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Competency Area 8: Cropping Systems

PO 36. Understand the aspects of crop management that can affect long term sustainability of different cropping systems.

Cropping systems are a community of plants managed by farmers to achieve a set of goals. Long-term sustainability can be defined as the management and conservation of natural resources in a manner to ensure continued satisfaction of human needs for future generations. Soil is the basic resource for sustainable cropping. Measurable indicators of soil productivity and soil quality can be a major component for evaluating long term sustainability.
Basic aspects of crop management that impact long-term sustainability include crop rotation, companion and cover crops, fallow, fertilization, and residue management systems. We can measure and attempt to understand these crop management practices relative to long-term sustainability using the following indicators:

Soil productivity
Measures of soil productivity need to be meaningful to local farmers. Interpretation of soil productivity indicators requires an understanding of the biological mechanisms that impact soil and crop behavior.

Soil quality
Soil biological activity and community structure, along with soil physical structure, are good indicators of healthy soils. Over time such indicators should be stable or improving, to allow for cropping system sustainability.

Crop yield
Crop yields can be extremely variable, due to uncontrolled environmental conditions. Long-term yields for a given cropping system must be relatively stable to achieve long-term sustainability.

Pest management
 Insect, pathogen, and weed populations need to remain relatively stable or need to decline with acceptable crop management practices. If pesticide application rates or frequency of application are increasing over time, system sustainability is impacted.

Net greenhouse gas emissions
Sustainable cropping systems of the future will need to rank relatively high for minimizing net greenhouse gas emissions.

Economic inputs
Crop value is often beyond the control of producers, but the stability of input costs will greatly impact economic sustainability. Heavy reliance on inputs with very unstable pricing (e.g. fuel, N fertilizer) will threaten economic sustainability.