施石灰和秸秆还田对双季稻产量和氮素吸收的互作效应

红壤稻田面临土壤酸化和肥力偏低的双重挑战。施石灰和秸秆还田分别是稻田土壤酸化改良和培肥的有效措施,但二者的互作效应尚不清楚。本研究连续4年(2015—2018年)在江西省开展施石灰和秸秆还田双因素田间定位试验,旨在探明施石灰和秸秆还田对红壤双季稻田水稻产量和氮素吸收的互作效应。结果表明,施石灰和秸秆还田均显著提高了早、晚稻的产量和氮素吸收,且二者具显著的协同促进效应。秸秆还田下,施石灰使早稻产量和氮素吸收分别增加10.7%和15.5%;而在秸秆不还田下,增幅仅分别为4.4%和9.7%。秸秆还田下,石灰使晚稻产量和氮素吸收分别提高18.7%和24.6%;但在秸秆不还田下,增幅则分别为10.5%和5.7%。施石灰对早、晚稻产量和氮素吸收的促进效应随试验年限的增加而减弱。石灰对土壤pH值的提升效应随试验年限的延长显著降低。试验4年后,石灰对土壤有机质和全氮含量均无显著影响;秸秆还田显著提高了土壤有机质含量,而对全氮含量无显著影响。因此,秸秆还田配施石灰能够协同实现双季稻增产、土壤酸化改良与培肥。本研究表明在此酸性的红壤双季稻田上每4年左右施用一次石灰为宜。

Interactive effects of liming and straw incorporation on yield and nitrogen uptake in a double rice cropping system

Soil acidification and low fertility limit crop productivity in red paddy soils. Liming and straw incorporation are effective practices to alleviate soil acidification and improve soil fertility, respectively, while their interaction is still unclear. A four-year field experiment was conducted in a double rice cropping system with red paddy soil in Jiangxi province to examine the interactive effect of liming and straw incorporation on rice yield and nitrogen (N) uptake from 2015 to 2018. Either liming or straw incorporation increased grain yield and N uptake in both early and late rice seasons. Lime application increased yield and N uptake by 10.7% and 15.5% under straw incorporation, while by 4.4% and 9.7% with straw removal in the early rice season, respectively. In contrast, liming enhanced yield and N uptake by 18.7% and 24.6% in the straw-incorporated treatments in the late rice season, respectively, whereas only by 10.5% and 5.7% in the straw-removed treatments. The effect of liming on enhancing grain yield, N uptake and soil pH for both early and late rice diminished in the present of time. Neither soil organic matter nor total N content was significantly affected by liming after the four-year experiment. Straw incorporation significantly increased soil organic matter, but had no effect on total N. Therefore, limes should be applied along with straw incorporation to simultaneously increase double rice yield, alleviate soil acidification, and improve soil fertility on acidic paddies. Besides, our results suggest that limes should be applied approximately every four years in the double rice cropping system with acidic red soil.