杨树混交模式养分变化及林木增长率的研究

A Study on Nutrient Dynamics and the Relative Increment Rate in Different Types of Poplar Intercropping

通过杨树与豆科乔、灌木树种混交以及轮作等生物措施，定量研究不同处理对土壤营养元素和林地生产力的影响。河南与北京的两地试验林，采用统一的试验设计，５个处理，３次重复，试验林分别为３．２ｈｍ２和１．８ｈｍ２。１９９２～１９９５年试验结果表明，不同处理间树高、胸径的相对增长率差异极显著（α＝０．０１）、显著（α＝０．０５）或较显著（α＝０．１０）。北京点处理间相对增长率胸径Ｆ＝３．９１６＊、α＝０．０５，树高Ｆ＝２．４２３＊、α＝０．１０。民权点胸径Ｆ＝２８．７６＊＊、α＝０．０１，树高Ｆ＝３．３９＊、α＝０．０５。杨树混交模式土壤营养元素变化呈现规律性；杨树混交和刺槐纯林有利于林地土壤肥力的改善；杨树重茬林地营养元素含量普遍下降。

Through the intercropping of poplar with legume,arbors and shrubs and the rotational cropping of poplar,the effects of different treatments on the soil nutrient elements and the forest land productivity were studied quantitatively.The experimental stands in Henan Province and Beijing cover an area of 3.2 hm 2 and 1.8 hm 2 respectively,where the same experimental design with five treatments and three replications were adopted.The results from 1992 to 1995 showed that the relative increment rates of height and diameter at breast height ( DBH ) were significantly different between treatments at 0.01,0.05 and 0.10 level.At the site in Beijing,the relative increment rates of DBH and height were significantly different between treatments at 0.05 level ( F =3.916) and at 0.10 level ( F=2.423 ) respectively,at the Minquan site in Henan Province,the relative increment rates of DBH and height were significantly different at 0.01 level ( F=28.769 ) and 0.05 level ( F=3.39 ).The soil nutrient elements of different types of mixed poplar stands varied regularly;poplar mixture and black locust can improve the soil fertility of the forest land;in the poplar continuous cropping forest land,all the amount of soil nutrient elements declined and the land productivity degranded significantly.