滴灌条件下马铃薯耗水规律及需水量的研究

Patterns of water consumption and requirements of potato under dropping irrigation

通过田间试验,用水量平衡法和蒸渗仪实测了不同滴灌灌水控制方式下的马铃薯耗水量。结果发现,在滴灌条件下,马铃薯水分腾发量(ET)受土壤基质势下限的影响要比灌水频率大。在土壤基质势高于-25kPa时,ET主要受气象因素的影响;土壤基质势降低时,会导致马铃薯腾发量的下降;当土壤基质势低于-45kPa时,马铃薯就会受到明显的水分胁迫,引起腾发量大幅度下降。大于或等于1次/4d滴灌灌水频率对马铃薯的腾发量影响不明显;但当滴灌灌水频率为1次/6d或1次/8d时,由蒸渗仪测得的马铃薯腾发量明显低于更高频率处理。可以用-25kPa水势处理下的腾发量作为滴灌马铃薯的参照腾发量。研究表明,20cm蒸发皿的蒸发量与马铃薯腾发量之间有非常好的相关性,用20-cm蒸发皿的蒸发量作为灌溉计划的参考量是可行的。

The field experiment adopted the water balance method and a lysimeter to measure the water consumption of potato in different mode of drop irrigation. It showed that in drop irrigation, soil matric potential affected the evapo-transpiration of potato more strongly than the irrigating frequencies. Where the soil matric potential was more than -25 kPa, the ET mainly depended upon metrological factors; Decreased soil matric potential could lead to decreas ET; where the soil matric potential was more than -45 kPa, potato obviously suffered from water stress that resulted in a greatly decreased ET. Where the irrigating frequency was 1 or more than 1 every four days, it did not remarkably affect the ET of potato; but where the irrigating frequency was 1 every six days or 1 every eight days, the ET of potato measured by a lysimeter was obviously higher than what it was in the treatment with a higher irrigating frequency. So the ET in the treatment with a water potential of -25 kPa could be taked as the reference ET of potato. In addition, the experiment showed that the evaporation of a 20-cm evaporating dish was very comparable to the ET of potato and thus it was feasible to adopt the evaporation of the 20-cm evaporating pan as a reference in irrigation planning.