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If you're looking for ways to trim no-till herbicide bills, research done in Paraguay indicates seeding cover crops can help you get the job done. Keeping the soil covered can be an effective way to reduce weed concerns when no-tilling.
As a bonus, adding cover crops to your no-till program can help reduce costly nitrogen purchases. The reason is that some cover crops can be converted into valuable supplies of low-cost nitrogen fertilizer.
The key reason that cover crops can reduce the need for herbicides is due to aggressive growth, alelophatic action and the large amount of biomass they produce, says Rolf Derpsch, an official with the GTZ Soil Conservation Project at the Ministry of Agriculture and Livestock in Paraguay.
The idea of trimming herbicide usage worked for several years in these South America trials. But when excessive rains occurred, herbicides were needed to control weeds in no-tilled fields as would be the case in North America.
With doublecropped soybeans no-tilled with wheat in a continuous rotation (rotation 1), Derpsch found five herbicide applications were necessary each year to maintain weed-free crops in this area of South America. One herbicide application was made before the wheat was no-tilled and four more were applied before or at the time the soybeans were no-tilled. Total cost of the five herbicide applications was $42.55 per acre.
In rotation 2, sun hemp and sunflowers were used as short-term cover crops and no-tilled as soon as possible after harvesting corn to eliminate the fallow period…