Abstract:
Objective The aim was to clarify the response of microbial activity and crop yield to peanut shell and its biochar in upland red soil.
Method Field located experiments were carried out in the red soil area of Jiangxi Province, and seven treatments were set up according to the principle of “Equal carbon return to field”. ① CK: conventional management, ② S1: application of peanut shell (3000 kg hm−2), ③ S2: application of peanut shell (4500 kg hm−2), ④ S3: Application of peanut shell (6000 kg hm−2), ⑤ BC1: application of peanut shell biochar (1000 kg hm−2), ⑥ BC2: application of peanut shell biochar (1500 kg hm−2), and ⑦ BC3: application of peanut shell biochar (2000 kg hm−2). All treatments were planted with sweet potatoes. The effects of peanut shell and its equivalent biochar on microbial activity and sweet potato yield in dryland red soil were studied by measuring soil basal respiration, soil microbial biomass carbon and soil enzyme activity during the growth period of sweet potato.
Result The application of peanut shell and its biochar could both increase soil respiration intensity and soil microbial biomass carbon content. They increased the activities of soil FDA hydrolase and soil dehydrogenase in the seedling stage of S2, with 54.78% and 47.79%. The application of peanut shell and its biochar had promoting effects on soil catalase and soil invertase activities. The catalase activities increased most significantly in the early stage of tuber formation, reaching 31.33%, and the soil invertase activities increased most significantly in the seedling stage, reaching 69.42%. The application of peanut shells and biochar with the same carbon content could increase the yield of sweet potato. The yield of sweet potato had a very significant positive correlation with soil microbial biomass carbon, and a significant positive correlation with soil basal respiration.
Conclusion Appropriate amount of peanut shell and its biochar could improve soil fertility and increase the yield of sweet potato. This experiment can provide scientific basis and practical guidance for the improvement of red soil fertility in dryland, the comprehensive utilization of crop straw and the implementation of circular agriculture.