氮量对高产水稻品种产量和氮效率的影响

Effects of nitrogen application amount on yield and nitrogen use efficiency of high-yield rice varieties

2018~2019年设置田间小区试验,以主栽高产型水稻品种松粳3号为试验材料,设0、75、105、135、165 kg·hm^(-2)等5个供氮水平,调查水稻分蘖、干物质积累、氮积累、产量和氮效率等指标。施氮促进水稻分蘖发生,施氮和不施氮处理分蘖数差异显著,随施氮量增加,拔节、抽穗、成熟3个时期分蘖数增加量分别为49.54%~65.15%、62.36%~82.90%和63.13%~87.92%(P<0.05),施用氮肥分蘖成穗率增加12.99%~15.13%(P<0.05)。施用氮肥显著增加水稻干物质积累和氮积累,施氮量相差60 kg·hm^(-2)以上植株干物质及氮素积累量差异显著。水稻产量、单位面积颖花数随氮量增加而增加,结实率随氮量增加而降低。氮量和产量关系符合线性加平台模型,转折点施氮量为137~138 kg·hm^(-2),对应产量为9080~9166 kg·hm^(-2)。随氮量增加氮肥吸收利用率无明显变化或显著增加,具有年际间差异。随氮肥用量增加,氮肥生理利用率、农学利用率(2019年除外)、偏生产力显著降低。施氮量在137.5 kg·hm^(-2)以上虽未造成减产,但前期低温年(2019年)氮量由135 kg·hm^(-2)增至165 kg·hm^(-2),造成氮肥农学效率显著降低。耐肥的高产水稻品种,施氮量增加不易造成减产,但氮效率降低,适量施氮对实现高产水稻品种高产和氮高效相统一尤为关键。

Songjing No.3 was used as the experimental material,from 2018 to 2019,field plot experiments with five nitrogen levels(0,75,105,135 and 165 kg·hm^(-2))were conducted to investigate rice tillering,dry matter accumulation,nitrogen accumulation,yield and nitrogen use efficiency.There was a significant difference of rice tiller numbers between nitrogen application and no nitrogen treatment.With the increase of nitrogen application,rice tiller significantly increased by 49.54%-65.15%,62.36%-82.90%and 63.13%-87.92%at jointing,heading and maturity stages,respectively,and the earbearing tiller rate was increased by 12.99%-15.13%(P<0.05).Nitrogen application could significantly increase the dry matter and nitrogen accumulation of rice,and there was a significant difference among treatments with nitrogen application rate of more than 60 kg·hm^(-2).Rice yield and spikelet numbers per unit area were increased,but grain filling rate was decreased with the increase of nitrogen rate.The relationship between nitrogen rate and yield was in accordance with the linear plus platform model.The nitrogen application at the turning point was 137-138 kg·hm^(-2),and the corresponding yield was 9080-9166 kg·hm^(-2).The effect of N on nitrogen recovery efficiency had interannual differences.With the increase of nitrogen fertilizer application rate,nitrogen physiological utilization rate,agronomic utilization rate(except for 2019),and partial factor productivity decreased significantly.The nitrogen application amount above 137.5 kg·hm^(-2) would not cause yield reduction,but the early low temperature year(2019)would cause a significant decrease of nitrogen agronomic efficiency.The increase of nitrogen application rate was not easy to cause yield of high-yield rice varieties reduction,but lead to the reduction nitrogen use efficiency.Appropriate nitrogen application was especialy critical for high-yield rice varieties to achieve high yield and high nitrogen use efficiency at the same time.