Table 1.

Description of sample collection sites.

Farm	No. of cores	Crop at time of collection	Previous crop(s)	Recent manure
1	6	W. wheat	Soybeans, corn	Yes
2	4	Warm and cool perennial grasses	Warm and cool perennial grasses	Yes
3	6	Wheat, fallow, millet	Wheat, fallow, millet	Yes
4	2	Mix vegetables	Mix vegetables	No
5	11	Oats, corn, alfalfa, pasture mix∗	Oats, corn, alfalfa, pasture mix∗	Yes
6	7	Pasture, oats, w. wheat	Soy, pasture, oats, corn, w. wheat	Yes
7	10	Corn	Soybeans, corn	Yes
8	10	Soy, oats, alfalfa, corn, pasture	Soy, oats, alfalfa, corn, pasture	Yes
9	7	Pasture, oats, corn, sorghum, millet	Pasture, oats, corn, sorghum, millet	Yes
10	8	Soybeans	Corn	Yes
11	16	Popcorn, hay, pasture, soy, barley	Popcorn, hay, pasture, soy, barley	Yes
12	11	Wheat, soy, corn, alfalfa, pasture, oats	Wheat, soy, corn, alfalfa, pasture, oats	Yes

Samples for each depth were formed in the field at the time of sampling, resulting in two soil samples location. A “yes” in the “recent manure” column means that some or all of the samples from that farm were collected from areas which had received manure within the last three years. Not all fields within a farm necessarily had “recent manure.” ^∗Pasture mix contains (pasture, oats, buck wheat, turnip, radish). “W. wheat” indicates winter wheat. “Soy” indicates soybean.