Studies on influence of cultivation patterns on characteristics of nitrogen utilization and distribution in rice

Pot experiments were conducted to evaluate the influence of no tillage with straw incorporation on characteristics of nitrogen utilization and distribution in rice using 15N tracer techniques in the early seasons of 2006 and 2007. The test plant was Jinyou 253. Four treatments, no tillage-straw incorporation(NT-S), no tillage(NT), conventional tillage-straw incorporation(CT-S), conventional tillage(CT) were designed. The results showed that: 1) Nitrogen fertilizer uptake and distribution in rice plants were influenced by soil tillage practices. NT increased the ratio of nitrogen fertilizer uptake in grain and root, and decreased the distribution in leaves and stem. 2) Lower grain yield was observed under NT compared to CT, but the difference was not significant. The difference of total nitrogen uptake in rice plants was not significant under different tillage practices, but higher proportion of nitrogen uptake from fertilizer and nitrogen recovery efficiency were found under NT compare to CT. 3) Straw incorporation had a significant effect on nitrogen fertilizer utilization. Under NT-S decreased the accumulate of nitrogen uptaken from basal and tillering fertilizer, however, increased nitrogen uptake of fertilizer at earring. Under CT-S increased accumulate of nitrogen fertilizer of each stage of the growing period, consequently, increased the total nitrogen fertilizer absorption significantly. 4) Straw incorporation increased rice grain yield under both tillage practices, but decreased nitrogen fertilizer recovery efficiency under no tillage.