碎石含量和盖度对黄土高原农田土壤水分的影响

Effect of Rock Fragment Coverage and Content on Soil Moisture of Farmland in Loess Plateau

根据自然界中碎石存在的2种形式,布设碎石覆盖和土石混合2个试验,利用中子仪定期监测土壤水分变化,研究碎石对黄土高原农田土壤水分的影响,以期为黄土高原地区农业灌溉提供参考依据。结果表明,碎石覆盖及无碎石覆盖处理土壤含水量均随土层深度的增加呈先增加再缓慢减少的趋势,但碎石覆盖处理土壤含水量减小幅度明显低于无碎石覆盖处理,且随着碎石覆盖量的增加土壤含水量减小幅度变小;土石混合处理土壤含水量呈波浪式增加趋势,尤其是碎石含量高的处理,而无碎石混合处理呈平缓增加趋势,且其土壤含水量明显低于土石混合处理。总之,碎石覆盖和碎石镶嵌在土壤中均可以提高土壤含水量,其中碎石覆盖于地表可以有效抑制表层土壤水分蒸发,增加水分入渗深度;碎石镶嵌在土壤中可以改变土壤物理性质,增加土壤入渗率和大孔隙数量,且碎石含量越高,其对土壤物理性质的影响程度越大。

To study the effect of rock fragment on the change ot tarlmanct but, Loess Plateau, this paper designed two existence forms of rock fragment, rock fragment coverage and soil-rock fragment mixture, according the existence forms of rock fragment in nature,and mo- nitored the variation of soil moisture periodically. The results showed that both the rock fragment coverage and no rock fragment coverage made the soil moisture increased first and then decreased slowly with the increase of soil depth. But the soil moisture content of rock fragment coverage treatment decreased significantly lower than no rock fragment coverage treatment, and it de- creased less slowly with the increase of rock fragment coverage. The soil-rock fragment mixture made a wave increase of the soil moisture in particular the high rock fragment content treatment, but the soil moisture of no rock fragment mixed treatment increased gently and slowly. In short, rock fragment coverage can effectively inhibit the surface soil moisture evaporation, and increase the infiltrative depths ,while rock fragment stone inlaid in the soil can change the physical proper- ties of soil,and increase the infiltration rate and number of macropore, soil water content in soil, especially the high rock fragment content treatment.