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

Abstract

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.