PBL 5: Sustainable agroecosystems Flashcards
Agroecosystem
ecological systems that humans manage to produce food, fibre and other agricultural products of economic value
Characteristics of a sustainable agroecosystem
-maintenance of soil fertility
-water
-air resources for future generations
-internal regulating mechanisms (maintenance via trophic levels)
-recovery ability
-avoiding over dependence on external inputs.
Natural agroecosystem
benchmark, pre-industrial
Traditional agroecosystem
crop rotations, high autonomy (not relying on artificial inputs)
-high biodiversity and flexibility
-less output because it is at a lower intensity
-high interdependence on other species
-resilience
-local farmers: self consumption is prioritised)
Sustainable Agroecosystem
Goal: have a high yield while being environmentally friendly
-greater structural and functional similarity to natural region
-traditional agroecosystems used as a reference
-less dependence on non-renewables
-biological control but not artificial
Industrial Agroecosystem
-More regulated
-Tillage
-Machinery
-Chemical inputs
-High output
-Monocrops
-Purchased seeds
Parameters of agroecosystem sustainability: Ecological
-Soil health: color, experiments determine
-Amount of root network
- Retaining moisture content after rainfall (water holding capacity/micropores)
-pH levels
-Assess for soil erosion
-Compaction
-CEC
-Nutrient holding capacity
Parameters of agroecosystem sustainability: Hydrological Factors
-Water capacity
-Erosion
-Nutrient Leakage
-Waterlogging
Parameters of agroecosystem sustainability: Biotic Factors
-Presence of biodiversity
-Microbiomass: nutrient recycling, symbiosis (missing in modern agriculture)
-Balance between pathogenic and biomass interactions
-Pesticide resistance
-Rhizosphere structure and function: exchange+communication between microflora and root.
Parameters of agroecosystem sustainability: Ecosystem level of characteristics
-Keeping focus on crop production
-Measure sustainability of the crop via PI
-PI<1 (NPP> TOTAL BIOMASS ACC): net loss over time :(
-PI>1 (NPP< TOTAL BIOMASS ACC): :)
Productivity Index (PI)
(total biomass accumulated)/ (net primary productivity)
PI=2 is roughly sustainable
Other factors that could influence productivity
-Energy sources: resilience of the agroecosystem
-Resilience
-Population growth rate: demand vs supply
-Shifting eating habits/diets
-Generate diversity
Socioeconomic/Political factors that affect productivity
-Employment level (sustainable agroecosystems require more labor)
-Government subsisidies
-Investment rates
-Socioeconomic efficiency might reduce general crop efficiency/output
-Seasonal work
-Social justice
-Costs+returns comparison
-Education
Organic farming
a food production system that uses non-synthetic amendments as an alternative to conventional agriculture
-consumer driven
-Non-organic GMOs banned in the US
organic components
- Weed control:
-manual
-crop rotation
-cultural weed control - Insect control:
-Non-synthetic insecticides (some are more toxic than synthetic)
-Rotations - Socioeconomic aspects
-Profits can be compared to conventional, depending on country/data
-Fewer inputs
-Labour: more time spent on field
-Yield: some uncertainties, but mostly can match.
NOT ENOUGH LAND TO MATCH GLOBAL POPULATION ORGANICALLY
