不同施氮量对滴灌春小麦根系时空分布、氮素利用率及产量的影响

Effects of Nitrogen Fertilizer at Different Levels on Spatial and Temporal Distribution of Wheat Roots,Nitrogen Use Efficiency and Yield in Spring Wheat under Drip Irrigation

为明确新疆干旱区滴灌春小麦不同施氮量对小麦根系的时空分布、氮素利用率及产量的影响。以‘新春19号’为试验材料,利用田间定位试验,研究在小麦拔节期、抽穗期、开花期及成熟期施氮量0kg/hm^2(N_0对照)、150kg/hm^2(N_1)、300kg/hm^2(N_2)、450kg/hm^2(N_3)4个处理,对小麦根系根长密度、根体积、根质量等在0~100cm土层的垂直分布、动态变化及产量构成因素和产量的影响。结果表明:开花期是各处理小麦根长密度、根体积与根质量变化最为剧烈阶段;0~20cm是各处理根量值(根质量、根体积、根长密度)最大层;施氮量适宜(N_2)时,表层根量增加,氮素利用率最高;施氮量过高(N_3)可获得较高的表层根量和产量,但导致最低的氮素利用率;施氮量过少(N_1)可获得较高氮素利用率,但土层根量和产量较低;氮素严重缺乏(N_0)导致表层土壤根系数量减少,影响养分吸收并导致产量最低。建议在新疆干旱区滴灌春小麦区域采用施氮量300kg/hm^2更有利于实现节肥和高产的统一。

Field experiment was conducted to understand the spatial and temporal distribution of wheat roots,nitrogen use efficiency and yield in spring wheat under drip irrigation in the arid region of Xinjiang.The spring wheat cultivar‘Xinchun 19＇was used as test material.Four nitrogen amount treatments of 0（control）,150kg/hm^2（N1）,300kg/hm^2（N2）and 450kg/hm^2（N3）were done in the fixed field trail.The experiment detected the vertical distribution and dynamic change of root length density,root volume,root mass of wheat in 0-100 cm soil depth at jointing stage,heading stage,flowering stage and mature stage.The results showed that flowering period was the most active period for wheat root length density,root volume,root mass.The largest amount of roots（root mass,root length density and root volume）was found at range of 0-20 cm depth.Total amount of root system in the surface layer was increased in the appropriate nitrogen treatment（N2）and had the highest NUE.Although excessive nitrogen（N3）obtained higher amount of root and yield for wheat,the lowest NUE was also found under the treatment.Low nitrogen amount（N1）obtained higher NUEbut the total amount of root and yield was lower.An acute shortage of nitrogen（N0）caused decrease in root number at surface layer of soil,hard nitrogen absorption and lowest yield for wheat.Therefore,it is better to use nitrogen application at N2treatment（300kg/hm^2）in the area of spring wheat under drip irrigation in arid region of Xinjiang,so as to realize the unity of fertilizer-saving and high yield.