不同土壤添加剂对太湖流域水稻产量及氮磷养分利用的影响

Effects of different soil additives on rice yield and utilization of nitrogen and phosphorus in the Tai Lake region

为探讨土壤添加剂对太湖流域稻田面源污染的控制效果,选用生物炭、微生物菌肥和硝化抑制剂三种土壤添加剂作为供试材料,通过盆栽试验研究其单独施用及两两组合配施对水稻生长、产量、肥期田面水养分动态、养分吸收利用以及土壤肥力等的影响。研究结果表明:各添加剂处理均可保证水稻的正常生长,并表现出增产效果,生物炭添加处理、微生物菌肥与生物炭组合处理及生物炭与硝化抑制剂组合处理水稻产量分别较施肥对照处理提高了57.5%、66.1%和45.4%。各添加剂的施用对植株吸氮量的影响不显著,仅微生物菌肥与生物炭组合处理显著提高了氮回收效率,但是所有添加剂处理均显著提高了氮肥农学利用效率和生理效率,生物炭处理和微生物菌肥与生物炭组合处理效果最佳,各添加剂处理对水稻的磷素吸收利用没有影响。微生物菌肥单施处理提高了水稻基肥期田面水氮浓度,而其他处理则表现为显著降低,特别是与生物炭的组合处理;蘖肥期各处理对田面水氮浓度影响不大;穗肥期除生物碳与菌肥配施处理外,其他各添加剂处理均显著提高了田面水氮浓度。添加剂处理还略微增加了基肥期和穗肥期的田面水总磷浓度,但差异不显著。各添加剂处理对收获后土壤肥力指标没有影响。综合产量、氮肥吸收以及田面水氮磷流失风险,微生物菌肥与生物炭组合处理可促进水稻生长,显著提高水稻产量,有效降低水稻生育前期氮素流失风险,缩短养分流失风险期,并能维持土壤肥力,值得应用于太湖流域稻田的面源污染控制上。

Agricultural nonpoint source pollution has been one of the main causes of water eutrophication in the Tai Lake region. Biochar,microbial agents, and nitrification inhibitors, individually or in combination, were added to the paddy soil in this study in order to evaluate the effect of different soil additives on paddy nonpoint pollution control. The effects on rice growth and yield, N and P uptake by rice, N and P concentration in surface water, and soil nutrient status after harvest were investigated. The results showed that all the soil additives ensured rice growth and promoted yield, with biochar, biochar combined with microbial agents, or nitrification inhibitors significantly increas-ing rice yield by 57.5%, 66.1%, and 45.4%, respectively, compared with the treatment without soil additive. The biochar combined with microbial agents treatment significantly increased the plant N uptake and N recovery efficiency, but all the treatments with additives significantly improved the agronomy efficiency and physiological efficiency of N, with the biochar treatment and the biochar and microbial agent combination treatment performing the best. Compared to the treatment without additives, the treatment with microbial agents increased the total N concentration in surface water, whereas other treatments, especially the treatment combining biochar with other additives, significantly decreased the total N concentration in surface water for the basal fertilizer stage. At the panicle fertilizer stage, all treatments with additives,except the combination treatment of biochar and microbial agents, obviously increased the N concentration of surface water. The total P concentration of surface water increased slightly at the basal and panicle fertilizer stages, but the difference was not significant when compared with the treatment without additives. No significant difference was observed in the soil fertility between the treatments with and without soil additives. For comprehensive consideration of yield, nitrogen use efficiency, and nutrient loss risk of surface water, the treatment combining microbial agents with biochar was best for maintaining the high paddy yield and reducing nutrient loss risk during the early fertilization period of the paddy. Therefore, this combination treatment is promising for controlling nonpoint source pollution in the Tai Lake region.