红壤植蔗区施磷的淋溶风险评估

摘要

[目的]研究红壤地区施用磷肥对甘蔗吸收磷的影响及进行磷淋溶流失风险评估,为蔗区科学合理施用磷肥提供参考依据.[方法]田间试验设不同施磷量处理,测定蔗茎和蔗叶产量及磷素养分含量、土壤Olsen-P含量等指标;室内试验按种植区主汛期的年均降雨量分批次进行模拟降雨,分别收集易溶性和枸溶性磷肥淋溶液,分析磷浓度和总量.[结果]施磷处理比不施磷处理的蔗茎、地上部生物量分别提高了3.0％～8.3％和2.4％～7.1％,其中均为150 kg P205/hm2处理增产最高;施磷比不施磷处理的地上部的磷素吸收量提高16.1％～30.1％,大于150 kg P2O5/hm2施磷量处理间,磷素吸收量差异不显著;随施磷量的增加,土壤CaC1,-P和Olsen-P含量分别提高35.9％～778.6％和25.8％～230.2％;淋溶液磷的浓度和总量均随土壤有效磷含量的增加而增加,增幅达26.38％～53.68％和23.67％～49.70％,且处理间增幅差异显著.施用易溶性磷肥的淋溶液中磷浓度比枸溶性磷肥高10.44％.[结论]施磷量为150 kg P205/hm2对红壤地区甘蔗生长较好,但可使土壤淋溶液总磷浓度的提高0.03 ～0.05 mg/L,施用易溶性磷肥比枸溶性磷肥淋溶液中磷浓度高10.44％,磷淋溶风险更大.%[Objective] To provide a reference for the scientific and rational application of phosphate fertilizer in sugarcane field,the effects of phosphate fertilizer application on the phosphorus uptake of sugarcane in red soil area were investigated and the risk of phosphorus leaching loss was evaluated.[Method] The field experiment was conducted with different phosphorus application rates,measured the yield of sugarcane stalks and leaves,and analyzed phosphorus nutrient content.After the sugarcane was harvested,the content of soil Olsen-P in each phosphorus level was determined,and the regression equation of phosphorus application rate and Olsen-P content in soil was obtained.Then,laboratory experiments were conducted to simulate the rainfall in batches according to the annual average rainfall in the main flood season of the planting area.Separately collected leaching solution by using soluble phosphate and citric acid soluble phosphate,analyzed its phosphorus concentration and total amount.[Result]The biomass of sugarcane and aboveground biomass increased by 3.0 ％-8.3 ％ and 2.4 ％-7.1％,respectively,compared with those without phosphorus treatment,and all of them were 150 kg P2O5/hm2 with the highest yield increase.Phosphorus uptake with phosphorus treatment was 16.1％-30.1％ higher than that of non-phosphorus treatment,and there was no significant difference in phosphorus absorption between treatments that phosphorus was more than 150 kg P2O5/hm2.With the increase of phosphorus application,the content of CaCl2-P and Olsen-P in soil increased by 35.9 ％-778.6 ％ and 25.8 ％-230.2 ％,respectively.The concentration and total amount of phosphorus in leaching solution increased with the increase of soil available phosphorus content.The increase was 26.38 ％-53.68 ％ and 23.67 ％-49.70 ％,and there were significant differences between the treatments.The concentration of phosphorus in leachate which applied the soluble phosphate fertilizer was 10.44 ％ higher than that of the citric acid soluble phosphate fertilizer.[Conclusion] 150 kg P2O5/hm2 was the most suitable phosphorus fertilizer for sugarcane,and it could increase phosphorus concentration in leachate by 0.03-0.05 mg/L The risk of phosphorus leaching was greater by applying the soluble phosphate fertilizer than the citric acid soluble phosphate fertilizer.