Winter Cover Crops: Planning for Cover Crop Success
Josh Copes, James Hendrix, Lisa Fultz, Syam Dodla, and Naveen Adusumilli
Crop harvest is in full swing across most of Louisiana. As we move into October, now is the time to begin planning your winter cover crop management strategy. Cover crops are used for several purposes including: protecting soil from erosion, improving soil structure, scavenging and cycling of soil nutrients, increasing organic matter, helping to alleviate hardpans, etc. Cover crop selection will depend on the goals a producer would like to accomplish by planting a winter cover crop. Having a clear objective for planting a cover crop, will also aid in cover crop management. For example, if minimizing soil erosion is the main objective, selecting a cereal cover crop, would be a good choice. The fibrous root system of cereals will help prevent top-soil from leaving the field. Cereal winter covers are good nutrient scavengers as well. In contrast, a tap-rooted cover crop like forage/tillage radish is better suited for deep nutrient scavenging and potentially aids in loosening a soil compaction layer or preventing one. Mixes of cereal and legume covers can reduce early season N fixation issues in corn. Preliminary data collected by AgCenter scientists has shown that in soybean, legume cover crops can supply N for early growth needs until nodules develop. Other important considerations when selecting a winter cover crop includes: cash crop to be grown following cover crop termination, and winter cover crop termination. Be sure to plant only quality seed, this will help eliminate weed seed contamination issues. Seeding rates should be adjusted for germination percentage or pure live seed per pound. When planting legumes, make sure the rhizobium inoculant strain is correct for the legume that is to be planted and always inoculate. If planting pre-inoculated legume seed be sure to get pure live seed per pound and adjust seeding rates accordingly; some pre-inoculated seed are larger and therefore have less pure live seed per pound.
Cover crops should be planted as soon as possible following main crop harvest. When planted earlier in the fall, growth/biomass production will be maximized prior to cold weather which will slow growth and development of the cover crop. Planting your cover crop soon after harvest, is especially important if corn will be planted. Early cover crop termination, when planting corn, combined with late planting of a cover crop (November) will reduce overall biomass production, therefore minimizing the benefits of the cover crop. Legumes are generally slow growing if planted too late (November), and biomass production will be minimal prior to the onset of cold weather. If fields are enrolled in a NRCS conservation program, that requires cover crops, be sure to follow the NRCS’s cover crop guidelines. Below is a link that contains NRCS seeding rates and planting dates for common cover crops grown in Louisiana. The planting window for most winter cover crops will be October 1 to mid-November. Ranges for average first frost dates for Monroe, Shreveport, Alexandria, and Baton Rouge are November 15, 18, 19, and 29th, respectively (https://www.farmersalmanac.com/average-frost-dates). Posted below, hyper link 2 and 3 are some useful tools may aid in further refinement of accomplishing the intended goals for your farm.
- NRCS planting dates and seeding rates for common cover crops grown in Louisiana:
- Cover Crop and Tillage Scenarios (Potential Scenarios and their implications on incentives payments.):
- Q & A of Conservation Policy and Crop Insurance Surrounding Cover Crops:
- Cover Crop Economics Decision Tool: