Elements that are removed from the ecosystem to make the operation yield more grain more quickly (that is, to make it more efficient) would otherwise actually provide benefits to farming. The plants removed by tillage, for example, could have helped to prevent erosion and flooding and to stabilize and rebuild soil. They would have provided habitat for insects and birds, some of them natural enemies of crop pests. Now, as pests grow resistant to pesticide, their numbers increase because their natural enemies have been wiped out.
