论文部分内容阅读
【目的】对南方赤红壤区不同施磷量下稻田土壤的磷素平衡及其潜在环境风险进行评估,为该地区合理施磷、减轻农业面源污染提供依据。【方法】采用大田定位监测试验,3个不同年份(2011 2013年)早、晚稻分别设置4个施磷水平(施磷范围为P2O50、63 81、126 162、252 324 kg/hm2,分别用P0、P1、P2、P3表示),连续3年测定早、晚稻的稻谷和稻秆产量,分析其磷养分含量,以施磷水平与水稻地上部磷素累积量间的差值表示土壤磷素表观盈余量。同时,采集施基肥和穗肥后1、2、3、5、7和9 d的田面水,测定总磷含量,利用Split-line模型对2011 2012年每造水稻收获后小区耕层土壤Olsen-P含量和所有监测时间点的田面水总磷平均浓度进行分段回归,并对二者之间的相关关系进行分段回归拟合。【结果】施磷量P2O563 81 kg/hm2的处理稻谷产量显著提高,但磷肥施用量增至2倍时,稻谷产量无明显增加,继续增至4倍时,前3造水稻稻谷的产量增加也不明显。施磷可不同程度地提高水稻地上部的磷素累积量、土壤表观磷素盈余量和Olsen-P含量,且三者均随施磷量的增加而增加。在施肥后1 3 d内无磷处理田面水总磷浓度较高,是磷素流失的高危险期;施磷量P2O563 81 kg/hm2的处理显著提高了施肥后2 d内田面水的总磷浓度,而P2O5252 324 kg/hm2的处理在监测期间田面水总磷浓度均显著高于无磷处理。Split-line模型模拟土壤Olsen-P与田面水总磷的关系,得出在本试验区土壤环境条件下,可能导致田面水中磷激增的土壤Olsen-P临界含量为19.0 mg/kg,对应的施磷量为P2O563 kg/hm2,与土壤磷素持平的施磷量一致。【结论】综合考虑水稻产量效应、土壤磷素表观平衡和磷素环境风险,在本研究区域目前的土壤环境条件下,P2O563 kg/hm2为水稻产量较高、环境风险较小的推荐施磷量。
【Objective】 The objective of this study was to evaluate the phosphorus balance and potential environmental risk of paddy soils under different phosphorus levels in the hilly region of southern China so as to provide a basis for rational phosphorus application and mitigation of agricultural non-point source pollution in the region. 【Method】 According to the field monitoring test, four phosphorus fertilizers (P2O50, 63 81, 126 162, 252 324 kg / hm2, respectively) were set up in early and late rice in three different years (2013 2013) , P1, P2 and P3). The yield of rice and rice straw in early and late rice was measured for three consecutive years. The content of phosphorus was analyzed. The difference of phosphorus content and phosphorus accumulation in aboveground part of rice was taken as the indicator of soil phosphorus View the surplus. At the same time, the surface water of base fertilizer and panicle was collected at 1, 2, 3, 5, 7 and 9 d after harvest, and the total phosphorus content was determined. Using split-line model, P content and the average concentration of total phosphorus in surface water at all monitoring time points, and the correlation between the two was fitted by piecewise regression. 【Result】 The results showed that the yield of paddy with P2O563 81 kg / hm2 was significantly increased, but the paddy yield did not increase obviously when the application of phosphate fertilizer increased to 2 times, Not obvious. Phosphorus application increased phosphorus accumulation, apparent phosphorus surplus and Olsen-P content in shoots to varying degrees, and all three increased with phosphorus application. In the first 13 days after fertilization, the total phosphorus concentration in surface water was higher, which was a high risk of phosphorus loss. The treatment with P2O563 81 kg / hm2 significantly increased total phosphorus While the total phosphorus concentration in surface water of P2O5252 324 kg / hm2 was significantly higher than that of non-phosphorus treatment during the monitoring period. Split-line model was used to simulate the relationship between Olsen-P in soil and total phosphorus in surface water. The results showed that the critical value of Olsen-P in soils was 19.0 mg / kg under the soil environmental conditions in this experimental area, The amount of phosphorus was P2O563 kg / hm2, which was the same as that of phosphorus with the same level of soil phosphorus. 【Conclusion】 Considering the effects of rice yield, apparent phosphorus balance and phosphorus environmental risk, P2O563 kg / hm2 is the recommended phosphorus application with higher yield and less environmental risk under the current soil environmental conditions in this study area the amount.