Term
| Why is soil micro so important? |
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Definition
agriculture
maintaining environmental quality |
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Term
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Definition
an environment for microorganisms
formed in a wide variety of environments ranges from arctic(soil carbon pool stored) regions to antarctic valleys(no vascular plants) |
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Term
| Large microbial communities are present where and why? |
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Definition
| Deeper subsurface zones cause roots cannot penetrate |
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Term
| A microbial activity done by dolomites |
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Definition
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Term
| What occurs between the spaces of soil particles |
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Definition
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Term
| texture of soil determind by pore space |
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Definition
| Gas diffusion, Sandy soil=large pore space drains quickly |
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Term
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Definition
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Term
| rainfall/irrigation have what effect on soil |
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Definition
| changes soil from aerated to isolated pockets of water |
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Term
| shifts in water content and gas flux effect... |
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Definition
| conc. of c02 and co and other gases in soil |
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Term
| roots of plants growing in aerated soils.. |
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Definition
| consume oxygen and release carbon di oxide |
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Term
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Definition
Mineral Soil: Less then 20% organic matter
Organic Soil: Soil that is made up of mostly organic,natural matter |
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Term
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Definition
Soil organic matter(SOM)
helps to retain nutrients
maintain soil structure
hold water for plant use
changes environmental conditions and agricultural management practice |
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Term
| Microbial degradation of plant materials creates... |
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Definition
production of C02 incorporated into microbial biomass.
small fraction of decomposed plant material remains as SOM |
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Term
| SOM is divided into two types of fractions |
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Definition
| humic and non humic fractions |
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Term
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Definition
dark brown-black
due to chemical transformation of the microbial metabolic products
Complex blend of phenolic commpounds, polysacc and proteins. |
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Term
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Definition
no significant biochemical degradation
Represents 20% of total soil organic matter. |
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Term
| Process Degradation of plant material and development of SOM 3 Steps |
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Definition
1. Carbs and proteins broken down
C02 respired and remaining is incorporated into new biomass
2.Complex carbs(cellulose)-degraded
Fungi and bacteria(Strep,baccilus and pseudomonas)- extracellular cellulase enzyme- cellobiose and cellotriose. Degraded and assimilated as glucose monomers.
3.Very resistant material - lignin(woody plants) degraded by Basidiomycete fungi & Actinmycetes Produce extracellular phenoloxidase enzyme |
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Term
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Definition
| small part of total soil volume |
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Term
| How do you prevent erosin |
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Definition
| use reduced tillage- retain amount of crop residue(SOM formation) and water retention. |
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Term
| How is nitrogen important |
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Definition
Due to N2 limiation- nitrogen fertilizers added, Soil carbon- Nitrogen ratio
C/N ratio - 20 or more - do not stimulate growth
C/N ratio - <20 microbes covert ammonium nitrate biomass(proteins and nucleic acids) |
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Term
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Definition
Agricultural fertilizers-chemically synthesized includes fossil fuel combusion
Nitrogen fertilizers: liquid ammonia and ammonium nitrate
Ammonium added- attracted to negatively charges clays in soil and retained till used by plants. |
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