施氮量对滴灌高产春大豆根系生长及产量的影响

Effect of nitrogen fertilizer amount on root growth and yield of spring soybean in drip irrigation

为揭示施氮量对滴灌高产春大豆根系生长及产量的影响规律,在田间滴灌条件下采用挖掘取样法研究了0 kg·hm^(-2)(N_0)、75 kg·hm^(-2)(N_(75))、150 kg·hm^(-2)(N_(150))、225 kg·hm^(-2)(N_(225))4种施氮量对新大豆27号0~80 cm土层根系干物质量、侧根长度、表面积、根系活性、伤流量、根瘤数、根瘤质量及产量的影响。结果表明:随着施氮量的增加,0~80 cm土层根系总干物质量、侧根总长度、侧根总表面积呈现先增后降的变化趋势,均以N_(150)处理最高,在R_5(始粒期)期分别较N_0增加27.3%、49.46%、38.14%,其中,0~20 cm土层分别较N_0增加27.0%、29.02%、34.24%;R_5期N_(150)单株伤流量较N_0增加176.0%,R_2(盛花期)期0~20、20~40 cm土层根系活力N_(150)分别较N_0增加44.3%、25.1%;R_5期N_(150)单位面积根瘤数及质量分别较N_0减少8.74%、34.6%;施氮可增加产量,以N_(150)产量最高,为4 889.62kg·hm^(-2),氮肥农学利用效率3.58 kg·kg^(-1)。施氮增加产量主要是促进0~20 cm土层根系生长,提高0~40 cm根系活力的结果。

In order to investigate the effect of nitrogen application amount on root growth and yield of spring soybean with high yield in drip irrigation,the excavation sampling method was used to study the effects of four nitrogen fertilizer amount treatments,which are 0 kg·hm^-2（ N0）,75 kg·hm^-2（ N（75））,150 kg·hm^-2（ N（150）） and 225 kg·hm^-2（ N（225）） on soil root dry weight,root length and root surface area,activity and bleeding rate,nodule number,quality of 0 ~ 80 cm soil layer and yield of New Soybean No. 27. the total root dry weight,total lateral root length,and total lateral surface area of lateral roots,and the treatment was highest at N（150） and was at R5（ initial grain size）.The results showed that the total dry weight,the length of lateral root and the surface area of lateral roots in 0 ~ 80 cm soil layer showed a trend of increasing at first and then decreasing with the increase of nitrogen application amount. and all of them was highest at N（150） treatment,compared with N0 treatment,the total dry weight,the length of lateral root and the surface area of lateral roots in 0 ~ 80 cm soil layer at R5 period increased by 27.3%,49.46% and 38.14%,respectively. while its in 0 ~ 80 cm soil layer at increased by 27.0%,29.02% and 34.24%. The wound flow of each plant at R5 increased by 176.0%. The root activity of N（150） treatment in 0 ~ 20 cm and 20 ~ 40 cm soil layers at R2 increased by 44.3% and 25.1%,respectively,The number and quality of root nodule at R5 stage in N（150） treatment decreased by 8.74% and 34.6%,The yield of N（150） treatment was higher,which was 4 898.62 kg·hm^-2,and the utilization efficiency of nitrogen fertilizer was 3.58 kg·kg^-1. Nitrogen application can increase spring soybean is mainly to promote the root growth of 0 ~ 20 cm soil layer and increase the root activity of 0 ~ 40 cm.