太湖地区高产高效措施下水稻氮淋溶和径流损失的研究

在太湖地区,采用田间小区试验,研究了高产高效措施对水稻季氮素淋溶和径流损失的影响。结果发现,水稻季总氮(TN)和可溶性有机氮(DON)淋溶随土壤深度的增加而降低,不同深度下氮淋溶形态不同。60 cm处DON浓度要高于硝氮(NO–3-N)和铵氮(NH4+-N),占TN的40.5%~58.9%;80 cm处NO–3-N的浓度要高于DON和NH4+-N,占TN的52.3%~60.7%。相比当地常规处理,高产高效处理的NO–3-N淋溶减少了51.7%~54.7%,仅占施肥的0.5%~0.9%。在氮的径流损失中,NH4+-N占TN的48.1%~56.4%,而NO–3-N占TN的36%~53%。试验中氮素通过径流途径的损失量很低,仅占施肥的0.34%~0.59%。高产高效处理的氮淋溶和径流损失之和分别为10.59 kg/hm2和10.18 kg/hm2,低于常规处理(13.41 kg/hm2)。除此之外,高产高效措施的作物产量(11.14~12.22 t/hm2)和农学利用率(11.8~12.5 kg/kg)均显著高于当地常规处理。水稻收获后,高产高效处理的土壤TN相比常规处理提高了6.8%~8.1%,有机质含量提高了8.6%~9.2%。综上,高产高效措施不仅有利于作物产量和氮素利用率的提高,还削弱了氮在土-水界面的迁移,是作物增产且环境友好型的有效措施。

Study on N Leaching and Runoff Under Integrated High Yield and High Efficiency Practices in Paddy Fields of Taihu Lake Region

The influence of integrated practices for high yield and high efficiency on nitrogen (N) leaching and runoff under rice-wheat rotation was researched with field plot experiment in Taihu Lake Region. It was found that leaching of total nitrogen (TN) and organic N (DON) declined with the increasing of soil depth and the forms of N leaching changed with soil depth. DON in the percolation water at 60 cm depth, which accounting for 40.5%-58.9% of TN, was higher than NO3--N and NH4+-N. NO3--N in the percolation water at 80 cm was higher than DON and NH4+-N and accounted for 51.7%-54.7% of TN. NH4+-N loss was the main form of N runoff, and accounted for 48.1%-56.4% of TN. However, N losses via runoff were indistinctive, only accounting for 0.3-0.6% of fertilizer application. The total loss of N leaching and runoff in the high yield an high efficiency treatments was 10.59 and 10.18 kg N/ha, which was lower than in the current treatment with a value of 13.41 kg N/ha. The rice yield in high yield and high efficiency treatments was 11.14-12.22 t/hm2, and the agronomic efficiency reached 11.8-12.5 kg/kg, which were significantly higher than in the traditional treatment. After harvest, the soil TN content increased by 6.8%-8.% and soil organic matter by 8.6%-9.2% in high yield and high efficiency treatmetns comapared to traditional treatment. In short, high yield and high efficiency practices increased crop yield and N use efficiency, weaken the migration of N through water to soil and do benefits to both crop yield and environment.