| With much more emphases having been put on cases of environment and resource recently, the studies on transfer rule for nutrient and pollutant in agricultural area between soil and water is getting more and more important. As the readily losing nutritional element, P is the studying hot in the field of environmental science. Quite a few researches on P transfer have been focused on red soil, brown soil, black soil and so on, but the studies on purple soil in south-west China is infrequent. To find out the rule of P transfer in purple soil agricultural area, This work is carried out in purple soil agricultural ecology system institution in Yanting CERN. We have designed different testing spots, which including different cultivate manner sections (1.Bridge tillage, BT; 2. Flat tillage, FT; 3.Down slope tillage, DT;), paddy filed, well and pond. We collect runoff from different cultivate manner sections and water in paddy field, well, pond termly from Apr.2002 to Apr 2003. we also get a rainfall samples in Aug .2002. After analyzing different forms of P (Total P, Dissolved P, ortho-P) in the samples, the transfer rules of P in runoff and underground leakage from different cultivate manners have been opened out. We account burthen of P load by NFS (none point source ) ways in the study area. The preliminary conclusions about the works set out as follows:(1) After the rainfall runoff analyzing showed: there is no utter negative correlation between loading phosphorus in runoff and time. In this area, The highest load of P-pollutants is paddy filed. Among all kinds of P-pollutants, the content of dissolve phosphorus and ortho-phosphrous in runoff are beyond watchful concentration for eutrophication, the concentration of ortho-phosphrous in runoff is fluctuating around 0.06mg/L. When taking measures to resolve NPSP (none point source cultivate manner pollution) in the area , we should pay attention to the load of dissolve phosphorus and ortho-phosphrous.(2) P load from cropland mostly is in the form of PP(Particulate P). The amount of TP(total Phosphorus) isn't high, but the concentration of DP and ortho-phosphrous should be noticed, because the bimestrial rain from June to July in 2002, all forms of P of the sample gotten in 4th, Jul 2002 are head and shoulders above other samples. After comparing the three different cultivate manner sections, we find some laws: the load of TP in runoff is diverse by cultivate manner sections, in shortime rain theamount of TP load with runoff is FT>DT>BT :, while in longtime rain is DT,BT>FT.(3) After analyzing surface water sample from different ponds, we found P in the ponds which mainly immit by runoff from cropland and paddy-field are higher than forest ones. But in low water times, the great-mount of P release from sludge, which make the P concentration in surface water much higher than plentiful rain days. It can be shown that the potential pollute caused by P releasing from endogenesis is greatly. We should attach importance to P from endogenesis.(4) Through monitor water samples from well periodicly, we find that the P has less influence on ground water, but if there is catchments circumambience the well, it will be pollute the water in well.(5) The contribution of DP to TP is predominated over other forms of P, Which occupancies share of 44.1%. The PP occupancies share of 36%, the contribution of PO4-P and OP are 16.7%, 11.7% respectively. So we can say that P load from the watershed is mainly hi the form of DP.(6) To a certain extent, There is liner relation between P concentration and runoff amount. But there isn't utter negative correlation between loading phosphorus concentration and runoff amount., when the runoff amount increasing to a given quantum, the concentration of P in the runoff will decrease. It can be designed as parabola, the correlative coefficient R2=0.9871. Just as the relation between runoff and P concentration, there is the resemble relation between leakage P and rainfall, th...
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