An Agricultural Research Service scientist has found an innovative way to manage the tons of animal waste that are produced each year on dairy farms. But the idea isn't entirely his; African herdsmen have been practicing it for hundreds of years.
Mark Powell, an agroecologist at the agency's U.S. Dairy Forage Research Center in Madison, Wis., studies how nutrients are cycled on dairy farms. He's knows that whatever goes into an agricultural system-the forage and supplements fed to cows-must come out.
According to Powell, just one dairy cow excretes about eight gallons of urine and the same amount of manure every day. This waste contains natural fertilizers like nitrogen and phosphorus that can be applied to fields to give forage crops a boost. But if they're not spread strategically, the nutrients can build up in soils and could leach into waterways.
Now, after 15 years spent in West Africa watching traditional pastoral societies herd their animals, Powell thinks he's discovered an approach that optimizes the waste's potential, while being easy on the environment.
According to Powell, manure is African herdsmen's only fertilizer, so they don't waste a bit of it. They situate their animals directly onto croplands being prepared for the next season's plantings. Eventually, the animals are shifted from one section of the field to another, their hooves tilling the manure and urine right into the soil.
In contrast, most U.S. dairy farmers keep their cows indoors and truck the manure daily out to fields. In his studies with this system, which he calls "corralling," Powell has found that farmers who let their cows gather directly onto fields can watch their crop production nearly double, while saving on fertilizer costs. Consumers can also be content knowing that livestock are getting a breath of fresh outdoor air.
Read more about this research in the September 2005 issue of Agricultural Research magazine. ARS is the U.S. Department of Agriculture 's chief scientific research agency.
Source: U.S. Department of Agriculture, Agricultural Research Service
