The effects of long-term no tillage and stubble retention on soil nutrient, grain and forage productivity in a forage-crop rotation system in rainfed areas

We explored the changes in crop and forage productivity and their driving factors after 22 years of conventional tillage (T), conventional tillage combined with stubble retention (TS), no tillage (NT), and no tillage combined with stubble retention (NTS) in a forage-crop rotation system on the Loess Plateau. The results indicated that TS and NTS increased system production by 19% and 32%, respectively. Among them, NTS had the greatest effects on maize yield, wheat yield, soybean biomass, which increased by 19%, 14% and 52%, compared with T, respectively. Moreover, the NTS had the highest soil carbon and nitrogen accumulation, enzyme activity and soil conditions. The soil carbon and nitrogen storages of NTS increased by 41% and 53% in the 0-10 cm soil depth, respectively. Moreover, the activities of βG (β-glucosidase), CBH (cellobiohydrolase), βX (β-xylosidase), LAP (leucine-aminopeptidase), NAG (β-N-acetylglucosaminidase) of NTS increased by 45%, 98%, 39%, 50% and 53%, respectively.