Inorganic Phosphorus Formation,Transferation And Availability Of Grassland In Western Heilongjiang Province

Grassland experiment and pot experiment were carried out to study inorganic phosphorus formation, transformation and availability in grassland of western Heilongjiang province. The objective of this study was to resolve the deficiency of phosphorus in the grassland and improve the state of phosphorus in the continuous system: soil-grass-milk cow. The results showed as foliows: Jiang BaifnandGuYichu Fractionation of inorganic soil phosphorus was used to divide inorganic soil phosphorus of four meadow soils into six parts. In them, Ca (Ca2 + Ca8+Ca10) was Predominant and Ca10 occupied the largest percentage of it. The phosphorus fertilization significantly increased the content of inorganic soil phosphorus, especially for Can and Al. There was a certain relation of growth and decline between one fraction of inorganic soil phosphorus and another. When inorganic phosphorus fertilizer was added to grassland, it mainly transferred into Ca8. During the grass and corn5s vigorous growth period, Ca2 was so easily absorbed by the grass and corn that it rapidly decreased, which caused that other fractions of inorganic soil phosphorus transferred into Ca2. However, high content of Soda lime obviously affected transformation of inorganic soil phosphorus. When pH>9. 5, Olsen桺 and Ca2 was rapidly raised. Ca2 was the most available to the grass, and Ca8 was followed. The Availability of Al and Fe was lower than Ca2 and Ca8. In addition, 0桺 and Ca10 were hardly absorbed by the grass, whose availability was very low. Soil phosphorus activator released residual phosphorus, which cased the increase of Olsen and enhanced the grass product. Soil phosphorus activator more significiantly activated inorganic soil phosphorus as well as improved the grass product when combined with phosphrus fertilizer than it was used alone. But soil phosphorus activator had little effect of activation for never fertilized grassland. Student: Zhang Haijun major: Soil Science Advisor: Professor Wang Zhaorong...