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35 Cards in this Set
- Front
- Back
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What are the goals of conventional agricultural?
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Production
Profit Cheap Food |
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Why are current Agriculture Practices are Now Sustainable?
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Soil Degradation
Depletion of Water Resources Environmental Pollution Loss of genetic diversity Fossil fuel dependency (due to transport and synthetic fertilizers) |
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Define Sustainability/Sustainable Agricultural
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Economically viable, Ecologically friendly, and socially just
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Define Agroecology.
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The application of concepts and principles is the design and management of sustainable agroecosystems.
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Describe the history of sustainable Agricultural programs and policy in the US.
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Started with sustainable development.
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What are the four emergent principles of Ecosystems and Application to Agroecosystems?
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Energy Flow
Nutrient Cycling Population Regulating Mechanisms Dynamic Equilibrium |
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What are Seven Ecological Principles that support the Agroecosystem Concept?
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1. Promote Biodiversity
2. Promote water efficiency 3. Efficient use of energy 4. Closure of Nutrient Cycle 5. Reduce external Inputs 6. Decrease environmental impacts 7. Increase stability |
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What are four main structural properties of communities?
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1. Vegetative Structure
2. Species Diversity 3. Trophic Structure 4. Stability |
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How to measure Species Diversity?
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Shannon Diversity Index
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What are the effects of Agroecosystems on Natural Ecosystems?
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Habitat fragmentation
Modify biotic interactions Modify abiotic environment Change water availability Increase soil erosion |
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What are the six basic practices of conventional agriculture?
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1. Intensive Tillage
2. Irrigation 3. Synthetic Fertilizer 4. Chemical Pest Control 5. Monoculture 6. Crop-Genetic manipulation |
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What are the first and second laws of thermodynamics?
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1. Energy is neither created nor destroyed.
2. Transformations of energy are inefficient, releasing in form of waste heat |
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1.Define Gross primary production
2.Define Net Primary Production 3.Define Respiration |
1.Total energy assimilated primary producers.
2.energy accumulated 3.Respiration=gross-net |
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What factors limit primary productivity?
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Light
Temperature Water Nutrients |
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Define Ecological Energy Inputs.
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Direct or indirect solar gains that remain fixed regardless of human manipuation
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Define Cultural Energy Inputs.
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are supplied by humans to achieve agricultural objectives there are 2 kinds:
Biological-derived from human + animal energy Industrial-non biological sources (fossil fuel, hydro, nuclear) |
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Liebig's Law of the Minimum.
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organisms are generally limited by only a single physical factor that is in shortest supply relative to demand.
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Why is Nitrogen (N) so important?
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-often the limiting nutrient in many ecosystems
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What are the three main N Cycling processes?
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Nitrification
Denitrification N Fixation |
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Talk about Industrial N
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Haber-Bosch process
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Describe the 6 N Losses to Agroecosystems.
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1. Surface runoff
2. Leaching 3. Denitrification 4. Volitazation 5. Harvest 6. Burning |
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What are 4 functions of soils in Ecosystems?
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Habitat for plants
Habitat for organisms Recycling nutrients and wastes Water purification |
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Components of Soil.
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50% space (solid)
50% air and water |
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Define Bulk Density
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weight of solids per unit volume of soil, low bulk density=higher porosity
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Define tilth
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physical condition of soil in relation to plant growth
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Describe the 4 soil modification processes.
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Addition
Deletion Transformation Translocation |
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Describe the 5 soil forming factors that account for soil differences.
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Climate
Relief Organisms Parent Material Time |
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How does the soil habitat support such a diversity of organisms?
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Many microclimate and microhabitat
Heterogeneous both spatially or temporarily 3D Surface and spaces creation of many niches |
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Why is soil organic matter important?
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Increased porosity
Increased soil aggregation Increased soil water-availability |
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What are some specific examples of indicators of soil health?
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Soil physical prop
soil biological prop Crop condition |
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What is the formula for Shannon Diversity Index?
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H'= -(SUM)pilnPi
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Why should land managers understand soil biology?
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nutrient cycling soil stability
water quality plant health |
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Describe Arbuscular Mycorrhizae.
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Diverse host taxa
Fungi have not free living Function in host and soil Confer a variety of benefits |
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Rhizobium
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Legumes
Bacteria can live in soil Function within host tissue only Benefit host by N uptake |
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What are the two types of biotechnology?
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Selective plant breeding
Transgenic modification |
