Effectiveness of exogenous carbon addition on accelerating soil fertility build-up and maize yield in newly constructed terraced farmland

LI Yi; ZHANG Qingwen; WEI Xinyuan; LI Mengni; SHI Yulong; HE Jinqin

doi:10.13522/j.cnki.ggps.2025143

Abstract：[Objective]Poor fertility and low organic matter content are critical constraints limiting the productivity of newly constructed farmland.This paper evaluates the effectiveness of applying exogenous carbon in accelerating soil fertility development in such soils.[Method]A field experiment was conducted in a maize-growing newly constructed terraced land in a region in the mountainous southern Ningxia.It involved seven treatments:no fertilization(CK),chemical fertilization(NPK),and combinations of chemical fertilization with addition of five exogenous carbon materials:composted straw(NPK+BS),manure(NPK+BM),organic matter-rich bio-organic fertilizer(NPK+BC),organic fertilizer(NPK+OF),and compound microbial fertilizer(NPK+CM).In each treatment,we measured the change in physical and chemical soil properties,soil nutrients,components of organic carbon,as well as enzymatic activity and maize yield.[Result]Exogenous carbon addition significantly increased soil moisture content,total nitrogen,ammonium nitrogen,nitrate nitrogen,available phosphorus,MBN,MBC,SOC,as well as dissolved carbon,particulate and mineral-associated carbon,while exerting minimal effects on soil bulk density,pH,and total phosphorus.We also found that exogenous carbon notably enhanced the activities of β-glucosidase,alkaline phosphatase,and N-acetyl-β-D-glucosaminidase,with the NPK+CM and NPK+BM treatments showing the most pronounced effects on enzymatic activity and SOC accumulation.All carbon-amended treatments significantly improved maize yield,with NPK+BM achieving the highest grain yield.[Conclusion]Exogenous carbon application can rapidly and significantly enhance soil fertility and maize yield in newly constructed terraced farmland.Among all tested treatments,combining chemical fertilization with either compound microbial fertilizer(NPK+CM)or manure(NPK+BM)was the most effective.These findings can help improve soil fertility build-up and crop productivity in newly constructed farmland.