We planted a warm-season cover crop cocktail on 40 acres during the weekend of May 18th. See our seed chart and details here. We’re hoping the cocktail will supply all the benefits of typical one- or two-variety cover crops (organic matter production, erosion prevention, nutrient availability) and greatly amplify all these benefits with diversity. Cocktails planted on other farms have shown that all the plant varieties cooperate and thrive instead of compete. Many believe this is caused by the plant varieties leaking their signature root exudates into the soil profile to stimulate their desired segment of beneficial soil biology. With a field’s entire soil biology stimulated like never before, the whole soil/ biology/ plant ecosystem starts cranking! It’s really neat stuff! On our three-acre field, which has the best soil quality out of the 40 acres, we’re already seeing these very positive effects including drought resistance, very high quality plants, and low bug and disease pressure.
Let’s start with our neighbor’s east field. This field was in roundup-ready soybeans for about a decade until fall 2010. We planted a sorghum-sudan & cowpeas cover crop in spring 2011, rotovated that in with beneficial microbes, then planted a winter rye & vetch cover crop last fall. We then successfully mow-killed the vetch and planted the summer crop cocktail this May. Cocktail plant quality doesn’t look as great as our stupendous 3-acre field, but the cocktail is growing despite suffering in the eastern U.S. heat wave. This field’s soil test results are good, not great. It is short on calcium and micronutrients like zinc.
The wide view pic above shows that buckwheat and dwarf essex rape are currently dominating. These plants are the tallest and are blooming profusely with white and yellow flowers. It would be ideal to mow these two before they set seed, but I don’t want to cut the other plants in the cocktail. Mowing plants at flowering ensures most of the nutrients stay in the soil. When plants make seed, the plant sucks nutrients and sugars from the soil to assist in seed production. This is a tradeoff that goes along with a highly diverse (20 varieties) cocktail. On the plus side, these two plants are giving us free seed that will germinate later.
The ferny-looking plant in the middle foreground is phacelia. Its beautiful purple bloom should pop out any day now. The brassicas and millets surrounding it are showing some stress from near 100-degree heat for several days and no rain for three weeks.
Our Best Field Shows Cocktail Benefits
Now let’s go to our 3-acre field. I mentioned in the first paragraph that this is the best field out of the 40 acres. Its soil test results are good, showing decent nutrients for our very sandy soil. We took it out of roundup-ready soy production in fall 2008 and planted pasture grasses that failed to thrive for three years. We rotovated the grass in fall 2011 while spraying beneficial microbes, then planted rye and vetch for the winter. This spring we mow-killed the rye and vetch and planted the cocktail. On top of this management, we spread horse manure compost (we go get free horse manure and compost it for about 9 months in static piles).
I’m not sure if the compost explains the health of this field or if it’s the combination of everything we’ve done. But something is going on! Some orchard grass survived our rotovating, and it looks night-and-day different from orchard grass in our existing pasture just 20 feet away. The orchard grass in our pasture is lackluster and starting to go dormant in the drought. The grass that survived rotovating in the 3-acre field is still dark, dark lush blue-green with no signs of going dormant yet. Imagine if we had all our pastures filled with grass like this! It’s some good quality grass for our future livestock.
Take this above pic of sorghum (looks like corn) surrounded by the other cocktail plants. The sorghum looks great despite high heat and drought and no nitrogen fertilizer. This makes me super happy because the soil is clearly providing nitrogen to this nitrogen-hogger of a plant. Only soil that has reached a decent level of health with a nicely functioning biology community can do this. The brassicas around this sorghum plant have very large waxy leaves with very little insect pressure. I can’t get brassicas in my veggie garden to look this good. Something great is going on in this field!
Here’s a pic of sunn hemp and camelina in the center with brassicas all around. Sunn hemp (left) and camelina (right) look similar at this point, but that will change soon. Sunn hemp can get giant-tall. Camelina is an oil seed brassica like dwarf essex rape. It’s starting to flower, so it will probably stay short.
We’re excited to see what sunn hemp can do in our fields. It’s a legume, and we inoculated the seed with its preferred Rhizobium bacteria. This bacteria works with the plant to create huge golf-ball sized nodules on sunn hemp roots. These Rhizobium nodules fix nitrogen from the air in return for sugary root exudates from the plant. When sunn hemp dies, the nitrogen will get released into to soil, hopefully just in time for our next winter cover crop’s grasses (oats and rye) to pick it up and use. This is how cover crops can be a giant nutrient recycling machine that keeps high quantities of necessary nutrients available rather than locked up in the soil. On top of the nitrogen benefit, sunn hemp can grow up to 10 feet tall! That’s a lot of nice biomass that holds carbon, nutrients and vitamins. It will make high quality mulch for the soil after we mow it down.
Here’s an extra large mustard plant surrounded by millets and blooming buckwheat.
Here’s a sunflower popping up with cowpeas, millets, brassicas and some weeds. I’m not gonna lie!
I’m very excited to see this cosmos and can’t wait to see its hot pink flowers! I haven’t seen the other flowers/herbs we planted such as dill, coriander, alyssum.
To give you an idea of how well the brassicas are growing in this 3-acre field, check out this turnip. The top of the bulb is already 3 inches wide! Brassicas stimulate earthworms and other important soil animals and can suck up a lot of nitrogen and phosphorus that was otherwise stuck and unavailable in the soil, so we’re very, very happy the brassicas are growing so well.
Time to take it down a notch and talk about what didn’t work.
Our pasture seeding is a failure. We planted the same 70 pounds of seed per acre in our existing pastures that we planted in all the other fields, but so far we have just a few wimpy soybeans rising above the grass. We didn’t expect the cocktail to grow fabulously in our pastures, but we thought many more plants would grow. Seems our big mistake was not waiting until the pasture grass went dormant. The cool season grasses were way too competitive with the new seeds in May and June. We’ll wait to see if more cocktail plants start growing as the cool-season pasture grass starts to poop out in July and August.
Another failure is our neighbor’s west field. I wrote at the bottom of this post how mowing the vetch twice in this field allowed a lot of sunlight to get through and prompt volunteer annual ryegrass to sprout and grow like crazy. Well, the annual ryegrass is strongly competitive and has prevented the cocktail from growing. I should have made sure the annual ryegrass was dead before we planted the cocktail. We sure are learning our share of expensive lessons!
We’ll let the cocktail grow for another six or seven weeks, then mow it to kill in mid to late August. Then we’ll come in and no-till drill (plant) a cocktail for winter. Many of the summer plants will survive mowing and won’t die until the first hard frost, which happens around Halloween here. We have some experience with this with sorghum-sudan going into rye and vetch. We’ll see how it turns out transitioning with cocktails.
We hope come mow-time in August that most of the plants are flowering or starting to make seed. Plants at this stage are easy to mow-kill. In the meantime, we’re very happy we experimented and planted this cocktail. Each plant variety is doing its own little thing in the fields such as stimulating soil biology, manufacturing carbon for the soil, and harvesting minerals that will be very available for subsequent plants to use and thrive. It’s way cool to use plants that will go to work for us and contribute all these benefits for improved soil health!