A Study On The Relation Between Leaf Nutrient Status And Chlorosis Of Kiwifruit

Recent years, the Chlorosis of kiwifruit, a kind of physiological disease, became widespread and serious in Shaanxi province. This paper determined nutrient elements of green leaves and different class chlorosis leaves of "Qinmen" kiwifruit tree (Actinida deliciosab cv.'Qinmen'), including nitrogen (N), phosphorus (P), potassium (K), iron (Fe), manganese (Mn), copper (Cu), zinc(Zn),calcium (Ca),magnesium (Mg),boron (B) and content of chlorophyll, in order to find how various elements affect chlorosis, and gave a prescription curing Chlorosis of Kiwifruit. The results were listed as follows:1 The comparison of nutrient element contents showed that chlorosis leaves were high in nitrogen, phosphorus and potassium, and low in calcium and manganese. While the difference of total iron content between green leaves and chlorosis leaves was not obvious. Perhaps lower copper consistency is one main cause of chlorosis of kiwifruit in certain kiwifruit orchards.2 The results of factor analyzing showed that there was a better relevance between the occurrence of chlorosis and the nutrition level of kiwifruit orchards. The elements copper, phosphorus, iron, manganese, magnesium, potassium were important for the health of kiwifruit. chlorophyll of leaves. The results of chlorosis leaves' factor showed that calcium, boron, iron and zinc were relevant to the chlorosis of kiwifruit. Under the first class of chlorosis, higher content in nitrogen and potassium can restrain kiwifruit to absorb iron and zinc. As a result, the nutrient balance of kiwifruit was destroyed. Under more serious chlorosis condition, calcium , boron and magnesium in high content is the main cause induced chlorosis.3 The R2(j) value of chlorosis leaves showed that nitrogen, manganese and magnesium effected the chlorosis under the condition of first chlorosis level, and iron is the restrictive element. Under the second and third chlorosis level, the copper and potassium is important as well, and potassium was the restrictive element.4 Based on above-mentioned conclusion, there were 15 prescriptions for chlorosis. The results showed that the 6# and 15# were good, although 15# has some reverse effect without enough water. This paper had appropriate scale after experiment.