A prototype manure spreader, developed at the University of Wisconsin-Madison, can deliver a predetermined amount of manure to the field and may lead to better manure management. Only 2 percent of Wisconsin farmers credit nutrients from applied manure within 10 percent of the university guidelines, says Peter Nowak, a rural sociologist at UW-Madison's College of Agricultural and Life Sciences. Nowak surveyed 1,400 Wisconsin farmers and found over-applied manure was largely responsible for excess nitrogen, phosphorus and potassium on farm fields. Excess nitrogen contaminates groundwater.
Excess phosphorus runs off into lakes and streams and promotes algae growth, reducing water quality.
These methods are cumbersome and have limited accuracy. Brian Holmes, a researcher in the CALS Department of Biological Systems Engineering, and graduate student Paul Paluch have developed a prototype side-discharge manure spreader. The computerized spreader can apply manure within 10 percent accuracy based on the rate the farmer specifies. The operator simply keys in the amount to apply and the spread width of the manure. The manure spreader has five load cells, one in each axle and one in the hitch.