深松对春玉米根系分布及氮素积累与利用的影响

2015—2016年以先玉335和郑单958为试验材料，设置深松+旋耕（S+R）和旋耕（R）2个处理，研究了深松对春玉米根系分布及氮素积累与利用的影响。结果表明：深松疏松了土壤，有利于根系的生长，促进根系下扎，深松措施下先玉335和郑单958完熟期总根干重较旋耕处理分别提高了7.35%和9.25%，其中20~40 cm土层分别提高了15.52%和24.07%，30 cm以下土层根条数和根幅明显增加。深松改善根系形态特征，增加了根系与氮素的接触机会，促进了春玉米对氮素的吸收和累积，使单位重量根系氮素吸收量明显提高，吐丝前S+R处理的先玉335和郑单958单位重量根系氮素吸收量较R处理分别提高了11.22%和12.03%，处理间差异达到了显著水平。S+R处理的氮素吸收效率先玉335和郑单958较R处理分别提高6.11~6.40 kg·kg^-1和7.17~7.51 kg·kg^-1，氮肥偏生产力分别提高了3.86~8.00 kg·kg^-1和5.40~9.86 kg·kg^-1，氮素积累量分别提高了33.73~35.66 kg·hm^-1和27.85~36.61 kg·hm^-1。与先玉335相比，郑单958对深松更为敏感。

Effects of subsoiling on roots distribution and nitrogen accumulation and utilization of spring maize

The subsoiling plus rotary tillage (S+R) and rotary tillage (R) were studied for their effects on root distribution and nitrogen (N) accumulation and utilization of spring maize using Xianyu 335 and Zhengdan 958 as experimental materials from 2015 to 2016. The results showed as following. The subsoiling loosed soil and promoted the root system growing down. Compared with R, the total root dry weight of Xianyu 335 and Zhengdan 958 of S+R increased by 7.35% and 9.25%, respectively, among of which the total root dry weight increased by 15.52% and 24.07% in 20~40 cm soil layer and the root number and root width under 30 cm soil layer also increased significantly. The improvement of characteristics of root morphology increased the contact opportunity between root and N, which improved the N absorption and accumulation of spring maize and made the N uptake per unit weight root increased obviously. Compared with R, the N uptake per unit weight root of Xianyu 335 and Zhengdan 958 of S+R before silking stage increased by 11.22% and 12.03%, respectively, and the difference between treatments reached a significant level; the absorption efficiency of N of Xianyu 335 and Zhengdan 958 with S+R increased by 6.11~6.40 kg·kg^-1 and 7.17~7.51 kg·kg^-1, respectively. Partial productivity of N fertilizer with S+R increased by 3.86~8.00 kg·kg^-1 and 5.40~9.86 kg·kg^-1; the N accumulation in the aboveground part with S+R increased by 33.73~35.66 kg·hm^-1 and 27.85~36.61 kg·hm^-1. Compared with Xianyu 335, Zhengdan 958 was more sensitive to subsoiling.