Straw incorporation helps inhibit nitrogen leaching in maize season to increase yield and efficiency in the Loess Plateau of China

Abstract Straw incorporation and nitrogen (N) fertilization are the two important strategies to increase soil fertility and crops productivity, however their improper utilization reduces yield results in environmental pollution and wasting resources. The objective of the experiment was to evaluate the effects of straw incorporation and N fertilization and their interaction on the grain yield, nitrogen resource utilization, nitrate nitrogen (NO3−-N) dynamic changes and leaching from 2017 to 2019 in a wheat/maize rotation system in the Loess Plateau region. The experiment consists of two factors; one factor was N rates; 0 (F0), 150 (F150), 225 (F225), 300 (F300) kg ha-1, and the other factor was straw management; no straw incorporation (–S) and straw incorporation (+S). As a whole there were eight treatments in the experiment. Our results suggested that straw incorporation increased grain and nitrogen uptake, and 150 and 225 kg ha-1 increased grain and nitrogen uptake by 43.6 % and 61.8 % compared with no N fertilization. Increasing N rates gradually decreased the nitrogen recovery efficiency (NRE) and nitrogen agricultural efficiency (NAE). The unutilized N was mainly retained in the soil in the form of nitrate N, and some of the N infiltrates to 100−200 cm soil layer, showing a high N application and high leaching phenomenon, and straw incorporation effectively prevented nitrate N infiltration, and increased the nitrate N content of 0−100 cm in the middle and late stages of maize growth. Based on normalization and fitting results of yield and nitrate N accumulation in 100−200 cm soil layer, we also comprehensively evaluated the effects of N application and straw management on grain yield and environmental benefits.