晋西黄土区核桃-谷子间作系统水肥影响域

Distance of edge influence of soil moisture and nutrients in walnut-millet intercropping systems in the Loess Plateau in west Shanxi Province

为了定量判定晋西黄土区果农间作系统水肥主要竞争区域,以核桃-谷子间作系统为研究对象,对土壤水分和土壤养分进行定位监测,采用移动窗口法定量判定间作系统中土壤水分和土壤养分的影响域。结果显示：当窗口宽度为2时,移动窗口法能有效地判定出土壤水分和土壤养分的影响域。40-100 cm土层,距树行不同距离处的土壤水分和土壤养分含量相异性较小,难以判定影响域;综合0-40 cm、0-100 cm土层的土壤水分状况,土壤水分的影响域范围是距树南侧1.75 m到距树北侧1.25 m,影响宽度为3 m,即主要竞争区域为距树南侧1.75m到距树北侧1.25 m;不同的土壤养分指标影响域的范围不同,综合考虑土壤养分的四个不同指标（有机质、全氮、速效磷和速效钾）及其在0-40 cm、0-100 cm两个土层的分布情况,土壤养分的影响域是距树南侧2.25 m到距树北侧2.25 m,影响宽度为4.5 m,即主要竞争区域为距树南侧2.25 m到距树北侧2.25 m。建议在土壤水分和土壤养分的主要竞争区域,采取改变垄沟、起垄覆膜、选择性施肥等措施,缓解核桃、谷子之间的竞争,提高资源利用效率,增加当地农民经济收入。

In order to divide the main competition area for intercropping systems and provide a theoretical guidance for the sustainable and efficient management of intercropping systems on the Loess Plateau in west Shanxi Province,the walnut-millet intercropping system was studied.Soil moisture and nutrients in the intercropping systems were monitored.Moving split window technique was used to detect the distance of edge influence of soil moisture and nutrients in the intercropping systems.The results showed that when the window width reached 2,the distance of edge influence of soil moisture and nutrients could be detected by moving split window technique.It is difficult to determine the distance of edge influence in 40-100 cm soil layer because soil moisture and nutrients content at different distances from the tree row were quite similar.Combining soil moisture in 0-40 cm and 0-100 cm soil layers,distance of edge influence of soil moisture was from 1.75 m away in the south to 1.25 m away in the north side of the tree,that was to say influencing width was 3 m,which means the main competition area of soil moisture ranged from 1.75 m south of the tree to 1.25 m north of the tree.Different soil nutrient indicators had different distance of edge influence.Taking into account of the distribution of four soil nutrient indicators（organic matter,total N,available P and available K） in 0-40 cm and 0-100 cm soil layers,distance of edge influence of soil nutrients was 2.25 m south away from the tree to 2.25 m north away from the tree and the influencing width was 4.5 m,which means the main competition area was from 2.25 m south of the tree to 2.25 m north of the tree.Changing ridge and furrow,covering ridge and fertilizing selectively in the main competition area of soil moisture and nutrienls was proposed to ease the competition between walnuts and millet so as to improve efficiency of resource use and increase the income of local farmers.