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Cover Crops

Cover  crops are grown specifically to improve soil texture, organic matter and fertility.  Legumes (bell beans, fava beans, vetch, Austrian field peas, clovers)  are popular cover crops as they harbor bacteria on their roots that fix atmospheric Nitrogen into the plant, up to 100 LBS/ acre.  The nitrogen and organic matter are added to the soil when the crop is tilled under.  Grasses and grains such as barely and oats, add organic matter to the soil and reduce erosion.   Buckwheat is an warm season annual grown in the summer that does not fix nitrogen, but does concentrate Phosphorous and add organic matter.  In addition to improving soil fertility, cover crops can reduce weeds and attract beneficial insects.

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Tilling in a Winter Cover Crop

Fall/ Winter cover crops - Sowing a cover crop in the fall is one of the best things you can do for your garden.  It will protect your soil from erosion and compaction from harsh winter rains, add up to 100 LBS of Nitrogen/ acre, increase organic matter, improve soil tilth (tilling) and attract beneficial insects - what more could you ask for?  Be sure to plant your cover crop by mid October in order to get some growth before the winter cold sets in - cover crops planted later may not grow enough to protect the soil through the winter and are likely to develop less biomass and fix less Nitrogen. 

Inoculate your cover crops for the right bacteria!- Legumes host beneficial bacteria in nodules on their roots.  It is these bacteria that do the important work of capturing  Nitrogen from the air and fixing it in a form the plant can absorb and use.  If the proper bacteria are not present in your soil then legumes will not fix nitrogen, but just use up nitrogen that's already present.  Some cover crops come inoculated (rhizo-coated ), others require an inoculant.  It's best to inoculate your cover crops for the first two years of planting them, after that the beneficial bacteria should become established in your soil.  You can test your legumes by pulling up the green plant before it has set seed and inspecting the root nodules.  When the proper bacteria are present the crushed nodules will have a pink color.  Nodules that are pale or white on the inside lack the proper bacteria and are not fixing nitrogen.

Here are the favored cover crops for the Mid Klamath Region:

Buckwheat is a great warm weather cover crop - sow any time between May and August when the soil is warm.  It grows quickly, out competing weeds, concentrates phosphorous, and attracts beneficial insects.  Buckwheat does not fix nitrogen, so the main benefits are building organic matter, protecting the soil and smothering weeds.  

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Buckwheat Cover Crop

Bell Beans are actually a type of fava bean bred to be round (to fit in mechanical seeders), more cold tolerant, and develop a lot of biomass.  Bell beans yield the most Nitrogen of any cover crop, up to 100 LB/ acre.  A good healthy crop can be five to 6 feet tall.  Plant 1-4 LB/ 100 ft2, or 80 - 125 LB/ acre. 

Austrian field peas sprout and grow in cool conditions, tolerate heavy soil, and are hardy to 10 degrees F.  The tendrils and flowers are excellent in winter salads.  Plant at 2-4 LB/ 100 ft2, 70-120 LB/ acre.

Vetch is a leguminous vine that is cold tolerant, provides excellent livestock forage and attracts beneficial insects.  Plant with upright crops such as oats, barley or bell beans for support.  Plant at 1-3 LB / 100 ft2, 30 -60 LB/ acre

Annual grains, i.e. barley & oats - Annual cold weather grains such as barley and oats have fibrous root systems that protect the soil and scavenge extra nutrients, especially Nitrogen, that was not utilized by summer crops. fixing it in the plant so that it is not lost to winter rains.  Barley is an allelopath, which inhibits the germination of competing weed seeds.  Annual grains do not fix Nitrogen, but improve soil texture by adding organic matter.  Plant at 2-3 LB/ 100 ft2, 60-90 LB/ acre.

Cover Crop Mix - You can combine all of these cover crops into a mix to get the cumulative benefit of each.  Here's a suggested mix that uses 50% bell beans, 25% Austrian field peas, 15% vetch and 10% barley or oats, for a mix that is lighter on the grains and heavy on the nitrogen fixers.    Feel free to change the proportions to fit your specific site needs.

Cover Crop Mix for Mid Klamath Region

 

LB/ 100ft2

LB/ acre

enough for 1 acre

enough for ½ acre

enough for ¼ acre

Bell beans

2-4 LB

80-125

50 LB

25 LB

12.5

Austrian Field Peas

2-4 LB

70-120

25 LB

12.5 LB

6.25

Vetch

1-3 LB

30-60

7  LB

3.5 LB

1.6875

barley or oats

2-3 LB

60-90

7.5 LB

4 LB

2 LB

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