RALEIGH, NC – Earlier this year the Carolina Farm Stewardship Association and NC State hosted the 2023 Organic Commodities and Livestock Conference on NCSU’s campus. The all-day event included a trade show, featured speaker Patrick Brown of Brown Family Farms of Henderson and a variety of seminars.
The seminar topics included soil health in high tunnel production systems; processing, marketing and distributing local meats; genetics for grazing dairies; and management strategies for organic sweet potato production.
Kyle Holton of Advancing Eco Agriculture discussed the myriad factors which affect plant health as well as the practicality of using a systems approach to managing crops, with an eye to reducing inputs and increasing the regenerative nature of ag systems.
“Everything which is grown has a relationship with the microbial population, fungal and bacterial,” Holton said. When you treat the soil to rid it of microbes, he said, the first ones to come back are the fastest growing – just like when you clear a field, the first plants to return are fast-growing weeds.
“We want to have full microbial systems,” Holton said. “We want to find management practices which hold on to existing ecosystem pathways, whether in the air or the soil.”
Healthy soil ecosystems make nutrients available to plants. Getting your soil right with the proper measure of amendments will help you build healthy soil ecosystems. For example, chlorophyll requires magnesium, so a magnesium-deficient environment would have a natural limit on crop growth. Also, plants need iron and manganese, but in their reduced form – and they are often found in soils in their oxidized form. This is why soil tests are so important.
In conclusion, Holton said, it’s important to focus on how biological ecosystems impact agriculture.
Chris Reberg-Horton and Alex Woodley of NC State gave a presentation on species selection and residue management of cover crops in organic systems. As part of their presentation they showcased a new online tool which can be used to determine how much nitrogen a cover crop provides to your farm’s soils.
Cereal rye is the number one planted cover crop. Hairy vetch provides a lot of biomass but because it is a prolific seed setter it will also, Reberg-Horton said, “volunteer like no one’s business” in successive years. Hairy vetch also tends to skew most of its growth toward the end of winter, so in autumn and early winter it won’t provide much ground cover.
Crimson clover requires nicely drained soil with plenty of moisture. It does better in the red clay soils of North Carolina’s Piedmont than the sandy soils of eastern North Carolina. Winter pea, clover and vetch all contribute about 100 lbs. N/acre. There are a lot of winter pea varieties in the market. Unlike vetch, peas do come on strong in autumn.
“I think oats marries best with peas,” Reberg-Horton said, “especially if you are trying to do organic no-till.” Oats are the most winter sensitive of the cereals, so it’s important to get them in in October, not November.
For organic no-till soybeans in North Carolina, Reberg-Horton recommended straight rye. “Just grow a gracious plenty of it. You need to plant by November 15.” Grow rye until the soft dough stage. For organic no-till corn, you can use the oat-pea combo, he said.
If you’re trying to crimp your cover crop and drill into it, a rye-pea mixture will respond to crimping. Vetch, due to its architecture, will be the most difficult to crimp. Crimson clover is in between rye and vetch.
“You may want to fertilize your cover crop,” Reberg-Horton said. “Think of it as a weed management tool.”
He does not recommend wheat as a cover crop because it can serve as a Hessian fly reservoir, which is not neighborly to area farmers who grow wheat.
Whether cover crops will be host to diseases which could affect specialty crops the following season is something you should determine by checking with your specialty crop specialist, Reberg-Horton advised.
Woodley discussed the management of cover crop termination. Ultimately, timing is determined by the planting needs of your cash crop, he said, but the longer you are able to let the cover crop grow, the more nitrogen will be fixed and the more biomass will develop.
The manner of cover crop termination, Woodley said, will affect the rate of nitrogen mineralization. The slowest rate of mineralization will come from crimping. The fastest rate would be flailing the crop then discing it in, perhaps with a vertical tillage tool. If you’re discing in the cover crop, peas are easiest to disc in, then vetch, then rye.
There is now an online cover crop nitrogen calculator, found at covercrop-ncalc.org. You can use this tool to determine how much additional fertility behind that provided by your cover crop.
The calculator works by using inputs from the farmer, including field location, cover crop dry weight biomass, cover crop N concentration and if possible cover crop water content at termination and cover crop residue chemistry.
While for some areas in the southern part of the Mid-Atlantic it may be too late this year to use this tool to calculate needed applied fertilizer, there could be regions farther north where it could be used to determine optimal fertilization rate for warm season crops.
For more information on this tool, check with your local Extension agent – it could help you better manage your fertilize costs and increase your profits.
by Karl H. Kazaks