New technologies are enabling modern farmers to customize crop management for different areas within a given field. Known as site-specific management, this approach is intended to maximize crop yield while minimizing costs and environmental risks, according to a UC Davis precision-agriculture expert. "Farmers were actually practicing site-specific management before the advent of mechanization, as they observed the progress of each part of their field and perhaps applied a little extra manure to spots that looked weak," says Richard Plant, a professor in the Department of Agronomy and Range Science. But agricultural mechanization led to more uniform management systems that distanced farmers from their crops. Only in the 1990s did computers and imaging technology make it possible and economical to return to more localized management systems. Site-specific management includes the use of satellites and aircraft to produce images that reveal soil conditions and plant growth. Instruments are being installed on harvesters to monitor the yield of grain from different parts of a field and on other farm equipment to precisely control cultivation and herbicide application. Other instruments are being used to detect soil conditions and nutrient status of plants at given locations. In a recent issue of the journal Computers and Electronics in Agriculture, Plant projects site-specific management will likely increase the demand for trained, skilled agricultural workers and may promote further consolidation of farms into large operations. He suggests that site-specific management techniques would have to be modified for use in less-developed countries, where farms tend to be much smaller than in North America.