南疆核桃与小麦间作系统种间根直径及比根长空间分布特征

Spatial Distribution of Root Diameter and Specific Root Length in Walnut/Wheat Agroforestry System in Southern Xinjiang

采用根钻法取样,对南疆和田核桃冬麦间作系统根系的空间分布特征进行研究,通过分析核桃/冬麦间作不同种植模式中核桃（Juglans regia L.）和冬麦（Triticum aestivum L.）的地上部生物量、土地当量比（LER）及地下根系生物学特性的空间分布,为南疆核桃冬麦复合系统的合理配置和高效生产提供理论依据。结果表明,核桃/小麦间作系统核桃树和小麦的地上部生物量下降。核桃/小麦间作系统地上部生物量和土地当量比（LER）（1.620、1.617）均大于1,相比相应单作模式有较高土地利用效率。间作条件下的核桃树和小麦根直径（RD）比单作相应土层根直径（RD）小,但间作条件下的核桃树和小麦比根长（SRL）比单作相应土层SRL大。复合系统中0-40cm土层1a生核桃和2a生核桃的根直径比单作1a生核桃、单作2a生核桃的根直径降低30.36%、26.18%;复合系统中与1a生核桃间作、与2a生核桃间作0-40cm土层的小麦根直径,比小麦单作降低23.7%、59.2%。复合系统中0-40cm土层的1a生核桃、2a生核桃的比根长,比1a生核桃单作、2a生核桃单作增加14.3%、6.7%;复合系统中与1a生核桃间作、与2a生核桃间作0-40cm土层的小麦比根长比小麦单作增加2.1%、22.5%。核桃树与小麦根系在0-40cm土层生态位重叠,促使间作核桃树和小麦根直径、比根长分布不均匀。

A study was conducted to discuss the spatial distribution of root system of walnut trees and wheat in walnut-wheat intercropping system by soil coring method at Hetian in southern Xinjiang.Aboveground biomass,land equivalent ratio and the spatial distribution of roots biological characteristics were analyzed in the different walnut trees（Juglans regia L.）/wheat（Triticum aestivum L.）agroforestry systems.The results showed that aboveground biomass of walnut and wheat decreased in the walnut/wheat intercropping system.The land equivalent ratio of aboveground biomass（1.620and1.617）of walnut/wheat intercropping system were greater than 1,compared with the corresponding sole systems,it had a higher efficiency in land use.Root diameters of intercropped walnut tree andwheat were lower than it in the cocorresponding soil in sole systems,but specific root length of intercropped walnut tree and wheat were higher than it in the cocorresponding soil.Root diameter of intercropped 1-year-old walnut,2-year-old walnut decreased by 30.36%and 26.18%compared with its sole1-year-old walnut,2-year-old walnut in 0-40 cm soil of agroforestry ecosystem,Root diameter of intercropped wheat with 1-year-old walnut,2-year-old walnut decreased by 23.7%and 59.2%compared with its sole wheat in 0-40 cm soil of agroforestry ecosystem.specific root length of intercropped 1-year-old walnut,2-year-old walnut increased by 14.3% and 6.7% compared with its sole 1-year-old walnut,2-year-old walnut in 0-40 cm soil of agroforestry ecosystem,specific root length of intercropped wheat with 1-year-old walnut,2-year-old walnut increased by 2.1% and 22.5% compared with its sole wheat in 0-40 cm soil of agroforestry ecosystem.The roots of walnut tree and wheat had niche overlap in the 0-40 cm soil.It caused that root diameter and specific root length of intercropped walnut tree and wheat distributed unevenly.So the results can offer an important strategy for suitable pattern and efficient production of walnut trees/wheat agroforestry system in southern Xinjiang.