| 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. |