Drought 2012: Can Improving Soil Decrease Risk?

It sure has been an interesting year when it comes to evaluating red clover stands that were frost-seeded into wheat. In the southwest part of Michigan where we haven’t received any rain for an extended period, most of our red clover is burning up. In other parts of the state where they have had rain, farmers are calling me to develop a management plan for outstanding clover stands.

At W.K. Kellogg Biological Station where most of my research is located, our frost-seeded red clover plots are burning up. However, in our organic wheat, the red clover remains green and has a pretty good stand. Obviously, if we do not receive any more rain it will die over time.

Seeing this difference in red clover survival made me contemplate why. So, our cover crop team came up with several possible hypotheses.

We applied 70 lbs/A of actual Nitrogen to the conventional wheat and NO Nitrogen to the organic wheat:

  • The Nitrogen in the conventional system may have stimulated the above ground growth of the red clover and not as much root growth. The limited amount of nitrogen in the organic studies may have resulted in better red clover root growth, which allowed it to survive these extremely hot dry conditions.

The conventional wheat yield was taller and higher yielding than the organic wheat:

  • The better yielding wheat resulted in greater competition for the red clover when water was limiting. Since the organic wheat didn’t grow as tall and yielded less, red clover had enough moisture to establish and tolerate the drought.

The last hypothesis is that our organic sites have had a very strict, three-crop-rotation over the years; corn-soybean-wheat, and red clover has been frost-seeded whenever wheat was in the rotation. Our conventional fields have had mostly a corn/soybean rotation without red clover. Even though we inoculated the red clover and had a good stand prior to the drought, the soil quality of these sites is not as good as the organic sites where we have a more complete crop rotation.

So, what does this all mean? Frost-seeding red clover established best when we have adequate moisture. It can establish and grow even in high yielding wheat where Nitrogen has been applied. But without adequate moisture, the conventional system’s red clover is more susceptible to dying as compared to our organic soils.

To me, this has implications for the future. As our climate changes and we have unusual weather patterns, it becomes more important to improve our soil quality. By developing a three-year crop rotation with cover crops, you can enhance your soil quality. Enhancing your soil quality can ultimately decrease your risk from these environmental challenges.

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