施氮对象草分蘖数、株高、产量的影响及分析模型的构建*

 采用完全随计区组设计，以德宏逸生象草干物质产量、株高及分蘖数为指标，采用Microsoft Excel设计直线回归模型，分析施氮量与分蘖数、株高及干物质产量的回归方程、相关系数、回归方程显著性检验的F值、相关系数显著性检验的T值及相应的F_0.01,F_0.05,T_0.01,T_0.05的参考值。结果表明，分蘖数与施氮量的回归方程为：y=0.005219x+7.860714，相关系数r=0.9564；株高与施氮量的回归方程为：y=0.101794x+179.8571，相关系数r= 0.936744；干物质产量与施氮量的回归方程为：y=0.030710x+15.28571，相关系数r= 0.977123。说明施氮量与分蘖数、株高、干物质产量存在极显著的相关性，证明氮肥施用量对德宏逸生象草的生长性能有极显著的影响。分析施氮量和德宏逸生象草干物质增加量关系可知，既要维持象草的高产又要考虑经济效益，尿素施用量在700～800kg N/hm²之间为宜。采用Microsoft Excel进行直线回归分析及显著性检验，无需编程，一般科技人员易于掌握，模型构建完成后，每次只需变更数据即可得到准确结果。

The Relationship of Nitrogen Application on the Number of Tiller, Height and Yield of Elephant Grass and Linear Regression Model

Using randomized complete block design to study on the tiller number,height and yields of elephant grass(Pennisetum purpureum) at 7 nitrogen application level.By using the internal function of Microsoft Excel to establish linear regression model to study on the relationships between nitrogen quantity and tiller number,height and yields of elephant grass.The result shows that the linear equation and correlative coefficient between tiller number,height,yields and amount of nitrogen application as following: y=0.005 219 x 7.860714 and r=0.956 4,y=0.101 794x 179.857 1 and r= 0.936 744,y=0.030 710 x 15.285 71 and r= 0.977 123,respectively.The relationship of DM yield and amount of nitrogen application shows that DM is the highest at 414 kg N/hm2.However,to keep high DM yield and economical benefits,input and output should be considered.So the best N application should be between 300 kg/hm2 and 400 kg/hm2.The advantages of using Microsoft Excel to establish linear regression model are that we do not need to edit program,so it can be used popularly.