施氮量对不同冬小麦品种表层根系特性及物质生产形成的影响

Effects of Nitrogen Application Rate on Superficial Roots Characteristics and Matter Production of Different Winter Wheat Varities

为明确氮肥促进小麦物质生产形成的根系农艺机制,于2018—2019年在山西农业大学小麦试验基地进行大棚池栽试验,以3个小麦品种山农29、良星77、良星99为主区,以150、270 kg/hm^(2)共2个施氮量为副区,研究不同小麦品种0~20 cm根系特性、植株干物质积累特性、产量和氮素利用效率的差异及其对氮肥的响应。结果表明,高氮处理较低氮处理显著提高了越冬、开花和成熟期表层根长,尤其开花期Ⅰ级根尖端数、Ⅱ级根长、根体积、根表面积密度,Ⅲ级根长、根体积、根尖端数和根表面积密度;降低了花后表层总根和各级根长、根体积衰减速率,尤其显著降低了Ⅲ级根、总根的根长衰减速率和根体积衰减速率;提高了各生育阶段干物质积累量;显著提高产量7.3%~13.6%、氮素利用效率1.0%~8.2%,尤以山农29差异显著;山农29较良星77和良星99显著增加了各生育时期表层(0~20 cm)总根长,显著降低了花后根长衰减速率和根体积衰减速率,显著提高了各生育阶段干物质积累量,显著提高产量15.6%~31.4%、提高氮素利用效率5.3%~15.9%;小麦开花期表层Ⅰ级根长和根尖端数与生育后期地上部干物质积累,Ⅲ级根长、根体积、根尖端数和根表面积密度与成熟期干物质量、产量和氮素利用效率显著正相关。

To clarify the root agronomic mechanism of nitrogen fertilizer promoting the production of wheat,a greenhouse experiment was carried out in the wheat test base of Shanxi Agricultural University from 2018 to 2019.Based on three wheat varieties:Shannong 29,Liangxing 77,Liangxing 99 as the main area,with 150,270kg/hm^(2) of two nitrogen rate levels as the secondary area,different wheat varieties 0-20 cm root characteristics,dry matter accumulation characteristics,yield and nitrogen use efficiency and their response to nitrogen fertilizer were studied.The result showed that compared with low nitrogen,high nitrogen significantly increased the root length of surface level at wintering stage,anthesis and maturity,especially the tips ofⅠlevel root,the root length,root volume and root surface area density ofⅡlevel root,the root length,root volume,root tips and root surface area density ofⅢlevel root,reduced the root length decay rate and the root volume decay rate of total root and every level root in surface soil layer,significantly reduced the total root andⅢlevel root's root length decay rate and root volume decay rate,increased dry matter accumulation in each growth stage,yield was significantly increased by 7.3%-13.6%,nitrogen use efficiency was increased by 1.0%-8.2%,and the difference of Shannong 29 was significant.Compared with Liangxing 77 and Liangxing 99,Shannong 29 significantly increased the total root length of the surface layer(0-20 cm)during each growth stage,significantly reduced the root length decay rate and root volume decay rate,significantly increased the dry matter accumulation in each growth stage,significantly improved yield and nitrogen use efficiency by 15.6%-31.4%and 5.3%-15.9%,respectively.TheⅠlevel root length and root tip number in surface soil layer at anthesis were positively correlated with the accumulation of dry matter in the upper part of wheat,Ⅲlevel root length,root volume,root tip number and root surface area density were positively correlated with the dry matter quality at maturity,yield and nitrogen use efficiency.