微地形对大西沟新疆野杏萌发层土壤因子的影响

野杏是新疆野果林的主要建群种和种质资源树种。野杏在种子萌发成苗期,幼苗的根系主要分布在0—15 cm土层中。为了阐明坡向、坡位、坡度和坡形等微地形因子对野杏种子萌发层土壤特征和养分分布的影响,在新疆伊犁州霍城县大西沟的封育野果林内(44°26′01.09″—44°26′17.12″N,80°46′27.49″—80°47′03.26″E)设置样地,测定0—15 cm土层的土壤砾石、酸碱值、有机质和全氮、全磷、全钾、水解性氮、有效磷和速效钾含量,分析各土壤因子和地形因子的关系。结果表明:(1)东北坡土壤养分含量较高,其土壤砾石含量、酸碱值、有机质、全磷、水解性氮和速效钾含量与东南坡、南坡皆存在显著差异(P0.05),阴坡的土壤有机质、全氮、有效磷和速效钾含量都高于阳坡,不同坡向的土壤特征和养分分布存在显著差异(P0.05);(2)不同坡位的土壤有机质、全氮、全磷和有效磷含量均表现为中坡位下坡位上坡位,土壤砾石、全钾和速效钾含量均呈现上坡位中坡位下坡位,全钾、全磷和有效磷含量在同坡位分布较均匀,不同坡位的土壤特征和土壤养分分布无显著差异(P0.05);(3)不同坡度下的土壤水解性氮和有效磷含量是缓坡中坡缓中坡陡坡,土壤砾石、酸碱值、全氮、水解性氮、有效磷和速效钾含量有显著差异(P0.05),陡坡土壤有机质、全氮、水解性氮和有效磷含量均低于其他坡度,而土壤砾石、土壤酸碱值和全钾在陡坡土层中含量最高,缓坡与缓中坡的土壤养分含量丰富,陡坡较为贫瘠,坡度对土壤特征和土壤养分分布有显著影响(P0.05);(4)不同坡形下的土壤砾石、全钾、水解性氮、有效磷和速效钾含量是凸形坡凹形坡直线坡,不同坡形下的土壤特征和土壤养分(除全钾和速效钾)均存在显著差异性(P0.05)。野果林地形因子对野杏萌发层土壤特征和土壤养分分布有显著影响,东北坡、中坡位、缓坡和凸形坡土壤养分含量较为丰富,是适宜野杏萌发的地形。研究结果可为探究影响野杏种子萌发和生长的气候与土壤水热等因子奠定良好基础。

Effects of microtopography on germination layer soil factors in Armeniaca vulgaris Lam. in Daxigou

Armeniaca vulgaris Lam. is the dominant constructive species and germplasm resource tree in the Xinjiang wild fruit forest. In the seedling stage, A. vulgaris seedling roots are mainly distributed in the 0-15 cm soil layer. To elucidate the effects of microtopography, such as slop aspect, position, and shape on soil characteristics and nutrient distribution in the seed germination layer of A. vulgaris, a sample plot (44°26''01.09"-44°26''17.12"N, 80°46''27.49"-80°47''03.26"E) was set up in the wild fruit forest in Daxigou, Huocheng County, Yili Prefecture, Xinjiang. The content of soil gravel, pH, organic matter and total nitrogen, total phosphorus, total potassium, hydrolytic nitrogen, available phosphorus, and available potassium in the 0-15 cm soil layer were measured, and the relationship between soil factors and topographic factors were analyzed. The results showed that in the 0-15 cm soil layer:(1) the soil nutrient content in the Northeast slope was higher, and soil gravel, pH, organic matter, total phosphorus, hydrolyzable nitrogen, and available potassium were significantly different between the Southeast and South slope (P < 0.05); content of soil organic matter, total nitrogen, available phosphorus, and available potassium in the shady slope were higher than those in the sunny slope, and the soil characteristics and nutrient distribution in different slopes were significantly different (P < 0.05); (2) in different slope positions, the soil organic matter, total nitrogen, total phosphorus, and available phosphorus all showed moderate slope > down slope > up slope position. The content of soil gravel, total potassium, and available potassium all showed upward slope > middle slope > downhill slope position. The content of total potassium, total phosphorus, and available phosphorous were more homogeneous in the same slope position. There was no significant difference in soil characteristics and soil nutrient distribution in different slope positions (P > 0.05); (3) in different slopes, the content of soil hydrolyzable nitrogen and available phosphorous were gentle > mid > slow > steep slope, the soil gravel, pH, total nitrogen, hydrolyzable nitrogen, available phosphorus, and available potassium had significant differences (P < 0.05). The content of soil organic matter, total nitrogen, hydrolyzable nitrogen, and available phosphorus in steep slopes were all lower than those in other slopes. However, the content of soil gravels, soil pH, and total potassium were the highest in the steep slopes. So, the content of soil nutrients in the gentle and moderate slopes were rich, and the steep slopes were more barren. The slope degree has a significant effect on soil characteristics and nutrient distribution (P < 0.05); (4) under different slope shapes, the contents of gravel, total potassium, hydrolyzable nitrogen, available phosphorus, and available potassium were convex > concave > linear slope, soil characteristics and nutrients (except total potassium and available potassium) were significantly different between different slope shapes (P < 0.05). In the wild fruit forest in Daxigou, the topographic factors have a significant effect on the soil characteristics and nutrient distribution in the germination layer of A. vulgaris. The soil nutrient content in the Northeast, middle, gentle, and convex slopes are relatively rich, and the soil conditions are suitable for A. vulgaris germination. These results provided a good base for research on the seed germination, growth, and the monitoring of environmental factors.