@book{511072,
	author = {Duley, Frank Leslie,},
	title = {Estimating the amount of crop residue on a field /},
	publisher = {U. S. Govt. Print. Off.,},
	year = {1958].},
	series = {	Agriculture handbook (United States. Department of Agriculture) ;},
	address = {[Washington,},
	note = {1, 2. Mulching.}
}