“Can Sunnhemp Outgrow Morning Glory?”

I get the most interesting questions on my website.  Some provoke editorial response:

Biological agriculture is a race between crops and weeds.  The farmer’s job is to give his crops an unfair advantage in competition for sunlight.  One way is growing cover crops to smother invasive weeds.  Sunnhemp (Crotalaria juncea) is an effective mulch crop for weed suppression.

Wild Morning Glory (Ipomoea species) is the bane of my existence.  Closely related to sweet potatoes, morning glories thrive in poor soils, are immune to most insects, and grow so rapidly that they overwhelm all surrounding plants.

In Butler County (30 miles north of Pittsburgh, Pennsylvania) morning glories are like intermittent epidemics.  Some years you rarely see a vine.  Other seasons your fields are covered.

I returned from a business trip to find my neighbor’s back-40 strangled by herbicide resistant morning glories.  Vines blanketed the land like Kudzu (Pueraria montana).  He sprayed tankfuls of glyphosate trying to save his soybeans.  All that did was make the weeds mad.   6 weeks later, vengeful vines obliterated his GMO corn.

My neighbor was hitching up his 8-bottom moldboard when I offered to help.  George has a dim view of “organic farming” but he likes spending money even less, so it was not a difficult decision:  Plow everything under or let Eric make a fool of himself.  Hmm. . .

My solution:  60 pounds per acre of rotary seeded Sunnhemp followed by a 30-year-old sickle-bar mower.  Sow-And-Mow eliminated his weed problem.  The Sunnhemp reached 8 feet high in 7 weeks, shading all competing vegetation.

Next, I broadcast 12 pounds per acre of Dutch White Clover (Trifolium repens) into the standing cover crop then mowed the Sunnhemp with a bush hog.

In Autumn I no-till drilled 60 pounds per acre of pelleted Winter Rye (Secale cereale) into the mature clover.  The field required no other work until grain harvest the following summer.

There is a lesson to be learned here:

RULE:     Always seed cover crops at maximum rates for weed control.

RULE:     Do not plow, disk, or harrow — this only encourages weed germination.

RULE:     Keep fields covered with growing crops at all times to kill weed seedlings.

Follow these rules and weeds will NEVER get established in your fields.

This is what Biological Agriculture is all about:  Crop competition keeps weeds controlled without need for mechanical cultivation or chemical herbicides.  Let nature do the heavy lifting.

Related Publications Include:     Managing Weeds as Cover Crops; Trash Farming; Planting Maize with Living Mulches; Living Mulches for Weed Control; and Crops Among the Weeds.

Other Articles of Interest:     Weed Seed Meal Fertilizer; Organic Herbicides; Pelleted Seed Primer; and Forage Maize for Soil Improvement.

Would You Like to Know More?     Please visit:  http://www.worldagriculturesolutions.com  — or —  send your questions about biological weed control to:  Eric Koperek, Editor, World Agriculture Solutions, 413 Cedar Drive, Moon Township, Pennsylvania 15108 United States of America  — or —  send an e-mail to:  worldagriculturesolutions@gmail.com

About the Author:     Mr. Koperek is a plant breeder who farms in Pennsylvania during summer and Florida over winter.  (Growing 2 generations yearly speeds development of new crop varieties).

 

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MANAGING WEEDS AS COVER CROPS

The trick to biological farming is knowing how to manage weeds.  “Manage” does NOT mean “kill”.

Internet trolls are bombarding my e-mail box with comments like:  “You can’t plant crops in weeds!  That’s why they invented tractors”.  Horse power is irrelevant and yes, you can plant crops in weeds:  I manage 90,000 acres without herbicides or mechanical cultivation.  Here is how I do it:

(1)  Manage Weeds as Cover Crops.  Think of weeds as a multi-species cover crop that costs nothing to seed.  This will save you about $40 per acre, right off the bat.  $40 x 90,000 acres = $3,600,000.  We are not talking tree-hugging here.  This is serious agronomy.

Grow weeds to protect your top soil.  A typical corn-soybean farmer in Iowa loses 2 1/2% of his land yearly = 20 tons of earth per acre = $450 per acre at $22.50 per ton (U.S. average top soil price, delivered).  Weeds have value.

If you don’t have enough weeds for a winter cover crop, seed 3 to 4 bushels of oats per acre.  Oat roots prevent soil erosion over winter.  Oats winterkill so no herbicides are needed.  Surface trash is minimal and will not interfere with conventional planting equipment.

(2)  RULE:  Keep Fields Green.  Photosynthesis is the process where plants use water, air and sunlight to make sugar.  More photosynthesis = more sugar = more plant growth = higher yields.  Bare fields are not profitable.  Smart farmers keep their soil covered with growing plants year-round.  Plant cash crops whenever possible.  Sow cover crops for mulch or fertilizer.  Seed weeds when there is no time or money to grow anything else.  The goal of biological farming is to produce the most possible organic matter per square foot.  Grow anything rather than leave soil bare.

The underlying principle of biological weed control is plant competition.  Keep the ground covered with growing crops year-round and weeds do not have a chance to get established.  Never leave the soil bare, not even for a single day.

For example:  Plant winter wheat into standing Dutch White Clover (Trifolium repens) using no-till equipment.  Next summer, harvest wheat then immediately (the same day) plant turnips into wheat stubble and clover living mulch.  Field stays green year-round.  Weeds cannot grow because they are constantly shaded by competing plants.

(3)  Sow Weed Seeds.  If you have tired, sick or dead ground, or no top soil, go to your nearest grain elevator and fill your truck with weed seeds.  These are usually free.  Some elevators charge a nominal fee for “elevator screenings” which contain many weed seeds.  Sow liberally, at least 40 pounds per acre.  Prepare for amazement.  Weeds are Nature’s Band-Aid, a fast growing cover crop evolved specifically to heal bare earth.  On steep slopes or mine reclamation sites, spread straw or spoiled hay mulch to protect germinating weeds.

(4)  Fertilize and Water Your Weeds.  Every time I say this, half my audience leaves the room.  No, I am not crazy.  Yes, I do know what I am talking about.  I farm without any government subsidies and each acre earns substantial profit.  It pays to feed and irrigate weeds (if possible).  Remember:  Weeds are a cover crop.  You want every field blanketed with a luxuriant jungle of weeds at least 6 feet high.  So water and fertilize as needed, and do not worry about what your neighbors say.  Farming is not about yields; farming is about the bottom line.  Weeds put money in your pocket.

(5)  Feed the Weeds and the Weeds will Feed Your Crops.  Weeds have enormous root systems in proportion to their stems and leaves.  Many weeds also have tap roots that plunge deep into the subsoil.  Translation:  Weeds are great at scavenging nutrients that would otherwise leach away.  Weeds have quick growth response to plant food so a little fertilizer goes a long way.  A few pounds of nitrogen create a vast jungle of vegetation that makes good mulch and fertilizer.  The average weed contains twice the nutrients of an equal weight of cow manure.  Broad leaf weeds rot quickly so fertilizer elements are rapidly recycled for crop use.  Plant crops and weeds together and yields often increase.  The reason is ecologic synergy = plant symbiosis.  Weeds both compete AND cooperate with neighboring plants.  Water and nutrients are shared so crops and weeds grow better.  I learned this lesson farming melons.  The best fruits came from the weediest fields.  So I started planting melons into weeds.  The weeds provided light shade and the melons followed weed roots down into moist subsoil.  Come drought and clean cultivated fields produced little or no crop.  Melons and weeds yielded fair crops.  Irrigated melons and weeds overfilled my trucks with fruit.  Think about this the next time you buy a drum of herbicide.

(6)  Use Weed Seed Meal Fertilizer.  How would you like to slash fertilizer costs?  Get weed seeds or screenings from your local elevator.  Grind them with a hammer mill or roller mill.  Broadcast 4 tons per acre or drop 10 pounds per 25 feet of row.  Unlike chemical fertilizers weed seed meal will not burn crop roots so you can hurl nutrients with wild abandon.  If you do not have any weed seeds, use any other waste seed like spoiled corn, brewer’s grain, or broken soy beans.

To use LIVE weed seeds as fertilizer broadcast seeds into a standing cover crop like Red Clover (Trifolium pratense).  Earthworms, ants, beetles and other critters eat the weed seeds.  Clover kills any weeds that germinate.  Caution:  Don’t try this unless you have a tall, aggressive cover crop that blankets the soil with dense shade.

(7)  RULE:  Apply Chemical Fertilizer Only to Growing Plants.  This rule covers all crops (including weeds) without exception.  It makes no sense to spread fertilizer on bare ground.  Chemical nutrients are wasted unless there are live roots waiting to absorb them.  For best results, synthetic fertilizers should be applied in small doses throughout the growing season, ideally diluted in irrigation water.  Feed growing crops only and well water stays pure = free of nitrates.

(8)  Good Farmers Grow Fungi.  The Fungi Grow the Crops.  Think of all the pipes, wires and roads needed to run a modern city.  Without these conduits life would be nearly impossible.  A corn field is no different.  Under the soil surface is a jungle of lifeforms, a whole zoo full of critters exceeding the combined population of the world’s largest cities.  And every one of these underground citizens depends on fungi for survival.  Millions of miles of microscopic fungi tie the underground world together.  Fungi are the interstate highway system of the soil ecology.  Water and nutrients are conveyed to hungry roots.  Plants share resources through fungal networks.  Many crops are so dependent on fungi that they cannot exist without these symbiotic micro-organisms.  Kill the fungi and the soil ecology collapses.  Yields plummet and fields become sick and barren.  Try to farm dead soil and you will spend vast sums for synthetic fertilizers, pesticides, and irrigation.  Today, this is called “conventional agriculture” and most growers lose money on every acre they plant.  There is a better way to farm.

Fungi like cool temperatures, a moist environment, plenty of air, and lots of organic matter.  Rip up the ground with plows and the fungal network is destroyed.  Soil temperatures spike, the earth is parched, a cyclone of oxygen rushes into the ground, and organic matter burns away in a firestorm of excess decomposition.  The result is like dropping a nuclear bomb:  Billions of critters die and the soil ecology is devastated.  Recovery takes years.

Sell your plows, disks and harrows — you don’t need them.  Grow weeds or other cover crops and leave the fungi alone.  Open the soil just enough to get seeds or transplants into the ground.  Further disturbance cuts profits and yields.

(9)  Till Your Fields with Earthworms.  My Grandfather taught me:  “Feed the worms and the worms will tend your crops”.  Common earthworms (Lumbricus terrestris) eat organic matter and excrete enough manure to grow 200 bushel corn = 11,200 pounds per acre.  They also burrow 6 feet into the subsoil.  My fields average 1 million worms per acre.  That’s about 23 worms per cubic foot = 1,200 miles of burrows per acre.  When thunderstorms drop 2 inches of rain per hour my neighbors’ fields wash away.  My soil stays in place.  When drought bakes the county, my corn yields over 100 bushels per acre (without fertilizer, herbicides, cultivation or irrigation).  How is this possible?  Plant clover and earthworm populations double.  I seed clover into weeds and the worms feast on the multi-species “salad bar”.  Mind you, this process does not occur overnight.  It took 12 to 15 years to wean my fields off synthetic nutrients.  That’s 4 to 5 generations of earthworms.  I used to borrow mountains of cash to buy farm chemicals.  Now I plant clover and have no debts.

(10)  Grow Your Own Fertilizer:  Conventional green manures are plowed into the soil.  A less invasive technology is called Chop-And-Drop.  Use a rotary mower, flail mower, bush hog, forage chopper, or common lawn mower to cut plants into small pieces that decompose quickly for rapid nutrient cycling.  Immediately sow or transplant another crop before weeds start germinating.  Alternatively, knock down cover crop with a roller-crimper or sickle-bar mower then plant through the mulch using no-till equipment.  For example, I sow Hairy Vetch = Winter Vetch = Vicia villosa in October then roller-crimp vines in May.  Vetch controls weeds and fixes sufficient nitrogen for 200 bushel corn or any other crop I want to grow.  Remember:  Chop plants into small pieces for fast-acting fertilizer.  Crimp or cut whole plants for mulch.  Finely chopped plants will NOT control weeds.

(11)  Use Mulch-In-Place.   Think of how much money you will save if you don’t have to buy herbicides or cultivate fields multiple times.  The savings in diesel fuel alone will pay for a 2-week vacation anywhere you care to go.  Let your neighbors plant seed in cold ground.  Be patient and give your weeds more time to grow.  Wait until the soil warms and weeds are at least 5 feet high.  Kill weed cover crop with a roller-crimper or sickle-bar mower then immediately seed or transplant through weed mulch with no-till equipment.  Mulch retards weed growth 4 to 6 weeks — just enough time for your crop to germinate and start covering the rows.  Once the crop canopy closes weeds are shaded and there is no more work until harvest.

There are many variations of Mulch-In-Place.  For example, use a forage chopper to deposit weed mulch into convenient windrows then transplant pumpkins or other fast-growing vine crops through the mulch.  Alternatively, mow strips through weed covered fields.  Transplant vine crops down mowed rows then roll out drip irrigation tape.  Use mowed weeds to mulch crops until plants are established.  Once vines begin to run they overwhelm weeds between rows.  Standing weeds protect vine crops from insect pests.

If you do not have weedy fields, sow winter rye = cereal rye = Secale cereale at 3 bushels per acre.  Roller crimp or sickle-bar mow when rye reaches 5 to 6 feet high or when grain reaches soft dough stage.  Immediately seed or transplant through rye mulch using no-till equipment.  Note:  Mulch-In-Place works with just about any cover crop that grows at least 5 feet high and produces 4 to 5 tons of mulch per acre.

Who needs Monsanto?  Grow mulch crops and never buy herbicide again.  Sell your spray rig and pay off farm debts.

(12)  Use Weeds to Control Insect Pests.  Plant weeds with your crops and you will never have to buy insecticides again.   Set 4 rows of tomatoes then leave a strip of weeds.  Seed 4 rows of sweet corn and leave another strip of weeds.  Plant 4 rows of sweet potatoes with a third strip of weeds.  Drill 4 rows of sunflowers and a fourth strip of weeds.   Alternate crops and weeds across fields and farms, following land contours.  Adjust strip widths to match planting and harvesting equipment.  Weeds provide food, shelter and alternate hosts for beneficial insects.  The good bugs eat the bad bugs.  Native weeds should cover at least 5% to 10% of every farm, even if you also grow insectary plants.  I learned this lesson the hard way.  I grew dozens of crops with small flowers especially to feed predatory and parasitic insects.  Biological control was only partly successful until I planted native weeds next to crops needing protection.  Close proximity is essential as many beneficial insects penetrate only 200 feet into a field over the course of a growing season.  Remember:  You need a mix of native weeds AND insectary plants to protect cash crops.  Maintain biological diversity and pests rarely cause economic damage.  I have not purchased insecticides (organic or synthetic) in 18 years.

(13)  Plant into Standing Weeds (Sow-And-Go).  This works best with fall planted winter grains like wheat, barley, and rye.  Seed directly into standing vegetation using no-till equipment.  (Standing weeds trap winter snow).  If desired, you can seed Dutch White Clover (Trifolium repens) at 8 to 12 pounds per acre with winter cereals.  The clover provides 90% to 95% weed control, about as good as glyphosate (Roundup).  Expect 60% to 70% of conventional yields without fertilizer or irrigation.  In a dry year you might lose your crop.

If you do not have no-till equipment, try surface seeding = Sow-And-Mow.  This works best with pelleted seed.  Broadcast seed into standing weeds then immediately roller-crimp or cut vegetation with a sickle-bar mower to cover and protect germinating grain.  Come back next summer and harvest your crop.

Alternatively, broadcast winter grain into standing weeds then mow with a rotary mower or flail mower to chop vegetation into small pieces.  Immediately till field with a rear-tine rototiller set to skim soil surface at 2 inches depth.  Make only 1 pass across field.  Your field will look ugly but will make a good crop = 40 bushels (2,400 pounds) of wheat per acre in cool, temperate climates with 40 or more inches of rainfall yearly.

If you have no farm machinery, try the ancient Roman practice of Stomp Seeding.  Fence field securely.  Broadcast seed into standing vegetation.  Turn in livestock (cattle, sheep or goats) until they eat about 1/2 of the vegetation and stomp the other half into mulch.  Livestock must be well crowded in order to make this work.  Allow each animal only enough space to turn around = use very high stocking densities = mob grazing.  For example, 600 to 1,200 cows per acre.  Directly forage is exhausted, move livestock to a new enclosure or fresh pasture.  If field is “tired”, “sick” or barren, feed livestock in their enclosure until they deposit 1/2 to 1 pound of manure per square foot = about 11 to 22 tons per acre, then move animals to another enclosure.

(14)  Plant into Living Mulches.  This is ideal for transplants or crops with large seeds.  For best results use no-till equipment and low-growing legumes like Dutch White Clover (Trifolium repens) or Crimson Clover (Trifolium incarnatum).  Seed Dutch White Clover at 8 to 12 pounds per acre, or Crimson Clover at 14 pounds per acre.  Seed or transplant directly cover crop reaches mature height of 6 inches for Dutch clover or 12 inches for Crimson clover.  It is good practice to mow clover before planting to give crops a head start.  Watch field carefully.  When the FIRST seedling emerges, immediately mow field as close to soil surface as possible.  If clover is especially vigorous, it may be necessary to mow again 2 weeks later.  Note:  If desired, you can grow corn (Zea mays) with tall-growing Red Clover (Trifolium pratense) using the same method.  No fertilizer, herbicides or cultivation are necessary if clover grows a full year before planting maize.

Planting into clover is a good way for farmers to learn how to work with weeds.  Clover is convenient to grow because its height is easily controlled.  Alternatively, you can make your own cover crop mix and use this as a substitute for naturally weedy fields.  Combine 2 cool season grasses + 2 cool season legumes + 2 cool season broad leaf plants + 2 warm season grasses + 2 warm season legumes + 2 warm season broad leaf plants + 2 root crops (tillage radish, stock beets, or turnips) = 14 species cover crop mix.  Plant at least 20 pounds per acre.  If desired, more species can be added.  For best economy, select cheap seed to keep costs below $40 per acre.

Remember:  All living mulches compete with their companion crops for water, light and nutrients.  For example, Dutch White Clover grows only 6 inches high but this is enough to shade the lower stems of wheat.  Plant Dutch clover with tall wheat varieties and yields are normal.  Seed Dutch clover with semi-dwarf or dwarf wheat and yields may drop 30% to 50%.  Use common sense when pairing cash crops with clover, weeds, or any other living mulch.  Combine tall varieties with low-growing cover crops.  Water and fertilize for both cash crop AND cover crop.  If necessary, retard or kill companion crop by mowing, mulching or roller-crimping.

(15)  Grow Crops and Animals Together.  2,000 years ago the Romans discovered that manure is more profitable than meat.  It pays to keep animals just for their manure.  Pastures grow better when grazed.  Crops grow better when dunged.  There is a significant difference in growth between plants fed manure or artificial nutrients.  No one has yet figured out why.  Drive a herd of cattle into high weeds (or a mixed species cover crop).  Let the cows graze until they have eaten 1/2 of the forage and stomped the rest.  Move herd to fresh pasture then immediately sow small grains or other crops with no-till equipment.  No herbicides, cultivation or chemical fertilizers required.

The cheapest way to keep livestock is to graze them on fresh, green grass.  Move herds to new pasture at least once daily and do not re-graze paddocks until forage has recovered.  This is called rotational grazing and eliminates the costs of building barns, making hay, and spreading manure.  If you don’t have tidy pastures seed mixed-species cover crops or graze native weeds.  What the cows don’t eat the goats will, and what the goats don’t like the sheep will relish.   Range chickens 3 or 4 days behind cows and the birds eat the fly maggots.  Nothing goes to waste and meadows stay clean and sanitary.

Not all weeds are good to have around.  When weeds get out of control there are 2 easy ways to recover ecologic balance:  (1)  Grow cover crops in series, or  (2)  Graze with mixed livestock.  Cover crops overwhelm weeds by shade and competition.  Mixed livestock eats everything in sight.  Either way, problem weeds are eliminated and crop rotation can proceed normally.

(15)  Think Unconventionally.  If everyone around you grows corn, plant something else.  If everyone says you have to spray, don’t.  Conventional wisdom is often just plain wrong.  Do not be afraid to experiment.  Every year I reserve about 2% of my land for agricultural research.  I learned to farm by doing the opposite of what the “Experts” advised.  Along the way I have enjoyed amazing success and spectacular failure.  Both are equally instructive.  Monsanto says weeds are bad and should be eradicated.  I think differently.  For example, in my garden (a jungle of weeds), I thin Bull Thistles (Cirsium vulgare) until they stand about 1 foot apart, then I plant 1 pole bean seed per thistle plant.  The beans climb the thistles and I do not have to cut poles.  My spray-by-the-calendar neighbors told me to cut the weeds or mulch them into oblivion.  Instead, I conducted a paired comparison of 100 beans on thistles with 100 beans on poles.  Thistles beat poles by a slight margin, 3.55% over a 5-year trial.  This is only one of many examples of symbiosis between weeds and crops.  Widely spaced weeds often increase crop yields.  I don’t recommend planting beans and thistles on a commercial scale, but neither do I insist on weed-free fields.  Weeds spaced 3 feet apart (about 5,000 weeds per acre) no longer bother me.  The tomatoes don’t seem to mind and I don’t have to spray for hornworms.  Learn from nature or buy from Monsanto.

Related Publications:  Weed Seed Meal Fertilizer; Trash Farming; No-Till Hungarian Stock Squash; Planting Maize with Living Mulches; Living Mulches for Weed Control; Pelleted Seed Primer; Crops Among the Weeds; Forage Maize for Soil Improvement; and Rototiller Primer.

Would You Like To Know More?  Please visit:  http://www.worldagriculturesolutions.com  — or —  send your questions to:  Eric Koperek, World Agriculture Solutions, 413 Cedar Drive, Moon Township, Pennsylvania, 15108 United States of America  — or —  send an e-mail to:  worldagriculturesolutions@gmail.com

About the Author:  Mr. Koperek is a plant breeder who farms in Pennsylvania during summer and Florida over winter.  (Growing 2 generations yearly speeds development of new crop varieties).

 

 

 

 

LIVING MULCHES FOR WEED CONTROL

Long before there were herbicides, diesel tractors, or rotary cultivators, smart farmers learned to manage their weeds.  How did they do it?  Here’s how:

Living mulches suppress weeds, reduce soil erosion, enhance soil fertility, attract beneficial insects, and help retain soil moisture.  The best living mulches are low-growing, nitrogen fixing legumes.  Dutch White Clover (Trifolium repens) is a good example.

Before seeding clover or any other living mulch, remember that two crops are growing on the same land at the same time — the mulch crop and a cash crop.  Success requires careful management or both crops may fail.

All living mulches compete with their companion crops.  The extent of competition and consequential yield loss vary with management and crop type.  For example, under drought conditions shallow rooted crops generally show more yield loss than deep rooted crops.  Low or slow growing crops may be overwhelmed by more aggressive companion crops.

As a general rule, living mulches are not recommended where drought is expected because yield losses are too high.  However, many crops benefit from clover mulches during dry conditions — the clover shades the soil, retards evaporation, and increases humidity around the cash crop.

Transplanting Vegetables into Clover

Dutch white clover makes good living mulch for TRANSPLANTED vegetable crops provided:  (1)  Crops are irrigated,  (2)  Crops are fertilized, and  (3)  Crops are protected for the first 4 to 6 weeks from competition by the clover.

1 to 2 inches of water are needed weekly to grow both clover and vegetables without undue competition for moisture.  If water is limiting, it is best to drip irrigate the cash crop rather than water the entire field.

Nitrogen fertilizer is not often required for small grains but is recommended for maize, fruits and vegetables.  The reason is that clover fixes about 100 pounds of nitrogen per acre but these nutrients are not immediately available — they are retained by the living mulch.  Phosphorous and potassium should be applied according to crop requirements along with lime to correct soil acidity.  Dutch white clover needs sulfur and responds well to powdered agricultural gypsum at 2 to 3 tons per acre.

Dutch white clover grows only 6 to 8 inches high so there is little competition for light except when crops are young.  Mow a narrow strip where transplants will be set, or apply a circle of mulch around transplants to give crops a head start.  Once crops are established they will overgrow the clover and produce normal harvests.

Aggressive, fast-growing crops like tomatoes, peppers, okra, melons, squash, sweet potatoes, gourds & pumpkins all do exceptionally well when transplanted into Dutch white clover.  Cucumbers are slower growing and require extra mulch to protect them from early season competition with the clover cover crop.

Stake-less = self-supporting tomato varieties (with thick upright stems) grow well in Dutch white clover.  The living mulch keeps fruits clean and allows easy harvest even in rain-soaked fields.

Once established, Dutch white clover is an aggressive mulch crop that blots out most weeds.  Walk the fields and hand pull any weeds that escape the clover.  Alternatively, thin weeds to at least 1 yard or 1 meter apart.  Thinly spaced weeds will not significantly affect quality or yields of cash crops (but will provide food and shelter for beneficial insects).  Weedy fields often require little or no insecticides to control crop pests.

Direct Seeding into Standing Clover

Dutch white clover is not well suited to direct-seeded crops, especially those with small seeds or slow germination.

Common potatoes are an exception, especially if whole tubers are planted to establish the crop.  Roto-till a narrow strip just wide enough to get the seed potatoes in the ground.  After planting, over seed tilled rows with additional clover seed to maintain soil coverage.  The potatoes grow through the clover without trouble.  Fall potatoes (planted after hard frost in November) averaged 22.8 tons per acre when grown in irrigated Dutch white clover.  Adjacent non-irrigated fields averaged 16.4 tons per acre, the yield loss due to water competition.

Costa Rican Indians grow dry beans by broadcasting seed into the weediest fields available.  The weeds are then hand cut and left as mulch to protect the germinating beans.  Yields are low, only 400 to 500 pounds per acre, but there are no costs other than labor for planting and harvesting.

The same technique works with Dutch white clover.  Spring turnips broadcast into standing clover averaged 10.8 tons per acre when the clover was intensively grazed for 3 days and the seed stomped into the soil by sheep.  Adjacent plots mowed 1-inch high averaged 14.3 tons per acre.  Control plots (no grazing or mowing) averaged only 0.90 tons per acre because of intense competition from the clover.  In comparison, winter turnips (sown after the first snow) averaged 13.1 tons per acre.

These results demonstrate the importance of timing when sowing any small-seeded crop into Dutch white clover.  Ideally, seed should be sown when the clover is dormant.  The next best choice is “sow and mow” (or sow and graze).

Direct seeding into standing clover is not recommended unless the clover is knocked back to reduce competition with the primary crop.

In non-irrigated, non-fertilized fields, flint corn transplanted on 40 inch centers into mown Dutch white clover averaged 68 bushels per acre (along with 1,300 pounds of dried beans and 9,600 pounds of pumpkins).  Adjacent fields transplanted into Red Clover (Trifolium pratense) were overwhelmed and failed to make a crop.

Careful timing is essential when planting mixed crops into living mulches or bare soil.  For example, in a maize-bean-pumpkin polyculture, the primary maize crop should be at least 18 inches high (4 to 8 leaves) before beans or pumpkins are sown, otherwise the grain will be smothered by the companion crops.

Strip cropping combines the pest control advantages of polycultures with the high efficiency of mechanized agriculture.  For example, fields seeded into mown Dutch white clover with 4-row strips of maize alternated with equal width strips of dry beans and winter squash (maize-beans-maize-squash, et cetera) out yielded individual crops grown as monocultures.  The yield advantage for maize alone averages 15% when grown in narrow 4-row strips with other companion crops.  Yield increases from strip-cropping are attributed to better light penetration into the maize canopy, and reduced pest populations in the beans and squash.

Living mulches work especially well with intensive horticulture systems like truck farms and market gardens where careful management and judicious cultivation (including mulching and mowing) prevent the companion crops from overgrowing the cash crops.  When crops are planted into living mulches, entire farms (up to 25 acres) can be run with only a small rear tined roto-tiller and common lawn mower.  Leaving strips of hay, wildflowers, and clover between cash crops and around field borders creates a sanctuary for beneficial predatory insects that help keep pest populations under control.

Seeding Small Grains into Clover

Seeding small grains into living mulches works best when:  (1)  The companion crop is dormant or its growth retarded by mowing, grazing, or rolling, and  (2)  The grain crop is selected for a competitive growth habit.  Heirloom (non-dwarf) varieties usually pair well with understory legumes like Dutch white clover.  Alternatively, clover can be broadcast into standing grain that is well established (8 to 12 inches high).  Again, careful timing is essential to prevent the cover crop from overwhelming the cash grain.

In non-irrigated, non-fertilized fields, fall seeded wheat averaged 28.1 bushels per acre when broadcast into dormant clover.  Spring seeded wheat averaged 21.6 bushels per acre when the crop was “frost seeded” (planted in frozen soil).  Late spring “sow & mow” wheat averaged 19.9 bushels per acre while wheat broadcast into standing clover barely made a crop, only 3.4 bushels per acre.  In comparison, broadcast planted spring wheat top-seeded with clover when the wheat was 8 inches high averaged 15.4 bushels per acre.  To put these yields in perspective, conventionally drilled & cultivated spring wheat (without clover) averaged 39.7 bushels per acre (without irrigation) and 78.5 bushels per acre (with irrigation).

Extra water and fertilizer reduces competition for moisture and nutrients resulting in higher yields.  In irrigated, fertilized fields, fall seeded wheat averaged 70.4 bushels per acre when broadcast into dormant clover.  Frost seeded spring wheat averaged 56.5 bushels per acre, while late spring (sow & mow) wheat averaged 61.9 bushels per acre.  Spring wheat broadcast into standing clover failed to make a crop, while clover sown into standing 12 inch high wheat averaged 74.7 bushels per acre.

Sometimes Old Ways are Best

The clover-wheat-turnips rotation common during the Renaissance is a good example of how cover crops and living mulches can be integrated with modern low-till and no-till agriculture.  Typically, the clover cover crop was “hogged down” (uprooted by foraging pigs); this eliminated the need to plow and harrow.  Wheat was then broadcast by hand and the seed trod into the ground by sheep or cattle.  Turnips were broadcast into the wheat as the heads were filling out, and clover was broadcast over the turnips a few weeks before harvest.  This rotation reliably averages 40 bushels of wheat per acre under European weather conditions without the need for irrigation, synthetic fertilizer, machinery, fossil fuels, or agrochemicals.  (Favorable rain or irrigation boosts this average to 80 bushels per acre).  Low production costs more than compensate for modest yields, a primary consideration for most farmers operating on slim profit margins.

Thoughtful Weed Management

The key point to intelligent weed control is to disturb the soil as little as possible, just enough to get a crop into the ground.

Remember that weeds have evolved specifically to rapidly colonize bare soil.  The more soil is tilled, the more weeds are stimulated to grow.  Conventional bare earth agriculture invites weed invasions.  In order for crops to coexist with weeds and living mulches, a different approach is needed.  Ideally, crops should be over seeded or transplanted with the minimum possible disruption to both soil and surface vegetation.  Often, specialized equipment is needed.  For example:  Why dig a long furrow when only a few discrete holes are needed for seeding?

Without irrigation and fertilization, competition between living mulches and cash crops can reduce yields 50% or more.  Poor judgment (such as seeding at the wrong time) can result in crop failure.

Clearly, there is significant competition from living mulches; the question is whether the savings from reduced tillage and other costs are outweighed by observed yield reductions.  These differences may not be significant depending on how the crops are marketed.  For example, the premium for “organic” produce and the profits from artisan breads are substantial.  In this case, lower yields are offset by higher margins from specialty products sold to niche markets.

Agronomy Notes

>>>  Dutch white clover and winter wheat can be seeded at the same time.  Remember to plant only after the Hessian Fly Date for your area.  This technique works well with all winter grains.

>>>  Top seeding Dutch white clover usually requires a separation of 7 to 14 days between plantings (about the time it takes for the cash crop to germinate).  Slower growing crops need more time to become established.  For example, sweet corn should be at least 6 inches tall before over seeding with Dutch white clover.  Rule-of-Thumb:  Maize should have 4 to 8 leaves (16 to 24 inches tall) before top seeding with Red Clover (Trifolium pratense) or any other type of tall growing clover.

>>>  Organic herbicide may be used instead of mowing, grazing or cultivation to control Dutch white clover prior to planting a cash crop.  For example, a narrow strip of clover can be killed with herbicide before transplanting vegetables.  Use spray shields to prevent herbicide drift.  It is important to disturb as little of the living mulch as possible — kill just enough clover to get the crop established.  Removing too much plant cover favors weed growth.

>>>  If clover seed is unavailable or too expensive, use weeds as living mulch.  This technique works best with fast growing vine crops.  For example:  Choose the weediest field available then transplant melon seedlings on 10 to 12 foot centers.  Mulch each transplant liberally with straw or any other convenient material.  Mulch is necessary to keep weeds at bay only until vines begin to run.  Once started, vines will overgrow the nurse crop.  Melons thrive in the light shade of weedy fields.  As an added benefit, vines growing among weeds rarely have insect problems.

>>>  Red Clover (Trifolium pratense) seed is usually less expensive than Dutch white clover (Trifolium repens).  Sweet corn, popcorn, flint corn, flour corn, pod corn, and dent corns all grow well when planted with red clover.  Top seed = over seed maize with red clover at the last cultivation or when plants have 4 to 8 leaves.  The corn plants are tall enough (about 1 1/2 to 2 feet high) so that competition with the living mulch is minimal.

>>>  Any type of maize can be seeded directly into standing red clover using a no-till planter with a fluted coulter.  Two weeks later the field should be closely mowed with a swathing board and divider to keep the clover from falling on the planted rows of corn.  Alternatively, clover can be mowed directly before seeding.  Watch regrowth carefully; a second mowing may be required 2 weeks later.  No herbicides are needed if maize is planted into standing clover; nitrogen fertilizer is not required if clover has grown on the land for 1 or more years.

>>>  Maize is sensitive to drought, especially during pollination and when ears are filling out.  For highest yields apply 1 to 2 inches of water weekly to prevent moisture competition between crop and living mulch.

>>>  Planting hybrid sweet corn into standing red clover yields about 415 sacks per acre on average when sweet corn is seeded 8 inches apart within rows and 30 inches between rows = 25,979 seeds per acre.  Actual plants per acre is approximately 21,000 (17% field loss rate is common).  1 sack = 52 ears = 4 baker’s dozen = 21,580 marketable ears per acre.  Note:  Yield figures are discounted 50% for typical losses to crows, deer, groundhogs, coons, earworms, undersize or poorly pollinated ears, and other causes.

>>>  It is best to use pelleted seed when hand dropping or broadcast seeding into living mulches.  This is especially true for large-seeded crops like peas, beans, maize, melons, and squash.  Pelleted seeds greatly increase germination and stand establishment rates.

>>>  Seedling survival and stand establishment are optimal when planting is done with no-till equipment.  Expect 20% to 25% loss rates when broadcasting naked, unprotected seed into living mulches or other standing vegetation such as hay or weeds.

>>>  Biological agriculture is all about managing little details, for example, choice of companion crop:  Flour corn top seeded with sweet clover (Meliotus officinalis) was overwhelmed and failed to make a crop.  Flour corn planted with standard (tall) red clover yielded 37.4 bushels per acre.  Flour corn planted with medium red clover yielded 41.8 bushels per acre.  Flour corn planted with Dutch white clover yielded 47.6 bushels per acre.  Yield differences were entirely due to living mulch height.  Taller clovers compete more strongly with maize cash crops, especially when corn plants are young.

>>  Every farm has different soil and micro-climate.  Agronomic practices that work in one field may fail in another.  For best results, every farmer should maintain one or more research plots so that new methods can be tested and adapted to local conditions.

Related Publications

Managing Weeds as Cover Crops; Weed Seed Meal Fertilizer; Trash Farming; No-Till Hungarian Stock Squash; Planting Maize with Living Mulches; Organic Herbicides; Pelleted Seed Primer; Crops Among the Weeds; Forage Maize for Soil Improvement; Forage Radish Primer; and Rototiller Primer.

 For More Information

Readers who have any questions or require additional information about living mulches should contact the Author directly:

Please visit:  http://www.worldagriculturesolutions.com  — or —  send your questions to:  Eric Koperek, Editor, World Agriculture Solutions, 413 Cedar Drive, Moon Township, Pennsylvania, 15108 United States of America  — or — send an e-mail to:   Eric Koperek = worldagriculturalsolutions@gmail.com

Most agricultural universities publish extensive literature on cover crops, nurse crops, living mulches, green manures, and crop rotation.  Contact your County agricultural extension agent or search the Internet for relevant publications.

About the Author

Mr. Koperek is a plant breeder who farms in Pennsylvania during summer and Florida over winter.  (Growing 2 generations yearly speeds development of new crop varieties).