浙北地区秸秆全量还田下氮肥用量对单季晚粳稻生长和土壤养分、碳库的影响

为了明确浙北地区秸秆全量还田下单季晚粳稻适宜的施氮量,通过大田试验,采用随机区组设计,根据当地农户施肥习惯,设置4种施氮水平(以纯氮计,N 0,不施氮;N L,165 kg/hm²;N M,240 kg/hm²;N H,315 kg/hm²),研究了浙北地区秸秆全量还田下氮肥调控对单季晚粳稻生长和土壤养分、碳库的影响。结果表明:N M和N H的水稻分蘖数、株高、叶面积系数、叶绿素含量及地上部分干物质重均高于其他处理。在稻田土壤方面,N M的土壤速效磷和速效钾含量较N 0,N L和N H处理分别显著(p<0.05)增加了43.16%,30.13%,13.13%和31.86%,22.13%,15.81%;N M的可溶性有机碳和微生物有机碳含量较N 0和N L处理分别显著(p<0.05)增加了88.47%,13.99%和37.10%,15.39%。在产量方面,N M的产量最高,较N 0,N L和N H处理分别增产51.70%,15.39%,9.45%。综上所述,在本试验条件下,秸秆全量还田施用240 kg/hm²纯氮为浙北地区单季晚粳稻最佳氮肥调控模式。

Effects of Nitrogen Application on Late Single Season Japonica Rice Growth,Soil Nutrient and Carbon Pool Under Full Straw Returning in Northern Zhejiang Province

In order to determine the appropriate nitrogen application amount of single season late japonica rice under the full amount of rice straw returning to field in northern Zhejiang Province,the field experiment was carried out,and the random block group design was adopted.Four nitrogen application levels such as no nitrogen application(N 0),165 kg/hm²(N L),240 kg/hm²(N M),and 315 kg/hm²(N H)were set according to the fertilization practice of local farmers.We investigated the effects of nitrogen application on the growth,soil nutrients and carbon pool of single-season late japonica rice in northern Zhejiang Province under the condition of full straw returning to field.The results showed that:rice tillering number,plant height,leaf area index,chlorophyll content and dry matter of aerial part weight under treatments of N M and N H were higher than other treatments;in terms of paddy under the straw returning full amount,the soil available phosphorus,available potassium of N M significantly increased by 43.16%,30.13%,13.13%and 31.86%,22.13%,15.81%(p<0.05),respectively,compared with N 0,N L and N H treatments;the dissolved organic carbon and the soil microbial biomass organic carbon of N M significantly increased by 88.47%,13.99%and 37.10%,15.39%(p<0.05),respectively,compared with N 0 and N L treatment;in terms of yield,the highest yield was found in treatment N M,which was 51.70%,15.39%and 9.45%higher than N 0,N L and N H treatments,respectively.In conclusion,under the setting conditions of this experiment,pure nitrogen rate of 240 kg/hm² was the best nitrogen fertilizer regulation model for single-season late japonica rice in northern Zhejiang Province under the full straw returning to the field.