甘肃山地核桃园土壤水热和养分的变化特征

摘要

为给核桃园土壤管理提供理论依据,对甘肃省康县和清水县核桃园土壤温度、水分变化和矿质养分含量进行了测定与分析,探究了山地核桃园土壤水热和养分的变化特征.结果表明:核桃生育期土壤温度变化曲线呈倒"V"形,不同深度(20~80 cm)土层的年平均温差小于1.0 ℃;随着土层深度的增加,土壤温度的变幅减小,土壤最高、最低温度的出现时间均推后;坚果生长前期(坐果期至硬核期),土壤温度随土层深度的增加而降低,而坚果生长后期(硬核期至成熟期)不同土层的温度相近;土壤温度的变异系数(CV,%)随土层深度的增加而降低.土壤含水量也随土层深度的增加而增加,而其变异系数也随之降低;20 cm深的土壤含水量的变幅最大,80 cm深的变幅最小,平均变异系数为2.42%~5.84%;不同土层的土壤含水量表现为,核桃生长前期的变幅较大而生长后期的变幅较小.土壤有机质、全氮、碱解氮、速效钾及硼、锌含量随土层深度的增加均呈降低趋势;全磷、全钾含量差异不大;钙、镁含量随土层深度的增加而呈降低趋势(康县试验园)或较大变化特征(清水县试验园);两地土壤偏碱性或碱性.%In order to provide some theoretical basises for soil management of walnut orchard, we measured and analyzed soil temperatures, moistures, mineral nutrient contents of walnut orchards in Kang County and Qingshui County of Gansu Province, and researched variation characteristics of soil temperature, moisture and nutrients. The results show that the soil temperature curve was reversed "V" shape at growth period of walnut, and the annual average temperature difference in different soil depth (20-80 cm) was within 1.0 ℃. With soil depth increased, variation range of soil temperature was decreased, and occurrence time of the maximum and minimum temperatures delayed. At the early stage of nut growth (from nut setting stage to shell-hardening stage), the soil temperature was decreased with soil depth increased. While at the later stage of nut growth (from shell-hardening stage to mature stage), the temperatures of different soil layers were similar. The variation coefficient(CV, %) of soil temperature was decreased with soil depth increased. The soil moisture content was increased with soil depth increased,but its variation coefficient was decreased.The variation range of soil moisture content in 20 cm soil layers was the maximum and that in 80 cm soil layers was the minimum, and mean variation coefficient was 2.42%-5.84%.The variation range of soil moisture content at the early stage of walnut growth was bigger than that at the later stage. The contents of organic matter, total N, alkali-hydrolyzable nitrogen, rapidly available K, B and Zn in soil were decreased with soil depth increased. The total P and total K contents had little difference. The contents of Ca and Mg were decreased in Kang County test orchard or changed with a wide range in Qingshui County test orchard with soil depths increased. The soils in the two orchard were alkalescent or alkaline.