COLUMBUS – It’s easy to recognize the benefits mulches afford vegetable crops, but the challenge lies in choosing which mulch performs the best and doesn’t lighten the wallet.
Color my world. Many vegetable growers, especially in fresh-market tomato production, use black plastic as their mulch of choice.
But other mulch options exist, especially for those growers thinking of organic production, says Elaine Grassbaugh, an Ohio State University horticulture and crop science research associate.
The black plastic, the same as what growers use in strawberry production, does well to capture and retain heat, a main ingredient in tomato plant performance success. However, black plastic is labor intensive and expensive, both in installing the plastic and removing it at the end of the season.
A two-year study, conducted by Grassbaugh, found that some organic mulches (wheat straw, shredded newspaper and composted bark) provide a viable alternative to black plastic. They are cheaper to obtain, easier to maintain, lend to comparable marketable yields and serve the same benefits to the tomato plants as black plastic.
“Black plastic is the mulch that is traditionally used in tomato production,” said Grassbaugh. “But these organic mulches can be used as a way of getting away from the costs associated with black plastic.”
Plow them under. One benefit of organic mulches is that you can plow them into the soil at the end of the season, adding organic matter back into the soil, he said.
In the study, Grassbaugh found that shredded newspaper performed better than the other organic mulches.
With a 4-inch thick application, the wheat straw decomposed faster than the newspaper. “By mid-season the mulch will be gone and that’s just going to create problems with weeds,” said Grassbaugh.
When the newspaper got wet, it was observed that the mulch formed a solid mat, which significantly aided in weed suppression, Grassbaugh added.
Drawbacks. With the wheat straw, growers would be hard pressed to make it through the growing season with only one application. Additionally, volunteer wheat from the straw could provide additional headaches.
Bark has other drawbacks. When it decomposes, it removes nitrogen from the soil, leaving less available for the plants.
One drawback to the shredded paper could be finding a consistent source, explained Grassbaugh. Another aspect of the study found that growers could be saving on chemical costs. The mulches were treated with fungicides and herbicides. The study was then replicated and mulches were applied without chemical treatments,” said Grassbaugh.
Results showed that the mulches treated without chemicals were just as effective against weed suppression and diseases as those mulches that were treated.
Just use it. It may be at a grower’s discretion to choose a mulch, but ultimately, using any kind of mulch drives the success of production performance.
In the study, tomatoes growing under the mulched environment outperformed those growing on bare soil, producing up to eight times more yield in specific instances.
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