Investigation On The Nutritional Composition Of Walnut And Regularity Of Its Nutrient Requirements

Walnut(J.regia L.) is not only the first species of tree that yields dry fruit oil, but also the important economic tree species in China. Shanxi province is one of the major areas of walnut production in China, and it is also the important base of walnut export. The exterior qualities of twenty varieties of walnut planted in Shanxi province were investigated and their nutrient components were analyzed. And a preliminary study was made on the annual periodic change of mineral nutrient content in walnut-orchard soil and leaf blades of 8 years old walnut. The purpose of this research is intended to provide scientific evidence for the good development of walnut industry in Shanxi province. The main findings are as follows:1. The twenty varieties of walnuts planted in Shanxi province all behave better economic character, having characteristics of fine appearance, big meat, high kernel ratio, meat easier taken and light color.2. Crude fat content of the twenty varieties of walnut kernel is in the range of 60.97% to 69.63%; crude protein content is in the range of 16.38% to 23.00%; Kis in the range of 0.28% to 0.41%; Ca is in the range of 0.10% to 0.30%, and Mg is 0.13% to 0.21%, Fe is 49.3～96.8mg-kg"1, Mn is 36.1～87.0 mg·kg-1, Cu is 11.1～16.9mg-kg-1,Zn is 20.2～51.6mg·kg-1.The walnut kernel mainly consists of five kinds of fatty acids, whose contents from high to low are:linoleic acid, oleic acid, a-Linolenic Acid, palmitic acid, stearic acid, in which the unsaturated fatty acid content reaches above 90%, and the linoleic acid(ω-6)/α-Linolenic Acid(ω-3) content ratio basically corresponds to the recommended values(5～10):1 of (ω-6)/(ω-3) in human diets which are developed by United Nations FAO. Different varieties of walnut kernel all contain 17 kinds of amino acids that human body requires, including 7 kinds of essential amino acids.3. Studied on the change laws mineral nutrients in walnut-orchard soil in its whole growth stages. The seasonal changes of total N, available K and available Cu are not obvious. The content of available P goes up in the prophase and goes down in the anaphase. The content of soil organic matter, NO3-N presents, available Zn, available Mn, available Fe, available B changes similarly with the seasonal change, and presents wavy change. The change of soil exchangeable Ca content presents the tendency of going up firstly and going down secondly. The change of soil exchangeable Mg content presents the tendency of jumping greatly, then declining greatly, finally going up in stability. The soil's available S presents the "low-high-low-high" seasonal change.4. Studied on the annual periodic change laws of eight-year-walnut (Liaohe No.1 and Jinlong No.2) blade's nutrient components. The results show that the mineral nutrients of two varieties of walnuts'leaf blades change similarly, only differ in content. The N, P, K content of blade declines gradually with the development of growth stages. The contents Cu and Zn in blade changes likely, presenting the tendency of "down-up-down". The Fe content of blade presents the tendency of going down firstly and then going up. Whereas the contents Ca, Mg and Mn in blade changes similarly, presenting the tendency of going up gradually in its whole growth stages.