Phosphorus Dynamics And Characteristics Of Fractions In No-Tillage Paddy Field

Rice was one of the major Grain crops in Hubei province China. The no-tillage is an important agricultural practices to implement low-carbon economy. No-tillage had implemented promotion over large areas, but the study of paddy tillage is not perfect. This study aimed to explore P transformation in no-tillage (NT) paddy fields in the region and contribute to further optimization of no-tillage technology. Test point was located at Hubei Province Wuxue City was rape-rice rotation system in 2008 and 2009. The four treatments in this study were no-tillage+no fertilizer (NT0), conventional tillage+no fertilizer (CT0), no-tillage+compound fertilizer (NTC) and conventional tillage+ compound fertilizer (CTC) in rice (Oryza sativa L.) cultivation. This study was conducted to Mainly studied floodwater and percolation water P dynamics, leakage losses and effects of tillage and fertilizer on available phosphorus (AP), total P (TP), phosphatase activities, organic P (OP) and inorganic P (IOP) and their fractions, soil P adsorption-desorption and solid ability to fixed P et al. The results indicate:1) Reactive phosphorus (RP)/total phosphorus (TP) in Percolating water was 61.13%-92.74%, was mainly P state in percolation water; Application of P fertilizer significantly enhanced concentration of TP, dissolved P (DP) and particulate phosphorus (PP) concentrations in floodwater, in witch concentration of TP respectively came up to 9.79±0.65 mg/L和8.25±0.29 mg/L in NTC and CTC. It was the key time in one week after P application to control P losser; P fertilizer applied, floodwater DP concentrations remained 0.04 mg/L-0.1 mg/L, leakage of water RP concentration remained 0.047 mg/L-0.117 mg/L, contributed to eutrophication, indicated that this part of the environmental impact of phosphorus can not be ignored; P concentrations in floodwater is higher in NTC than CTC.2) P application significantly increased AP, TP in 0-5cm layer soil, their content decreased with layer deepened, and this tendency was more significant in NT than CT. TP content increased year by year in CT. NT did not afect AP and TP in 0-5cm layer soil, but TP is significantly higher in NT than that in CT, while AP is significantly higher in CT than that in NT. Fertilizer and tillage did not affect AP and TP in 5-20cm layer soil.3) P application restrained Soil phosphatase activity, NT promoted soil phosphatase activity. Distribution of Soil phosphatase activity in the soil was similar to AP, but phosphatase activity was not relevant to AP in surface soil, while relavant toAP in deep soil by correlation analysis.4) P fixed capacity of the soil is relatively stable, was not subject to fertilization and tillage. P application reduced the P buffering capacity and adsorption, while increased the desorption capacity, but adsorption is not a simple contrast with desorption. Buffering ability in NTO higher than that in CTO, in CTO was higher than that in CTC, in NTC was higher than that in NTO.5) Fertilizer and tillage did not affect the TOP content. The content of OP fractions and ratio of each fractions to TOP were as follows:Moderately labile organic P (MLOP)> moderately stable organic P (MROP)>highly stable organic P (HROP)> labile organic P (LOP). Fertilizer restrained the transformation of LOP. Tillage promoted the transformation of LOP. The content of IOP fractions and ratio of each forms to TIOP were as follows:Fe-P, O-P> Al-P> Ca-P; Fe-P and O-P was major existing form of IOP. CT promoted the transformation of Al-P and Fe-P. correlation analysis showed, Al-P, Fe-P, Ca-P, O-P and MLOP existed better correlation to AP in NT than that in CT.