The best cover crops and why you should grow them
Updated: Sep 27, 2022
Cover crops have been used for many years to maintain soil vs growing a crop for sale. They are grown mainly for the benefit of the soil rather than the crop yield. Cover crops are commonly used for weed management, reducing soil erosion, help build and improve soil fertility and also soil quality, help reduce crop diseases and pests, and promote biodiversity.
How cover crops reduce soil erosion
Vegetation plays a vital role in controlling erosion by:
Shielding the soil surface from the impact from rainfall.
Holds soil in place.
Prevents crust formation.
Improves the soil’s capacity to absorb water.
Slows the velocity of runoff.
Soaks up water between storms through the plants.
Types of cover crops
Soil type, depth, water-holding capacity, and fertility all affect plant growth. Depending on the crop you intend on planting you can increase fertility by growing legumes and incorporating them at the proper time in order to provide nitrogen. If you have clay or if water penetration is poor in your soil, cover crops with fibrous root systems, such as cereals, can be grown to improve the physical structure of the soil.
Types of Grasses/Grains
Broadleaf Cover Crops
Planting cover crops
Plant your cover crop strategically in the fall so that in will grow faster than the weeds in the spring. Maximum effects are achieved by planting early in the fall or in the late summer into a prepared seedbed followed by an irrigation to increase germination, early growth, and soil cover.
Cover Crop Seedbed Preparation
Regardless of the cover crop species selected, soil preparation for planting is relatively standard. Preparing a well granulated, soft, friable, and moist seedbed generally works well for virtually any cover crop species.
No-Till versus Till
Whether to till or not is an important consideration while choosing a cover crop strategy. Preventing soil erosion and saving energy are two benefits to no-till management strategy. Another benefit is firm footing in wet weather, which can make a tremendous difference, especially if your area receives a high volume of rains. Growers also often report fewer insect and mite pest problems in no-till areas.
What is no till? No-till planting refers to the planting of primary crops into actively growing cover crops. This practice can be used when planting a grain crop. The other type of no-till involves planting into a bed where the cover crop was killed 2 or 3 weeks before planting time.
Seeding Cover Crops
Cover crop seed can be planted either with a drill or a broadcast seeder. Drills place the seed with much more precision than broadcast seeders but either can be used. Watering after seeding helps ensure successful germination and establishment of the crop. Once germinated, many cover crop species can survive drought fairly well.
Mowing cover crops
Mowing the cover crop can actually improve cover crop establishment and performance. Mowing removes taller weeds that can shade the cover crop. Mowing also encourages the growth of shoots from the crown of the plant, spreading, and flowering. Many cover crop species are pasture forages which respond well to grazing.
Green manure from annual cover crops
Green manure cover crops are typically planted from roughly September to early December or into the spring. They consist of winter annual grasses, legumes, or flowering plants. If the green manure is used to add nitrogen, legumes are used alone or in combination with non-legumes, usually cereals. These plants store nitrogen in their roots and are tilled/mulched into the soil to decompose and add nutrients to the soil.
How much nitrogen for cover crops
Research indicates that legume cover crops can fix from 50 to 200 pounds per planted acre of nitrogen. The amount of fixation depends on the cover crop species, soil pH, soil temperature, soil moisture, soil nitrogen status, and inoculation.
Although invisible to the naked eye, soil microorganisms are an important part your soil, and are a potentially valuable asset to your next harvest. The value lies in the role they play in the decomposition of organic matter, improvement of soil structure, cycling of nutrients, and as a living reservoir of nutrients. The microbial community is most beneficial to the grower when it is diverse, abundant, and active. Microbial populations play active and passive roles in soil fertility and should be taken into consideration to improve soil health.
At the end of the day we could go on and on about cover crops and the numerous benefits to planting them. There is no universal cover crop for all agricultural operations. The choice of cover crop systems depends largely on the benefits you hope to gain from the cover crop. Cover crops should be chosen for their suitability for a production system and the style of farming that the manager wishes to use. The cover crop’s physical stature, water use, and ease of establishment/maintenance are only a few reasons why they should be chosen carefully. That being said, there are a tremendous amount of cover crops to choose from. Start small and experiment to determine which type will most benefit you.