Effects on Rice Growth of System of Rice Intensification under No-till Paddy in Korea

Abstract

The objectives of this research were to investigate the system of rice intensification (SRI) on early growth, grain yield, and yield components under Chinese milk vetch residue-mulched no-tillage cropping systems at silt loam soil. The field was prepared as a split-plot design with three replications, main plots consisted of Dongjinbyeo, and Sobibyeo as a cultivar, and subplots consisted of <TEX>$10{\times}10$</TEX> cm, <TEX>$20{\times}20$</TEX> cm, and <TEX>$30{\times}30$</TEX> cm as a planting density. Weed infestation during rice growing season was more severe in wider planting density <TEX>$30{\times}30$</TEX> at 35 days after transplanting (DAT), and <TEX>$20{\times}20$</TEX> cm at 95 DAT in both Sobibyeo and Dongjinbyeo. The maximum plant height was recorded in Sobibyeo compared with Dongjinbyeo, <TEX>$10{\times}10$</TEX> cm and <TEX>$20{\times}20$</TEX> cm planting density compared with <TEX>$30{\times}30$</TEX> cm from 20 DAT until 60 DAT. Among the three planting densities, SPAD values were significantly greater in planting density of <TEX>$20{\times}20$</TEX> cm both in Sobibyeo and Dongjinbyeo followed by <TEX>$30{\times}30$</TEX> cm compared with closer planting density of <TEX>$10{\times}10$</TEX> cm. The lowest grain yield was observed in wider planting density of <TEX>$30{\times}30$</TEX> in both Sobibyeo and Dongjinbyeo due to lower number of panicle per unit area. Our findings suggest that optimum planting density for SRI in no-tillage paddy was <TEX>$20{\times}20$</TEX> cm and it should be useful the systems to small-scale rice farmers in Korea as a sustainable farming system.