Effects of straw return rate on soil nitrogen dynamics and wheat yield formation in dryland wheat fields
LIANG Yi-fei, WANG Guang-ze, WANG Hao-ying, DUAN Cheng-jiao, LI Li, XIE Jun-yu, LI Ting-liang
2026, 65(5):
63-69.
doi:10.14088/j.cnki.issn0439-8114.2026.05.010
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To address issues such as excessive chemical fertilizer application in dryland wheat fields on the Loess Plateau, and to clarify the effects of different straw return rates replacing chemical fertilizers on soil nitrogen pool dynamics and yield formation in dryland winter wheat systems,a field experiment was conducted in the dryland wheat region of southern Shanxi on the Loess Plateau from 2018 to 2023 (five consecutive years), with four treatments: no straw return (S0), half-rate straw return (S1/2), full-rate straw return (S1), and double-rate straw return (S2). The impacts of different straw return rates on soil nitrogen fertilizer use efficiency, soil nitrogen pool dynamics, and winter wheat (Triticum aestivum L.) yield formation were systematically analyzed. The results showed that straw return replacing chemical fertilizers reduced soil residual nitrate nitrogen. Compared with the initial stage of the experiment in 2018, the total nitrate nitrogen accumulation in the 0-200 cm soil layer at harvest in 2023 decreased by 54.40%-87.54%, whereas that in the 160-200 cm soil layer increased by 4.55%-425.32%, indicating a downward leaching trend of nitrate nitrogen. In terms of nitrogen budget, straw return substituting chemical fertilizers increased soil nitrogen surplus and apparent nitrogen loss; specifically, S2 significantly increased these indices by 70.70% and 198.89%, respectively, compared with S0 (P<0.05). Straw return enhanced soil labile organic nitrogen contents. The contents of microbial biomass nitrogen, dissolved organic nitrogen, light fraction organic nitrogen, and total nitrogen in S2 were significantly higher than those in S0 by 62.58%, 33.09%, 160.00%, and 14.29%, respectively (P<0.05), while no significant change was observed in heavy fraction organic nitrogen content. Straw return increased dryland winter wheat yield, with the grain yield in S1/2, S1, and S2 significantly higher than that in S0 by 11.06%, 17.73%, and 31.80%, respectively (P<0.05). Overall, double-rate straw return [10 682 kg/(hm2·a)] could be recommended as an important technical measure for green and sustainable production of winter wheat in dryland areas of the Loess Plateau.
