盐渍化耕地秸秆深埋配施氮对玉米根系及产量的影响

Effects of nitrogen application with straw deep-buried on maize root system and yield in salinized farmland

为探究盐渍化耕地秸秆深埋下不同施氮水平对玉米根系形态和产量的影响,在河套灌区开展了为期两年的田间试验。试验设置对照(CK)、不施氮(N0)、施氮135 kg·hm^(-2)(N1)、施氮180 kg·hm^(-2)(N_(2))、施氮225 kg·hm^(-2)(N_(3))5个处理,分别在拔节期、吐丝期、成熟期采集玉米根系样品。结果表明,盐渍化耕地秸秆深埋下,适量施氮(N_(2))显著促进玉米根系生长,全生育期总根长、根表面积和根体积,相比N0处理分别增加67.65%、86.71%和62.95%,根干质量两年平均增加94.63%,根冠比平均增加16.43%。过量施氮(N_(3))虽对40~60 cm土层根系有促进作用,但总体上仍表现出抑制作用,相较于N_(2)处理,N_(3)处理生育期总根长、根表面积和根体积分别减少12.45%、17.48%和18.07%,根干质量两年平均减少11.68%,根冠比平均减少8.22%。相比CK处理,适量施氮(N_(2))处理两年平均增产4.96%。因此,建议河套灌区玉米适宜的施氮水平为180 kg·hm^(-2),研究成果可为优化盐渍化地区玉米施氮水平及提高秸秆资源化利用提供理论依据。

To explored the effects of different nitrogen application levels on the root morphology and maize yield under straw deep burial in salinized arable land,a 2-year field experiment was carried out in Hetao Irrigation District.The experiment included five treatments:CK(control group),N0(no nitrogen application),N1(135 kg·hm^(-2)),N_(2)(180 kg·hm^(-2)),and N_(3)(225 kg·hm^(-2)).Maize root samples were collected at jointing stage,silking stage and maturity stage.The results showed that under the condition of straw deep burial,in the whole growth period,compared with the treatment without nitrogen application(N0),the total root length,root surface area and root volume increased by 67.65%,86.71%and 62.95%,respectively.The average root dry weight was increased by 94.63%and the average root shoot was increased by 16.43%.Although the overapplication of nitrogen(N_(3))promoted the root system in the 40-60 cm soil layer,it still inhibited the root system in general.Compared with N_(2) treatment,the total root length,root surface area and root volume of the growth period were reduced by 12.45%,17.48%and 18.07%,respectively.The average root dry weight was reduced by 11.68%and the average root shoot ratio was reduced by 8.22%in the two years of N_(3) treatment.Compared with the control treatment,the 2-year average yield of N_(2) treatment was increased by 4.96%.The optimal nitrogen application level for maize in Hetao Irrigation District was 180 kg·hm^(-2).The results can provide a theoretical basis for optimizing the nitrogen application level of maize tillage and improving the utilization of straw resources in salinized arable land.