中文摘要：

以华北地区西瓜/棉花间作群体为研究对象,于间作共生期内西瓜不同生育阶段设置不同灌水下限,分析了不同水分下限对西瓜/棉花间作水分生产效率及土地利用效率的影响。结果表明,西瓜/棉花间作具有显著的间作优势,其中,西瓜膨大期灌水下限为田间持水率的70%（PD70处理）时,保证了西瓜产量较高的同时显著提高了棉花籽棉产量,PD70处理水分生产效率虽低于单作西瓜处理,但高于其他间作处理和单作棉花处理,该处理总产出值亦较其他处理偏高。间作各处理土地当量比均大于1,其中,PD70处理显著高于其他处理。因此,该地区西瓜/棉花间作系统在共生期西瓜膨大期灌水下限为田间持水率的70%有利于间作系统的协调生长,可以达到节水高产高效的目标。

英文摘要：

The field experiment was conducted to investigate the effect of soil moisture threshold on water pro- ductivity and land use efficiency in watermelon-cotton intercropping system at the North Plain of China. The resuits indicated that watermelon-cotton intercropping system had significantly intercropping advantage. The treatment with lower threshold of 70% field capacity （PD70 treatment） increased the cotton yield significantly, meanwhile, guaranteed the watermelon yield during its expanding process. The water productivity （WP） of PD70 treat- ment was lower than watermelon monoculture, but higher than other treatments remarkably. Moreover, the land equivalent ratio of each intercropping treatment was greater than 1, and PD70 treatment kept the maximum. In conclusion, the treatment of PDT0 is beneficial to the coordinate growth of watermelon-cotton intercropping system and can realize the high production and high efficiency.