不同农业土地利用类型对北方传统农耕区土壤养分含量及垂直分布的影响

Effects of Agricultural Land-use on Soil Nutrients and the Vertical Distributions in Traditional Cultivated Region,Northern China

为了探讨果树和蔬菜种植对传统农耕区土壤质量的影响,对北京市延怀盆地果园、蔬菜地土壤与传统种植作物玉米、豆科作物土壤的化学性质及养分垂直分布进行了比较研究,结果表明:(1)在100cm土层中,不同农业利用类型土壤中总有机碳(SOC)、全氮(TN)、全磷(TP)、速效磷(AP)含量均呈现自上层向下层逐渐降低的趋势,养分含量的差异主要发生在0～10cm和10～25cm土层中。(2)在0～10cm土层中,种植果树土壤中SOC含量最高,种植蔬菜土壤中的TN、TP、AP最高;在10～25cm土层中,种植蔬菜的土壤中SOC、TN、TP、AP含量最高;在25～40cm土层中,种植蔬菜的土壤中AP含量显著高于种植其他作物土壤中AP含量;在40～70cm土层中,种植果树的土壤中TP含量显著高于种植其他作物土壤中TP含量;在40～100cm土层中,4种农业土地利用类型土壤中SOC和TN含量差异不显著。(3)种植果树有利于土壤质量和碳库含量的提高;蔬菜地养分含量较高,但存在较大水体富营养化的潜在风险。

The pressures of development and major shifts of land use in agro-ecosystem have increased the need to assess the impact of land use change on soil nutrients. This study was conducted in an area with intensive agricultural land use in Yanqing basin, Beijing Municipality of China to assess effects of land use change on soil organic carbon （SOC）, total nitrogen （TN）, total phosphorus （TP） and available phosphorus （AP）. Soil sample cores to 100 cm depth were collected from orchard land, vegetable land, Maize （Zea mays L.） land and legume （soybean （Glycine max （L.） merr.） and alfalfa （Medicago sativa L.） land in 2005. Tile results showed that （1） in the whole soil profile （0 - 100 cm depth） SOC, TN, TP and AP concentrations were higher in upper layers than lower layers. However, most of the changes occurred within the upper layers of 0 - 10 and 10 - 25 cm.（2） SOC concentrations are the highest for orchard land and TN, TP and AP concentrations are the highest for vegetable land within 0 - 10 cm layers; and SOC, TN, TP and AP concentrations are the highest for vegetable land within 10 - 25 cm layers; AP concentrations are significantly higher for vegetable land than the other land use within 25 - 40 cm layers; and TP concentrations are significantly higher for orchard land than the other land use within 40- 70 cm layers; There were no significant differences in SOC and TN concentrations among the four land use types through the 40 - 100 cm soil profile.（3）orchard land could increase soil nutrient contents and carbon stocks to improve the soil quality, while vegetable land could increase soil nutrient contents and the risk of water eutrophication too.