The right cover crops for no-till spring and fall peas

The right cover crop might be a better soil preparation prior to peas than tillage. At a farm meeting in Maryland in May, farmers and researchers said they had seen as good or better yields of no-till peas following specific cover crops compared to conventionally planted peas, and this goes for both spring and fall pea crops.

These peas were planted no-till after forage radish using a MaterMacc Planter. Photo credit: : Dave Liker, Gorman Farm

These peas were no-till seeded after forage radish using a MaterMacc Planter without herbiides. Photo credit: Dave Liker, Gorman Farm

Fall peas into German foxtail millet

Your spring peas may still be in the ground, but it’s time to be thinking about fall peas. If you’ve given up on fall peas, perhaps this is the season to try them again, and NOW is the time to get your cover crop in the ground in preparation. Dave Myers and colleagues at the University of Maryland Upper Marlboro research farm wanted peas in time for pick-your-own pumpkin operations in Maryland. They seeded German foxtail millet at a rate of 25 lb/acre at the end of May/beginning of June, let it grow until mid-August, and then they no-till seeded peas into the growing millet without any herbicides. As the millet senesced, the peas continued to grow into the fall, maturing just in time for pumpkins. If you’re thinking some other millet might suffice, Dave was pretty adamant that German foxtail millet is the way to go with this one.

Their timing was for southern Maryland, and getting the timing just right in your system may take a little tweaking, but now is certainly the time to start. If you were contemplating putting in a quick crop of buckwheat, maybe try German foxtail millet as a summer cover crop instead? You can read more about their experiment here and see some pictures of peas growing in millet here.

Spring peas after forage radish

No-till seeded peas into forage radish "residue" in Maine, where soils are cold.

No-till seeded peas into forage radish “residue” in Maine, where soils are cold.

We’ve talked about spring peas after a radish cover crop before, but we now have corroboration from colleagues at the University of Delaware that a forage radish cover crop seeded in early fall creates a perfect seedbed for early spring peas. Gordon Johnson has been looking at a variety of cover crops for improving productivity and soil quality in processing vegetables in Delaware and he and his team found that no-till seeded processing peas  following a radish cover crop performed exceptionally well compared to peas seeded after vertical tillage, chisel plowing or no-till seeded into bare ground. Johnson said the biodrilling from radish (and mustard, which they looked at too), helped the pea plants, which are sensitive to compaction. In their sandy soils, getting enough fertility to the cover crop in fall can be a challenge and as with all cover cropping systems, fitting a cover crop into the rotation requires a commitment to cover crops that most people might reserve for their cash crops.

Farmer Dave Liker in Laurel, MD, had his best crop of sugar snap peas ever last year when he no-till seeded them into forage radish residue. This year, his results weren’t as good and his stands were spotty, but he said “If I had tilled before planting, I think it would have been even worse.” Peas can be finicky and no system is guaranteed to produce a perfect crop every time, but all indications are that no-till seeding after a radish cover crop yields as well or better than conventional tillage prior to peas.

Seedcorn maggots led to zero emergence in the weed plots whereas they were insignificant in the radish plots.

Seedcorn maggots led to zero emergence in the weed plots whereas they were insignificant in the radish plots.

In our limited work with peas at the University of Maryland, we had a few unanticipated results that highlighted one aspect of a winterkilled radish cover crop that may be beneficial. In the spring of 2012, an exceptionally warm year led to an early outbreak of seedcorn maggots. While we had zero (yes, zero) emergence in the “no cover crop” control where winter weeds had been tilled in, emergence in the radish plots was fine. The flies that lay the eggs are attracted to decomposing green matter, and we speculate that the lack of green matter in the radish plots kept them away, while the weeds present in the tilled no cover crop plots lured them in.

Sometimes it can be hard to know what’s eating a crop or leading to low emergence. Digging around may show any number of larvae or there may be birds or even mice (!) eating pea seeds in the ground. While no-till seeding after radish may decrease seedcorn maggot pressure, tillage may help to reduce pest pressure of other sorts.

To find out if any system works in your soil with the pests that like your farm (I won’t call them your pests), start small at first, and always have a “control” treatment so you can really compare the new system to your old system.

These two cover crop-based systems for no-till peas highlight the different cover crop niches, even for the same cash crop, depending on the time of year. The mulch provided by the senescing millet cover crop is likely a large part of the success of that system for fall peas. In August and September as those fall peas are getting established, keeping the soil cooler and retaining moisture is desirable. In spring, it is not, and forage radish or other winterkilling brassicas allow the soil to warm up and dry out as is needed.

Sharing systems that work with each other

At the aforementioned farm meeting in Maryland, one issue that came up in discussion was how to get information on systems that work to farmers. I was embarrassed to admit that I hadn’t read about Dave’s millet-pea trials, despite the fact that learning about these systems is part of my job. How can we share systems that work with each other? This will be the topic of another post. For now, I’m happy to have learned from Dave that there’s a great way to grow no-till fall peas.

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