【摘要】 在平原沙地的三年生泡桐人工幼林内进行了为期一年的试验工作,对幼林的氮、磷、钾、钙、镁和锰六种营养元素的季节性变化及生物循环进行了评价。试验结果为(1)泡桐树体内约含35种元素;(2)生长季节内六种营养元素的含量呈不同的变化,其中叶子中的氮含量自展叶至叶成熟逐渐增高,其后又逐渐减少;磷和钾的含量趋于减少;钙、镁和锰的含量则趋于增加;(3)生物循环的三个过程,吸收量为574.5359公斤/公顷,存留量为290.9192公斤/公顷,归还量为283.6167公斤/公顷,存留和归还两部分几乎各占吸收量的一半;(4)六种营养元素的循环速率平均为0.49,氮、磷、钾、钙、镁、锰的循环速率分别为0.69,0.25,0.21,0.56,0.57,0.79。根据试验结果,对林地的生产潜力和施肥量作了初步讨论。更多还原

【Abstract】 The experimental work on 3-year paulownia forest was made in 1983,inorder to evaluate the effects of seasonal changes and biological cycling of six nu-trient elements,N,P,K,Ca,Mg,and Mn.The results are(1)thereare 35 elements found in paulownia trees;(2)the contents of the six nutrient ele-ments have different changes during the growing season,N,P and K tend to decre-ase;Ca,Mg and Mn tend to increase in leaves;(3)inthree processl bio of esogical cycling the quantities of uptake,retention and restitution are 574.5359,290.9192,283.6167 kg/ha/yr.respectively;and(4)the average cycling rate ofthe six nutrient elements is 0.49,of which N,P,K,Ca,Mg,Mn are 0.69,0.25,0.21,0.56,0.57,0.79 respectively.Upon these results,the potential prod-uctivity and fertilization to the soil were discussed preliminarily.更多还原