Soil carbon storage or sustainable conservation agriculture practices-Which should be our goal?

Abstract

Practices such as no-tillage, cover crops, or diversification of crop rotation are thought to be capable of addressing climate change challenges while ensuring food security. Public and private sectors at national and international levels are currently incentivizing farmers to adopt these practices to increase soil carbon (C) levels, thus helping to mitigate climate change. However, increasing soil C levels with an expectation of mitigating and adapting to climate change needs further evaluation. Reduced soil disturbance, retention of crop residues, planting cover crops, or diversification of crop rotations with perennials are indeed effective, especially in the long term (>10 years), in improving soil properties that enhance climate change adaptation, but not so much climate change mitigation. However, planting of cover crops, considered to be one example that represents conservation agriculture, is currently practiced on only 4.7% of cropland in the United States. Further, we question whether current programs that pay for C stored in soil are sufficient to incentivize farmers to change their operations due to the high cost to test soil C to validate their efforts. We propose that to promote wider adoption of sustainable conservation agricultural practices, and to make large-scale positive impacts through their use, farmers should be paid to "do the right thing" instead of paying them based on soil C accrual. The literature indicates that doing the right thing includes (1) continuous no- or minimum-soil disturbance, (2) permanent biomass soil cover, (3) biodiversity in crop rotations, and (4) applying or practicing these three principles on a continuous year-after-year basis. Paying farmers to "do the right thing" versus paying farmers for C credits will lead to much higher adoption rates of sustainable conservation agricultural practices by farmers. This will in turn lead to improved crop production and soil and environmental quality.