Planning for Sustainable Farming – Feed the Soil

©Pam Dawling 2014Twin Oaks Community, Central Virginia

Author of Sustainable Market FarmingNew Society Publishers

SustainableMarketFarming.com facebook.com/SustainableMarketFarming

What’s in This Presentation

Planning for sustainable farming – feed the soilGrowing and maintaining healthy soilsCrop rotationsCover cropsCompost making (& growing)Organic MulchesResources

Grow Healthy Soil

Healthy soil grows healthy plants

Feed your soil, not your plants

Tatsoi. Credit Wren Vile.

What are Healthy Soils?

• Healthy soils produce good crop yields, without degrading the environment.

• They promote plant, animal, and human health. • Healthy soils produce sturdy crops that resist

pests and diseases. • But don’t blame the victim! Diseases need three

things for the disease to take hold: a susceptible host, a disease organism and suitable conditions.

• Grow strong plants and make the conditions unsuitable for diseases and pests. Sometimes plagues still strike!

Healthy Soil is AliveOne acre of organic soil can have 2400 pounds of fungi and 1500 pounds of bacteria. These contribute to good soil structure, breakdown nutrients, and increase levels of organic matter. USDA image

Signs of a Healthy Soil

• Has good crumb structure, lets air and water in and out.

• Resists erosion and compaction.• Absorbs, holds and releases nutrients.• Promotes good root growth.• Provides good habitat for soil organisms.• Has a moderate pH (6.0 – 7.0).• Has low levels of salts and toxins.• Has balanced fertility with adequate levels of

nutrients.

Crop Rotations Bring Many Benefits

Maximize productivity,Optimize the health and fertility of the land, Reduce pests and diseases,Increase opportunities to plant cover crops, Meet Organic Certification requirements,Make the planning work easier on the brain.

Before Planning a Rotation

Decide how your farming will support youDecide what you want to growFigure out how much of what you needHave an idea of when to plant each crop.Planning is definitely circular, but you need to

start somewhere!

Steps to Creating a Permanent Rotation

a. Figure out how much area is needed for each major crop (the ones needing the largest amount of space).

b. Measure and map the land availablec. Divide into equal plotsd. Group compatible crops together to fill each plote. Determine a good sequencef. Include cover cropsg. Include no-till cropsh. Try it for one year, then make improvements

Space Needed for Major Crops• Sweet corn: 6 or 7 plantings of about 3,500 ft2 (322 m2) each

• Spring planted potatoes: about 7,000–9,000 ft2 (644–828 m2)

• Summer planted potatoes: about 7,000–9,000 ft2 (644–828 m2)

• Spring broccoli & cabbage: 4,000 ft2 (368 m2)

• Fall broccoli & cabbage: 7,000 ft2 (644 m2)

• Winter squash: about 8,200 ft2 (736 m2)

• Watermelon: about 9,000 ft2 (828 m2)

• Sweet potatoes: about 4,300 ft2 (396 m2)

• Tomatoes: 4,000 ft2 (368 m2)

• Peppers: 2,200 ft2 (202 m2)

• Garlic: about 3,600–4,000 ft2 (332–368 m2)

• Fall carrots: about 3,600–4,000 ft2 (332–368 m2)

Divide the Land into Equal Plots

In our gardens, the 7,000–9,000 ft2 (644–828 m2) crops (spring planted potatoes, summer planted potatoes, fall broccoli & cabbage, winter squash, watermelon) will naturally each fill one plot in our rotation,

so that was a good size to aim for in setting plot size.

This size produced 10 plots, suggesting a ten part rotation

Group Other Crops Together to Use About the Same Area:

Two or three corn plantings together in one plot (3,500 ft2 (322 m2) each)

Spring broccoli together with overwintered garlic (4,000 ft2 (368 m2) + 3,600–4,000 ft2 (332–368 m2 ))

Tomatoes together with peppers 4,000 ft2 (368 m2) +

2,200 ft2 (202 m2)

Left to right: Broccoli under rowcover, garlic, strawberries. Photo Kathryn Simmons

Walk Around our RotationYear 1. Winter Squash followed by Rye and Austrian Winter Peas

• 8,200 ft2 of winter squash will satisfy our

needs. That fills one plot.

• Winter squash are sown in late May, so there is

time for a legume winter cover crop to reach

flowering before we need to prep the soil for the

squash.

• We have one other main crop also in the cucurbit

family: watermelon, so we plan to keep that

distant time-wise in the rotation

• Winter squash finishes on our farm on Halloween,

early enough to include crimson clover or Austrian

Winter Peas in the following cover crop mix

Year 2. Late Sweet Corn and Sweet Potatoes

• Our late (6th) corn sowing and our sweet potatoes are both planted late in the season. Having them share a plot works in terms of allowing the preceding crimson clover or Austrian winter pea cover crop time to flower.

• Late corn can be under-sown with oats and soy to provide a winter cover crop that is easily incorporated before the potato planting next March.

• The sweet potatoes finish in October, too late to sow oats before next year’s spring potatoes. So we follow the sweet potatoes with wheat.

Sweet potatoes and late corn. Photo Bridget Aleshire

Year 3. Spring Potatoes Followed by Fall Brassicas

• Potatoes are said to do well after corn, so we put our spring potatoes after the previous year’s late corn, and our summer potatoes after the previous year’s middle corn planting.

• We harvest the potatoes in early July, till in compost and immediately transplant our fall broccoli and cabbage.

• We undersow the fall brassicas with a mix of clovers (white, red and crimson) about a month after transplanting. This becomes Year 4’s All Year Green Fallow.

Potatoes emerging in spring. Photo Kathryn Simmons

Year 4. All Year Green Fallow The clover sown under the fall brassicas

grows all next year, if all goes well. We have contingency plans: In spring, once the warm weather has

arrived, if the weeds are too bad, or the clover stand not thick enough, we turn the clover under and sow sorghum-sudangrass hybrid with soy. This gets mowed to a foot (30 cm) when the sorghum-sudan is four feet (1.2 m) tall, to encourage deeper rooting for better soil drainage, and can stay until killed by the frost.

If the plot is looking good, we let the clover grow all summer, mowing to prevent the clover seeding.

In August, we review again: if we still have the clover we may turn it under and sow oats. Or we may leave it over winter.

Fall broccoli under-sown with clovers

Year 5. Early Sweet Corn, Half Followed by Garlic

• We get two food crops in year 3 and none in year 4. The Green Fallow is ready for disking early in year 5 to plant our first sweet corn.

• The early corn can be followed by fall garlic.

Sweet corn under-sown with soybeans. Photo Kathryn Simmons

Year 5-6. Sweet Corn → Oats →Garlic →Buckwheat →Carrots

A tight rotation: After early corn in year 5, we

sow oats and divide the plot. We keep half for spring broccoli

in year 6. We mow the other half from

time to time until late fall (year 5), then disk and plant garlic.

We harvest the garlic in June of year 6, sow buckwheat and soy,

Then sow fall carrots in late July or early August.

That half-plot grows 3 food crops in 2 years.

Garlic harvest, Photo Rayne Squier

Year 6. Spring Brassicas in the Other Half.

Spring broccoli and cabbage can be followed by rye, hairy vetch and Austrian winter peas sown in early September, in good time to grow a thick stand for no-till tomatoes in year 7. Photos Kathryn Simmons

Year 7. Paste Tomatoes and Peppers• We mow the cover crop close

to the ground, let it wilt for a day, then transplant paste tomatoes and peppers into the dead mulch in early May.

• The mulch does break down after about six weeks, so then we roll out bales of spoiled hay between the rows.

• This crop doesn’t finish till the frost, and we have all the posts to remove before we can sow a cover crop, so it is usually rye with Austrian winter peas.

Year 8. Watermelon

• Watermelons are not planted till mid-May, so the Austrian winter peas have time to flower before we disk the cover crop under in preparation for planting.

• We have finished with watermelon harvesting by late September, so we disk the plot and sow rye with crimson clover for the winter cover crop.

Crimson Sweet watermelon and morning glory. Photo Kathryn Simmons

Year 9. Mid-season Sweet Corn

Mid-season corn is finished in time to establish rye and crimson clover, which will do well and produce lots of nitrogen and biomass before we need to plant the June potatoes in year 10. Three varieties of sweet corn sown on the same day, to extend the harvest. Photo Kathryn Simmons

Year 10. Summer Potatoes• Our second round of potatoes are

planted in mid-June, giving the crimson clover plenty of time to flower before we need to disk and plant.

• To combat the heat of summer, we hill and mulch the potatoes immediately after planting.

• They are ready to harvest in October, and we follow with rye and crimson clover or Austrian winter peas.

June-planted potatoes. Photo Kathryn Simmons

Benefits of planned crop rotations

This tight crop planning might sound mind-boggling, but for us it’s very worthwhile. The division of the gardens into 10 plots gives us mental and

psychological advantages - we don’t have to think about the whole of the area all of the time.

In spring we “open up the rooms” one or two at a time to plant. By the beginning of July everywhere is in use.

In August we start to put the plots “to bed” with their winter cover crops.

Annual expansion and contraction of the space needing our attention helps us to stay sane and focused and keep perspective.

This system helps us get high productivity from our land, while taking good care of it.

Cover Crops - Oats For early spring food crops, a

preceding cover crop of oats (maybe with soybeans) is ideal, as it winter-kills and is easy to incorporate.

Oats need to be sown at our farm in August or early September (by 9/17), so they need to follow an early finishing crop, such as spring brassicas, spring potatoes or early corn.

Photo Oklahoma Farm Report

No-till Cover Crops We plant our tomatoes and peppers

into a mowed cover crop of winter rye, hairy vetch and Austrian winter peas. Austrian winter peas are said to reduce the incidence of Septoria leaf spot in following tomato crops, so we now include them in our no-till planting.

This reduces inversions of the soil, and the vetch (if plentiful) can supply all the nitrogen the tomatoes need.

Rye and vetch is best sown here in early to mid-September, creating another restriction on which crops the tomatoes could follow.

Winter rye and hairy vetch. Photo Kathryn Simmons

Leguminous Cover Cropso To get best value from crimson clover,

we need to wait until it flowers — mid-April at the very earliest — before turning it under.

o So after crimson clover it’s best if the next food crop goes in after the end of April, such as later corn plantings, winter squash, transplanted watermelon, tomatoes, sweet potatoes or June-planted potatoes.

o Another factor is that crimson clover is best sown here before October 14, so it has to follow a crop that is finished by then.

Crimson clover flower, Photo Kathryn Simmons

Late Fall Cover Crops• Austrian Winter Peas can be sown as late as

11/8 here, so we add them to our later rye and wheat cover crop sowings.

• Photo FifthSeasonGardening.com

• Winter wheat is easier to incorporate into the soil in spring, but winter rye can be planted later than any other cover crop.

Popping in Summer Cover Crops

If we have a four week gap between crops in warm weather, we sow buckwheat.

If we have 6 weeks, we sow soy with buckwheat.

Japanese Millet Sorghum-sudangrass

Shown here after mowing. Photo Kathryn Simmons

Cover Crop Opportunities Undersowing at last cultivation (oats

and soybeans in corn shown here.) After vegetable crops, in summer or

fall In spring, between an early vegetable

crop and a later one After long season crops, for winter Late winter or early spring, if the area

will not be planted with vegetable crop until late spring. We use oats.

Frost-seeding of small seeds such as clover: Broadcast in the early morning, when ground is frozen. As it thaws, the water draws the seeds down into the soil. Works well for clovers.

To replace a crop failure.

Photo Kathryn Simmons

Fitting the Cover Crop With the Goal • Smothering weeds: sorghum-sudan, cereal rye, buckwheat,

brassicas (we don’t do brassica cover crops – rotation, bugs).• Fixing nitrogen: clovers, vetches, Austrian winter peas, cowpeas,

soybeans, lentils, sunn-hemp. • Scavenging leftover nutrients : small grains, brassicas, annual

ryegrass (we don’t use annual ryegrass either – danger of it becoming a weed)

• Improving soil drainage: sorghum-sudangrass, sunflower, daikon, sweetclover, alfalfa, brassicas, sugar-beet or forage-beet (never tried that.)

• Grazing: brassicas, clovers, small grains, annual ryegrass. • Bio-fumigation: brassicas, sorghum-sudan, sunn-hemp, sesame.• Killing nematodes: Pacific Gold mustard, white lupins, Iron and

Clay cowpeas, OP French marigolds, sesame.

Incorporating Cover Crops into the Soil

• If possible, grow to early bloom for max biomass• Incorporate before plants set seed• Mow with a rotary mower (eg bush hog) which

chops the plants into small pieces. (Sickle-bar mowers and scythes leave long strawy plants)

• Till shallowly, put cover crop where soil life is most active, not deeper.

• If direct-sowing the next crop, incorporate cover crop 3-4 weeks before sowing date, especially winter rye.

Compost Making• Many farms make their own compost -this

improves the soil, uses materials that could otherwise be a waste disposal problem.

• USDA Organic Certified Farms need to follow Organic rules.

Compost is Central to our Soil Fertility Program.

• One of our community businesses is making and selling tofu. Okara is a high-nitrogen waste product from tofu making, the part of the soybeans that doesn’t go into the soymilk.

• We mix in high-carbon sources such as sawdust (waste from our hammock-making business) or woodchips that we trade for with a neighbor.

• We also add kitchen scraps from our dining hall, • and sometimes weeds or crop refuse from our garden. In the

summer we don’t collect up the weeds, just let them die in place, as that is easier.

• We don’t have specialized compost-turning machines or screens. We use the tractor bucket to lift and turn the piles.

Compost Making is Both Art and Science

• There are several methods and recipes. • Most people strive to make hot (aerobic) compost,

by combining 1 to 3 parts high-carbon materials with 1 part high-nitrogen materials in a 25:1 to 40:1 C:N ratio, with enough water to make the piles damp and enough air to keep the bacteria alive.

• The initial mesophilic stage lasts for the first two to three days after the pile is made. Bacteria which are active at 90°F–110°F (32°C– 43°C) begin to break down the sugars, fats, starches and proteins.

Hot (aerobic) compost• The pile heats up and moves

into the thermophilic stage, which lasts several weeks. Temperatures in the middle of the pile can reach 120°F–150°F (48°C–66°C).

• Thermophilic bacteria increase, and keep working as long as decomposable materials remain available and the oxygen supply is adequate.

• Pathogens, weed seeds and fly larvae are destroyed, and the particle size of the compost becomes smaller.

Large-scale compost-turning equipment

When the pile starts to cool, turn it• A decrease in temperature shows that more oxygen or more water is

needed. • The pile benefits from turning during this stage to provide more oxygen

and remix the material, so that all of it can be composted. • Turning also prevents the pile from overheating — above 150°F (66°C), the

thermophilic bacteria can be killed. • During turning, more water can be added if needed to keep the pile damp

but not dripping.

Large scale compost-turning machinery

Compost Trouble-Shooting

Too much water will cause air to be excluded, and the pile will slow down, go anaerobic, and emit foul-smelling by-products.

High-nitrogen mixes are likely to lose (waste) nitrogen by volatilization as ammonia.

Some loss is inevitable, but compost-makers strive to minimize loss by getting a good balanced mix.

If there is not enough nitrogen in the mix, the pile will not heat up and the process will move slowly.

When the Compost Stops Heating After the compost materials have all been consumed by the bacteria and the nitrogen

mineralized (converted to nitrates which will be available as plant nutrients), the pile cools to around 100°F (37.7°C).

It can no longer be reheated by more turning, and it is left to cure for about thirty days. This allows beneficial microorganisms to recolonize the compost.

The carbon in mature compost is resistant to further breakdown, and the nitrogen, initially contained in the bodies of microbial soil life forms, slowly becomes available to the plants.

It is then ready to be used, or if you like, screened first.

Large-scale compost screening equipment

Finished Compost

Finished compost ideally has a C:N (carbon:nitrogen) ratio of 10:1.

If the C:N ratio is greater than about 25:1, almost no nitrogen is available from the compost and it is unable to mineralize.

Between 16 and 20:1, about 10 percent of the N is available.

Even at a C:N ratio of 10:1, only half of the nitrogen is available in the near term.

Compost is a Long-Term Plan! Because it breaks down slowly, generally about 10

percent of the nitrogen will remain after harvest for the next crop (assuming an adequate amount of good finished compost was used).

Some growers aim to build the soil to a high overall fertility level, and then maintain that level with smaller applications of compost each season.

Others aim to apply a consistent amount each year. Whatever your aim, it is generally agreed that the

occasional shortfall in compost application will not be too dire if the soil fertility is high from previous applications.

How Much? Compost enhances the soil organic matter and humus, and

improves soil structure. Its effects last longer in the soil than cover crops and crop

residues, especially in humid conditions where the breakdown of plant material is very rapid.

In addition, compost can add a range of beneficial bacteria and fungi to the soil, which can inoculate plants against diseases by inducing systemic acquired resistance in them. The plants produce antibodies and other protective compounds before any infection occurs.

In his Winter Harvest Handbook, Eliot Coleman recommends spreading compost at 5 gallons/ 25 ft2 or 15 tons/acre (8.6 l/m2) of raised beds, for each successive crop.

Growing Compost Materials

• If you have land where you are not growing food crops and don’t want to improve the soil by growing cover crops, you can grow compost crops, to cut and haul to your compost piles.

• This can be a good way to grow food crops very intensively in a small area, with the compost crops growing elsewhere.

Organic Mulches

• Organic mulches such as straw, hay, sawdust, woodchips, tree leaves, newspaper and cardboard all add organic matter to the soil.

• Here we are preparing a new strawberry bed mulched with two layers of newspaper and dried sorghum-sudangrass cut from the plot in the background.

Photo Luke J Stovall

Resources - General ATTRA attra.ncat.org SARE sare.org -A searchable database of research findings SARE Crop Rotations on Organic Farms, A Planning Manual, Charles

Mohler and Sue Ellen Johnson, editors. extension.org/organic_production The organic agriculture community

with eXtension. Publications, webinars, videos, trainings and support. An expanding, accessible source of reliable information.

Growing Small Farms: growingsmallfarms.ces.ncsu.edu click Farmer Resources. Debbie Roos keeps this site up to the minute.

Jean-Paul Courtens , Roxbury Farm www.roxburyfarm.com. Under the Information for Farmers tab you’ll find great stuff.

The Center for Environmental Farming Systems at North Carolina State University has good information on compost-making, such as Composting on Organic Farms.

Compost recipe software is available from Cornell University www.cfe.cornell.edu/compost/science.html

Resources - slideshows Many of my presentations are available at www.Slideshare.net . Search for Pam Dawling. You’ll find Crop Rotations Cold-hardy Winter Vegetables Fall Vegetable Production Intensive Vegetable Production on a Small Scale Succession Planting for Continuous Vegetable Harvests Sustainable Farming Practices Crop Planning for Sustainable Vegetable Production Mark Cain Planning for Your CSA: www.Slideshare.net (search for Crop Planning) Planning the Planting of Cover Crops and Cash Crops, Daniel Parson SSAWG 2012

www.slideshare.net/parsonproduce/southern-sawg Cover Crop Innovation by Joel B Gruver www.Slideshare.net Cover crops for vegetable cropping systems, Joel Gruver,

www.slideshare.net/jbgruver/cover-crops-for-vegetable-crops Finding the best fit: cover crops in organic farming systems. Joel Gruver, Some overlap with previous

slideshow. www.slideshare.net/jbgruver/cover-crops-decatur Tom Peterson Farm Planning for a Full Market Season Appalachian Farmers Market Association and

Appalachian Sustainable Development http://vabf.files.wordpress.com/2013/02/tom-peterson-farm-planning-for-a-full-market-season.pdf

Resources - books The Complete Know and Grow Vegetables, J K A Bleasdale, P J Salter et al. Knott’s Handbook for Vegetable Growers, Maynard and Hochmuth The New Seed Starter’s Handbook, Nancy Bubel, Rodale Books The Organic Farmer’s Business Handbook, Richard Wiswall, Chelsea Green Sustainable Vegetable Production from Start-up to Market, Vern Grubinger, The New Organic Grower, Eliot Coleman, Chelsea Green Extending the Season: Six Strategies for Improving Cash Flow Year-Round on the

Market Farm a free e-book for online subscribers to Growing for Market magazine Sharing the Harvest, Elizabeth Henderson and Robyn Van En Organic Farmer’s Business Handbook, Richard Wiswall Gardening When it Counts, Steve Solomon Grow a Sustainable Diet: Planning and Growing to Feed Ourselves and the Earth,

Cindy Conner, New Society Publishers, (worksheet based). DVD/CD set Develop a Sustainable Vegetable Garden Plan

Crop Planning for Organic Vegetable Growers, Daniel Brisebois and Frédéric Thériault (Canadian Organic Growers www.cog.ca)

Planning for Sustainable Farming – Feed the Soil

©Pam Dawling 2014Twin Oaks Community, Central Virginia

Author of Sustainable Market FarmingNew Society Publishers

SustainableMarketFarming.com facebook.com/SustainableMarketFarming