Tilling can remove weeds and the waste from last season's crops and help break down old plant material into fertilizer. But it can also increase the risk of soil erosion by rain or wind.

耕作可以清除杂草和上一季的农作物残茬，并且有助于将原来的农作物残茬分解成化肥，但它也会增加因风蚀、水蚀造成水土流失的风险。

That's why researchers are prospecting for more alternatives, preferably ones that don't rely on food crops or a 51 cents-per-gallon tax break.

这就是研究者探求更多替代燃料的原因，最好是不依赖粮食作物或每加仑51美分减税的替代燃料。