白洋淀沿湖农田不同施氮水平对夏玉米土壤及土壤溶液硝态氮含量的影响

Effect of Different Nitrogen Rates on NO_3^--N Concentration in Soil and Soil Solution in Summer Maize Surrounding Farmland along Baiyangdian Lake

在白洋淀周边农田进行田间试验,研究了不同施氮水平对夏玉米产量及氮肥利用率、土壤硝态氮累积量和土壤溶液硝态氮含量的影响。结果表明:夏玉米在施氮量为180 kg hm-2时达到最高产量,为9766 kg hm-2,不同氮肥水平的氮肥利用率在35.5%~46.2%之间,在120 kg hm-2时的利用效率最高,达到46.2%。土壤中硝态氮累积量在玉米整个生育时期呈现先下降后升高的趋势;过量施氮的Con N、Opt N+30%处理导致硝态氮在土壤中大量累积,夏玉米季整个种植期间Con N、Opt N+30%处理土壤溶液硝态氮始终处于较高浓度,提高了硝态氮淋溶风险。综合考虑产量和环境效益,在本试验条件下,白洋淀地区夏玉米的合理施氮量应控制在N 180 kg hm-2左右。

A field experiment was carried out along Baiyangdian Lake to study effects of different nitrogen rates on summer maize production, N use efficiency, and NOa--N accumulation in soil, and NO3--N concentration in soil solution. The highest spring maize yield reached 9766 kg hm-2; the nitrogen use efficiency ranged from 35.5% to 46.2% under different rates of N fertilization, which reached the highest 120 kg hm-2 when 120 kg hm-2 was applied. The cumulative NO3--N concentration in the soil throughout the growth stages presented a wane-and-wax trend. The overuse of N resulted in large nitrate accumulation in soils. ConN and OptN＋30% had higher NO3--N concentration in the soil solution throughout the whole growth stages, and therefore enhanced the risk of nitrate leaching into the Baiyangdian water. Considering the yield and environmental effect comprehensively, a reasonable amount of nitrogen application should be controlled under the rate of N 180 kg hm-2.