The Effects Of Modified Phosphate Rock On Spring Wheat In Calcareous Soil And Their Mechanism

Highly Surface-activated Minerals (HSAM, inorganic activator) and organic activator were selected, and four different origin and quality phosphate rock (PR) were activated with the two activators to make modified phosphate rock (MPR). Structure of the MPR were analyzed using IR analyze technique , while the available P, water soluble P and oxide of PR and MPR were analyzed to understand the structure changes from PR to MPR, and the possible mechanisms in the activation process. Meanwhile, biological effects of the MPR were studied using different spring wheat varieties in calcareous soil. All of the results can be the base for the fertilization of MPR in calcareous soil. The main contents and results include: PR was activated with inorganic activator through different methods and MPR was made to find the optimum method for PR activation. The results of soil cultivation experiment using corn seedlings in calcareous soil showed that, there is significant difference in the growth, P uptake and soil available P content between different making methods of MPR, in which the fourth method is the best. Therefore, the fourth method is the best making method for the PR activation with inorganic activator in the study condition. The structures of four PR and eight MPR were analyzed using IR technique. The IR spectrogram results showed that the structure of PR were changed significantly after activation. Compared with normal PR, the characteristic spectrogram of H2P04-and HPO42-were appeared, which indicated that the activation improved the release of available P in PR. There is difference in the structure change degree among origin and quality of the four PRs. PRⅢshowed the best activation effect in the four PR both with inorganic and organic activator, PRⅣis better, PRⅣis the worst.　The available P, water soluble P and oxide in PR and MPR were analyzed to understand the relatives between activation effect of PR and the agricultural properties of PR. The results showed that: (1) The activation effects of PR have the positive relative with the quality of PR both with inorganic activation and organic activation. (2) The effect direction of the inorganic activator and organic activator is different. Inorganic activator is beneficial to the increase of available P, and organic activator is beneficial to the increase of water soluble P. (3) In the four PRs, MgO content of PRⅢis the highest and the total oxide content is the lowest. This is the possible reason for the best effect of MPRⅢbecause of the higher MgO content, the higher solubility of PR. The biological effects of the MPR in calcareous soil were studied through soil cultivation method. The results showed that : MPR can significantly increase the dry matter of shoot and total biomass, P uptake and N uptake, and soil available P content, which indicate that MPR not only can be beneficial to the growth of the spring wheat, but also avail the P and N uptake of spring wheat. Compared with PR, MPR can increase the DM of total biomass from 5.44% to 64.84%,P uptake from 8.56% to 101.25%, N uptake from 13.18% to 46.59%, and correspond SP to 67.92%-108.59%,27.51%-85.18%,52.12%-91.20% respectively. Therefore, MPR has the obvious fertilizer effect in calcareous soil. The effect of different PR and MPR on different spring wheat varieties is significantly different. The effect of organic activator is better than inorganic activator. P uptake and utilization efficiency is different among different spring wheat varieties. The variety of 038014 showed higher biomass, P uptake, P utilization efficiency and higher level soil available P in the four varieties. Therefore, 038014 can be a higher P efficient variety. But the variety of Yongliang 4 showed the lowest P uptake and utilization efficiency to the insoluble P in PR and MPR in the four varieties. Wuchun121 also showed higher P efficient to PR and MPR,and its ability of P uptake and utilization is only lower than 038014. While the variety of Ganchun 20 showed higher P uptake to PR and MPR, but lower utilization efficiency. Therefore, there is significant difference in different spring wheat varieties to P in PR and MPR, which presents the basis for the research of phisiological mechanism of plant insoluble P utilization, and the possibility for the genetic improvement of spring wheat varieties.