Alternative fertilizer and irrigation practices improve rice yield and resource use efficiency by regulating source-sink relationships

Abstract

Abstract Understanding the inherent characteristics based on leaf and root source and grain sink under an improved cultivation practice is important to achieve both high grain yield and resource use efficiency in paddy rice. A field experiment to investigate the characteristics was conducted across two years using Wuyunjing24 with five cultivation practices including no nitrogen (N) application (0 N), local farmers' practice (LFP), and three improved cultivation practices (ICPs) consisting of improved fertilizer N practice and higher plant density (ICP1), the same practices as ICP1 but with alternate wetting and moderate drying (AWMD) rather than with the continuous flooding (CF) irrigation (ICP2), and the same practices as ICP2 but plus organic fertilizer application (ICP3). The results showed that all three ICPs could synchronously increase grain yield and resource use efficiency, and the increase was the most for ICP3 and followed by ICP2, when compared with LFP. The total number of spikelets, shoot and root biomasses, total leaf area index (LAI), effective LAI, grain weight-leaf ratio, specific leaf N content, and leaf photosynthetic rate, zeatin and zeatin riboside contents in panicles, leaves and roots, and the activities root of spikelets (the ratio of root activity to spikelet number) during grain filling were significantly increased with the improvement in cultivation practices. The results suggest that the improved cultivation practices are useful to achieve high yield and high resource use efficiency through improving source and sink characteristics and coordinating their relationships.