【摘要】 以露地土壤(栽培芹菜)为对照,对上海郊区栽培年限5年(栽培西瓜)和9年(栽培番茄)的温室土壤进行浸水淹灌处理96h,研究不同栽培年限温室土壤剖面盐分在浸水淹灌后的垂直再分布规律。结果表明:露地土壤的表土层(0～15cm)、次表土层(16～30cm)及心土层(31～60cm)的各盐基离子均有向下淋洗运移的趋势。对温室土壤而言,淹灌后表土层盐分含量有所下降,次表土层盐分含量明显高于灌水前的初始含盐量,心土层盐分含量变化甚微。这说明温室土壤表层的盐基离子随着淹灌土壤水向下运移,并非直接洗脱进入地下水体,而是在土体的次表土层内受阻并逐渐聚集。栽培年限5年和9年温室土壤次表土层的平均容重分别为1.48和1.54mg·m-3,表明在温室土壤的次表土层可能已经形成一个容重较大的紧实层,阻断温室土壤的毛管孔隙作用,阻碍浸水淹灌时土壤毛管水携盐下行运动,使得土壤次表土层含盐量明显上升。更多还原

【Abstract】 A comparative plot experiment was carried out to study the effect of the leaching flooding on salt redistribution in the profiles of greenhouse soils, with different cultivation history of 5 years （cultivated with watermelon） and 9 years （cultivated with tomato）, using the open field soils （cultivated with celery） as check. Both the greenhouse soils and the open field soils were flooded with water for 96 h. The results showed that the content of salt ions in the open field soil profiles tended to decrease with the order of the surface layer （0-15 cm）, the subsurface layer （16-30 cm）, and the subsoil layer （31-60 cm）, due to the leaching process. In the greenhouse soils, salt was washed out and removed from the surface layers and accumulated in the subsurface layer finally. Salt content in the subsurface layer was higher than the initial value before flooding, while slightly changed in the subsoil layers after water flooding. It was obvious that salt in the surface layer of the greenhouse soils was not directly washed out with downward capillary water and entered the groundwater. Salt ions gradually accumulated in the subsurface layer instead, during the flooding process. Results indicated that a compact layer has been formed in the subsurface layer, with the bulk density of 1.48 and 1.54 mg·m^-3 in the 5-year-cultivated greenhouse soils and 9-year-cultivated greenhouse soils, respectively. This further supported the fact that the increase of salt content after flooding in the subsurface layer of the greenhouse soils was possibly attributed to the destruction of the compact layer against the capillary pore, which therefore led to the blocking of the capillary water movement and the increase of salt content in the subsurface layer.更多还原