Effects Of Different Management Systems On Crop Yield And Soil Fertility In Middle To Low Yielding Field

In this study, a long term winter wheat-summer maize rotation experiment was conducted since 2007 to find effects of different nutrients and cultivation management strategies on crop yield, shoot growth status, nutrients uptake, soil fertility and soil Nmin accumulation in a typical middle to low yielding level field in Quzhou, Hebei province. In this experiment, the different management strategies on field productivity increasing was studied in order to provide a theoretical basis for soil fertility and farmland productivity increasing for middle to low yielding field in the North China Plain. The main conclusions were as follows:In this experiment, there was significant yield difference among different nutrient and cultivation management strategies. The yields for Control treatment were significant lower than farmers practice (CCON and HCON) and OPT (COPT and HOPT) treatments, and had the trend of yield decreasing year by year; there were no significant yield difference between conventional farmers cultivation and nutrient management strategies with high yielding and high efficiency management strategy. With significant lower nutrients input than conventional treatments (CCON), the OPT treatments in high yielding high efficiency management strategy (HOPT) did not show yield and upland biomass decreasing. For the nutrients uptake, the control treatments (CK) significantly lower than CON and OPT treatments. The N, P and K uptake for high yielding and high efficiency management strategy was significantly higher than conventional farmers management strategy, which suggest the high yielding and high efficiency strategy could significantly increasing nutrients uptake.Compared to the initial the high yielding high efficiency management strategy significantly increased the soil fertility. There were no effects on soil pH under different management strategies, but the high yielding high efficiency management significantly reducing the soil bulk density, increasing the soil organic matter content (OM), soil total N and exchangeable K content. Compared to the conventional management strategy, the soil OM increased 2.59~2.67 g/kg, the soil total N content increased 0.11~0.17 g/kg and the soil exchangeable K increased 32.~29.3 mg/kg. And for the Olsen-P content, only the HOPT treatments significantly increased about 9.82 mg/kg.than before sowing in 2007.For the soil nitrate residual after 6 crops growing, the farmers conventional management strategy significantly increased the nitrate in 0~90cm and 90~180 cm soil layer depth, and had the trend of leaching downward. There were no significant nitrate accumulation for OPT treatments in this research. As to the soil nutrients balance, the phosphorus and potassium balance of the management system of high yield and high efficiency had surpluses, while the conventional management system had deficiencies. After 6 crops season, only the nitrogen balance value of the management system of high yield and high efficiency with optimized nutrient management systems (HOPT) was 68 kg/hm~2, and the nitrogen balance rate was 5.5%.The results showed that the high yielding and high efficiency management strategy could significantly increasing the soil productivity and soil fertility, and it has the potential to be used in middle to low yielding field.