底墒差异对压砂地西瓜耗水规律的影响

通过田间试验研究了播前灌水营造底墒差异对压砂地土壤水分动态变化、西瓜耗水规律、西瓜产量和水分利用效率的影响。结果表明：播前灌水造墒处理不同程度提高了1 m土层土壤水分含量，但灌水定额过大（70 m³·667m^-2和55 m³·667m^-2）会引起水分深层渗漏；西瓜生育前期耗水量随着播前灌水量降低而降低；西瓜需水高峰期，当1 m土层底墒在222～270 mm范围内，耗水量随1 m土层底墒增加而降低；底墒差异还会影响收获期1 m土层土壤水分含量；综合西瓜产量和水分利用效率，在试验区域内，当西瓜生育期降雨量在85 mm左右，1 m土层土壤储水量在250 mm就可保证西瓜正常生长。另外，压砂地夏季休闲措施提高了土壤水分含量，1 m土层土壤储水量增加了2.7 mm，为下一季作物提供了良好的土壤水分条件。

Impacts of different soil water storage to water consumption rule of watermelon in land of gravel-mulching

Through the field experiments, have researched the dynamic changes of different soil water storage to the soil water, impacts of water consumption rule of watermelon, yield and water use efficiency on gravel field. The results showed that irrigation before sowing to increase the soil water content in 1 m soil layer. But if the irrigating water quota was too much as 70 m³·667m^-2 or 55 m³·667m^-2, will be caused the deep percolation losses. The water consumption of watermelon during earlier growing stage was dropped with the decrease of soil water storage in 1 m soil layer during earlier growing stage. When soil water storage before sowing was at the range of 222 to 270 mm, the water consumption of watermelon will be decreased with increase of irrigation amount at the peak period of water requirement. The different soil water content before sowing will be influenced the soil water content in 1 m soil layer during harvesting season. Comprehensive consideration of watermelon fruits yield and its water use efficiency, when the rainfal l was 85 mm during watermelon growth stage, soil water storage of 250 mm in 1 m soil layer before sowing could guarantee its normal growth in the test area. In addition, the treatment of summer fallow for the land with gravel-mulching, will enhanced soil water content, the soil water storage increased 2.7 mm in 1 m soil layer. It provides suitable soil water condition for subsequent crop.