Tillage and N-source affect soil fertility, enzymatic activity, and crop yield in a maize-rice rotation system in the Indian Terai zone

A field experiment (2017-2019) was undertaken to study the short-term effects of tillage [zero tillage (ZT), conventional tillage (CT), and alternate tillage (AT)] and sources of organic and mineral fertilizer N [NS0-control, NS1-recommended doses of fertilizer (160:50:100), NS2-recommended level of fertilizer and crop residue (6 Mg.ha(-1)), NS3-75% of recommended N as fertilizer (120 kg.ha?(1)) and 25% N (40 kg.ha?(1)) as farm yard manure (FYM), and NS4-75% of recommended N as fertilizer and 25% N as vermicompost] on yield and soil quality under a maize-rice rotation system. Among N sources, NS4 produced the highest maize grain yield (10 Mg.ha?(1)). Residual effects of N sources on mean rice grain yield were evident only in crop residue (NS2)- and vermicompost (NS4)-treated plots. After the harvest of two complete maize-rice crop cycles, higher content of dehydrogenase activity (DHA) and urease activity (UR) were observed in the soil under AT as compared to ZT and CT at 0-10 cm (p < 0.05). Similarly, microbial biomass carbon (MBC) and microbial biomass nitrogen (MBN) also recorded positive changes at 0-10 cm soil depth, especially in NS2 and NS4 treatments. AT resulted in the highest total soil carbon (TOC) (8.10 g.kg(-1)), followed by CT (6.73 g.kg(-1)) and ZT (5.98 g.kg(-1)). Fertilizer N treatments, however, influenced the NO3-N accumulation beyond the root zone, where crop residue-based (NS2) fertilizer N treatment resulted in the highest NO3-N (32.52 kg.ha(-1)), and the lowest NO3-N (14.48 kg.ha(-1)) was observed in the FYM-based (NS3) treatment. Therefore, the practice of alternate tillage and integration of vermicompost (40 kg.N.ha(-1)) and chemical fertilizer (total 120 kg.ha(-1)) sources should be mostly recommended to farmers in the Terai region of India.

Automated summary

A field experiment was conducted to study the short-term effects of different tillage methods and organic and mineral fertilizer sources on yield and soil quality in a maize-rice rotation system. The results showed that alternate tillage and the integration of vermicompost and chemical fertilizer had a positive impact on yield and soil quality.