Soil health benefits of different cropping systems after three years of the organic transition period
Under the food security crisis and the global pandemic happening, the demand for organic agriculture products is dramatically increasing. Currently, if a farmer wants to shift to an organic system, he/she has to go through a three-year organic transition period which is challenging due to the regulation on chemical usage, lower yield, lower economic profit, etc. One of the primary solutions in addressing these issues is to improve soil health by using an appropriate cropping system. Therefore, we evaluated the impact of a novel perennial grain crop intermediate wheatgrass (IWG) (Thinopyrum intermedium) with existing annual and perennial cropping system on soil health during the organic transition period. We hypothesized that IWG treatment will have higher microbial biomass, total carbon (C) content, and better aggregate stability compared to other annual cropping systems because of its perennial growth habit. Six different treatments/ transition systems including IWG, IWG + Alfalfa, Alfalfa, Wheat + Red clover, corn/soybean + winter cover crops (winter rye/hairy vetch), and conventional cropping system of corn/soybean rotation were established. A series of soil health analyses were conducted to evaluate the soil health from physical, chemical, and biological indicators which included the mean weight diameter of soil aggregates, microbial biomass C, and total soil C. The results showed a significant improvement in soil aggregation while soil C did not show any dramatic change. The IWG system increased gram-negative bacteria and actinomycetes community as compared to other systems. The conclusion was, after three years of perennial practices, IWG was able to improve some soil properties that can improve soil health in the long run.