灌溉也没用：气候变化对人工灌溉区比雨水浇灌区的打击更大。

Irrigation may not help: climate change will hit irrigated systems harder than rain-fed ones.

目的描述人工灌溉区钉螺生长繁殖特征，为实施生态学方法控制钉螺提供理论依据。

Objective to explore the rule of growth and multiplication of snails in man made irrigation, and thus to provide evidence for snail control with ecological method.

美国加利福尼亚州中部一城市，位于默塞德西北偏西。它是农业灌溉区的商业中心。人口22,282。

A city of central California west-northwest of Merced. It is a commercial center in an irrigated farming area. Population, 22,282.