Crop Comments: Jump-starting soil biology

A few years ago, a friend of mine who lives in a Mediterranean country was visiting upstate New York. As we rode around the countryside, he asked me why there was so much abandoned farmland. I told him small-dairy farmers once rented and worked those fields that we had just driven by (mostly three to five acres). But those dairy farmers went out of business, mostly due to low milk prices. Surviving nearby large farms couldn’t afford to work such small fields. A lot of land that could produce a clover/grass hay crop economically got failing grades when subjected to a corn/alfalfa rotation… or worse yet to a continuous corn non-rotation. My observation of many hundreds, if not thousands, of soil test results shows that an alfalfa hay stand on average needs about a ton more lime (100 percent ENV) per acre than a clover stand.]
I believe that much of this abandoned land can be brought back into production before hawthorn and other woody native species take over. To jumpstart this reclamation, let’s start by brush hogging standing goldenrod and accompanying grasses [usually brome (which doesn’t need much phosphorus)]. Often such candidates for reclamation are rental parcels that didn’t get mowed at all this year, or at least as much as the owner would have preferred. Sometimes absentee landowners just want a “year-round” crop person to cut their hay, not charging them any rent for the land. The non-absentee landowner may take some of the hay as rent, to feed a couple horses. Usually those landowners end up with an agricultural property tax break, as their cropland is annexed (per the judgment of the tax assessor) to the crop program of a full-time farmer. Left un-mowed, that standing vegetation usually ends up as a thatchy mess. Come spring, new vegetation has to work its way through rotting materials when the snow finally melts.
We need to get dead plant materials — like chopped up goldenrod, burdock, and, yes, bromegrass — down to where they actually contact the soil. This allows them to self-compost under the influence of geo-thermal warmth. Think about how often a field, under a foot or more of snow in January, is sufficiently unfrozen for a tractor and manure spreader to get royally stuck. Despite this manure mishap, geothermal warmth should be thought of as a friend to the dairy/crop person. These chopped, formerly living, materials are well on their way for becoming food for plants that appear next spring. Often those plants surfacing next spring come from clover seeds that had lain dormant for years in the seed-bank under foot.
The meadow in question may not have been harvested during the growing season which is now wrapping up, because it stayed too wet all, or at least most, of the growing season. But if brush hogged still this fall, it will decompose under the snow this winter. Mulched vegetation will decay and start contributing organic matter by the time fields start to green up in April. As the soil’s organic matter (O.M.) increases due to self-composting, its moisture-holding capacity also increases.
Many agronomists, myself included, look at healthy soil O.M. as both a water reservoir and a carbon sequestration tool. Speaking of water, sometimes a field with less than perfect drainage gets wetter than it needs to be for the following reason: the soil receives an acceptable amount of moisture, generally 3.0 to 3.5 inches per month, in most of the Northeast. But if the organic matter is depleted (which I define as less than four percent), and the soil nutrition is very lacking, much of that moisture, which could have supported a five-ton hay crop, stays in or on the ground, just because other nutrients were limiting. In this situation, desirable vegetation is inadequate, the ground is unnecessarily moist, and Mother Nature sends weeds to help hang onto her soil. Clearly in this situation we need to soil test to identify the deficiencies, and then correct them.
Let’s examine composting more proactively than the “self” version. Creating enough compost to make a significant nutrient contribution to a decent-sized meadow or cornfield can be quite a challenge. Properly formed compost is a special commodity. But to officially be called compost, certain temperature goals must be achieved and documented. Otherwise, you must refer to this soil amendment package as aged vegetable waste/animal manure. Often I advise folks on the effective use of compost (or whatever you end up calling it) in their crop program. And I ask them how much of this material they apply per acre. Invariably the answer is “not enough”.
The most impressive compost benefit I ever witnessed occurred on an old hay meadow, where I had taken soil samples a few years ago. The pH was in the upper fives, and the phosphate level was very low. Worse than that was the super-abundance of horse nettle, or wild tomato (Solanum carolinense). The farmer in question had enough compost to apply about 1,500 pounds per acre on the nettled meadow, after the first cutting was harvested. The compost source materials were rotted hay, barn bedding pack, manure from pigs, cattle, and chickens. While the first cutting hay was about 10 percent horse nettle, the second and third cutting hays showed less than one percent of this noxious, toxic weed.
Trying to find a redeeming feature for this weed, I checked online where I learned about an old down-home folk remedy in which nettle fruit — which resembles a tiny yellow tomato — can be made into tea to be drunk by folks who think they have worms. Poulticed nettle leaves were touted as a cure for poison ivy. One can always find a silver lining. But for most folks, directly or indirectly, compost presents predigested nutrients to the topsoil, making the desirable plants healthy enough to fight off the bad guys. Quite a testimonial for the benefits of a vigorous soil biology.

2018-10-15T20:06:34+00:00October 15th, 2018|Eastern Edition, Western Edition|0 Comments

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