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石羊河下游因水资源减少而退耕大面积土地,测试其物理性质,旨在为管理提供依据。选择不同退耕时期(1年、2年、3年、4年、5年、8年、15年、24年和31年)土地,分层采集0~40 cm范围内土样,分析其容重、孔隙度和机械组成。结果表明:随着退耕年限增加,土壤粘粒呈减少趋势,粉粒增加,退耕4年达到最大,之后则略有增减;土壤垂直剖面的土壤粒度分异性增大,而变化最大的土层为0~10 cm。退耕土壤容重随着退耕时间延长而增加,退耕3年之后的不同深度的土壤容重及孔隙度的差异变小。随着退耕年限增加,土壤质地变粗,通透性增加,土壤质量下降。退耕3~4年期间的土壤物理性质相对变化明显,是退耕地管理的关键时期。
Due to the decrease of water resources in the lower reaches of Shiyang River, large areas of land are decontaminated and their physical properties tested to provide the basis for management. The land samples of 0 ~ 40 cm were collected in different strata during different periods (1 year, 2 years, 3 years, 4 years, 5 years, 8 years, 15 years, 24 years and 31 years) Porosity and mechanical composition. The results showed that with the increase of returning farmland age, the clay content decreased, the grain size increased, the maximum was reached after 4 years of conversion, and then increased or decreased slightly. The soil particle size distribution of the vertical profile increased, Is 0 ~ 10 cm. The bulk density of returned farmland increased with the extension of the time of returning farmland, and the difference of soil bulk density and porosity at different depths after three years of farmland conversion became smaller. With the increase of returning farmland, soil texture becomes thicker, permeability increases, and soil quality declines. The physical changes of soil physical properties during the 3 ~ 4 years of conversion have obvious changes, which is a crucial period for the management of the conversion of cultivated land.