Selecting Summer Cover Crops

It’s tempting to cash crop every season, but eventually – especially on Coastal Plain soils – you’ll run into problems with disease pressure impacting yields. In addition, farming on Coastal Plain soils with their low level of organic matter makes using recommended herbicide label rates tricky; low organic matter results in a narrow window between efficacy and phytotoxicity, negatively affecting yields.

Cover crops can help remedy these problems. Summer cover crops are an option few Northeast growers use because there is only so much time in-season to cash crop, but it’s an option worth serious consideration. Summer cover crops add versatility to your cropping rotation – another chance to address weed and disease pressure plus build organic matter; another chance to boost future yields.

Don’t miss Cover Crop Field Day
Date: December 11, 2014
Location: Now or Never Farm, 37 Welisewitz Road, Ringoes, NJ
Host: USDA NRCS and North Jersey RC&D
Contact: For Information and RSVP (by Dec. 8) call USDA NRCS 908-782-4614×3

Summer Cover Crops that Work for NE Coastal Plains Soils



Buckwheat – An annual broadleaf with succulent stems that decompose quickly.

Best Features:
■ Weed Suppression – Quick cover, easily established; Dense canopy created within two weeks of planting.
■ Nitrogen and Phosphorus scavenger.
■ Topsoil conditioner (but will not breakup hardpan).
■ Shortest window of the Summer cover crops – 40 days.
■ Plant after danger of frost. Drill 50-60 lb/A at 0.5 to 1.5 inches deep in 6-8 inch rows. Use heavier rates for quicker canopy development.
■ Don’t plant into hard soil or wet spots.
■ Mow or incorporate after flowering, but before seed set.
■ Cost: $15-25/A; $1.25/lb


Cowpea(Iron Clay and Red Ripper) – A summer annual legume; tall, viney varieties best for cover crops; succulent residue decomposes quickly.

Best Features:
■ Nitrogen Source – Makes N available for fall crops. In Northeast, the maximum nitrogen fixed in 60 to 90 days is about 130lb nitrogen/A.
■ Heat and drought tolerant with deep taproots.
■ Plant after danger of frost.
■ Drill in rows 6 to 8 inches apart at 40lb/A or broadcast at 70 to 120lb/A.
■ Red Ripper matures earlier than Iron Clay and has resistance to rootknot nematodes and wilt.
■ Cost: $1.50 – 1.70/lb


Sunnhemp(Tropic Sun) – An annual legume; tall and herbaceous with erect fibrous stems.

Best Features:
■ Nitrogen Source – Slow release.
■ Residue – large amounts, long lasting organic matter.
■ Weed suppression.
■ Nematicidal compounds produced.
■ Drill in narrow rows at 30 to 50 lb/A or broadcast 40 to 60 lb/A.
■ Cost: $2.60/lb



SorghumSudangrass (Sudex) – An annual grass; tall and fast growing.

Best Features:
■ Residue – Produces the largest amount of organic matter.
■ Weed suppression – competes well and produces allolepathic compounds.
■ Disease suppression.
■ Nematicidal compounds produced.
■ Due to production of allolepathic compounds, wait a few weeks before replanting the subsequent crop.
■ Drill 15 to 35 lb/A at 0.5 to 1.5 inches deep or Broadcast 17 to 40 lb/A. Apply 40 – 60 lb nitrogen/A at planting.
■ Cost: $1.00/lb


Summer Cover Crops and Soils Needs

Consider the pros and cons of integrating summer cover crops into your particular operation. Weigh the short term costs of not cash cropping, cover crop seed costs and crop management, against long term gains of soil disease suppression, herbicide “buffering,” nutrient scavenging, and improved soil moisture holding capacity.

Troubleshooting with cover crops:
Want mainly weed suppression and soil aeration?
Choose Buckwheat – a fast growing crop that competes well with weeds. Its fibrous roots break up soil. It works especially well before fall grains and finishes before ideal seeding dates.

Want nitrogen input?
Choose Cowpea or Sunnhemp – both fix nitrogen for release when incorporated. Cowpea provides nitrogen for fall crops; Sunnhemp, due to high lignin content, has slow decomposition with slow release of nitrogen making it less available for fall crops. Expect to spend as much in cover crop seed and management as you would pay for an equivalent amount of nitrogen using commercial fertilizer.

Want pest suppression?
Choose Sorghum-Sudangrass or Sunnhemp – both help control weeds, soil- borne diseases, and nematodes. Weed control is via competition and production of allolepathic compounds.

Want to remedy “excessively drained” soils?
Choose Sorghum-Sudangrass or Sunnhemp – both have fibrous, dense root systems providing organic matter residues which improve soil structure, allowing increased water holding capacity.

Want more organic matter with all the fringe benefits?
Choose Sorghum-Sudangrass – the biggest producer of organic matter in this line-up of Summer cover crops suited for Coastal plain soils. Mowing enhances organic matter production even further. Sorghum-Sudangrass has a great benefits profile, it’s easy and cheap.

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