不同施肥模式对春玉米产量、水分利用效率及硝态氮残留的影响

通过2年田间试验,研究了减量施氮和减氮配施不同比例控释肥对黄土旱塬春玉米产量、水分利用效率及土壤硝态氮残留量的影响,旨在为黄土高原旱作农业区提供合理的施肥管理模式。试验于2017年4月至2018年9月在黄土旱塬雨养农业区进行,供试作物为春玉米,采用半覆膜种植方式,一年一熟制。试验共设置CK(不施氮肥)、N1C1(控释尿素65%+普通尿素35%,N200kg/hm^2)、N1C2(控释尿素50%+普通尿素50%,N200kg/hm^2)、N1C3(控释尿素35%+普通尿素65%,N200kg/hm^2)、N1(减氮模式,普通尿素,N200kg/hm^2)、N2(传统施氮模式,普通尿素,N250kg/hm^2)6个处理,测定土壤含水量、收获期土壤剖面(0—300cm)中的硝态氮含量及春玉米产量。结果表明:与N2处理相比,减氮处理(N1)并没有减少作物产量,反而显著增加作物产量(p<0.05),2017年、2018年分别增加9.6%和6.9%,土壤水分利用效率分别提高13.3%和10.2%(p<0.05)。同等施氮量(200kg/hm^2)下,与全尿素N1处理相比,2017年配施不同比例控释肥的各处理降低了春玉米的产量和水分利用效率;2018年N1C2处理较N1处理显著增加春玉米的产量和水分利用效率(p<0.05),分别增加7.7%和11.6%。此外,试验2年后减氮模式N1和减氮配施一定比例的控释肥处理显著减少土壤剖面(0—300cm)中硝态氮的残留量(p<0.05),与N2处理相比,N1处理减少了61.2%;同等施氮量(200kg/hm^2)下,与N1处理相比,N1C2处理降低了50.8%。

Effects of Different Fertilization Modes on Spring Maize Yield, Water Use Efficiency and Nitrate Nitrogen Residue

A two-years experiment was designed to examine effects of different nitrogen (N) reduction and controlled-release urea application ratio on spring maize yield, water use efficiency and nitrate-N residue, so as to provide a reasonable fertilization management model for the dryland farming systems on the Loess Plateau. The experiment was performed from April 2017 to September 2018 in the rain-fed agricultural area of the Loess Plateau. Spring maize was planted with half plastic film mulching in one crop per annum. The experiment included six treatments, CK (no nitrogen fertilization treatment), N1C1 (the treatment of 65% controlled-release urea and 35% urea, N 200 kg/hm²), N1C2 (the treatment of 50% controlled-release urea and 50% urea, N 200 kg/hm²), N1C3 (the treatment of 35% controlled-release urea and 65% urea, N 200 kg/hm²), N1 (reduce nitrogen fertilization mode, urea, N 200 kg/hm²), N2 (conventional nitrogen fertilization mode, urea, N 250 kg/hm²).The soil moisture content, the yield of spring maize and nitrate nitrogen content in soil profile (0-300 cm) at harvest period were measured. The results of two years experiment showed that compared with the N2 treatment, N1 treatment did not reduced the crop yield, but significantly increased the crop yield (p<0.05), which increased by 9.6% and 6.9% respectively and significantly increased the water use efficiency (p<0.05), by 13.3% and 10.2% respectively in 2017 and 2018. Under the same nitrogen application rate (200 kg/hm²), compared with N1, the treatment of applying a certain proportion of controlled-release fertilizer reduced the yield of spring maize and the water use efficiency in 2017; the treatment of N1C2 significantly increased the yield of spring maize and the water use efficiency (p<0.05) by 7.7% and 11.6%, respectively in 2018. In addition, after two years of experiment, the reducing nitrogen application and applying a certain proportion of controlled-release fertilizer could significantly reduce the amount of residual nitrate nitrogen in soil profile (0-300 cm) (p<0.05), the N1 treatment reduced by 61.2% compared with the N2 treatment. Under the same nitrogen application rate (200 kg/hm²), the N1C2 treatment reduced by 50.8% compared with the N1 treatment.