不同材料对河套灌区土壤磷素淋溶分布的影响

Impact of Soil Amended with Different Materials on Phosphorus Leaching in Hetao Irrigation District

【目的】进一步加强对内蒙古河套灌区农业化肥面源污染进行监测和探讨治理措施。【方法】采用大田土壤淋溶试验,分析了河套灌区农田在活性炭、膨润土、生物菌肥、颗粒有机肥、聚丙烯酰胺、聚丙烯酸钾、腐殖酸、缓控肥8种材料处理对玉米生育期内土壤淋溶液中总磷和可溶性磷动态特征变化的影响。【结果】与常规处理相比,膨润土、活性炭、聚丙烯酸钾、聚丙烯酰胺处理土壤淋溶液总磷质量浓度平均降低24.76%、21.32%、18.36%、17.31%;可溶性磷质量浓度平均降低32.47%、31.15%、28.45%、22.82%;与常规处理相比,生物菌肥、腐殖酸、缓控肥处理土壤水TP和SP质量浓度降低不太明显,颗粒有机肥可增加土壤水中磷素量;作物累积吸磷量随施肥量的增加而增加,但增加幅度较小。磷素一般主要集中在0～40 cm土壤淋溶层,在40 cm以下淋溶层,磷素量随淋溶层增加而基本保持不变。在土壤水中可溶性磷所占的比例较大,达到土壤水淋溶液中TP的47.6%～82.1%,平均值为67.8%,可溶性磷为土壤水磷素主要存在形态。【结论】8种材料均在不同程度上对土壤淋溶液总磷和可溶性磷具有影响,其中以膨润土、活性炭、聚丙烯酸钾、聚丙烯酰胺效果最为明显。

[Objective] Soil amendment is a technique to improve soil productivity, and the objective of this paper is to study the change of phosphorus leaching in soil amended with different materials in Hetao Irrigation District, Inner Mongolia Hetao. [Method] The experiment was conducted in a corn field in Hetao Irrigation District with soil amended by activated carbon, bentonite, biological fertilizer, organic fertilizer, granular polyacrylamide and polyacrylic acid potassium, and humic acid fertilizer, respectively. During the experiment, we measured the change in total phosphorus （TP） and soluble phosphorus （SP）, and analyzed phosphorus leaching. [Result] Com- pared with conventional treatment, soil amended with bentonite, activated carbon, potassium polyacrylate, and polyacrylamide reduced the total soluble P by 24.76%, 21.32%, 18.36% and 17.31%, respectively; and the concentration of soluble P by 32.47%, 31.15%, 28.45% and 22.82% respectively. Compared with the conventional treat- ment, soil amended with biological fertilizer, humic acid and slow-released fertilizer did not have a noticeable im- pact on TP and SP concentration in soil water, while the soil amended with granular organic fertilizer increased phosphorus content in soil water. The phosphorus taken up by plant increased slowly with fertilizer application. Phosphorus was mainly found in the 0-40 cm soil, while below 40 cm the phosphorus content remained also unchanged. The fraction of soluble phosphorus in soil water was large, reaching 47.6% to 82.1% of TP in found soil water at an average of 67.8%. Soluble phosphorus was the main form of phosphorus in soil water. [Conclusion] The eight amending materials affect total phosphorus and soluble phosphorus differently, and compared with oth- ers, bentonite, activated carbon, potassium polyacrylate and polyacrylamide affected P more significantly after being amended with soil.