Studies On Maize Rhizosphere Environment And Phosphorus Usage

In this paper , on basis of water culter and model test, rezhobox experiment was conducted to deal mainly with effect of P level on the root morphorlogical, maize rhizosphere pH, dynamic changes of available-P, rhizosperic phoshatase and inorganic phosphorus fractionation by different genotypes of maize in chernozem, The objects are to provide theoretical basis and effective measure for effectively using phosphorus resources in soils, rationally applying phosphate fertilizer, raising phosphate fertilizer benefit, and cultivate the efficient phosphorus of genotypes maize. The major results were summarized as follows:The results of water culter indicated: in +P treament the maize growth of three genotypes is better than that of in -P treatment, such as growth quantity, root length, root volume, root density and root surface area and so on. There are many differents in three maize genotype. Synthetical compare , in the condition of lack phosphorus jidan 180's adaptablity ability is better than simi25 and benyu 9.In the treatment of -P, we can see, the Km and C_min of jidan 180 is low, the Km and C_min of simi 25 is high, the Km and C_min of benyu 9 is highest. So we can draw a conclution, the l/Km of jidan 180 is higher than that of simi 25 and benyu 9. The Km and C_min of there genotypes of maize raise with P level raised, this is means that the l/K,n of maize is low. The lmax of there genotypes of maize in -P condition is higher than that in +P condition. It may be that the length of root in +P condition is lengther than that in -P condition, reduction the velocity of absorbing phosphorus of unit root length.In the rezhobox experiment, the effect of P level on the root morphorlogical is similarity with that of water culter. The ability of root adaptability of jidan 180 isbetter than that of simi25 and benyu9. in the -P condition. So the jidanl80 is the .efficient genotypes maize.pH of there genotypes maize rhizosphere soils, pH of rhizosphere soils is lower than that of no rhizosphere soils, it is unconspicious. the pH of -P treatment is similarity with that of +P treatment perhaps there is much CaCO₃ in chernozem, amortization of pH is major, the secretion of root is little during maize seeding stage.Rhizosperic phoshatase activity of maize rhizosphere soils is higher than that of no rhizosphere soils. In general,the alkaline phoshatase activity is higher than that of acidic phoshatase activity. Phoshatase is a inductive zyme, the phoshatase of microorganism and plant is mutuality relation with strength of lack phosphorus. The incremental breadth of phoshatase of jidanl80 is bigger than that of simi25 and benyu9 in -P and +P treatment . So the ability of activating organic phosphorus is better than sirni25 and benyu9.The variation of available phosphorus:organic-P and inorganic-p leachded by Na2CO₃ are both available phosphorus in soil. With the increase of phosphate fertilizer, the amount of available phosphorus is increase. The available phosphorus in maize rhizosphere soils is depressed than that of in no rhizosphere soil , with the increase of distance to rhizosphere, first, the inorganic is increase, then, discrease, the amount of available phosphorus is biggest in no rhizosphere soils. So we can say that the exhaust extent is rhizosphere soils.Transformation of inorganic phosphorus in soil:Absorbing phosphorus mainly comes from the rhizosphere soil, compare with no rhizosphere soil, the vane ratio of Ca2-P Ca8-P Al-P, Fe-P is superior.The sequence of four form of phosphorus is Ca2-P>Al-P>Ca8-P>Fe-P, the variation of O-P and Ca₁₀-P in chernozem is uncospicious, because it could not dissolved in the secretion of root. As for maize , it is a inavailable phosphorus.The relation of available phosphorus with inorganic phosphorus: Ca₂-P, Ca₈-P, Al-P, Fe-P, O-P have conspicious mutuality relation with available phosphorus, Ca₁₀-P has not relation with available phosphorus, O-P has cospicious mutuality relation with Ca₁₀-P, Ca₈-P Al-P Fe-P have...