不同灌水量对尖果沙枣耗水特性及生长的影响

干旱地区尖果沙枣（Elaeagnus oxycarpa）是水土保持的先锋树种。通过田间试验，利用中子水分仪和烘干法监测土壤水分变化，观测主要气象要素，结合水量平衡原理，计算出不同灌水量下尖果沙枣在生育期内的总耗水量以及日耗水强度，分析尖果沙枣各生长指标对水分的响应关系。结果表明:在实验灌水量条件下，尖果沙枣的耗水量随着灌水量的增加而增大,不同灌水量下尖果沙枣在生育期内的总耗水量依次为172.14 mm、301.11 mm、346.92　mm、372.53 mm、428.74 mm、564.62 mm和631.96 mm；各处理的耗水模系数与其对应的阶段耗水量保持着相同的变化规律。尖果沙枣属于前期耗水型树种，5、6月的耗水量较其他月份高。尖果沙枣逐月日平均耗水强度总体上表现为随着灌水量的增加呈逐渐增大的趋势。在30～90 mm灌水量中，[JP2]各生长指标随着灌水量的增加而增大，但当灌水量达到90 mm后，随着灌水量的增加各生长指标的差异性不再显著，其中以新枝长对水分的响应最为敏感。尖果沙枣的凋萎系数约占田间持水率的11.33%，土壤含水率保持在49.15%以上是不会限制尖果沙枣生长的。

Effects of Different Irrigation Volumes on Water Consumption and Growth of Elaeagnus oxycarpa

Elaeagnus oxycarpa is a pioneer species planted for water and soil conservation in arid area.In this study,neutron probe and oven drying method were used to monitor the change of soil moisture content,water consumption and water consumption intensity of E.oxycarpa were calculated using the water balance principle,and the growth of E.oxycarpa was analyzed.The results show that water consumption of E.oxycarpa was increased with increasing the irrigation volume,and the total water consumptions under 6 irrigation volumes were 172.14 mm,301.11 mm,346.92 mm,372.53 mm,428.74 mm,564.62 mm and 631.96 mm respectively.The change of water consumption modulus was similar to the variation of the corresponding water consumption.Water consumption of E.oxycarpa in May and June was higher than that in other months,and the average daily water consumption intensity was also in a gradual increase trend with increasing the irrigation volume.All the growth indexes of E.oxycarpa were increased with increasing the irrigation volume in an irrigation volume range of 30-90 mm,but their differences were not significant when the irrigation volume was higher than 90 mm,especially the response of new branch length to irrigation volume was the most sensitive.Proportion of wilting coefficient of E.oxycarpa accounted for 11.33% of the field water capacity.Growth of E.oxycarpa could not be restricted when the field water capacity maintained higher than 49.15%.