不同施氮量对巢湖流域水稻生长及氮素吸收的影响

Effect of Different Nitrogen Application Rates on the Growth and Nitrogen Uptake of Rice in Chao Lake Basin

[目的]研究巢湖流域水稻氮肥最佳施用量,为提高该区域水稻产量和氮素利用效率提供指导。[方法]采用大田试验方法,分别设置不施氮肥(N0)和施氮105 kg/hm^(2)(N1)、210 kg/hm^(2)(N2)、315 kg/hm^(2)(N3)共4个处理,分析水稻生长及氮素利用效率的变化。[结果]水稻有效穗数随着施氮量的增加呈现出先增加后降低的规律,N2最高,为196.7万/hm^(2);施氮可以显著增加水稻每穗实粒数,但各施氮处理间差异不显著;施氮与水稻产量符合报酬递减律,二者关系呈现为开口向下的抛物线,经拟合,当施氮量为202.6 kg/hm^(2)时,水稻可达到最高产量,为8732.5 kg/hm^(2)(R2=0.9892);水稻籽粒氮素含量在8.91~15.01 g/kg,各处理水稻籽粒氮素含量由高到低顺序为N3>N2>N1>N0;不同处理间水稻籽粒氮吸收量差异显著,N2最高,为132.12 kg/hm^(2),N0最低,为54.81 kg/hm^(2),各处理水稻籽粒氮吸收量由大到小顺序为N2>N3>N1>N0;各处理秸秆氮吸收量均远低于籽粒,N2、N3处理显著高于N1和N0;N2的氮素当季回收率最高,为48.62%,而N1的氮素农学利用率和氮素偏生产力则最高。[结论]在巢湖流域水稻产区,氮肥施用量为210 kg/hm^(2)时,水稻生长及氮素利用效率较高,是较为适宜的施氮量。

[Objective]The optimal nitrogen fertilizer application for rice in the Chao lake basin was studied to providing guidance for improving rice yield and nitrogen utilization efficiency in this region.[Method]The field experiment method was used to analyze the changes in rice growth and nitrogen use efficiency by setting up(N0)no nitrogen fertilizers,apply nitrogen 105 kg/hm^(2)(N1),210 kg/hm^(2)(N2),315 kg/hm^(2)(N3)to four treatments,separately.[Result]The number of effective panicles in rice also showed a pattern of first increasing and then decreasing with the increase of nitrogen application,with N2 being the highest at 196.7×104/hm^(2);Nitrogen application could significantly increase the number of grains per panicle in rice,but there was no significant difference among different nitrogen application treatments;The relationship between nitrogen application and rice yield follows the law of diminishing returns,showed a parabolic curve with an opening downward.After fitting,when the nitrogen application rate was 202.6 kg/hm^(2),rice could reach the highest yield,which was 8732.5 kg/hm^(2)(R2=0.9892);The nitrogen content in rice grains ranges from 8.91g/kg to 15.01 g/kg,and the nitrogen content in rice grains of each treatment was N3>N2>N1>N0;There was a significant difference in nitrogen uptake by rice grains between different treatments,with N2 being the highest at 132.12 kg/hm^(2)and N0 being the lowest at 54.81 kg/hm^(2).The nitrogen uptake by rice grains in each treatment was N2>N3>N1>N0;The nitrogen absorption of straw in each treatment was significantly lower than that of grains,while N2 and N3 treatments were significantly higher than N1 and N0 treatments;The nitrogen recovery rate of N2 was the highest in the current season,at 48.62%,while N1 had the highest nitrogen agronomic utilization rate and nitrogen partial productivity.[Conclusion]In the rice producing areas of the Chao lake basin,when nitrogeh 210 kg/hm^(2)was used for nitrogen application,the rice yield was higher and the nitrogen utilization efficiency was also higher,making it an appropriate nitrogen application amount.