Equally crucial is lower-tech research into basics such as croprotation and mixed farming of animals and plants on small farms.
同样重要的是，开展对基础知识的低端技术研究，如庄稼轮作，在小型农场中发展动植物混养。
2
Between 1000 and 1300 Europe's urban population more than doubled, to about 70m (thanks partly to a new system ofcroprotation, made possible by better tools).
But the system has also encouraged farmers to alter time-honored croprotation practices and the mix of herbicides that previously had kept weeds in check.