Effects Of Slow-controlled Release Nitrogen Fertilizer Combined With Conventional Nitrogen Fertilizer On Characteristics Of Nitrogen Utilization, Yield,and Soil Physical And Chemical Properties In Mechanical-transplanted Rice

The effects of different slow-controlled release nitrogen (N) fertilizer and its combined with conventional urea (PU) in mechanical-transplanted rice on N uptake and utilization, grain yield, and the physicochemical and properties of soil were studied. Two research were designed with early-maturing indica rice Zhongjiazao 17 and medium-late indica hybrid rice Chuanguyou 7329 under N application amount of 150 kg/ha N rate in 2014?2015. (1) One research about effects of different slow-controlled release N fertilizers on N uptake and utilization, grain yield, and soil physical and chemical properties in mechanical-transplanted rice. This study was conducted with different rice type: Zhongjiazao 17, Chuanguyou 7329, and different slow-controlled release N fertilizers: coated with nitrification inhibitor(DMPP), coated with resin(RCU), coated with sulfur(SCU), total N fertilizer applied before transplanting, N splitting (before transplanting:tillering:panicle) ratio of=5:3:2 in 2014. (2) Another research, based on the result of 2014 experiments, about effects of combining slow-controlled release N fertilizer with PU on N uptake and utilization, grain yield, and soil physical and chemical properties in mechanical-transplanted rice. This study was conducted with different rice types: Zhongjiazao 17, Chuanguyou 7329, and different ratio combined slow-controlled release N fertilizer with conventional urea:RCU alone, PU alone,3 kind of ratio RCU:PU,7:3,5:5, 3:7, respective in 2015. The relationship between N translocation rate and yield formation in different periods; and the relationship between soil physical and chemical properties and photosynthetic characteristics during grain filling stage were also investigated in this paper. The main research results are as follows:1 Effects of different slow-controlled release N fertilizer combined with PU on yield and its compoments in mechanical-transplanted riceThe yield of Chuanguyou 7329 was significantly higher than Zhongjiazao 17. Compared with N splitting, RCU could significantly increase the effective panicle number, spikelet, and grain yield of mechanical-transplanted rice under different slow-controlled release N fertilizer; and no obvious difference was found in RCU which from different manufacturers. RCU increased yield 4.59%-6.60% was the optimum categories in this study. But the yield of SCU, DMPP was significantly decreased compared with N splitting. However, the yield of N fertilizer managements were significantly higher than no N treatment (CK) under different ratio combined slow-controlled release N fertilizer with PU, among them, RCU:PU(7:3) was the optimal ratio for this study, and it was higher than RCU alone 5.53%, higher than PU alone 28.05%. But other ratio revealed contrary trend.2 Effects of different slow-controlled release N fertilizer combined with PU on nitrogen utilization in mechanical-transplanted riceThe results showed significant interactions between variety types and slow-controlled release N fertilizers application on biomass, N accumulation, translocation and grain yield during main growth stages. Medium-late indica hybrid rice was significantly higher than early-maturing rice in N accumulation and translocation during different growth stages. The N apparent use-efficiency was much improved when resin-coated slow-controlled release N fertilizer was used. Compared with total N fertilizer applied before transplanting and N splitting, N accumulation of panicle, partial factor productivity of applied N, N agronomic efficiency, N apparent use efficiency and yield were increased by 6.07%-8.13%, 18.04%-25.73%,29.12%-41.42% and 4.85%-6.61%. RCU is the best among the slow-controlled release-release N fertilizers tested in transplanted rice, which had a significant effect on N accumulation and use efficiency in medium-late indica hybrid rice. However, SCU and DMPP were lower than PU in increasing yield and synergism, and were effective for translocation of vegetative organs and N transportation efficiency instead. On another hand, the N accumulation and N translation amount of RCU:PU(7:3) were significantly higher than RCU alone in the jointing mature stage, but the results of RCU:PU(5:5,3:7) had an opposite effect. The significant or extremely significant positive correlation(r=0.34*-0.94**) was found between variety types and slow-controlled release-release N fertilizers application in N accumulation, N translation, N utilization and yield, dry matter accumulation at main growth stages, which were more obvious in N accumulation with yield, dry matter accumulation of full heading stages.3 Effects of different slow-controlled release N fertilizer combined with PU on population quality characteristics of mechanical-transplanted riceThe tiller and photosynthetic of Chuanguyou 7329 was significantly higher than Zhongjiazao 17. Compared with N splitting, RCU could significantly increase the tiller number of jointing full heading stage, the Pn and SPAD of the late rice growth which Pn and photosynthetic potential of RCU in heading stage was increased by 1.31%-1.93% and 10.21%-15.87%. And compared with RCU alone, RCU:PU(7:3) could significantly increase the number of tiller during the jointing stage, and it could also maintain a high level of tiller number, SPAD, Pn and photosynthetic potential from jointing to mature stage.4 Effects of different slow-controlled release N fertilizer combined with PU on the physicochemical and properties of paddy soilThe soil organic matter content of two rice varieties was no significant difference in the whole period, but the content of total N and urease were different, the soil total N content was highest with Zhongjiazao 17 and the urease was highest with Chuanguyou 7329. However, the soil organic matter, urease activity and total N content showed a consistent trend in grain-filling stage:RCU:PU(7:3)>RCU alone, SCU and DMPP were significantly lower than N splitting. Therefore, RCU:PU(7:3) not only could increase the urease activity, organic matter and total N content of soil by the application of PU, but also could control these index in a higher level by the slow releasing of RCU. And then, it could increase the N supply to plants so as to realize the efficient use of N and N balance of soil.