| Organic Activator (OA) and Inorganic Activator (IA) were selected, and sixteen kinds of different Rock Phosphate (RP) were activated with the two activators to make Modified Rock Phosphate (MRP)– Organic Modified Rock Phosphate (OMRP) and Inorganic Modified Rock Phosphate (IMRP). The grade and chemical components of RP and the available P of RP and MRP were analyzed to prove up the relationship of activation effect and chemical components, and to discuss the mechanisms in the activation process farther based on it. Meanwhile, six kinds of RP and MRP of them were selected to take pot experiment under the controlled conditions, in order to understand biological effects of MRP in calcareous soil and the possible mechanisms of increase production. Furthermore, Jm170 strain - Phosphate Solubilizing Bacteria (PSB) with high P-dissolving capability and effect on plant growth was selected, the P-dissolving effect to four kinds of RP were studied under the condition of shaking flask experiment, in order to understand the relationship of the phosphate-dissolving effect and the grade and chemical components of RP, compare the activation effect of activators with the P-dissolving effect of Jm170 and understand the interaction between activators and Jm170 strian to RP. All of the results can be the base for the reasonable utilization of numbered P resources. The main results are as follows:1 OA and IA markedly increase the content of available P of RP which were tested, and the activation effect of IA was better than OA; the activation effect of OA and IA to different RP was significantly different, the main reason is that the effect of the grade and chemical components of RP to activation effect of OA and IA was different: The activation effect of OA was influenced by the grade and chemical components of RP, they were: MgO/P2O5(Total P)>grade>CaO>SiO2/P2O5>R2O3(Fe2O3+Al2O3)/P2O5. There were markedly positive correlation between the activation effect and the ratios of MgO, SiO2 and R2O3 to P2O5, and markedly negative correlation between the activation effect and the content of P2O5 and CaO. That is to say, the higher the ratios of MgO, SiO2 and R2O3 to P2O5, the lower the content of P2O5 and CaO, the more the activation effect of OA. It shows that OA fits the medium and low-grade phosphorus with the higher ratios of MgO, SiO2 and R2O3 to P2O5, which don't use for wet-process phosphoric acid because they can't satisfy the raw material.The activation effect of IA was influenced by the grade and chemical components of RP, they were: Citric available P rate>MgO>CaO /P2O5>Available P. There were markedly positive correlation between the activation effect and the content of MgO, the ratio of CaO to P2O5, and markedly negative correlation between the activation effect and citric available P rate, the content of available P. That is to say, the higher the content of MgO and the ratio of CaO to P2O5, the lower citric available P rate and the content of available P, the more the activation effect of IA. It shows that IA fits the medium and low-grade phosphorus with the higher MgO content and the ratio of CaO to P2O5, the lower citric available P rate.2 The biological effects of MRP were studied through soil cultivation method. The results indicated that:MRP had the obvious fertilizer effect in calcareous soil, the effect of partial treatment were outstanding, even more than SP. Compared with CK and RP, MRP was beneficial to growth of corn seedlings. MRP significantly increased not only the flag leaf area and the dry matter of shoot and total biomass, but P utilization efficiency of root and N uptake of shoot and root, especially N uptake of root. Biological availability of MRP did not equal with Chemical availability. It shows that it is noncorrelation between chemical availability and biological availability, it is indispensable to search new method for the right solution to the problem. 3 This paper studied the P-dissolving capability of Jm170 strain to four kinds of different RP and MRP. The results indicated that:Jm170 strain showed high P-dissolving capability to four kinds of RP, the P- dissolving effect was influenced by the grade and chemical components of RP. The higher the grade and the content of CaO, the lower the content of Fe2O3 and Al2O3, the more the P-dissolving capability. It shows that the P-dissolving effect of PSB is different from the activation effect of activator, PSB fits the high-grade phosphorus with the lower content of Fe2O3 and Al2O3.Under the condition of shaking flask cultivation, no interaction was found between Jm170 strain and activators which were tested. To a certain extent, the activators restrained the P-dissolving capability of Jm170strain to RP.
|
PDF Full Text Request