| Phosphorus is an essential plant nutrient in reclaimed water, and critical to agricultural production. Phosphorus transport and transformation both are important environment effecting factors in soil section. Plot irrigation experiments were conducted in water-lacked land of north China from September, 2007 to June, 2008, in Yang Liuqing Town, Xiqing district, Tianjin, China. And the experimental materials used was winter-wheat (Triticum aestivum), a main crop in North China. There were 4 types of irrigation water source (raw water, effluent of anaerobic tank, effluent of ecological pond and groundwater). Three types of treated swine wastewater were mixed with groundwater of 1:5 scale, and the irrigation amount was 830 m3·hm-2. We also set three irrigation amounts of anaerobic tank effluent: 830 m3·hm-2, 500 m3·hm-2 and 160 m3·hm-2. Through the experiment, we intend to find out the distribution characteristics of total phosphorus and available phosphorus in soil profile with a depth of 100 cm, the transformation characteristics of organic and inorganic soil phosphorus in 0-20cm and 20-40cm soil layers, the soil phosphorus adsorption and desorption characteristics in 0-20cm soil layer, and the different quality and yield of winter wheat between different treatments. This study was expected to provide some theoretical basises for the scientific system formulation of irrigation with livestock wastewater. The result showed that:(1) For all treatments, the content of available phosphorus and total phosphorus in soil had the similar vertical distribution in soil profile with a depth of 100 cm, while accumulated mainly in the topsoil(0-40cm soil layer), and decreased with the increase of depth. The content of available phosphorus and total phosphorus mainly varied with the depth to 40 cm under irrigation with different quotas of anaerobic effluent during the wheat growing season, it followed the sequence: high irrigation quota>middle irrigation quota >low irrigation quota. Through different growing stages of wheat, irrigation treatment with anaerobic tank effluent and ecological pond effluent had appropriate phosphorus content in topsoil, which meeted the plant's need as normal fertilizer. Irrigated with wastewater from different treatment strategies and quantity all increased the contents of total phosphorus and available phosphorus in soil, and there was a significant increase of percentage of available phosphorus in total phosphorus in various treatments after harvest. Treatment with raw swine wastewater irrigation had a significant accumulation both of available phosphorus and total phosphorus in 40-100cm soil layer. The leaching phenomenon also observed in anaerobic effluent treatments related to the increase of the irrigation quota. It was demonstrated that direct utility of swine wastewater and excessive anaerobic wastewater for irrigation should be avoided.(2) Under different irrigation treatments, the content and the proportion of Ca2-P, Ca8-P, Fe-P and Al-P increased mainly in 0-20cm soil layer. For different water sources and irrigation quotas, it followed the sequence: high irrigation quota>middle irrigation quota>low irrigation quota, raw wastewater>anaerobic effluent> ecological effluent.There was a significant increase in content of organic phosphorus in 0-20cm soil layer under irrigation treatment with different water sources, and it followed the sequence: raw wastewater>anaerobic effluent>ecological effluent. The proportion of organic phosphorus in total phosphorus increased in 20-40 cm soil layer with the increase of irrigation quota of anaerobic effluent.(3) With the evaluation of the phosphorus adsorption by linear form of the Langmuir equation it showed that different irrigation treatment with swine wastewater decreased phosphorus adsorption in different extend, the middle anaerobic effluent amount (500 m3·hm-2) treatment was the best in the soil phosphorus delivery potential.Treatments with raw wastewater irrigation and high anaerobic effluent amount irrigation showed significant phosphorus desorption abilities that enhanced the leaching risk.(4) Under different irrigation amount of anaerobic effluent, aboveground biomass, yield of winter wheat were the maximum in the middle amount (500 m3·hm-2) treatment. Irrigation with mixed water of anaerobic effluent and ecological effluent had the significant effects on increasing winter wheat aboveground biomass and yield, and the yield was the poorest in treatment of raw water irrigation for incoordination of nutrient supply which was inhibiting to the growth of crop.Take a comprehensive consideration among the factor above, we concluded that the better irrigation water amount was middle amount (500 m3·hm-2) of anaerobic effluent, and the irrigation source both were eco-pond and anaerobic effluents. On this condition, we can obtain high quality and yield of winter wheat with low risk of soil and water pollution. Considering the complex influence factors in field trail, it was suggested that long-term experiment of phosphorus transformation in irrigation water-soil systerm should be carried out in the future.
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