Farm Horizons, Sept. 2003

Summer's drought spreads the pain around

By Larry Etkin
Writer for Minnesota Science

"Sustainable agriculture" methods proved neither better nor worse than traditional farm techniques in this past summer's severe drought.

"This drought was so severe that generally most people felt that relative differences were simply erased. In other words, one of those treatments might have hit the floor sooner than the other one, but by the time we decided to go and look for differences, they'd both been on the floor so long you just couldn't see any difference," says Minnesota Agricultural Experiment Station agronomist Kent Crookston.

But though we also weren't able to learn very much about drought and sustainable ag techniques, says Crookston, who heads up the University's interdisciplinary working group on sustainable agriculture, the drought certainly didn't lessen interest in sustainability.

"I would say that the interest in working in sustainable agriculture is totally independent of the drought or its effects," he says.

"The general reaction we see is an overall increased interest in agriculture whenever there's a drought, but as soon as it rains the interest's gone. But I don't think the momentum that's present in sustainable agriculture research is attributable to the drought."

One surprising finding came from observations of drought stressed crops. Ridge tilling, which has had an overwhelmingly positive record to date, showed a potential problem with potassium deficiency on corn.

"Ridge tillage, a minimum tillage, this year didn't look good, and that was sort of a surprise.

Our hypothesis is that with the litter near the surface, the roots of ridge tilled corn proliferated near the surface. When the moisture dropped down below that area, those plants didn't have many roots down in the subsoil and couldn't get at the potassium that they needed," Crookston said.

"I also know of one quite striking effect of the drought on a field trial by a farmer cooperating with the Land Stewardship Project. They used fall-seeded rye to try and control weeds. Because of the drought, the rye became a serious contender for moisture, and this farmer had essentially a complete crop failure," he said.

"One might predict such results would be negative advertisement for sustainable farming," he continued, "because neighbors who were watching, or anyone who knew this, would think, 'I saw what happened to that guy when it was dry. I'm not about to try that because it could very well be dry next year or any year,' for example. People are prone to remember a disaster. But, in many areas the chemicals also completely failed because of the drought, and people could say that's a testimonial for an alternative approach."

"In terms of sustainable agriculture, there's the hypothesis that a soil which has not been given chemical fertilizers would be better able to withstand a drought. That's the hypothesis that the organic proponents put forth that hasn't been evaluated properly. It's very difficult to evaluate because you need a drought to do it and you can't command droughts, and there's no way you can simulate them in the fields.

"The trouble with the drought, and its effect on research, is droughts are so fickle. We could not have anticipated this drought in time to have done any research on it this year. And by the same token, we can't depend on a drought next year so that we can plan trials to study its effects. But we now have a place where good, well-designed trials will build a history of non-chemical versus a chemical approach. Then, in another drought year, we'll be able to move in to that site and measure or document the effects."

That site, acquired last year, is the Koch Farm located across the road from the Southwest Experiment Station at Lamberton. That new station property has had few chemical inputs over the past three decades. Soil nutrients are at near-natural levels.

"But either way, I don't see that the drought has altered our thinking or had any appreciable impact on what we'll be doing with our sustainable ag research," Crookston says.

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