摘要
The aim was to analyze effects of jujube planting years on changes of soil nutrient elements and explore the causes of orchard degradation by researching variation characteristics of soil nutrient contents in orchards with different planting years, providing theoretical support for the soil degradation of jujube or-chards. [Method] Soil samples were col ected in depth at 0-20 and 20-40 cm from the sites in or out of tree canopy scope in jujube orchards with 3, 5 and 7 plan-ning-years, to analyze contents of available N, P and K, organic matter, total N, salts, and trace elements, as wel as changes of nutritional elements. [Result] Avail-able boron, copper, iron, manganese, zinc and available potassium in soils of jujube orchards with 3, 5 and 7 years planting history reduced as planting year increased, which coincided with that in the soil of 20-40 cm. [Conclusion] Because trace ele-ments are never applied in southern Xinjiang, available B, Cu, Fe, Mn, and Zn and available K would be consumed by tree root growth. Due to root distribution differ-ences and ploughing effects in fields, the contents of nutrients tend to be volatile in or out of tree canopy scope. Tree root in deeper soils absorbs more nutrients, and soil nutrients would decrease dramatical y if additional chemical fertilizers are not provided, leading to soil degradation.
[目的]通过研究不同种植年限枣园土壤营养元素含量变化特征，分析枣园种植年限对土壤营养元素变化的影响趋势，探明枣园退化关键原因，为枣园退化提供理论支持。[方法]研究3年、5年、7年种植年限枣园，按照枣树冠幅内、外一周各取0~20 cm和20~40 cm各4个土样混合，分析土壤速效氮磷钾、有机质、全氮、盐分、微量元素含量，分析土壤营养元素含量变化特征。[结果]3年、5年、7年果园冠幅内外土壤0~20 cm和20~40 cm土壤微量元素（效硼、铜、铁、锰、锌）和土壤速效钾随着种植年限而降低；冠幅内土壤0~20 cm土壤速效氮、有机质随着种植年限增加而降低；冠幅外土壤20~40 cm的土壤有机质、速效氮、速效磷含量随着种植年限的增加而降低。[结论]由于新疆南部地区果园普遍不施微肥以及不施或少施钾肥，而随着种植年限的增加，果树根系及作物吸收消耗了土壤有效硼、铜、铁、锰、锌和钾元素，使得土壤微量及钾肥呈现降低趋势。同时果树和大田作物根系分布的差异性以及大田作物间耕作效应，使得冠幅内外在不同深度土壤养分含量存在差异性；果树根系较深，对冠幅外土壤深层养分吸收消耗较多，随着种植年限的增加，在施肥过程中不能及时补充就会造成土壤养分消耗降低，使得果园土壤退化。
基金
Supported by Science&Technology Support for Xinjiang(201191143)
Special Fund for Xinjiang Water Conservancy Science&Technology(2013T04,2013T05)
Key Laboratory of Construction Project of Xinjiang Academy of Agricultural Sciences(xjnkkl-2013-001)~~
作者简介
王治国（1980-），男，新疆人，硕士，助理研究员，研究方向：土壤生态与农业节水．E—mail：wangzhiguo214@126．com。通讯作者，冯耀祖（1973-），男，在读博士，研究员，研究方向：土壤生态与农业节水．E-mail：fengyaozu@sina.com
