【作者】 项大力；

【导师】 杨学云；

【作者基本信息】 西北农林科技大学 ， 农业环境保护与食品安全， 2009， 硕士

【摘要】 农业面源污染尤其是磷污染对地表水和地下水水质有潜在威胁。本论文利用长期肥料定位试验和大型渗漏池群的长期和短期试验相结合的手段,研究了关中不同肥料管理措施对土壤磷素淋失的影响,主要结论如下:1、塿土磷素可以达到120 cm土体以下,而且磷素淋失量随灌溉量的增加而增加,但高灌溉量处理降低了渗滤液中各形态磷的浓度。2、塿土即使多年不施磷肥,仍有少量磷淋出50 cm或100 cm以下土体。随磷肥施用量的增加,渗滤液中不同形态磷的浓度均有提高,在化肥和有机肥配合施用时尤其明显。在土壤Olsen-P含量达到约70 mg kg^-1时磷淋失量明显增加。合理施氮磷肥可减少塿土土壤水分下渗量以及随渗滤液淋失到土壤深层的磷量。3、深度小于80 cm的渗漏池,淋出土体的累积渗滤液量和累积全磷量随化学磷肥施用量的增加而减少。随土层深度的增加,不同施肥量处理累积淋失的渗滤液量和各不同形态磷累积量都有所减少,和50 cm深池相比,80 cm深池不同施肥处理的累积渗滤液量和累积全磷淋失量的衰减率相似。粘化层（77-155 cm）有效的减少了土壤渗滤液和磷素淋失。4、塿土磷素淋失的形态以可溶性全磷为主,占总淋失磷量的60%以上。土壤磷素含量较低时,淋失磷形态以可溶性有机磷为主,当土壤含磷水平高或大量施用有机肥时,钼酸盐反应磷淋出比率有所提高,而颗粒磷份额受施肥水平影响不大。5、长期不同施肥管理措施下,无论施化学肥（磷）料还是化肥有机肥配施处理都不同程度提高了土壤耕层全磷和速效磷的含量;不均衡施肥（PK）和有机无机肥配合施肥同时也明显地提高了土壤剖面中全磷、有效磷含量、有机磷含量以及碳酸氢钠溶液提取的有机磷含量。尤其是在大量施用化肥加有机肥及不均衡施肥（PK）,可显著提高0-80 cm土层有机磷的含量,有机磷是土壤磷素向下移动的很重要的形态。更多还原

【Abstract】 Agricultural non-point source pollution, especially the phosphorus from farmland, can exert a potential threat to the quality of surface waters and groundwater. The impacts of arable land management regimes on phosphorus leaching losses in a loess soil were examined by the agent of long-term fertilizer experiment and short term experiment on monolith lysimeter. The results were as follow:The losses of phosphorus leaching could be detected down to 120 cm soil depth, and the cumulative phosphorus in the leachates increased with increasing of irrigation rates, whereas the concentrations of various phosphorus fractions in leachates was low in high irrigation treatments.Few amount of phosphorus was detected in the leachates down to 50 cm or 100 cm soil depths for treatments those receiving no fertilizer for many years. The concentrations of various phosphorus fractions in the leachates increased with increasing of rates of phosphate fertilizers in the leachates, especially in the treatments receiving inorganic phosphatic fertilizer plus diary manure. The leaching losses increased substantially when soil Olsen-P reached to approximately 70 mg kg^-1. The better phosphatic fertilizer management could significantly minimize the leachates, therefore decreased the phosphorus leaching to deeper soil horizon.For lysimeters those have soil depth less that 80 cm, the cumulative leachates and total phosphorus （TP） losses were decreased with improvement of phosphatic fertilizer rates. The cumulative amouts of leachates and contents of phosphorus fractions in them were reduced with the increasing of soil depth under various fertilizer treatments. The decreased ratios of cumulative leachates were similar to those of various phosphorus fractions caused by 80 cm soil depth compared with 50 cm soil depth under all fertilizer treatments. The exist of argillic layer （77-155 cm） in the lossial soil can significantly imped the downward movement of soil water, thus the leaching losses of phosphorus.Phosphorus in the leachates were observed mainly in the form of dissolved phosphorus, the proportions of total dissolved phosphorus （TDP） to total phosphorus were higher than 60%. Of the total dissolved phosphorus, the concentrations of dissolved organic phosphorus （DOP） were higher than molybdate reactive phosphorus （MRP） where the soil phosphorus level were lower, while MRP were higher than DOP where the soil phosphorus level were relatively higher or receiving the high rates of organic manure. Whereas ratios of PP to TP were remain in the lower level.The contents of soil total phosphorus and Olsen-P in ploughed layer were increased more or less on treatments receiving annual application of P containing fertilizers for 18 years. Meanwhile the contents of total phosphorus, Olsen-P, organic phosphorus as well as the NaHCO₃ extractable organic phosphorus in soil profiles down to 100 cm were also significantly increased on treatments given PK or inorganic phosphatic fertilizer plus diary manure. Organic phosphorus is an important form in downward movement of phosphorus.更多还原