Effect Of Long-Term Application Of Organic Manure On Phosphorus Characteristics And Availability In Black Soil

Phosphorus is an essential element for plant growth, and phosphorus which was required for plant growth got from the soil and fertilizer. However, chemical phosphate fertilizer applied to soil was fixed, reducing the effective phosphorus to plants, thereby reduced the phosphate fertilizer utilization. The application of organic manure is the traditional fertilization methods of agricultural production, and the organic manure can enhance fertility of soils. The application of organic manure itself has a high phosphorus use efficiency, but also improve efficiency in the use of soil phosphorus. This article intended to discuss organic fertilizer to increase crop utilization of soil phosphorus efficiency in the angle of the various forms of phosphorus changes in the soil from long-term application of organic manure. Improve the theoretical system of the morphological changes of soil phosphorus in order to provide a theoretical basis for the production of soil management and fertilization, which has the great significance in theory and a wide range of applications in the production.In order to identify the changes of soil phosphorus in form transformation and phosphorus supply capacity after long-term application of organic manure, this study selected long-term experiment on the black soil of Northeast of China as soil test materials. Research after the long-term application of organic manure, the variation of various forms of phosphorus in black and forms of phosphorus in effectiveness, in order to clear phosphorus fertility of black soil in the evolution of features after long-term application of organic manure.(1) This study showed that long-term application of chemical fertilizer with organic manure significantly increased the total phosphorus content in the black soil, but different types of organic fertilizers increased the magnitude of phosphorus content differently.Under the conditions of different numbers of long-term application of pig manure, total phosphorus content of NPKM were54.9%,60.1%and64.3%higher than CK, respectively,42.2%,47.0%and50.8%higher than NPK. Under the conditions of different types of organic fertilizer, total phosphorus content of NPKST1、NPKST2and NPKM were only15.0%,18.3%,70.9%higher than the CK treatment, respectively,and compared to NPK treatments respectively, were only5.6%,8.6%and 56.9%higher.Long-term fertilizer with organic fertilizer can increase the available phosphorus content in black soil, due to the different types C/P of fertilizer, while the organic fertilizer was pig manure, the available phosphorus content in the black soil significantly increased. Under the conditions of different numbers of long-term application of pig manure, available phosphorus content of NPKM were10.4times,11.7times and13.5times higher than NPK treatments, and the available phosphorus content were significantly increased with the increase in the number of pig manure. The available phosphorus content of NPK treatments was3.3times than the CK treatment.When the organic manure was straw, available phosphorus content of NPKST1and NPKST2were only3.5times,4.1times higher than the CK treatment.Its contribution to the available phosphorus was basically the same as in the single application of chemical fertilizer.(2) Long-term application of organic manure significantly changed the content of inorganic phosphorus fractions in the black soil. After the application of different numbers of pig manure the relative content of inorganic phosphorus fractions were:Fe-P> Al-P> Ca8-P (Ca10-P)> Ca10-P(Ca8-P)> Ca2-P>O-P, compared to CK,NPK treatments, long-term application of chemical fertilizer and pig manure can significantly increase the absolute content and the relative content of Ca2-P, Ca8-P, Al-P and Fe-P while reducing the relative content of Ca10-P and O-P. When organic fertilizer applied were straw, the relative content of inorganic phosphorus fractions were Ca10-P> Fe-P> Al-P> Ca8-P> Ca2-P (O-P)> O-P (Ca2-P). Ca2-P, Ca8-P, Al-P, Fe-P and O-P relative content in the black soil decreased, while the relative content of Ca10-P had an upward trend.(3) Total organic phosphorus in black soil were no significant increased in long-term single chemical fertilizer. Long-term application of organic manure significantly increased the total organic phosphorus in black soil, but the increase of total organic phosphorus from straw is much less than the pig manure. After application of different numbers of pig manure,the content of organic phosphorus fractions in the black soil has increased, but the structure of the organic phosphorus fractions has not changed. The moderate labile of organic phosphorus and high-resistant organic phosphorus had the content fairly and relative percentages reached40%to53%,.They were the main component of soil organic phosphorus in black soil.Long-term fertilizer application of straw has changed the structure of the organic phosphorus fractions in the black soil, and reduced the moderate labile of organic phosphorus content of the black soil, also increased the relative content of highly resistant organic phosphorus. The moderate labile of organic phosphorus in the black soil were only33%to36%, less than processing47%of moderate labile of organic phosphorus relative content in a single chemical fertilizer. At the same time, after the application of straw, the relative content percentage of highly resistant organic phosphorus reached49%and41%, far greater than36%of the application of pig manure.(4) Long-term chemical fertilizer with pig manure can reduce the proportion of organic phosphorus in total phosphorus in the black soil, and increase inorganic phosphorus which were more easier to the absorption and utilization of plants. Organic fertilizer with high amount of straw will increase the organic phosphorus pool in the black soil, reducing inorganic phosphorus, and reduce the phosphorus capacity of soils.After long-term application of organic manure, there is a significant correlation between Olsen-P and Ca2-P, Ca8-P, Al-P and Fe-P. Ca2-P the, Ca8-P, Al-P and Fe-P can be seen as a source of available phosphorus in black soil, while the OP and Ca10-P only can be as a potential phosphorus source. After long-term application of different number of pig manure, the labile organic P, moderate resistant of organic P, highly resistant organic P and available phosphorus were significantly correlated in black soil. After long-term application of different types of organic manure, the moderate labile of organic P, moderate resistant of organic P,highly resistant organic P in the black soil and available phosphorus were significantly correlated.