| Phosphorus fertilizer applied to the soil will be quickly fixed by the soil for the two levels of available phosphorus,lead to utilization rate is low.In order to maintain crop yields,excessive use of phosphate fertilizers in farmland in China is very common.This leads to a large accumulation of phosphorus in the soil.Phosphorus is consisted in the soil,which is difficult to dissolve in the soil.But at the same time,the loss of phosphorus in farmland has brought a series of problems to the environment.For the fluvo-aquic soil,The amount of phosphorus and the form of phosphorus can greatly affect the capacity of soil P supply.Therefore,it is of great significance to improve the bioavailability of phosphorus and explore the complex relationship between different forms of phosphorus.In this paper,we used 31 P NMR and inorganic phosphorus fractionation method to explore the changes of inorganic phosphorus fractions and contents in the soil under long-term fertilization experiment.At the same time,to explore the effects of different fertilization treatments on soil nutrient content and crop yield were analyzed and studied.This paper attempts to explore the different fertilization on phosphorus availability and phosphorus leaching.The aim of this study is to reduce the risk of phosphorus in the water environment to provide a theoretical basis for reference.The main results are as follows:1)The content of total phosphorus and available phosphorus in soil were directly related to the application of phosphate fertilizer.The content of total phosphorus and available phosphorus in the soil of CK and NK treated of P fertilizer was basically maintained at the same level during the whole experiment.The content of total phosphorus and available phosphorus in NP,PK,NPK,OM and 1/2OM+1/2NPK treatments was significantly higher than that of CK.The content of total phosphorus and available phosphorus was increased with the increase of experimental years.The increase of available phosphorus was more obvious than that of total phosphorus in the soil.The effect of NPK treatment was better to others,and the application of organic fertilizer could be beneficial to the improvement of soil available phosphorus content.2)The accumulation of inorganic phosphorus in fluvo-aquic soil was mainly in 0-20 cm soil layer,which had little effect on 40 cm.Increase the proportion of organic fertilizer,will promote the microbial activity in the soil system and Promote the conversion of inorganic phosphorus to organic phosphorus.This indicates that the long-term application of organic fertilizer in fluvo-aquic soil can increase the phosphorus available for crop utilization without increasing the amount of phosphate fertilizer applied.3)In the calcareous soil,phosphorus mainly existed in the form of orthophosphate and phosphoric acid.The application of chemical fertilizer will increased the content of Orthophosphate in soil,but had little effect on the increase of the content of soil phosphate.On this basis,the application of organic fertilizer could increase the content of phosphate.31 PNMR technology is easy to cause the error of high organic phosphorus content.For this kinds of soils with high organic matter content and low metal ion content,the results are more accurate.4)Long-term application of organic fertilizer in the appropriate temperature of the crop yield is better.The effect of Potassium Fertilizer on crop yield was small in the short term.The effect of phosphate fertilizer on crop yield is better than that of nitrogen fertilizer.Long-term no fertilization treatment,There was no significant difference in inorganic phosphorus content.Long-term application of organic manure(OM)compared with the application of chemical fertilizers(NPK,1 / 2OM + 1 / 2NPK)can significantly increase soil available phosphorus source content. |
PDF Full Text Request