Abstract: The water requirement(WR) and water requirement rate(WRR) of alfalfa(Medicago sativa L.) were studied in Bashang area of Hebei province using a large scale no-weigh-lysimeter.Results showed that the WR of alfalfa was 243.4,134.2,184.0 and 561.6 mm at the first harvest,second harvest,third harvest and whole growth season(1st～3rd harvest) of 2010,respectively.The WR of first harvest was significantly higher than that of both second and third harvest(P<0.05),and the WR of third harvest was significantly higher than that of second harvest(P<0.05).The WRR was 3.9,4.5,3.5 and 3.8 mm·d^-1 at different stages,respectively.The WRR of second harvest was significantly higher than that of both first and third harvest(P<0.05),and the WRR of both first and third harvest did not have any significant difference.The Kc was 0.83,0.74,0.75 and 0.77 during different stages,respectively.The Kc of first harvest was highest,and the Kc of second harvest was similar to that of third one.According to the detected results of four consecutive years,a comprehensive analysis indicated that the WR,WRR and Kc of alfalfa during the whole growth season in Bashang area were 430~720 mm,3.1~4.9 mm·d^-1 and 0.77~1.12,respectively.

Key words: Alfalfa, Water requirement, Water requirement rate, Crop coefficient, Large scale no-weighting-lysimeter, Bashang area

摘要： 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(Medicago sativa L.)的需水量、需水强度和作物系数。结果表明:坝上地区2010年紫花苜蓿第1,2,3茬和全生长季(1～3茬)需水量分别为243.4,134.2,184.0和561.6mm,第1茬显著高于第2和第3茬(P<0.05),第3茬显著高于第2茬(P<0.05);需水强度分别为3.9,4.5,3.5和3.8mm·d^-1,第2茬显著高于第1和第3茬(P<0.05),第1茬和第3茬差异不显著;作物系数分别为0.83,0.74,0.75和0.77,第1茬最高,第2和第3茬相近。依据连续4年的测定结果综合分析认为,坝上地区紫花苜蓿全生长季需水量、需水强度和作物系数分别在430～720mm,3.1～4.9mm·d^-1和0.77～1.12之间。

关键词: 紫花苜蓿, 需水量, 需水强度, 作物系数, 大型非称重式蒸渗仪, 坝上地区