Relationships And Regulatory Approaches Among Yield, Nutrient Efficiency And Benefits Of Grain Crop

Food is the most necessary for human beings survival and development. China with most population in the world, increasing food production is always the first goal of agricultural production and improving resource use efficiency is the basis to achieve sustainable development of agriculture as well as increasing steadily farmers income is a key to the growth of national economy. However, the problem of high input, low efficiency and low benefit is serious in the current agricultural production. So, coordinating the relationship of yield, nutrient efficiency and benefit is currently facing major task, and it's a major issue of governments and scientists concern. So, based on the data derived from investigation on farmers'crop production in China, the current paper systematically compared the current situation and analyzed the relationship among yields, nutrient efficiencies and economic benefits of wheat, maize and rice. Moreover, basing on the data collected by monitoring farmers and weighting yields on specific sites, limiting factors on high yield, high nutrient efficiency and high economic benefit of wheat and maize were explored. Finally, the possibility ways to achieve high yield, high efficiency and high income were also proposed. The main results are summarized as follows:1 At present, the high yield, high nutrient efficiency and high economic benefits of crop production only could be met on few farms in China. Among the Farmers in planting of winter wheat, summer maize, spring maize, single rice, early rice and late rice in six provinces, less than 20% can simultaneously achieve high yield, high efficiency and high-income, but more than 40% were still in the status of low yield, low nutrient efficiency and low economic benefit.2 Nutrient efficiency and economic benefit were significantly enhanced, following by the increase of yield. There was a significant correlation between nutrient efficiency and yield in six provinces, except for Jiangsu province, with the correlation coefficients of 0.3056~0.8125. There was also a significant correlation between economic benefit and yield, and correlation coefficients were 0.3932~0.8642, and they can increase income 1.18~3.26 yuan when production increased by 1kg.3 With the increasing of fertilizer application, grain yield didn't increase accordingly due to there was no statistically significant correlation between them. The contribution of fertilizer to yield was only 5.1% and 0.67% in wheat planting two years, and in maize plating it was only 0.43% and 4.4%. It means fertilizer application is not the first factor of increasing yield. So, increasing production of grain can not simply rely on increased fertilizer input.4 With the increasing of fertilizer application, partial factor productivity of fertilizer significantly reduced. Significantly negative correlation existed between nutrient efficiency and fertilizer application rate in wheat planting in two years, and correlation coefficients were 0.9216 and 0.8688. The same as maize, so, reduced the amount of chemical fertilizer may raise the nutrient efficiency.5 With the increasing of fertilizer application, benefit didn't change accordingly. there was no statistically significant correlation between benefit and fertilizer application in wheat planting in two years and maize in 2009, and significantly negative correlation between them in maize planting in 2010, the correlation coefficient was -0.4330.6 It was difficult to achieve the high yield, high efficiency and high benefits, simultaneously, as result of considerable variations in management between different households for the same crop. The results showed that differences respectively were 10 days, 158 kg/hm2, 14 days and 11 days of sowing date, nitrogen fertilization rate, irrigation date and harvest date on maize fields in the same village. As the result, there were great differences among yield, nutrient efficiency and benefits. Difference of yield was 5805kg/hm2, nutrient efficiency was 41kg/kg, benefits was 7979 yuan/hm2.7 It was concluded that increasing the yield by optimizing management technologies of crop cultivation with combination of reducing fertilizer is a useful way to achieve high yield, high efficiency and high benefits. Farmers thought the main factors increased yield were variety and material input. They fertilized with the experience, and 71% of them didn't want to reduce fertilizer rate, while more than 50% would like to reduce under the guidance of technical experts. So, we need to strengthen agricultural services, and relevant departments need to hire technical experts to guide fertilizing regularly, at the same time training the cultivation and management technology.