黄土高原旱作区马铃薯叶片和土壤水势对垄沟微集雨的响应特征

于2011年在黄土高原半干旱地区以平地不覆膜为对照，研究了不同沟垄和覆膜方式对马铃薯叶片和土壤水势水势的影响。结果表明：不同沟垄和覆膜方式在不同土层和不同生育期对土壤和叶片水势的影响差异显著。（1）土壤水势日变化趋势：0～20 cm土层，土垄处理在开花期为先下降后上升型，土垄和覆膜垄处理在块茎膨大期为先下降后上升型，覆膜垄和全膜双垄沟播处理在成熟期为先下降后上升型，其余为逐渐下降型；20～40 cm土层，各处理土壤水势呈逐渐下降趋势。（2）叶片水势日变化趋势：开花期和块茎膨大期表现为双低谷型，双低谷分别在13：00和17：00，成熟期为“V”型，即单低谷型，低谷出现在17：00。各处理变化趋势相同，但水势存在差异。土垄处理在水分关键期（开花期和块茎膨大期）叶片水势显著高于其他处理，而全膜双垄沟播处理在成熟期最高。（3）生育期土壤水势和叶片水势均表现为先减小后增大的趋势。20～40 cm土层对叶片水势影响较大，土垄处理在该土层具有较好的水分状态，蒸腾作用较强加速了水分运移速率，是导致覆膜垄和全膜双垄沟播处理水势低于土垄的主要原因。在前期降雨较少的年份，由于较小的蒸腾作用，土垄处理可以保证马铃薯承受较小的水分胁迫；在前期降雨量较多的年份，覆膜垄和全膜双垄沟播处理则可以凭借其较大的蒸腾作用发挥较大的增产效果。

Responses of Potato Leaf and Soil Water Potential to Furrow-Ridge and Film-mulching Treatments in the Rain-fed Region of Loess Plateau

Experiment was conducted in the semi-arid rain-fed region of Loess Plateau, where rain-fed agriculture occupies a very important position and water is the main limitation in these areas. In this paper, we explored responses of potato leaf and soil water potential to furrow-ridge and film-mulching treatments. The results showed that potato planted by furrow and ridges with film mulched had a significant impact on leaf and soil water potential. In different soil layers, the diurnal variation pattern of soil water potential was different at different growth stages. In 0-20 cm soil layer, the diurnal variation pattern of soil potential of potato by the treatment of soil ridge (NM) at the stage of anthesis, the diurnal variation pattern of soil potential of potato by the treatment of soil ridge with plastic-covered (M) at tuber expansion period, the diurnal variation pattern of soil potential of potato by the treatments of plastic-covered ridge (M) and double-ridge with film covered (DR) at maturity were going down at first, and then going up at late afternoon, the diurnal variation of other treatments were going down gradually. In 20-40 cm soil layer, the diurnal variations patterns of soil potential of potatoes by all treatments were going down gradually. The diurnal variation patterns of leaf water potential had two different styles: double trough type and single trough type. All treatments were of the same trend. At the stages of anthesis and tuber expansion period, the diurnal variation patterns of leaf water potential were double trough type and the troughs occurred at about 13:00 and 17:00. At maturity stage, the diurnal variation pattern of leaf potential was single trough type and the trough occurred at about 17:00. The trend of soil and leaf water potential was decreased firstly and then increased with the growth periods. The 20-40 cm soil layer was the most important soil layer to leaf water potential. In this soil layer, soil ridge has kept soil under the soil ridge having the best moisture status, leading to leaf water potential of such a treatment being the highest. If the precipitation before the maturity stage is very small, potato planted by the treatment of NM will bear less soil water stress as a result of smaller transpiration rate. If the precipitation before the maturity stage is sufficient, potato planted by the treatment of M and DR can rich larger harvest relying on their greater transpiration rate.