Precision application of agrochemicals is an exciting and active area of research where pesticides and fertilizers are applied only where they are needed and at the appropriate concentration to elicit an optimum response. This approach requires accurate information on soil fertility and pest activity and an applicator that can automatically vary the application rate as desired.
Mechanical threshing based on human power, but especially on horses, became widespread in the United States and Britain as early as 1830. By 1850 virtually all grain in the United States was threshed by large mechanical threshers, which went from farm to farm during the winter months. Rental markets were extensive.