不同改良剂对黄土坡耕豆地水土及氮磷流失的影响

发布时间：2018-12-06 12:00

【摘要】：土壤改良剂对改善土壤结构、减少土壤及养分流失有着重要意义。通过野外人工模拟降雨试验,研究在暴雨(100 mm/h)条件下,不同改良剂(聚丙烯酰胺PAM、羧甲基纤维素钠CMC和腐殖酸HA)对坡耕大豆地的水土和氮磷流失过程的影响。结果表明:与对照处理CK相比较,施用PAM和CMC后,均表现出减小入渗、增加径流的作用,分别较对照处理增加径流20.8%和12.1%;HA处理较CK处理径流量略微增加,但变化较小。施加改良剂对控制土壤侵蚀的效果均优于对照处理,减沙作用表现为PAMCMCHA,泥沙累积流失量分别减少34.8%、22.5%和7.9%。施用PAM和CMC在径流中后期,对铵态氮流失的抑制作用优于HA和CK;而施加改良剂对水溶性磷流失过程的影响并不明显,PAM处理的径流中,水溶性磷流失总量最大,约为对照处理的1.13倍。不同改良剂处理的土壤剖面铵态氮质量分数差异较大,但表层15 cm总体表现为PAMCMCCKHA;HA处理促进大豆根系生长,增加了土壤渗透性及铵态氮的淋溶深度。土壤有效磷主要集中在表层10 cm土壤内部,10 cm以下质量分数极低。改良剂在黄土坡耕地的施用,对减少土壤侵蚀和控制养分流失方面能够发挥一定作用,可为改良剂的合理选择和施用提供科学指导。
[Abstract]:Soil modifier is of great significance to improve soil structure and reduce soil and nutrient loss. The effects of different modifiers (polyacrylamide PAM, carboxymethyl cellulose sodium CMC and humic acid HA) on soil and water loss and nitrogen and phosphorus loss in sloping soybean fields were studied under the condition of rainstorm (100 mm/h). The results showed that compared with the control treatment CK, PAM and CMC showed the effect of reducing infiltration and increasing runoff, which increased 20.8% and 12.1%, respectively, compared with the control treatment. The runoff of HA treatment was slightly higher than that of CK treatment, but the change was small. The effect of applying the modifier on controlling soil erosion was better than that of the control treatment. The effect of sediment reduction was as follows: the cumulative loss of PAMCMCHA, sediment was reduced by 34.8% and 7.9%, respectively. Application of PAM and CMC in the middle and late stage of runoff inhibited the loss of ammonium nitrogen better than that of HA and CK;. The effect of the modifier on the water soluble phosphorus loss process was not obvious. The total amount of water soluble phosphorus loss was the largest in the runoff treated with PAM, which was about 1.13 times of that of the control treatment. The mass fraction of ammonium nitrogen in soil profile of different modifiers varied greatly, but the surface layer of 15 cm showed that PAMCMCCKHA;HA treatment promoted the growth of soybean root system and increased soil permeability and leaching depth of ammonium nitrogen. The available phosphorus in the soil was mainly concentrated in the surface soil for 10 cm, and the mass fraction below 10 cm was extremely low. The application of the modifier in the cultivated land on the loess slope can play a certain role in reducing soil erosion and controlling nutrient loss, and can provide scientific guidance for the rational selection and application of the modifier.
【作者单位】：西安理工大学西北旱区生态水利工程国家重点实验室培育基地;中国科学院水利部水土保持研究所黄土高原土壤侵蚀与旱地农业国家重点实验室;
【基金】：国家自然科学基金重点项目“黄土坡地土壤养分随地表径流流失动力机制与模拟模型”(51239009)
【分类号】：S157

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