Ok, I’m convinced, I am going to plant cover crops

But which one(s) do I plant?

Picking a cover crop

• Step one: what is your planting window?

• Step two: what do you want to accomplish?

• Step three: follow the rules of rotation

Early spring (March)

• Oats

• spring field peas

• spring barley

• spring triticale

Forage peas planted late March, photo taken May 20.

May through July

• Sorghums

• millets

• teff

• cowpeas

• sunnhemp

• forage soybeans

• annual lespedeza

• Sunflowers

August through early September

• Almost everything!!! Warm-season crops grow well planted now but give up at frost

• Prime time for brassicas (turnips, radishes, rapeseed, kale, hybrid brassicas)

• Oats, spring barley, spring triticale

• Hairy vetch, spring field peas, crimson clover

• Rye, wheat, winter barley, winter triticale, annual ryegrass

Late September through early November

• Winter annual grasses

• Hairy vetch

Annual ryegrass

Rye Wheat (note barley yellow dwarf)

After early November

• Rye

What are you trying to accomplish?

• Build mulch and organic matter?

• Fix nitrogen?

• Provide grazing?

• Break up soil compaction and improve rooting depth?

• Control nematodes?

• Suppress weeds?

Build mulch and organic matter

• By far the best organic matter builders are warm-season grasses (primarily sorghums, secondarily millets)

• Next are winter annual grasses • Tops among legumes is sunnhemp • All cover crops add some organic matter to the

soil, any cover is better than nothing • No single cover crop will add significantly to

measurable soil organic matter, but many (particularly grasses) will contribute to a functioning organic layer at the soil surface

Brutis forage sorghum as a doublecrop

Fix nitrogen

• Best nitrogen fixers among legumes are sunnhemp, alfalfa, and sweetclover

• Hairy vetch and cowpeas are intermediate

• Spring field peas, crimson clover are lesser yet

How many pounds of nitrogen is contained in this crop of sunn hemp? This crop was planted after wheat harvest and photo taken in early September

Not the same as this hemp

Significant Yield Advantage with Cover Crops in the Rotation

SOURCE: Spring Field Day North Unit K-State Harvey County Experiment Field May 31, 2007. Hesston, KS

Economics of Double-crop Summer Forages after Wheat Kevin C. Dhuyvetter Department of Agricultural Economics Kansas State University kcd@ksu.edu -- 785-532-3527

SUNN HEMP RESEARCH AT K-STATE

How many pounds of N will this Hairy Vetch contribute to next years sorghum?

Break up compaction

• Brassicas are all good, but by far the best is Tillage radish (#1 choice)

• Sorghum-sudan hybrids are very good, work best if hayed or grazed at least once

• Annual ryegrass has a very dense but shallow root system that loosens surface soil

• Sunnhemp is a good annual legume

• Sweetclover is exceptional

Deepen the root zone

Conventional tillage Six years no-till with annual ryegrass cover between cash crops

Control nematodes

• Sunnhemp is effective against a wide range of species that attack other crops, even soybean cyst nematode (as much as 90% reduction)

• Sorghum-sudan works against many nematodes but not soybean cyst

• Annual ryegrass, rapeseed and cereal rye are moderately effective against soybean cyst

• Most brassicas help against a wide range of nematodes (ethiopian cabbage, mustards best)

Suppress weeds

• Can use high nitrogen sequestering crops to soak up nitrogen and starve weeds (annual ryegrass, rye, sorghum-sudan)

• Covers with quick growing canopies (buckwheat, sorghum) can outcompete weeds

• Rye is very allelopathic to some weeds (pigweeds, marestail) as well as to some crops (sorghum)

• Sorghum-sudan is allelopathic to many weeds as well as to some crops (wheat)

Annual Ryegrass Cover Crop Impact on Following Spring Rotation to Soybeans

What is the next crop you are rotating to?

• Corn and sorghum do best after legumes and brassicas

• Soybeans do best after winter annual grasses and brassicas

• Wheat does best after legumes

+10 bushel here!

Sequestering nitrogen is NOT good prior to corn! Note the ryegrass strip at the arrow

Best cover crops for late summer grazing

• Sorghum-sudan grass (My strong preference is a brachytic dwarf, brown midrib) graze 45 days after planting (rotational graze to avoid prussic acid)

• Pearl millet (45 DAP)

• Crabgrass (45 DAP)

• Teff (45 DAP)

• Cowpeas (45-60 DAP)

• Forage soybeans (graze at early podding)

• Korean lespedeza (NOT the same as Sericea!!) can overseed into growing wheat

Best cover crops for fall grazing

• Turnips, radishes, oats, field peas, canola, kale, all planted in August or early September

• Rye, annual ryegrass, barley, hairy vetch planted in September through October

• Delayed planting greatly diminishes fall grazing potential of the above

• Another option is red clover or sweetclover overseeded into wheat the prior winter, and grazed the fall after wheat harvest

Winter grazing

• Rye has lowest minimum growing temperature but is easily covered with snow

• Fall planted oats are fairly accessible through snow

• Brown midrib sorghums that do not form grain (either male-sterile or photoperiod sensitive) provide very high carrying capacity for dry cows

Spring grazing • Fall planted rye, ryegrass, wheat, barley

(earliest)

• Fall planted crimson clover or hairy vetch

• Second year red clover or sweetclover from previous years seeding into wheat

• Spring planted oats or field peas (not much production prior to May, when other pasture sources are usually available, but can be hayed prior to planting sorghum or soybeans)

Include wheat in your rotation (even on irrigated ground!)

• But I can’t make as much money on wheat as I can corn or beans!!

• Think long term: lettuce & wheat

• Can you add more income in the wheat year of a three year rotation?

Mixtures versus single species

• Single species easier to manage

• Mixtures more resiliant and reliable, can accomplish multiple goals at once

• Mixtures of diverse plant types promote more soil microbial activity

• Multiple root types, root exudates, layered canopy, etc of a mixture contribute to better results than a monoculture

Developing a mixture

• Try to have as many functional groups as possible EXCEPT the type of crop that will follow (this avoids harboring pests)

• Try to have legumes prior to high N demand crops, and grasses prior to legume crops

• Try to have each component suitable for the planting date (more flexible than for grain)

• Use a % of the full seeding rate for each component (e.g. 25% for four species mix)

Setting a drill for a mix

• Drills meter on volume, not weight

• A setting that will deliver 32 pounds of oats will deliver 60 pounds of wheat

• Add total number of bushels of combined components

• Set drill for that number of bushels of predominant component

Example

• A mixture of 32 pounds of oats, 30 pounds of peas per acre

• A bushel of oats weighs 32 pounds

• A bushel of peas weighs 60 pounds

• You have 1 bushel oats plus ½ bushel peas, or a total of 1.5 bushel

• Set drill for 1.5 bushel oats, or 48 lb oats

• Calibrate to ensure accuracy

• Mixtures usually flow faster than single species

My favorites

• Corn- beans: annual ryegrass+rye/triticale

• Beans---corn: aerial seeded sweetclover +hairy vetch+crimson clover (for lack of a better option!!!) NOTE HERE: I prefer planting wheat after soybeans rather than a cover crop

• Wheat- corn: radishes+oats+peas

• Wheatsoybeans: sorghums or radishes+ oats+rye+ryegrass

Thank you!