Optimization Of Nutrients Management Pattern In Rice Field And Analysis Of Increasing Production And Efficiency

Rice is the major grain crop in China. To meet the demand of food for increasing population and developing economy, the most important solution to safeguard the food security is to maintain the crop yield increase continually. With the increasing crop yield,the nutrient resource inputs are necessary to be increased. Nowadays, they are the hotspots that whether continually increasing the crop yield must depend on the large inputs of nutrient resources and whether the high crop production and high resource use efficiency can co-occur. In this study, we tested the nutrient management models of rice production in Jiangsu province to evaluate their effects on crop production and resource use efficiency from 2010-2014. The optimal models, containing optimizing both of Nitrogen application rate and plant density mode, optimizing Nitrogen and Potassium application rates mode and optimizing Nitrogen and Zinc application rates and application way mode, were also demonstrated in practical application. Moreover, the effects of different models on rice growth, yield and nutrient use efficiency, as well as the impact of the models on environment, were investigated, hoping to provide theory and practice basis for achieving high crop production and high resource use efficiency by nutrient resources integrated management. The main results were as follows:1. Integrated optimal N rates and plant densities could achieve high yield, high N use efficiency of rice. The results showed that: (1) The effect of production and N use efficiency of N rate were more than planting density in rice; (2) The leaf SPAD value and soil NH4+-N and NO3--N were increased, the N use efficiency of partial factor productivity(PFP) and agronomic efficiency (AE), and group canopy temperature were decreased, and the parameters of biomass, tillering number, yield and leaf area index were reduced after the first increase by increasing N rate in rice; (3) The biomass of high density was more than low density, but the difference was gradually reducing with the continuation of the growth process; (4) The best theoretical yield of rice were 9249 kg ha-1 and 9272 kg ha-1,and the N required 163 kg ha--1 and 185 kg ha-1 under high and low planting density,respectively.2. Integrated N fertilizer rates and K2O application methods could achieve high yield,high fertilizer and economic efficiencies of rice. The results showed that: (1) the high N rate significantly enhanced the yield of rice resulting from improving crop N nutrition level, but the N use efficiency and economic effect of optimal N management was more than high N rate; (2) The highest PFP, AE, the recovery efficiency (RE) and the economic effect of the K2O fertilizer were all obtained in the treatment applying 150 kg ha-1 in soil and 16.2 kg ha-1 by foliar spray (Ks150+KF16.2).3. The aims of grian Zn biofortification could be achieved by combination use of N and Zn fertilizers in rice production. The results showed that: (1) the concentration and accumulation of Zn in different up-ground organs (leaf, stem, grain) of rice plants were increased with increasing Zn application rate, and the concentration of Zn in various up-ground organs of rice was between 20.1 to 50.6 mg kg-1 at different growing stages. Zn concentration in the same organ changed a lot at different growing stages and the highest Zn concentration was always found in stems. (2) The accumulated Zn in stems was the highest among all organs during early growing period (tillering, flowering), and the distribution percentage of Zn in stems was more than 60%, higher than those in other organs. In late growing period (harvest), however, the accumulated Zn in the stems and grains werealmost equal (40%); (3) A series of parameters of Zn (Zn concentration,accumulation, transportation, contribution to grain, Zn requirement for 100 kg grain and Zn harvest index were all in the order of high N more than low N rates in rice.4. Optimal nutrition management could be to achieve high grain yield and high N efficiency on site-specific farmer cultivate rice in the experiment area. The results from 2011 to 2013 showed that: (1) The rice grain yield of OPT treatments (226 kg ha-1 N) was significant increased 5.5% when reduced 32.1% N fertilizer rate than FFP treatment (333 kg ha-1 N) due to the increase of grains per panicle, seed setting percentage, and 103-grain weight; (2) The N concentration, accumulation and N requirement for 100 kg grain of FFP treatment were significant more than OPT treatment, and improved N distribution to vegetative organ in rice plants; (3) Compared with the FFP treatment, the OPT treatment was also significant improved NUE of rice plants, and that the PFPN, AEN, REN and PEN was increased 55.5%, 79.1%, 18.8% and 48.7%, respectively; (4) There was a significant positive relationship between plant N accumulation and grain yield of rice, and the increase yield efficiency per unit N accumulation of OPT treatment more than FFP treatment. (5)Organic fertilizer can improve soil environment, can regulate the soil ionic groups and soil enzyme activities, and promote the optimization of nutrient management of rice.5. The method of straw return could achieve high yield, high K2O efficiency, and soil K balance in coordination with reduce K2O fertilizer rate. The results showed that: (1) The grain yield was increased by application K2O fertilizer due to the increase spikes of rice, the best theoretical yield of rice were 9336 kg ha-1 and 9191 kg ha-1, and the N required 76 kg ha-1 and 61 kg ha-1 under no- and half- straw return, respectively; (2) The K concentration and accumulation were increased with increasing K2O application rate in different organs of rice plants, and the treatment of half straw return was more than no straw return; (3) The soil available K and soil K balance were increased with increasing K2O application rate,and there were increased 4.0% and 128.5% than no straw return, respectively.6. Integrated Zn fertilizer typies and application methods could achieve high yield,high Zn efficiency and improve the Zn nutritional quality of rice. The results showed that:(1) Zn fertilizer application significantly increased the yield and Zn content in rice crops,and the average yield of rice in treatment with Zn fertilizer used as soil application was significantly higher than that of foliar application (by 5.2%), while the Zn content of leaf,stem and grain in foliar treatment were significantly higher than those of soil application(by 224,6%, 78.5% and 12.1%, respectively); (2) The yield increase rate of complex fertilizer of Zn and N or K treatments was significantly higher Zn and P treatment in soil application, while the Zn content increased of Kali-EPSO-Zn treatment was significantly higher than that of ADOB-IDHA-Zn and ZnSO4·7H2O treatments in foliar application; (3)The Zn-enriched rice grain can be production by foliar spray of high concentration and high intensity Zn fertilizer in rice growth stages, and the high rice yield and high grain Zn concentration were achieved by planting the Zn-enriched rice grain.