沙地樟子松人工林生长对非降雨季节土壤水分的影响

Effects of the growth of Pinus sylvestris var. mongolica plantation in sandy land on soil moisture in non-rainfall seasons

以13、25~27、42、56年生沙地樟子松人工林为研究对象,以相邻草地为对照,在非降雨季节取样,测定0~10、10~20、20~40、40~60、60~80、80~100 cm土层土壤水分及其他土壤理化因子,分析不同年龄樟子松人工林非降雨季节土壤水分的变化规律。结果表明:沙地营建樟子松人工林后,幼龄林0~100 cm层土壤水分高于草地;中龄林、成熟林土壤含水量在土壤剖面逐层递减,但中龄林20~100 cm层低于草地,成熟林高于草地;过熟林土壤含水量随土层的变化呈"S"型曲线;随着林分年龄的增加,土壤水分在0~10 cm层与林龄无显著关系,10~20 cm层与林分林龄呈显著负线性关系,20~100 cm层随林龄的增加呈先下降后升高趋势,尤其是过熟林,土壤含水量高于中龄林、成熟林;土壤含水量在10~40 cm层与碱解氮呈极显著正相关,在40~60 cm和80~100 cm层与有效钾呈显著正相关;而0~10和60~80 cm层土壤含水量与其他理化因子无明显关系。

We measured soil moisture and other soil physicochemical factors in depths of 0-10,10-20,20-40,40-60,60-80,80-100 cm in different aged( 13,25-27,42,56 a) Pinus sylvestris var. mongolica plantations and adjacent grasslands( as control) on sandy land in nonrainfall seasons. We further analyzed the variation patterns of soil moisture of different aged P.sylvestris var. mongolica plantations in non-rainfall season. The results showed that soil moisture in the 0-100 cm layer of young forest was higher than that of grassland. Soil moisture of middleaged and mature forests decreased gradually across the soil profile. Soil moisture of middle-aged forest in the 20-100 cm layer was lower than that of grassland,whereas soil moisture of mature forest was higher than that of grassland. Soil moisture in the over-mature forest showed an S-shaped curve in the soil profile. Soil moisture in the 0-10 cm layer did not change with the stand age,while that in the 10-20 cm layer was negatively correlated with stand age. The soil moisture in the 20-100 cm layer showed a trend of decreasing first and then increasing over stand age. Soil moisture in over-mature forest was higher than that of middle-aged and mature forests.The soil moisture was significantly positively correlated with the alkali hydrolyzable nitrogen in the10-40 cm layer,significantly positively correlated with the available potassium in the 40-60 and80-100 cm layers,but did not correlate with other physicochemical factors in the 0-10 and 60-80 cm layers.