sarah carlson is the strategic initiatives director at practical farmers of iowa, or p.f.i. >> nature doesn't like all that specialization, right. nature wants chaos. nature wants diversity. >> reporter: p.f.i. is a farmer- led non-profit organization that researches conservation practices, shares the findings with its members like sam bennett, and then gets them to spread the word to other farmers. when people think of iowa, the than corn and soybeans.ch more is that a problem? or, if it is, why is that a problem? e so, because of the cropping system that we hday where we just plant two crops for abt six months out of the year, we have no rootse ground in the wintertime. and so, we have a lot of chance for water to take poll r to nearbboy wadi >> reporester: p.ollutants calld nitrates, found naturally in soil and also ntained in fertilizers, have contaminated iowa's drinking water pply. it's costing hundreds of millions of dollars to clean it up. flooding because we aren't flash holding water on the landscape like we used to. >> reporter: record flooding earlier this year ft swaths o