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一、问题的提出 我国核桃树约2亿株,年产量约10～15万吨,居世界第二位。我省现有核桃林为21.37万亩,641.1万株,年产量达6411吨。而核桃树寿命长,有的200～300年生的大树仍然生长旺盛。盛果期的单株一般产量收获50kg,高的在100～500kg左右,个别的丰产单株最高可达2000kg以上。我省泾川县荔堡沟圈村仅一株树冠不大的60年生核桃树,年均产核桃
First, the issue put forward China’s walnut trees about 200000000, annual output of about 10 ~ 150000 tons, ranking second in the world. Existing walnut forest in our province is 21.37 million mu, 6.411 million, the annual output of 6411 tons. The long life of walnut trees, and some 200 to 300 years old trees are still vigorous growth. Fruit yield per plant during the fruit harvest 50kg, high in the 100 ~ 500kg or so, individual high yield of up to more than 2000kg. Jingchuan County, Liaoning Province, Liuguogou circle only a small tree canopy of 60-year-old walnut trees, with an average annual production of walnut