坝上地区紫花苜蓿的需水量、需水强度和作物系数（Ⅲ）

The Water Requirement, Water Requirement Rate and Crop Coefficient of Alfalfa in Bashang Area（Ⅲ）

采用大型非称重式蒸渗仪法，研究了河北坝上地区紫花苜蓿（Medicagosativa）的需水量、需水强度和作物系数。结果表明：坝上地区2009年紫花苜蓿第1、2、3茬和全生长季（1—3茬）需水量分别为156．6、255．6、172．2和584．4mm，第2茬显著高于第1和3茬（P〈0．05），第1和第3茬差异不显著；需水强度分别为2．7、5．6、4．1和4．0mm／d，第2茬显著高于第1和第3茬（P〈O．05），第3茬显著高于第1茬（P〈0．05）；作物系数分别为O．60、0．97、0．82和0．80，第2茬最高，第1茬最低。

The water requirement （WR） and water requirement rate （WRR） of alfalfa （Medicago sativa L） were studied in Bashang area of Hebei province with large scale no-weighting-lysimeter. The results showed that the WR of alfalfa during the first harvest, second harvest, third harvest and the whole growth season （1 st - 3rd harvest） in 2009 were 156.6, 255.6, 172.2 and 584.4 mm respectively. The WR of the second harvest was higher than that of the first and the third significantly （P 〈 0.05）, whereas that between the first and the third were not significantly different. The WRR were 2.7, 5.6, 4.1 and 4.0 mm/d respectively. The WRR of the second harvest was higher than that of the first and the third harvest significantly （P 〈 0.05）, and the WRR of the third harvest was higher than that of the first harvest significantly （P 〈0.05）. The Kcs were 0.60, 0.97, 0.82, and 0.80 mm/d, respectively. The Ke of the second harvest was the highest, and the Kc of the first harvest was the lowest.