Term
| What are the 4 essential plant growth factors? |
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Definition
| Plant growth requires sunlight, H20, Co2 , 02 and soil |
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Term
| What is the role of soil in plant growth? |
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Definition
| physical support, pore space, plant nutrients |
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Term
| What is meant by physical support? |
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Definition
| roots anchor plant to maintain upright stature so leaves can intercept sunlight. |
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Term
| What is meant by pore space? |
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Definition
| holds water and air available to plant, both are essential to root growth |
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Term
| What is meant by plant nutrients? |
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Definition
| soils supply varable amounts of nutrients. also soils retain / release nutrients applied as fertilizers, manures, and other organic sources. |
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Term
| What is most important for nutrient availability? |
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Definition
| Clay and organic matter ( OM ) are most important for nutrient availability... clays are minerals with negative surface charge that attract positive ions ( K, Ca) OM also has negative surface charge. |
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Term
| Essential plant nutrients... what are the criteria for establishing essentiality? |
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Definition
plant can not complete life cycle without the nutrient.
nutrient involved in a metabolic reaction. |
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Term
| What two categories are plant nutrients divided in? |
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Definition
Macronutrients- needed in large quantities for plant growth.
Micronutrients- needed in small quantities but just as important. |
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Term
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Definition
N,P,K,Ca, Mg, S
nitrogen, potassium, phosphorus, calcium, magnesium, sulfur |
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Term
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Definition
Fe, B, Cl, Mn, Zn
Chloride, Iron, Boron, Manganese, Zinc, Copper, Nickel |
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Term
| how do plants get nutrients from soils? |
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Definition
all nutrients must be dissolved in soil water for plants to absorb them
> 60 nutrients and elements in plants.
Common non essential elements:
Al, Si = acid soils
Na - basic soils |
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Term
| What is meant by organic matter? |
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Definition
| mineralization of N, S, and small amounts of P, micronutrients. |
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Term
| What is meant by mineral dissolution? |
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Definition
| P, micronutrients ( ie Zn, Fe, CU, Mn) |
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Term
| What is meant by surface exchange? |
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Definition
| Ca, Mg, K... needed by plants and humans in large amounts. |
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Term
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Definition
a major source of plant avaialble N ( S, and some micronutrients)
- mineralization and immobilization processes
- denitrification
- N2 fixing bacteria ( Rhizobia ) in legumes |
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Term
| What is surface exchange? |
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Definition
| Major source of plant available Ca, Mg, K |
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Term
| What is cation exchange capacity ( CEC) |
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Definition
- quantity of negative charge on clays and OM
- greater the clay and OM content the greater the CEC
the greater cation holding capacity, the more nutrients ( Ca, Mg, K, NH
- Al or H acid soils neutralized by limes
- Salty soils add gypsum ( CaSo4) |
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Term
| What is the importance of CEC in soils? |
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Definition
retains cations in soils, preventing loss through leaching ( Ca, Mg, K)
Provides plant available cations
buffers concentration of cations in soil solution |
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Term
| CEC in weathered soils is... |
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Definition
less than CEC in unweathered in soils.
Notes: clay and OM also has anion exchange capacity ( surface charge) but is much smaller than CEC |
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Term
| Nutrient deficiency symptoms in plants |
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Definition
- C,H,O are never deficient
- symptoms related to metabolic function
- expressed as ( chlorosis - loss of green color, yellowing, varies with specie and nutrient), stunting, or death |
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Term
| How are deficiency symptoms affected in mobile and immobile plants? |
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Definition
nutrients mobile in plant ( N,P,K,Mg) deficiency symptoms appear in older leaves first.
nutrients immobile in plant ( Ca, S, micronutrients) deficiency symptions in new growth first. |
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Term
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Definition
| It is important for chlorophyll, protein production, mobile in plant. |
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Term
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Definition
| energy transformations... seed/ fruit production, mobile in plant. |
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Term
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Definition
| It is important for water relations... mobile in plant. |
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Term
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Definition
| protein synthesis... immobile in pant |
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Term
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Definition
| growth hormones... immobile in plant |
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Term
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Definition
| oxidation/ reduction... immobile in plant |
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Term
| What is plant analysis, why do we do it? |
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Definition
it confirms visual deficiency symptoms
- reveals hidden nutrient stresses
- verify applied nutrients taken up by plants
- improves plant yield and quality. |
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Term
| How do we analyze plants? |
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Definition
- Plant tissue samples ( leaves, stems, collected at recommended plant growth stage)
- samples are air dried, sent to soil and plant analysis laboratory
- samples ground and digested in acid
- digests analyzed for total nutrient content. |
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Term
| Diagnosing plant growth problems: |
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Definition
| collect plant tissue from normal and problem areas. Proper diagnostics requires both plant and soil analysis. |
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Term
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Definition
- determines soils ability to supply plant nutrients.
- The soil test or extractant is designed to extract a portion of the nutrient from the same poo ( ie solution, exchange, organic, or mineral used by the plant) |
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Term
| Soil test information is used to: |
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Definition
1. Provide an index of nutrient availability in soil
2) predict the probability of obtainining a proitable response to fertilizer or lime.
3) provide a basis for fertilizer and lime recommendations |
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Term
| Soil testing nutrient reccomendation system: |
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Definition
1.) Collect representative soil sample from field
2) determine quantity of plant avaiable nutrient in soil sample ( soil test)
3) interpret soil test results ( low, medium, high, very high )
4) estimate the quantity of nutrient required by the crop ( nutrient reccomendation) |
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Term
| How do you take a soil sample? |
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Definition
obtain a 4 inch soil core
discard organic layer on top of soil
put 4 inch core in sampling bucket
discard soil below 4 inches |
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