Study on Nutritional Diagnosis of Populus×euramericana in Reclaimed Area by Coal Ash

The nutritional diagnosis of the leaves shows that in the reclaimed area bycoal ash, the trees of P.×euramericana are in a state of nutrition deficiency,so the application of N not only raised the N concentration of the leaves,but promoted bothe tree growthand its absorption of K,Ca,Mg etc.nutritional elements.The application of P mainly raisedthe P concentration of the leaves and solved the problem of P deficiency.(2) The correlation analvsis shows that the application of K helps to promote the absorption of P. From the result of K application,it shows that the appropriate K value of 1.5% proposed by J. Garbayeis obviously on the low side,which is not suitable for the poplar clone we’re dealing with.(3)The application of green manure can raised the Mg and P concentration of P.×euramericana’s leaves,but its mechanism of significant effect has to be studied further.(4)The N,Kconcentration of the leaves has a positive correlation with the growth of P.×euramericana,which shows that the higher the leaf concentration,the bigger the tree increment.On thecontrary,the P concentration of the leaves has a negative correlation with the tree growth,which shows that in face,the relationship between P concentration and tree growth is a kindof“diluted effect”.