Effect Of Phosphine On Rhizosphere Soil Properties And Available Phosphorus In Paddy

Phosphorus is one of the most important nutrient elements in the crust, which occupiesan important position in plant growth and soil ecology. At present, the soil phosphorusdeficiency has become the key restriction factor in the agricultural development, especiallyfor China. Phosphine(PH3), as a gas carrier in the phosphorus cycle, must play anirreplaceable role in dealing with the problem of lack of phosphorus. Studies on theinfluences of phosphine on rizhosphere process for rice seedlings are needed to offer moreinformation for available P in paddy.Simulated experiments were conducted to explore the effect of different concentrationphosphine on rice rhizosphere properties and phosphorus availability of rice seedlings. Soilp H, Eh, temperature, Fe2+, Mn2+, Phosphatase, urease, invertase and dehydrogenase weredetermined as indicators of soil chemical properties and microorganisms. To explore theeffect of high concentrations of phosphine on the P availability of crops in paddy fields, thecontents of MBP, P fraction, and available P in soil samples from rice cultivation, the biomassof rice, the root system activity and the P content in rice seedlings were determined undervarying phosphine concentrations. The main results of the present work are as follows:(1)p H in the rhizosphere soil dropped obviously and p H in the non-rhizosphere soilkept nearly constant, while Eh in the rhizosphere and in the non-rhizosphere soil bothincreased with phosphine treatments. The effects of phosphine on Fe2+, Mn2+ had similarity,(2)Phosphine treatments had no harmful effect to the soil enzyme activity, on thecontrary, phosphine have positive influence to soil enzyme activity was observed in this study.Moreover, enzyme activities in rhizosphere soil are generally greater than those innon-rhizosphere soil, exhibiting effects of the rhizosphere.(3)a certain concentration of phosphine caused activation of soil phosphorus that wasoriginally unavailable to plants. In addition, the higher phosphine concentration was, thehigher the effective phosphorus content in the rhizosphere soil was. Therefore, the higherconcentrations of phosphine in the paddy fields might have a positive effect on P availabilityin rice plants via the effect on the rhizosphere properties.