Effects Of Site Conditions And Rootstocks On The Changes Of Mineral Nutrition Contents In Leaves Of Sand Pear Trees

In this paper effects of site conditions and rootstocks on the changes of mineral nutrition contents in leaves of Housui ( Pyrus pyrifolia Nakai.cv.Housui ),Whangkeumbae(Pyrus pyrifolia Nakai.cv.Whangkeumbae) and Kousui (Pyrus pyrifolia Nakai.cv.Kousui) were researched through the methods of nutrient analysis of leaves and DRIS .The main results were as follows:1.The contents of nitrogen (N) ,phosphorus (P) and potassium (K) in leaves of Housui, Whangkeumbae and Kousui in low-yield group in tall sandy soil were analyzed by DRIS, the results showed that Housui and Kousui had the same sequence about fertilizer requirement ,which were K>N>P, but the nutrient ratios of nitrogen,phosphorus,potassium in the Kousui leaves were more balanced than that of Housui leaves The sequence about fertilizer requirement in Whangkeumbae was N>P>K. Therefore, Housui and Kousui should increase potassium application while Whangkeumbae need more nitrogen and phosphorus.2. By way of leaf nutrient diagnosis of Pyrus pyrifolia with DRIS, the result showed that average values of content of element in the leaves in high-yield group were obviously greater than that of low-yield group, but the standard deviation and coefficient of variation of nutrient ratios in high-yield group were less than that of low-yield group. It showed that the nutrient ratios of high-yield group were more balanced and the fertilizer sequences were matched through the DRIS index method and the diagnosis analysis. So DRIS diagnosis methods could judge the main mineral nutrient level status in leaves to guide fertilization.3. The leaves of Housui grown in the tall sandy soil had high contents of nitrogen, potassium and manganese, while grown in the yellow brown soil had high contents of iron, copper, zinc. The nitrogen and phosphorus in the leaves of Housui in the two kinds of soil were positively correlated through the correlation analysis.4. The content of zinc in the leaves of Housui (/Pyrus Pashia) was lower than that of Housui (/Pyrus betulaefolia Bunge) and Housui (/Pyrus calleryana Decne). The nitrogen was positively significant correlated with potassium in the leaves of Housui on different rootstocks. There was positively significant relationship between potassium and zinc in the leaves of Housui (/Pyrus Pashia) and Housui (/Pyrus betulaefolia Bunge), but potassium was negatively related to zinc in the leaves of Housui (/Pyrus calleryana Decne).5. The content of potassium in the leaves of Whangkeumbae (/Pyrus xerophila Yu) was lower than that of Whangkeumbae (/Pyrus betulaefolia Bunge) and Whangkeumbae (/Pyrus calleryana Decne), while the contents of magnesium and iron were higher. The content of manganese in the leaves of Whangkeumbae (/Pyrus calleryana Decne) was lower than that of Whangkeumbae (/Pyrus xerophila Yu) and Whangkeumbae (/Pyrus betulaefolia Bunge).6. During the whole sampling period,the content of calcium in the leaves of Housui (/Bartlett/Pyrus betulaefolia Bunge)was lower than that of Housui(/Pyrus betulaefolia Bunge) ,while the contents of magnesium and zinc were higher than that of Housui(/Pyrus betulaefolia Bunge).7. The correlation between the content changes of element in the leaves of Housui (/Bartlett/Pyrus betulaefolia Bunge) was the same as Housui (/Pyrus betulaefolia Bunge). There were positively significant relationship among nitrogen,phosphorus and potassium content changes in Housui(/Bartlett/Pyrus betulaefolia Bunge) and Housui (/Pyrus betulaefolia Bunge) leaves, but negatively significant relationship were found among the changes of calcium,magnesium,iron and copper contents.