At some point, too much fertilizer can actually cause the total yield to fall.

在某种程度上，过多的肥料实际会导致总产量下降。

Plants are nourished from the soil, but to provide optimum food, fertilizer can be applied to encourage vigorous growth.

植物从土壤中获得营养，但为了提供最佳食物，可以施肥以促进旺盛生长。

A simple change, like just the right spacing of seeds and smart use of fertilizer, can make a big difference.

一个简单的改变，比如恰到好处的种子间距和巧妙地使用肥料，就能产生很大的不同。

Recently, however, scientists have been finding that long-term use of these fertilizers can cause damage to the land and, even more dangerous, to people's health.

然而，最近科学家发现长期使用这些肥料会造成土地受损，甚至更危险的是，会对人们的健康造成危害。