不同施肥方式下洱海流域水稻-大蒜轮作体系氮磷径流损失研究

为寻找洱海流域水稻-大蒜轮作农田的合理施肥方式,以减少氮磷径流损失,研究了不同施肥方式对水稻-大蒜产量和地表径流氮磷损失的影响。结果表明:在等量氮肥输入的条件下,与习惯施肥(CF)相比,50%有机-无机配施(50%O)、100%缓释掺混肥(100%BB)处理下水稻-大蒜产量无显著差异,而100%有机肥处理(100%O)水稻-大蒜产量显著降低。CF和100%BB处理水稻氮(磷)肥农学利用效率高于其他处理,CF和50%O处理大蒜氮肥农学利用效率显著高于其他处理,100%BB处理大蒜磷肥农学利用效率最高。与CF相比,水稻季100%BB处理径流总氮、总磷流失量和氮、磷损失率最低,总氮流失量和氮损失率分别降低55.34%和86.95%,总磷流失量和磷损失率分别降低70.14%和89.07%。径流中硝态氮和铵态氮流失量之和占总氮流失量的13.19%~21.69%,磷流失以可溶态速效磷为主,占总磷流失量的83.25%~90.93%。研究表明,100%BB处理方式能够在保证作物产量的同时显著降低氮磷径流损失,是较为理想的施肥方式。

Nitrogen and phosphorus runoff losses during rice-garlic rotation in Erhai Lake basin under different fertilization methods

Rice-garlic rotation is the most common planting pattern in the Erhai Lake basin. Nitrogen and phosphorus runoff losses under conventional fertilization methods are the main factors that contribute to water eutrophication in Erhai Lake. In this experiment, the effects of different fertilization methods on the yields of rice and garlic and the surface runoff losses of soil nitrogen and phosphorus were studied. The results showed that when nitrogen fertilizer input amount was equal, the yields of rice and garlic under the treatments of 50% organic-inorganic fertilizer(50%O) and 100% slow-release bulk blending fertilizer(100%BB) were not significantly different from those of conventional fertilization(CF), whereas those of 100% organic fertilizer(100%O) treatment were significantly lower. The agronomic efficiencies of nitrogen and phosphorus for rice under CF and 50%O treatments were significantly higher than those of other treatments. The agronomic nitrogen use efficiencies for garlic under the addition of CF and 50%O were significantly higher than those under other treatments, but the highest agronomic phosphorus use efficiency for garlic was obtained under 100%BB treatment. During the rice season, the runoff loss amounts and loss rates of nitrogen and phosphorus under 100%BB treatment were the lowest, resulting in 55.34% and 86.95% reduction, respectively, for nitrogen, and 70.14% and 89.07% reduction, respectively, for phosphorus, compared with CF treatment. The runoff losses of nitrate nitrogen and ammonium nitrogen were 13.19%~21.69% of that of total nitrogen losses, whereas 83.25%~90.93% of total phosphorus losses were soluble phosphorus.