Cropping Intensity
Impacts
The use of crop rotations and cover crops increases cropping intensity beyond that of a monoculture-fallow system, which has led to the depletion of agricultural soils across the United States and the world. (Remember the Dust Bowl?)
Crop-rotations appear to have a small positive influence on SOC, but cover crops, which can be used as crop residue, greatly increase SOC content.
Cover crops also do not appear to harm cash crop yield when their residues are returned to to soil (in some cases they can increase yield!), and legume cover crops can help compensate for nitrogen loss from soil.
How does it work?
Cover crops can include varieties that are not optimized for harvest; this optimization often means that crop varieties produce very little below-ground biomass (roots), whereas cover crops with extensive roots systems can be used in order to promote deep, stable reserves of SOC.
​
Cover crops improve soil texture and water infiltration, especially if deep-rooted or tap-rooted varieties are planted, and they help prevent soil erosion during the off seasons.
​
​