摘要
为探讨植物根系吸收过程中氮素亏缺与补给及其影响，１９９４～１９９５年，通过沙培盆栽试验，研究了２ａ生杨树、刺槐及两者混植在全营养、缺氮、缺钾和缺磷条件下根、茎、叶中氮素营养的变化特性。结果表明：刺槐根含氮量２％～３％，刺槐茎、叶以及杨树根、茎、叶含氮量均为０．１％～１％，刺槐和杨树的含氮量均按根＞茎＞叶根面土分布。正常营养条件下，混交杨根面土含氮量约等于混交槐根面土含氮量＞纯槐根面土含氮量＞纯杨根面土含氮量。在极度缺乏Ｎ素时，植物生长受到抑制，但与正常植株相比植物的氮素百分含量并不低，杨树中氮素积累量由０．５１ｇ下降到０．０７９ｇ，刺槐中Ｎ素积累量由１．９４ｇ下降到１．２７ｇ。在极度缺乏Ｐ或极度缺乏Ｋ时，植物中氮素积累量受其影响都有不同程度的下降。杨树与刺槐混交，能够改良土壤中氮素的分布状况，提高杨树根、茎、叶中氮素含量，但２ａ生的混交杨在干重方面并不优于纯林杨，在全营养或缺磷条件下混交杨中氮素积累量高于纯林杨。
The experiments were carried out in 1994 and 1995. Two yearold Shanhaiguan poplar, Robinia pseudoacacia and mixed seedlings of both species were sand cultured with Hoagland′s solutions which had either complete nutrients or deficiency of either elements of N, P or K. Nitrogen element of root, stem, leaf were determined. The results showed that root N contents of Robinia pseudoacacia were 2%～3%, stem and leaf N conents of Robinia pseudoacacia and root, stem, leaf N contents of Shanhaiguan polar were about 0.1%～1%. N contents of both species descended according to the sequence:root>stem>leafrhizospheric soil. Under complete nutrition treatment, rhizospheric soil N contents descended as follows:mixed poplar stand>mixed Robinia pseudoacacia stand> pure Robinia pseudoacacia stand>pure poplar stand. Under extreme nitrogen deficiency treatment, growth was depressed although plant N contents were not reduced comparing to the control treatment. Therefor N accumulation per tree was reduced:the accummulation of N in poplar decreased from 0.51g/tree to 0.079g/tree, and that in Robinia pseudoacacia decreased from 1.94g/tree to 1.27g/tree. Under extreme deficiency of P or K treatment, the N accumulation was also affected by some extend. Mixing polar with Robinia pseudoacacia can improve the distribution state of N nutrition in soil and increase N contents in root, stem leaf of Populus sp. However, biomass of two yearold mixed poolar stand was not higher than that of pure poplar stand. Under complete nutrition or P deficient treatment, N accumulation of mixed polar stand was higher than that of pure stand.
出处
《河北林果研究》
1997年第2期108-113,共6页
Hebei Journal of Forestry and Orchard Research
关键词
杨树
刺槐
混交
氮素
积累量
生物量
mixed forest of poplar and Robinia pseudoacacia
nitrogen accumulation
biomass
