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苕子是一种很好的绿肥作物,农业上已经广泛使用,林业上也已开始种植.为了了解绿肥在改良土壤,促进林木生长上的作用,我场于一九七八年做了苕子压青试验,试验结果表明,压青能增加土壤多种养分含量,还能改良土壤理化性质,提高林木生长量.压青比不压青林木,胸径大1.6厘米,树高大79厘米,冠幅大27厘米.试验地是河滩粗沙土,砂粒粒径0.5—2.0毫米,砂层深2米以上。造林时进行了条带状换土,即每隔4米将沙换为一条宽2米,深0.6米的土带.土为生土,无结构的轻壤.1977年造林,植苗于带上,行距6米,株距2.5米,每亩56株.1978年平均胸径为6.75厘米。1978年苕子盛花时压青试验,方法是沟施,沿幼树两
Prickly heat is a good green manure crop, has been widely used in agriculture, forestry has also started planting.In order to understand the role of green manure in soil improvement, and promote forest growth, I field in 1978 made a prickly heat The results showed that the pressure of green can increase soil nutrient content, but also improve the physical and chemical properties of soil and improve the growth of trees. Compressed green ratio does not compress the trees, the diameter at breast height is 1.6cm, the height of tree is 79cm, crown Amplitude of 27 cm. Experimental site is the river beach coarse sand, sand particle size 0.5-2.0 mm, sand depth 2 meters above. When afforestation carried out strip change soil, that is, every 4 meters will be replaced by a sand 2 meters wide and 0.6 meters deep soil for soil, no structure of light soil. Afforestation in 1977, planting in the belt , Spacing 6 meters, spacing 2.5 meters, 56 acres per acre in 1978, the average diameter of 6.75 cm. In 1978, when the prickly heat of flowers bloom test, the method is to ditch facilities, along the sap two