农学，农艺学：农业的一个分支，主要研究土地的管理和作物的生产。

Agronomy a branch of agriculture dealing with soil management and crop production.

这可能是由于缺乏化肥、资源管理或农艺学不良、在错误的时间有太多水或太少的水。

It may be lack of fertilisers, poor husbandry or agronomy, too much water or too little at the wrong time.

按农艺学和用途可将中国作物分为8大类即粮食作物、经济作物、蔬菜作物、果树作物、饲用和绿肥作物、花卉作物、药用作物和林木作物。

The 8 kinds: food crop, economic crop, vegetable crop, fruit crop, forage and manure crop, flower crop, medicine crop and forest crop in China, according to agronomy and use were differentiated.