| Yongji region was located in southern of Shanxi Province,Winter wheat/summer maize rotation is a major crop growing system. Fertilizer application is a major agricultural production measures,appropriate application of fertilizer to increase crop yield and productivity of the land is of great significance. In recent years, increased fertilizer inputs to production has not synchronized growth, or even a decline in output, mainly because in the region, over-use nitrogen fertilizer are quite common, and P and K fertilizer was not concerned very much, farmers have become accustomed to this. Excessive application of nitrogen fertilizer may not only cause a lot of economic losses, but raises a number of environmental problems. The field experiment was to study different fertilization conditions under different fertilizer winter wheat and maize crop rotation, respectively, to study the rules of nitrogen,phosphorus,potassium nutrients uptake.Meanwhile,soil nutrients and the effects of nitrogen rate on crop yield,nitrate-nitrogen content, nitrogen use efficiency were studied. The objective of this study was to understand and master the proportion of nitrogen, phosphorus and potassium in the best manner, and provide a scientific basis for a reasonable fertilization in Yongji region. The main findings are as follows:1. A rotation cycle finishes topsoil soil nutrient content's change. The results indicated that the crop yields of nitrogen phosphous and potassium treatments were greater than other treatment. Soil total nitrogen and available p,k were increased in nitrogen phosphous and potassium treatment. On the contrary,total nitrogen and available phosphous were exhausted in the treatments without nitrogen and phosphous fertilizers. When phosphous and potassium fertilizers employ a certain amount, the increase of nitrogen fertilizer can increase soil nitrogen and phosphorus content of soil available, but the available P and K in soil decreased with nitrogen rate increasing. The combined application of nitrogen phosphous and potassium fertilizer (OPT) has maintained a better handle rotation around the soil nutrient content with the fertilizer nutrients changing in the soil before and after the rotation.2. The results showed that the nitrogen treatments nitrate-nitrogen content to be higher than nitrogen treatments and increases the soil nitrate-nitrogen content along with nitrogen rate also to increase along with it. Imbalanced applies fertilizer (Con,OPT-P and OPT-K) and N300 and N240 treatments processing soil nitrate-nitrogen content is obviously higher than optimized treatment,particularly N300 and N240 treatments 60-90cm and the 90-120cm soil layer nitrate-nitrogen content comparison the optimization treatment obvious add,explained that optimized treatment can reduce the soil nitrate-nitrogen effectively the drip washing, and improve nitrogen use efficiency.3. The results indicated that the crop yields of nitrogen phosphous and potassium treatments leaf area index and chlorophyll content are obviously higher than those of the unbalanced fertilization treatment. In the application of certain P and K fertilizers,winter wheat and summer corn leaf area index and chlorophyll content has increased with the increased use of nitrogen fertilizer. But when levels of nitrogen exceed Optimization (180 kg/hm~2), winter wheat and summer corn leaf area index and chlorophyll content and optimized remain at the same level.4. The results showed that different treatments can significantly promote the growth of crops and increase the accumulation of aboveground biomass. The accumulation of aboveground biomass in Optimization treatment was significantly higher than in imbalanced fertilization treatment. The crops aboveground biomass increased with the amount of nitrogen fertilizer. The optimization and N240,N300 in all treatments have the largest aboveground biomass,and there was no significant difference in the three treatments.5. Different treatments have a significant effect on the yield and its composing factors and economic benefits. The results showed that yield composing factors of the Optimization treatment compared better with its of imbalanced fertilization treatments(Con, OPT-N, OPT-P, OPT-K). That is the former compared with the latter has been increased. Yield and economic benefits of the Optimization treatment were higher than those of imbalanced fertilization treatment. In Winter wheat treatments, yield and economic benefits per hectare in the Optimization treatment respectively could achieve 3546. 6 kg and 4656. 73 yuan,representing an increase 1132.6kg and 1105.51yuan compared with OPT-N treatment, representing an increase 648. 2kg and 854.16 yuan compared with OPT-P treatment, representing increased 242. 6kg and 290.41 yuan compared with OPT-K treatment, representing an increasekg and 289.77 yuan compared with Con treatment. In summer maize treatments, yield and economic benefits per hectare in the Optimization treatment respectively could achieve 6196.1kg and 8300 yuan, representing an increase 1243.44kg and 1118.99yuan compared with OPT-N treatment,representing an increase 459.52 kg and 666.3 yuan compared with OPT-P treatment, representing an increase 165.11kg and 239.41 yuan compared with OPT-K treatment, representing an increase 198.89kg and 403.3 yuan compared with Con treatment. With the increase amount of nitrogen fertilizer application, yield and economic benefits for winter wheat and summer corn was increased, but nitrogen fertilizer application more than of 180kg/ha, yield and economic benefits of treatments(N180, N240 and N300) were not significantly different, yield and economic benefits of N300 treatment than those of N240 treatment has declined.6. the results showed that Whether winter wheat or summer maize,the recovery efficiency of applied N,physiological efficiency of applied N,agronomy efficiency of applied Nand partial factor productivity from applied Nwas generally decreased with Nrate increasing. Optimization treatment nitrogen use efficiency was higher than imbalance fertilization treatment, the results showed that nitrogen use efficiency of the nitrogen phosphous and potassium reasonable combined application treatment was beneficial to improve nitrogen use efficiency7. Analyzing crop yield, economically net income and environmental aspects, compared with other treatments, optimized N-fertilization is the best model in our experiment and is worth popularizing in yongji. |
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