be not fertile enough to justify cropping
不够肥沃，所以不值得耕种

cultivate inferior
开垦贫瘠土地 

The supply of good land is limited.
良田资源是有限的。

to feed a large population
养活众多的人口 

cause pollution and health problems
引起污染和健康问题

chemical fertilizer
化肥 

destroy harmful insects
消灭害虫 

Insecticides also kill helpful insects.
杀虫剂也会杀死益虫。

save water during irrigation
节水灌溉

use up ground water
用尽地面水 

increase food production to help feed the growing world population
提供粮食产量为不断增加的世界人口提供食物 

keep soil from drying out and prevents the loss of soil
避免土壤干化和流失

One important form of soil conservation is the use of windbreaks.
土壤保持的一个重要方法是利用防风林。 

be carried out in a way that does not damage the environment
以一种不破环环境的方式被执行 

avoid a possible grain shortage
避免可能出现的粮食短缺 

deserve to be called a broad-minded policy
应被视为有长远眼光的策略

invest more in agricultural technology
加大对于农业科技的投资 

Sustainable development methodes are designed to save resources.
开展可持续发展的目的在于节约资源。