【摘要】 干旱地区地表蒸发引起土壤水的散失是造成作物低产的重要原因之一。聚丙烯酰胺(PAM)与磷石膏(PG)是效果良好的土壤结构改良剂,用于改良土壤结构,可能影响土壤水分的运动/输运及蒸发过程。本研究以不同PAM与PG用量的组合,定量研究这两种土壤结构改良剂用量对土壤水分蒸发的作用效果及其作用机理。在实验室人工气候箱内,采用不同的土柱高度(10,20,30cm)、PAM用量(0、1、2、4gm-2)、及PG用量(0、200、400、800gm-2),在温度为恒定(15、25、25℃)、相对湿度为(50±2)%的条件下,用称重法逐日测量各处理的土壤蒸发动态过程。实验结果表明,土壤结构改良剂对蒸发确有抑制作用,且随着PAM用量的增加,累积蒸发量和蒸发失水比均有所降低;而PG的作用效果则不同,表现为随着PG用量的增加,累积蒸发量有所增加,且这种差异随着用量渐趋明显,而蒸发失水比在各PG用量间差异不显著。更多还原

【Abstract】 Water loss from soil profile through soil surface evaporation is one of the main reasons to cause lowered crop productivity in the arid and semi-arid regions. Polyacrylamide (PAM) and phosphogypsum (PG), as soil conditioners, have been used to improve soil structures and may influence soil water transportation process and consequently soil water evaporation process. A series of laboratory experiments were conducted to quantitatively investigate the impacts of different PAM and PG application rates and their combinations on soil surface evaporation. Experiments were conducted in artificial growth chambers, under different soil column heights (10, 20, and 30 cm), different PAM application rates (0, 1, 2, 4 g m-2), different PG application rates (0, 200, 400, 800g m-2) , and under the controlled environments at temperatures of 15,25 and 35 ℃ and a relative humidity of (50±2)%. The dynamic processes of soil surface evaporation were determined by weighting soil columns every day. The results showed that soil conditioner did restrain soil water evaporation, accumulative evaporation and percentage water losses decreased with the increase of PAM dose. But, PG was different, and accumulative evaporation increased with PG doses. Differences of Percentage water losses between treatments were not obvious.更多还原