
Term
| some ways to Enhance and Fine-tune the Weed Management Strategy |
|
Definition
Step 11. Keep observing the weeds and adapt practices accordingly.
Step 12. Experiment and stay educated. Keep up on new developments and practices. |
|
|
Term
| some ways to Keep observing the weeds and adapt practices accordingly |
|
Definition
-Keep notes
-What is suitable for one crop may not be for another |
|
|
Term
| some ways to Experiment and stay educated and keep up on new developments and practices |
|
Definition
-Night time cultivation
-Soil solarization
-Others… |
|
|
Term
| multiple approaches (“many hammers”) vs. relying on a few practices |
|
Definition
| Using multiple approaches (“many hammers”) to manage weeds will yield greater impact than relying on a few practices. |
|
|
Term
| Develop a weed management strategy that is designed for... |
|
Definition
|
|
Term
| some big hammers in weed management |
|
Definition
-Competitive crops
-Rotation
-Cover Crops
-Mulches
-Weed predators
-Livestock/grazers
-Cultivation tools
-Rollers/roller-crimper
-Flamers
-Growers Observation |
|
|
Term
| some little hammers in weed management |
|
Definition
-Solarization
-Organic herbicides
-Bioherbicides
-Soil microorganisms
-Crop-weed interactions |
|
|
Term
| number of weed management tactics used vs. effectiveness of weed management |
|
Definition
| the more tactics used, the more effective the weed management |
|
|
Term
| the extent to which you want to reduce weed biomass |
|
Definition
| you want to reduce weed biomass below levels that are economically damaging to the crop. |
|
|
Term
| the amount of BMP's normally adopted by growers |
|
Definition
|
|
Term
| some Biological Control Practices |
|
Definition
-Insects
-Selective grazing
-Biofumigation |
|
|
Term
| what insects can do to control weeds |
|
Definition
| may consume large numbers of weed seeds or feeding injury to plant or vector virus |
|
|
Term
| examples of how insects can control weeds |
|
Definition
-Thistle & adult thistle-head weevil, Rhinocyllus conicus
-Multiflora rose & rose rosette disease transmitted by fungi or a (mite) |
|
|
Term
| some examples of how selective grazing can be used as a biological control practice |
|
Definition
-Sheep: clean fields after harvest
-Weeder geese: useful against grass weeds and in perennial systems |
|
|
Term
| some examples of how biofumigation can be used as a biological control practice |
|
Definition
-Use of Brassica species (canola, Indian mustard) as cover crop or in rotation
-May be incorporated or left as residue
-Brassicas produce glucosinolates, which may be converted to cyanate compounds during decomposition
-Cyanates toxic to many bacteria, fungi, nematodes, insects, and germinating seeds |
|
|
Term
| effectiveness of biocontrol |
|
Definition
| Biocontrol is specific to the species and works well for infestations of a particular weed and typically in situations where immediate results are not necessary. |
|
|
Term
| Why do you need a soil applied herbicide? |
|
Definition
-some weeds can only be controlled with soil applied herbicides (Florida pusley)
-ALS-resistant pigweed
-absence of soil applied herbicide requires more management
-consistent weed control, higher yields, greater economic returns |
|
|
Term
| Peanut Yield in Response to PPI Herbicides |
|
Definition
| more yield with PPI herbicides |
|
|
Term
|
Definition
-20-25% of acreage
-late-season beggarweed
-tolerance of new varieties
-influence on TSWV |
|
|
Term
| the effect of DuPont Classic herbicide on TSWV in peanut |
|
Definition
-Studies conducted in 2000-2001 indicate…..
-Classic can increase TSWV but not always.
-Classic/TSWV interaction can reduce yields but not always. |
|
|
Term
| Strategies for weed management in peanut without herbicides |
|
Definition
-Cultural weed control
-Mechanical weed control
-Thermal weed control
-Chemical weed control (OMRI herbicides) |
|
|
Term
| when you must start cultivating |
|
Definition
|
|
Term
| some details about tine weeders |
|
Definition
-multiple rows of narrowly spaced spring-tines
-offers potential for weed control in-row
-high-speed implement
-tines vibrate, displacing seedling weeds
-made in neumerous widths for large scale operations
-successfully used in peanut, millet, Southern pea, velvetbean, and Vidalia onion |
|
|
Term
| control of crabgrass by cultivation in wide rows vs. in twin rows |
|
Definition
| higher % control in wide rows than in twin rows |
|
|
Term
| details about Brush-Hoe cultivator |
|
Definition
-power driven, vertical action implement
-rotating stiff bristles scour soil surface and kill seedling weeds
-rear steering used to guide brushes as close as possible to crop drill |
|
|
Term
| some early season abuse young peanut can tolerate |
|
Definition
-non-selective herbicides
-fire
-etc. |
|
|
Term
| when to begin solarization to effectively control yellow nutsedge in future crops |
|
Definition
|
|
Term
| when to end solarization to effectively control yellow nutsedge in future crops |
|
Definition
|
|
Term
| the length of effective solarization periods |
|
Definition
|
|
Term
| seeding rate vs. competitiveness with the weed |
|
Definition
| higher seeding rate means greater competitiveness with the weed |
|
|
Term
| some cultural controls for weed management |
|
Definition
-Crop rotation to enhance weed management
-Row patterns and plant populations for weed management
-Stale seedbed management
-Planting dates
-Cover crops
-Tillage system |
|
|
Term
| some details about crop rotations as a cultural control for weed management |
|
Definition
-Considered one the the foundations for sustainable crop production, including weed management.
-Premise that a weed species can be more effectively managed in one crop than another may offer opportunities for improvement.
-Converse is true – a weed species that cannot be effectively managed in crop may give the weed opportunities to proliferate. |
|
|
Term
| crop rotation is one of the foundations for... |
|
Definition
| sustainable crop production, including weed management |
|
|
Term
|
Definition
| Premise that a weed species can be more effectively managed in one crop than another may offer opportunities for improvement. |
|
|
Term
| if you can't effectively manage a weed,... |
|
Definition
|
|
Term
| some details of hand-weeding as a mechanical weed control tactic |
|
Definition
-It is obvious (and unfortunate) that hand-weeding is necessary in organic crop production and will be a treatment variable in future trials.
+An organic peanut grower from west Texas uses hand-weeding and multiple cultivations as standard practices. |
|
|
Term
| some thermal methods of weed control |
|
Definition
-Fire (i.e. burning cover crops)
-Propane flaming |
|
|
Term
| the criteria herbicides must meet in order to be used in certified organic production |
|
Definition
-must be “approved” by OMRI (Organic Materials Review Institute)
-These herbicides tend to be made directly from naturally occurring materials or from cultivated plant materials of certified organic origin. |
|
|
Term
| some details about organic herbicides |
|
Definition
-derived from naturally occurring products
-contact activity:
+non-systemic
+small weeds
+no residual weed control
-generally non-selective
-expensive when cost is calculated on a per acre basis |
|
|
Term
| contact activity of organic herbicides |
|
Definition
-non-systemic
-small weeds
-no residual weed control |
|
|
Term
| effectiveness of organic herbicides on grass |
|
Definition
| Not very effective on grass |
|
|
Term
| what thermal weed control must do to kill the weed |
|
Definition
| be hot enough long enough to kill the growing point |
|
|
Term
| In an organic system, this is essential for weed control. |
|
Definition
|
|
Term
|
Definition
| least significant difference |
|
|
Term
| the obvious things about weed control in an organic system |
|
Definition
-Handweeding is unavoidable
The lack of grass control is a challenge
+Propane flaming and Matran are reasonably effective on dicot weeds, but poor on grasses
+Grasses cause serious yield losses in peanut (competition and harvest losses)
-No residual weed control lengthens the time of intense weed control
-Cultivation appears to be one of the foundations of weed control in organic peanut |
|
|
Term
| what grasses do to peanuts |
|
Definition
| Grasses cause serious yield losses in peanut (competition and harvest losses) |
|
|
Term
| the effect of no residual weed control |
|
Definition
| lengthens the time of intense weed control |
|
|
Term
| this lengthens the time of intense weed control |
|
Definition
|
|
Term
| this appears to be one of the foundations of weed control in organic peanut |
|
Definition
|
|
Term
| Take home message on organic weed control in peanut |
|
Definition
-Avoid sites where weed problems are severe.
-The weed control war is won or lost during the first 3 weeks of the growing season.
-Weed control must be first priority during that period.
+No delays
+No distractions
-Establish a uniform crop stand so that crops are at a competitive advantage with weeds.
-Do not let weeds propagate.
-Use stale seedbed tillage to help deplete numbers of viable weed seed in the soil profile.
-Cultivate early and frequently.
-Avoid relying solely on new unproven technology, until tested and validated
+Propane flaming
+OMRI herbicides |
|
|
Term
| where to not plant peanut |
|
Definition
|
|
Term
| when the weed control war is won or lost |
|
Definition
| during the first 3 weeks of the growing season |
|
|
Term
| this must be first priority during the first 3 weeks of the growing season |
|
Definition
|
|
Term
| do this so that crops are at a competitive advantage with weeds |
|
Definition
| Establish a uniform crop stand |
|
|
Term
|
Definition
|
|
Term
| Use this to help deplete numbers of viable weed seed in the soil profile. |
|
Definition
|
|
Term
|
Definition
|
|
Term
| Avoid relying solely on new unproven technology, until... |
|
Definition
|
|
Term
| Most Common Cotton Weeds in Georgia; also the most troublesome |
|
Definition
-Palmer amaranth
-Tropical spiderwort
-Perennial nutsedges
-Texas panicum
-Wild poinsettia
-Morningglories |
|
|
Term
| some aspects of Cotton Weed IPM |
|
Definition
-Crop Rotation
-Crop Competition
-Cultivation
-Herbicides |
|
|
Term
| you need to take advantage of this when managing weeds |
|
Definition
| some weak spot in the biology of the weed |
|
|
Term
| What makes Palmer amaranth a super weed? |
|
Definition
1. Herbicide resistance?
2. Growth rate?
3. Large stature?
4. Competitive ability?
5. Reducing harvest efficacy?
6. Seed production?
7. Rapid spread? |
|
|
Term
| why Palmer amaranth is a super weed |
|
Definition
because it’s so competitive and so prolific
It can have 1 million seeds per plant |
|
|
Term
| what happened to the amaranth problem? |
|
Definition
| became worse over the past 20 years |
|
|
Term
| how Palmer amaranth is moving |
|
Definition
| has moved into the Midwest, as far north as Iowa |
|
|
Term
|
Definition
| having male and female flowers |
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
| gender of Palmer amaranth plants |
|
Definition
| Palmer amaranth is dioecious, which means it has male and female plants |
|
|
Term
|
Definition
|
|
Term
|
Definition
| plant that can't pollinate itself |
|
|
Term
| this enforces genetic diversity in Palmer amaranth |
|
Definition
|
|
Term
| one way herbicide resistance can move from farm to farm |
|
Definition
| The pollen of pigweeds can move quite a distance moving herbicide resistance genes from farm to farm. |
|
|
Term
| something superior about the p'synth of Palmer amaranth |
|
Definition
-Palmer amaranth found to have highest photosynthetic rate among C4 plants
+3-4 x that of many row crops such as corn, soybean |
|
|
Term
| this characteristic of Palmer amaranth leads to large growth rates and drought tolerance |
|
Definition
| having C4 photosynthesis, allowing them to have much more efficient p'synth |
|
|
Term
| an advantage of C4 plants |
|
Definition
| they are more efficient and can keep their stomata closed longer |
|
|
Term
| the most competitive pigweed |
|
Definition
|
|
Term
| Palmer amaranth is replacing this species of pigweed in the Midwest. |
|
Definition
| Common waterhemp (CW) has been the dominant amaranth species in the Midwest, but now is being replaced by Palmer amaranth |
|
|
Term
| how tough Palmer amaranth is |
|
Definition
| it can take the heat and endure drought |
|
|
Term
| why Palmer amaranth is very drought tolerant |
|
Definition
| because of its deep roots and very efficient photosynthesis |
|
|
Term
| one reason Palmer amaranth can outcompete crop plants |
|
Definition
| because it's so good at absorbing water and nutrients |
|
|
Term
| what obligate outcrossing does to the Palmer amaranth population |
|
Definition
| gives it much greater genetic diversity, which allows for increased chance of herbicide resistance traits to occur |
|
|
Term
| some details about dormancy in Palmer amaranth |
|
Definition
-After fall dispersal, mean germination temp 25-40 C
-After winter dormancy, germination >25C and light
-Fall germination regulated by phytochrome
+Red stimulates; Far-red inhibits
-Dormancy increases in seed from bottom 1/3 plant and plants exposed to heavy shade (87%)
-Seeds buried 10-cm for 3-6 mo induced dormancy and required red or natural light to break dormancy |
|
|
Term
| Fall germination regulated by... |
|
Definition
|
|
Term
| light that stimulates germination |
|
Definition
|
|
Term
| light that inhibits germination |
|
Definition
|
|
Term
| what burial will do to Palmer amaranth |
|
Definition
| Any amount of burial will expose the seed to far red light |
|
|
Term
| size of the seeds of amaranths (pigweeds) |
|
Definition
|
|
Term
| the potential number of seeds that can be found on one Palmer amaranth plant |
|
Definition
|
|
Term
| when small seeded species of weeds emerge |
|
Definition
| only if near the soil surface |
|
|
Term
| one way we can control Palmer amaranth |
|
Definition
| burying the seeds, since those seeds will germinate only if on the soil surface; therefore, any amount of burial will do it in |
|
|
Term
| the species of plants that emerge better thru mulch |
|
Definition
|
|
Term
| why cover crops can be very useful for pigweed control |
|
Definition
| because they increase the burial of the seed and also produce some allelochemicals |
|
|
Term
| the 2 stage process by which amaranth seeds germinate |
|
Definition
| They tend to go through a two-stage process from high dormancy caused by hard seed coat followed by low dormancy broken by temperature and plant hormone. |
|
|
Term
|
Definition
| abrasion of the seed coat |
|
|
Term
| Optimal temperature for pigweed seed germination |
|
Definition
|
|
Term
| what deep turn tillage does to Palmer amaranth |
|
Definition
| buries the weeds and keeps them from germinating |
|
|
Term
| how fast Palmer amaranth grows |
|
Definition
|
|
Term
| With some, maybe many, herbicides, this is when you gotta treat the weed. |
|
Definition
| within the first 10 days after emergence |
|
|
Term
| In addition to being a strong competitor for water and light, Palmer amaranth also has these tendencies. |
|
Definition
|
|
Term
| the weaknesses of Palmer amaranth |
|
Definition
1. Emergence depth! Has to be at surface to get red light
2. Seed life longevity?
3. Light requirement for emergence. |
|
|
Term
| regarding weeds, economic survival depends on... |
|
Definition
|
|
Term
| doing this with rye is a good way to control Palmer amaranth |
|
Definition
rolling rye
combine it with deep tillage
reduces work load on herbicide |
|
|
Term
| Make sure the Palmer amaranth doesn’t... |
|
Definition
|
|
Term
|
Definition
| anywhere there’s an opening |
|
|
Term
| Most Palmer amaranth emerges from this depth |
|
Definition
|
|
Term
| where the focus should be when trying to control weeds |
|
Definition
| how much work has to be done by the herbicide |
|
|
Term
| why it's good to use less herbicide |
|
Definition
| because the less you use the herbicide, the less you have to worry about resistant weeds |
|
|
Term
| potential benefits of developing integrated programs |
|
Definition
1. Labor, erosion, etc..
2. Prevents GR horseweed
3. Prevents GR ryegrass
4. Reduces Palmer 80%+
5. Moisture conservation
6. herbicides overtime
7. Higher yields?????? |
|
|
Term
| some things to consider in turf IPM |
|
Definition
-Agronomic Considerations & Weed Control
+Fertility, Irrigation, Soil pH, Compaction
-Weed Mgmt Risk Periods
-Thresholds
-Cultural Control
-Herbicides
+EIQ
+Tee to Green Case Study |
|
|
Term
| some Agronomic Considerations in Weed Control |
|
Definition
-Fertility
-Irrigation
-Soil pH
-Compaction |
|
|
Term
| some things to consider regarding herbicides |
|
Definition
-EIQ (environmental impact quotient)
-Tee to Green Case Study |
|
|
Term
| the 3 components of Environmental Impact Quotient (EIQ) |
|
Definition
-worker
-consumer
-ecological |
|
|
Term
| the numerical value provided by the Environmental Impact Quotient (EIQ) |
|
Definition
| Provides numerical value for a pesticide, applied at a specific rate |
|
|
Term
| how Environmental Impact Quotient (EIQ) can be used |
|
Definition
| Can be used to select pesticides or compare systems |
|
|
Term
| what Environmental Impact Quotient (EIQ) considers regarding the farm worker |
|
Definition
| Acute and chronic toxicity to humans. |
|
|
Term
| what Environmental Impact Quotient (EIQ) considers regarding the consumer |
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Definition
| Food residues, chronic toxicity to humans, leachability to groundwater. |
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Term
| ecological considerations made by the Environmental Impact Quotient (EIQ) |
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Definition
| Aquatic and terrestrial non-target toxicity (fish, bees), leachability, persistence. |
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Term
| equation for risk according to EIQ |
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Definition
| Risk = toxicity x potential for exposure |
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Term
| equation for the Farm worker Component of EIQ |
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Definition
Applicator + Picker=
(C * DT * 5) + (C * DT * P)
C= chronic toxicity
DT= dermal toxicity
P= Plant surface residue half-life |
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Term
| how the applicator is most likely to contact pesticides |
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Definition
| directly, through the skin, with repeated exposures over time |
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Term
| how the picker is most likely to be exposed to pesticides |
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Definition
| most likely chronic and through the skin. However, the pesticide exposure is transferred by the fruit (or vegetable) being picked, so the persistence on the plant surface is important. |
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Term
| some things to consider regarding chronic toxicity |
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Definition
-Average of Reproductive, Teratogenic, Mutagenic, & Oncogenic effects
-Low value if no evidence of carcinogenicity
-High value if probable human carcinogen |
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Term
| how the EIQ discerns the long-term health effects or “chronic toxicity” |
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Definition
| by taking an average of ratings of the reproductive, teratogenic, mutagenic, & oncogenic effects of the pesticides on small mammals. |
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Term
| how plant surface residues are measured |
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Definition
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Term
| what the measurement of plant surface residues shows |
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Definition
| the persistence of a pesticide |
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Term
| how the Consumer Component of EIQ is determined |
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Definition
Food residue + Groundwater=
(C * ((S + P)/2) * SY) + (L)
C=chronic toxicity
S=soil half-life
P=plant half-life
SY= what does SY stand for?
L=leaching potential |
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Term
| ecological component of EIQ |
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Definition
Fish + Bird + Bee + Beneficials=
Each organism X potential for exposure
[(F x R) + (D x ((S + P)/2) x 3) + (Z x P x 3) + (B x P x 5)]
where...
Fish toxicity (F)
Surface Loss Potential (R)
Bird Toxicity (D)
Soil half life (S)
Plant surface half life (P)
Bee Toxicity (Z)
Beneficial Arthropod toxicity (B) |
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Term
| the complete EIQ equation (the equation that factors in all components) |
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Definition
| EIQ={C x [DT x 5 + (DT x P)]+[(C x ((S + P)/2) x SY) + L]+[(F x R)+(D x ((S + P)/2) x 3)+(Z x P x 3)+(B x P x 5)]}÷3 |
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Term
| An EIQ value must be multiplied by... |
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Definition
| the rate at which it is applied. This yields a “field EIQ” that can be compared. |
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Term
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Definition
-Standardization of data & data gaps
-Weighting may not meet criteria of user
-Not site specific |
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Term
| some ways EIQ could be modified for turfgrass |
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Definition
-Adjust formula to better reflect turfgrass system
+replace bee toxicity with earthworm toxicity
+“User” for consumer (e.g. golfer)
+Weight factors appropriately for turfgrass
+Incorporate TurfPQ?
-Include site specific information such as soil type and water proximity |
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Term
| the 3 E's of pesticide selection criteria |
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Definition
-Efficacy
-Economics
-Environmental & health impact |
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Term
| competitiveness of turfgrass |
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Definition
| Healthy turfgrass is very competitive on its own |
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Term
| can Bermudagrass tolerate shade? |
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Definition
| Bermudagrass turf not tolerant of shade |
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Term
| the roots of most turfgrass weeds |
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Definition
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Term
| There’s some weeds that thrive in compacted soils; gotta relieve the compaction by... |
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Definition
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Term
| algae will go away if you take care of this |
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Definition
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Term
| Instead of asking ______ for weed x, ask ______. |
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Definition
what to spray for weed x
why weed x is there |
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Term
| mowing height vs. competitiveness |
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Definition
| The higher you keep the mowing height, the more competitive it is with weeds |
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Term
| how leaching increases the potential for exposure |
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Definition
| When something leaches, its persistence increases |
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Term
| which herbicides tend to have the greater impact on humans? pre-emergent or post-emergent? |
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Definition
| The pre-emergent ones tend to have less impact than the post-emergent ones |
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Term
| When you’re talking about pesticides, the poison is in... |
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Definition
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Term
| the "many hammer" concept |
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Definition
| don't rely on too much of anything to control pests or weeds |
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Term
| the purpose of rye cover crop... |
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Definition
| to reduce the emergence of Palmer amaranth |
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Term
| which rye is easier to roll and why? |
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Definition
| rye that has reached anthesis and started flowering because it has more brittle stems |
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Term
| rye must be rolled in the same direction as... |
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Definition
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Term
| advantages of rolling rye to control Palmer amaranth |
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Definition
+Improved control
+Reduced resistance
+Reduced labor
+Reduced erosion
+Lessens potential impact of winter weeds
+Moisture conservation
+Reduces thrips issues
+Compliance with intensifying EPA regulations |
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Term
| disadvantages of rolling rye to control Palmer amaranth |
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Definition
+Growers not really comfortable with it
+Time to get the rye established; you must get it established in the fall
+Requires more N fertilizer for at least first 5 years
+Strip tillage unit
+Roller
+Cooler soils due to early spring cotton planting |
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