Study On Correlation Of Measured Values Of Soil Available Phosphorus And Plant Uptake In Northern China

Phosphorus is an essential nutrient in plant growth, which is involved in the formation of many important compounds in plants. The phosphorus in plant mainly comes from the soil. According to the estimation of the national soil census, the phosphorus in 1 / 3 ~ 1 / 2 of soil is deficient in China. Therefore, timely and reasonable fertilization based on soil nutrient status is particularly important, while the testing for soil available nutrient fertilizer is a reasonable basis for the determination of reasonable fertilization. The traditional testing for soil available phosphorus is determined by conventional methods called Olsen method, which is adapted to the soil conditions widely and associated with the absorption of crops more availably. However, the traditional testing for NPK mainly executes respectively by using different extraction agents, which adapt to the elements is single; analysis costs are high; and the processes are cumbersome and can not be achieved serialization operation. And the process of analysis is slow and difficult to timely guide the production practice of agriculture. Chinese scientists have introduced some joint extraction and made a preliminary study, such as foreign soil nutrient status of systematic research method (ASI method) and Mehlich 3 method (M3 method), and AB-DTPA extraction agent.This study selected ASI method and M3 method of soil in agricultural land in northern China including the cinnamon soil, fluvo-aquic soil, brown soil and black soil for the extraction of available phosphorus, then take correlation and difference analysis with measured values of the conventional methods. Meanwhile pot experiment was carried out in order to measure the relevance between the test values of ASI method and M3 method and absorption of plants, in order to explore the application of ASI method and M3 method in the four major agricultural soils in northern China. This paper also introduces ASI method and M3 method, which are combined with Jiang Bo Pan's inorganic phosphorus in calcareous soil and makes a primary study. The major findings of this paper and conclusions are states as follows:(1) ASI method and M3 method in the determination of soil available phosphorus in the major agricultural soils in northern China including cinnamon soil, fluvo-aquic soil, brown soil and black soil; and the traditional Chinese method of determination--- Olsen method. All the results of these methods have reached a very significant positive correlation. However, in different soil types; the amount of extraction of available phosphorus is greater variation.(2) ASI method and M3 method in cinnamon soil, fluvo-aquic soil and brown soil on the measured values of soil available phosphorus and plant biomass of regression after they reached a highly significant positive correlation. ASI method and M3 method in cinnamon soil, fluvo-aquic soil and brown soil on the measured values of soil available phosphorus and plant P uptake also radiate a significant positive correlation.(3) ASI method and M3 method are not only correlate with the traditional method well but also the relevance of plants is also good, it can be applied to the major agricultural soils in northern China cinnamon soil, fluvo-aquic soil, brown soil and black soil available phosphorus determination.(4) ASI method and M3 method have extracted the plant second available phosphorus including the Ca8-P, Al-P, and Fe-P, and basically can indicate bioavailability of soil phosphorus.