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| Study on Niche of Agroforestry Systems in the Loess Plateau |
| Zhu Qingke,Zhu Jinzhao |
| College of Soil and Water Conservation, Beijing Forestry University, Key Laboratory of Soil and Water Conservation and Combating Desertification, Ministry of Education, 100083, Beijing, China |
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Abstract Based on the investigating spatial structure of roots of trees and wheat in interface and nearby soil between forest belt and crops in agroforestry systems on the Loess Plateau, the niche breadth, niche overlap indexes and niche similarity ratio were calculated according to structure of absorbing roots of trees and wheat. The feature of niche in water and nutrients of trees and wheat in agroforestry systems were analyzed. There is niche breadth of wheat mostly in the soil between 0-40 cm. Alth6ugh there is niche breadth of trees in the soil where ranges from under trees to 1H and 0-100 cm, there is niche breadth of trees mostly in the soil where ranges from 0-100 cm under trees, 0-60 cm in 0.5H to 0-20 cm in 1H. The niche breadth of trees is bigger than that of wheat, so trees can use water and nutrient in deep-layer soil. It makes for alleviating competition for water and nutrient between trees and wheat. But trees are in dominant position for competition in agroforestry systems. There is niche overlap between trees and wheat within 1H and mostly within 0.5H. It becomes negative impacting crops that can be alleviated by saving irrigation and fertilization.
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Received: 27 March 2003
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