不同氮肥施用方式下春玉米根系时空分布特征

通过剖析不同氮肥施用方式下,玉米根系统随生育进程在0～ 60 cm不同土层内分布特征及地上部产量和氮累积量的变化,以期为氮肥合理施用提供理论依据.以先玉335为供试品种,进行了4年田间定位试验.设3个处理:无氮区(N0);氮肥一次性基施200kg/hm2 (N1);氮肥分次施用(N2),基肥50 kg/hm2,拔节期1...

Characteristics of temporal and spatial distribution for root morphology in maize under different nitrogen application conditions

The distribution characteristics of maize root system in different soil layers of 0~60 cm with different nitrogen fertilizer application modes,as well as the changes of overground yield and nitrogen accumulation were analyzed,so as to provide theoretical basis for rational nitrogen fertilizer application.Four years of field experiment was conducted with Xianyu 335 as the experimental variety.Three treatments were set up:no nitrogen application (N0),the single basal application of 200 kg/hm²nitrogen fertilizer as base fertilizer (N1),50 kg/hm²nitrogen fertilizer as base fertilizer and 150 kg/hm;applied at jointing phase,with a total of 200kg/hm²(N2).The dynamic changes of dry weight,root length,root surface area and average diameter of root and the accumulation of dry matter and nitrogen in the mature period were measured.The yield,dry matter accumulation and nitrogen uptake of maize were significantly increased by nitrogen application.The yield,biomass and nitrogen uptake increased by 122.0%~177.9%,76.3%~127.8%,191.0%~272.4%,respectively.Low nitrogen promoted root growth and increased root to shoot ratio,in2013 and 2014,and the root to shoot ratios of N0 increased by 62.5%and 79.3%,75.8%and 75.8%,respectively,compared with N1 and N2 treatments.With the development of the growth process,compared with N0,N1 had an inhibitory effect on root growth,but the difference between years was significant:in years with abundant rainfall,root growth was inhibited at the 12-leaf stage,root length and root surface area of 0~50 cm soil layer were inhibited,with a decrease of 10.4%~43.0%;In normal rainfall years,root growth in all soil layers was inhibited at the flowering stage,with a decrease of 1.3%~47.6%.Compared with N2,the dynamic growth of roots in the 0~40 cm soil layer was inhibited under N1,and the dry weight,root length and root surface area of roots in the 0~40 cm soil layer were reduced by 15.3%,7.9%and 8.2%,respectively,at 20 days after flowering and maturity stage.The spatial distribution of roots in each growth stage in N2 was significantly better than that in N0 and N1,and the root showed the most significant effect at 20 days after flowering.The divided application of nitrogen fertilizer optimized the root morphology,promoted the deep distribution of the root system,and was more conducive to the absorption of nutrients.Moreover,it showed a stable interannual performance,which was a reasonable fertilization method to obtain high and stable yield of spring maize.