Discussion And Application Of Optimized Fertilization Mode For Annual Rice-Wheat In Hilly Region

The experiment was conducted in 2012-2014 on rice and wheat integrated demonstration base in Yizheng city, Jiangsu province, with combination of design of 6 kinds of wheat fertilization mode and 6 kinds of rice fertilization model, to study the effect of difference wheat and rice fertilization model on the total annual rice wheat and yield, economic benefit, nitrogen efficiency respectively, discuss the technology ways to improve the total annual yield and benefit of rice and wheat. The main results were as follows:1 The suitable fertilization mode for total annual high yield and high efficiency of rice and wheat in hilly region of Yizheng was high yield and high efficiency model 1 (HYHE1) of rice and high yield and high efficiency model 2 (HYHE2) of wheat. The total nitrogen application amount was 560 kg/hm2. The ratio in rice and wheat was 4:3. Compared with the traditional rice nitrogen application model of farmers, the rice yield increased but the total application amount of nitrogen fertilizer decreased by 20 kg/hm2. The combination model in rice increased the number of kernel per spike through increasing the proportion of base fertilizer application, increasing the amount of basal fertilizer, decreasing the amount of tillering and floral initiation fertilizer, and increasing the amount booting fertilizer. Under the condition of the total amount of nitrogen application invariable in wheat, decreasing the amount of application of elongation fertilizer and increasing the amount of tillering fertilizer could better play the role of nitrogen fertilizer, increase yield but also improve the nitrogen use efficiency.2 The total annual yield and economic benefits of using high yield and high efficiency fertilizer application model in Yizheng hilly area in rice and wheat could reach 16782.76kg/hm2 and 30451.18 RMB/hm2 respectively, significantly higher than that of the farmers’ traditional fertilization model. The yield structure of this combined fertilization model was:the number of spikes 330-350 million/hm2, total kernel number per spike 150-160, the kernel setting rate 80-82%, the 1000 kernel weight 25-26g in rice and the number of spikes 430-450 million/hm2, the kernel number per spike 36-38, the 1000 kernel weight 37-38g in wheat.3 The population characteristics of high yield and high efficiency in rice and wheat were as follows. The dry matter production after anthesis was as high as 5900-6000 kg/hm2, more than 1/3 of total dry matter production. The proportion of dry matter transported to kernels was high and the final economic index was above 0.40. The max LAI at tillering stage was about 6.3-6.5 and at the flowering stage the LAI was steadily about 5-5.5. The rate of tiller and the ratio of kernel weight or number and leaf area were as high as 42%-45% and 11-12 mg/cm2 leaf area or 0.28-0.30 grains/cm2 leaf area, respectively.4 This study indicated that the effects on increasing the yield were significantly different by applying the same amount of nitrogen on rice or wheat. Without nitrogen application the average yield of wheat was 1040 kg/hm2, while the average yield of rice was 4012 kg/hm2.The agronomic efficiency of nitrogen for rice was apparently lower than for wheat. The two-year average was 17.52 kg/kg for wheat, and 12.67 kg/kg for rice. On the contrary, the partial productivity of nitrogen for rice was higher than that of wheat. The two-year average was 23.59 kg/kg for wheat, and 28.91 kg/kg for rice. It could be concluded that nitrogen application was highly beneficial to increase yield for wheat, while rice was better at taking advantage of soil fertilizer with relatively little amount of nitrogen applied. Under the conditions of same amount of fertilizer application, the total annual yield of rice and wheat and the efficiency of nitrogen could be further enhanced through reducing the amount of nitrogen applied to rice and increasing the amount of nitrogen to wheat.5 Other beneficial combinations of fertilizer application model were also found under the conditions of the present study, such as the combination of both high yield and high efficiency management 2(HYHE2) of rice and wheat. Compared to the combined model in previous sections of this abstract, this combination demonstrated 3% less total annual yield, but reduced the total amount of nitrogen applied by 40 kg/hm2, which was the highest nitrogen efficiency among all the combinations. All these combinations found in the study significantly improved total annual yield, economic benefit, output-input ratio, nitrogen agronomic efficiency, use efficiency, and partial productivity. It could be concluded that it was possible to increase yield and efficiency while reducing nitrogen application through high-yield and high-efficiency nutrient management.