论文部分内容阅读
在铁杉幼林里施用氮肥,有时能提高生长量达50%,有时反而减少生长量20%。为了弄清施用尿素后铁杉林不同反应的原因,为合理施肥提供依据,就需要对加州铁杉施肥后营养和生长影响的原因作以探讨。试验选择了6块天然加州铁杉(纯林)幼林。这些林分都没有施过肥和进行过疏伐。再在每个林分内,各测设6个面积为0.0203公顷的圆形小区,从中随机选出3个,于1977年初冬施上粒状尿素,施肥量为每公顷224公斤;另外3个不施肥,作为对
Applying nitrogenous fertilizer in young hemlock forests can sometimes increase the amount of growth by up to 50% and sometimes reduce the amount of growth by 20%. In order to find out the reasons for the different reactions of hemlock hemlock after urea application, to provide the basis for rational fertilization, we need to discuss the reasons for the effects of hemlock after fertilization on nutrition and growth. Six young Hemlock (Betula platyphylla) young forests were selected. None of these stands were fertilized and thinned. Then within each stand, each of the six measuring area of 0.0203 hectares of circular plot, of which three were randomly selected in the early winter of 1977 coated with granular urea fertilizer 224 kg per hectare; the other three do not Fertilization, as right