It doesn’t matter where you live or what methods you use, all growers deal with weeds at one point or another. Weed pressure refers to the effects of weed growth in a field. Weed pressure is a serious issue, and has negative effects on yield and profit. Growers can lessen the effects of weed pressure by being proactive and using preventative measures such as planting cover crops.
What are Cover Crops?
Simply put, cover crops are plants that are planted to cover the soil, rather than for harvesting. According to Sustainable Agriculture Research and Education (SARE), cover crops are a long-term investment in improved soil health and farm management. While you may begin to see results from cover crops within the first year, it may take a few years before you see a positive financial return.
The Benefits of Cover Crops
Cover crops are primarily used to slow erosion, improve soil health, enhance water availability, smother weeds, help control pests and diseases, and increase biodiversity.
Improve Soil Fertility
One of the greatest benefits of growing cover crops is improved soil fertility. The variety in plant species and growth pattern increases organic matter and carbon, and can even reduce the need for applied nitrogen.
According to the Ontario Ministry of Agriculture, Food and Rural Affairs, legume cover crops can fix nitrogen for a subsequent crop. In addition, some cover crop species are credited with cycling nutrients that have moved below the root zone of typical annual crops. Deep-rooted cover crops can bring nutrients and moisture up from deep in the soil.
Research shows that planting cover crops can increase your crop yield.
According to SARE’s 2019-2020 National Cover Crop Survey, “In the face of relentless spring rain, cover crops helped many respondents plant earlier than they would have been able on conventionally managed fields. Though they did not garner as much of a yield benefit as would have been expected in a dry year, cover crop users still reported statistically significant yield increases in corn, wheat and soybeans.”
Growing deep rooted cover crops creates pores and channels for water to infiltrate. This gives water a path into the soil, as opposed to running off, decreasing soil erosion and increasing plant available water held in the soil.
More than half of the horticulture respondents also reported that cover crops increased their profitability.
Provide Pest Control
Cover crops can provide pest control by creating an inhospitable environment for certain pest species.
“Cover crops can help with weed control by reducing weed density and size”, according to Successful Farming. “The cover takes its share of water, light, and nutrients, limiting weed size and reducing the amount of needed herbicide. Identifying the species of weed to control, and the timing of emergence and growth, are key elements of a weed control program, as is planting a cover that will produce adequate biomass.”
Tips for Cutting Weed Pressure Using Cover Crops
Pick the Right Species
Choosing the right cover crops to plant is the first step in reaping the benefits that they offer. Each cover crop has a different specialty or purpose and it is important to choose the right one for the required job.
According to Successful Farming, “Cereal rye, or winter rye varieties planted in cooler climates, helps break up hard soil and inhibits small weeds from developing. The tillage radish, or daikon radish, has a deep taproot that reaches nutrients otherwise lost to leaching. Hairy vetch is excellent for fixing nitrogen. Red clover as a clover cover crop is a nitrogen scavenger that makes for good grazing and insect habitat. Cover crop mixes work in concert to perform a variety of tasks.”
Use a High Population
Once you’ve chosen the species you intend to plant, you want to plant them at a high enough population. The idea behind using a high population is that the bigger canopy you can develop the better, as weeds need sunlight to grow.
Terminate Without Tilling
As beneficial as cover crops are, killing them the right way and at the right time is critical. And that means without tillage. According to the United States Department of Agriculture, “Cover crops improve overall soil health by adding living roots to the soil during more months of the year and increasing organic matter in the soil. Tillage destroys all of those natural benefits.”
Instead, producers can terminate cover crops with herbicides that are compatible with the spring-planted crop.
Cover crops offer numerous benefits, but it takes time to see those benefits. In some cases, cover crop benefits can be seen in the first year of use, but in other cases it may take three or more years to see results.
Always remember that cover crops are a long-term strategy. Soil quality, weed pressure, and crop yields won’t improve overnight, but if you stick with it, you will surely see the benefits.