适宜滴灌施肥量促进河西春玉米根系生长提高产量

针对河西地区水资源短缺、作物水肥利用效率低等问题,研究不同滴灌施肥条件下河西地区春玉米根系生长与产量对水肥的响应关系,以期探索提高水肥利用效率的滴灌施肥模式。利用2 a的田间小区试验,以春玉米"强盛51号"为试验材料,设置4个灌水水平,2015年和2016年分别为I_(60)(60%ET_c)、I_(75)(75%ET_c)、I_(90)(90%ET_c)、I_(105)(105%ET_c)和I_(60)(60%ET_c)、I_(80)(80%ET_c)、I_(100)(100%ET_c)、I_(120)(120%ET_c),ET_c为玉米需水量;4个N-P_2O_5-K_2O施肥水平(kg/hm~2):F_(60)(60-30-30)、F_(120)(120-60-60)、F_(180)(180-90-90)和F_(240)(240-120-120),共16个处理。在生育期内对春玉米的根长、根表面积、根质量、根体积、根长密度进行观测,并统计地上部干物质量和产量。结果表明:灌水量为105%ET_c(2015年)和100%ET_c(2016年)与施肥量180-90-90 kg/hm~2组合的处理根长、根表面积、根质量、根体积均较高;相关性分析显示,各生育期根系特征参数与产量和地上部干物质量相关系数按大小排序表现出灌浆期大喇叭口期成熟期小喇叭口期的规律;在河西地区膜下滴灌施肥条件下,综合考虑根系生长、节水节肥及高产等因素,该地区灌水量90%ET_c~100%ET_c、180-90-90(N-P_2O_5-K_2O)kg/hm~2处理为最佳滴灌施肥策略。

Optimal drip irrigation and fertilization amount enhancing root growth and yield of spring maize in Hexi region of China

Water and fertilizer are generally 2 of the most important factors in determining the spring maize productivity and yield. In view of the problems of the shortage of water resources and the low efficiency of water and fertilizer use in Hexi area of China, 2-year experiments (2015 and 2016) were conducted to evaluate effects of different water and fertilizer supplies on root growth and yield of spring maize under fertigation. The test site was Shiyanghe Experimental Station of China Agricultural University located in Wuwei District, Gansu Province, Northwest China (37°52'N, 102°50'E; 1581 m a.s.l.). Using'Qiangsheng 51'as the test cultivar, the field experiment was subjected to 4 water supply levels, 60%ETc (I60), 75%ETc (I75), 90%ETc (I90) and 105%ETc (I105) in 2015, and 60%ETc (I60), 80%ETc (I80), 100%ETc (I100) and 120%ETc (I120) in 2016, in interaction with 4 fertilization levels that based on different ratios of N-P2O5-K2O, i.e 60-30-30 (F60), 120-60-60(F120), 180-90-90 (F180) and 240-120-120 (F240) kg/hm2. ETc was the average annual crop evapotranspiration. There were 16 treatments in total. Root growth characteristics such as root length, root surface area, root biomass, root volume, and root length density were measured during the maize growing season. Aboveground biomass, yield and yield components were counted after the final harvest. The results showed that the root length, root surface area, root biomass and root volume under 105%ETc (2015) and 100%ETc (2016) coupled with 180-90-90 kg/hm2 treatment were greater compared to the others treatments. The irrigation amount during the whole growth stage had a significant effect on the root growth near the drip tape side, at the plant base and far from the drip tape side. With the growth of plants in the 4 irrigation treatments during the 2 years, the root length density at different locations increased first and then decreased, and reached the maximum at the grain filling stage. The roots were mainly distributed in the 0-80 cm soil layer and the 0-100 cm soil layer at the 6 collars stage and after the 12 collars stage. In the 2016 F180 treatment, the total root length during the 12 collars stage to the filling stage compared to the 6 collars to 12 collars stage increased by 1.8 and 1.1 percent points in the I100 and I120 treatments, respectively. However, the corresponding values in the I60 and I80 treatments decreased by 6.6 and 3.8 percent points, respectively. The correlation analysis showed that the correlation coefficient between root characteristics with yield and aboveground biomass of each growth stage showed filling stage > 12 collars stage> maturity stage> 6 collars stage. From the perspective of water and fertilizer supply, it is the most important to ensure supply of water and fertilizer from the 12 collars stage to the filling stage, followed by stage from 6 collars to 12 collars, great potential of saving water and fertilizer may be at the stage from seeding to 6 collars stage. I100F180 harvested the highest yield (18269 kg/hm2). I90F180 treatment output was not significantly lower than the highest yield, while it saved irrigation water. Considering the water shortage condition in Hexi region of China, and high efficient use of water and fertilizer, 90%ETc -100%ETc combined with 180-90-90 kg/hm2 (N-P2O5-K2O) was suggested to be optimal for spring maize production under fertigation.