It’s All in the Mix

12/1/2012 7:00 AM
By Helen Margaret Griffiths New York Correspondent

Central NY Farmers Learn How to Choose Right Cover Crops

CORNING, N.Y. — No-till and cover crop mixes are not new concepts in agriculture, as participants were reminded during a recent cover crop workshop and tour held at the USDA-NRCS, Big Flats Plant Materials Center in Corning.

The event was attended by more than 100 people, including researchers, farmers, members of the seed industry and government staff. The seven presenters discussed various aspects of cover cropping and soil health.

Ray Archuleta, a conservation agronomist from the USDA-NRCS East Technology Center, Greensboro, N.C., started the morning with a demonstration that showed the value of cover cropping to soil structure.

“Tillage is very destructive to soil, and organic farmers till too much,” Archuleta said.

Soil structure is very important, and aggregate building needs to be occurring all the time. Cover cropping is a good way to cause aggregates, or clusters of soil particles, to form, he said.

A tour of the Big Flats field plots was conducted by Archuleta, Big Flats plant materials specialist Paul Salon and Penn State Extension specialist Charlie White.

Many plant species can be used as cover crops. Before making choices, the grower needs to be clear as to the purpose of the crop. The 180-plus plots observed on the tour included warm and cool season grasses, warm and cool season legumes, cool season mustards and biennial legumes.

The use of cover crops may be beneficial to improve soil structure, as erosion control, for nitrogen update to prevent leaching in the spring, as part of an IPM program for disease and insect control, or to provide carbon or nitrogen for the following crop.

Even though the initial financial outlay may be higher, Archuleta said, it is worthwhile using certified seed. Seeding in most cases does not require specialty equipment and can be accomplished using equipment used for forages.

Seeding date is critical, and for good fall growth in central New York state the “sweet spot” is Sept. 15, with Oct. 1 being the latest for good winter cover. Monocultures are not a good idea for many reasons. Having ground cover in the spring is desirable and can be accomplished in this part of the state using a mix such as radish, Austrian Winter pea, and barley or annual rye grass and, for easier killing, seeding cereal rye rather than rye grass.

The goal of Charlie White’s study, which is being conducted in both Pennsylvania and New York, is to identify the best cover crop mix to supply nitrogen for the next crop of corn.

The major barriers to farmers using cover crops are planting date and seed cost, White said.

“The cover crop needs to be an integral part of the farm system and not a tack on,” he said.

The mix in the field plots at Big Flats was fava bean, red clover and triticale. White had tried several legumes and the fava bean, even though it did winter kill, appeared the best, as leaves and stems did provide soil cover.

Archuleta stressed that to understand soil health problems, it is important to realize that soil is ecologically based and not a “chemistry box.”

“Earthworms are critical to soil health, and the most useful tool for determining soil health is the shovel,” he said.

Archuleta, like previous presenters, stressed the importance of identifying your goal prior to designing the cover crop mix. He gave some examples of mixes, one of which was an eight-species mix including three legumes used before a corn crop which gave excellent results. Another mix gave positive results with mob grazing of cattle.

For help with developing mixes, Archuleta suggested SmartMix Calculator developed by Keith and Brian Berns (www.greencoverseed.com/). This calculator allows the grower to choose from nearly 40 different species of legume, brassica, grass and broadleaf crops to make the mix that best fits their operation. With the various seeding rates, the C:N ratio, nitrogen fixation potential and diversity index are determined and frost tolerance predicted. Seeds per pound, seeds per acre, price per pound and total cost of the mix are calculated.

Quirine Ketterings, an associate professor in the Cornell University Department of Animal Science, Nutrient Management Spear Program, reported on a double-cropping study performed in the Hudson Valley at the Cornell University Valatie Research farm, which is not a dairy facility and has soil of low fertility.

The goal of the study was to determine the impact of rye, wheat and triticale on the corn yields. In the spring, nitrogen (106 pounds per acre) was applied to half the field. At harvest (May 2012), where no nitrogen was added the forage yield was similar for all three crops (2 tons per acre).

With the addition of nitrogen, rye outyielded (3.2 tons per acre) wheat and triticale (2.2 and 2.5 tons per acre respectively), but the protein content was 13 percent for all three, irrespective of whether nitrogen was added.

In all cases, a large amount of nitrogen was removed at harvest. The corn yields were low for all treatments, raising the question of whether this was a result of the large amount of nitrogen being removed with the forage harvest.

Kettering reminded the audience that this was a drought year, highlighting one of the main reasons that studies have to be performed for several seasons before conclusions may be drawn.

During the 2012-2013 season, on-farm studies with rye, wheat and triticale seeded after corn silage will be conducted with five nitrogen application rates. Additional information on these studies may be found at http://nmsp.cals.cornell.edu/.

Klaas Martens, an organic grain and cover crop seed producer in Penn Yan N.Y., suggested species to be used in cover crop mixes, and gave examples of how the presence of certain weed species can give indications as to soil health status.

Martens related an experience from their farm in which the choice of inappropriate species for cover crops prior to a bean cash crop resulted in nematode issues in the beans.

He gave suggestions on how to incorporate cover crops into the farm system, which included frost seeding mustards, summer seedings of buckwheat, brown mid rib Sorghum Sudangrass and Japanese millet.

“In a New York state summer, a grower doesn’t know what to expect, so one needs to hedge one’s bets,” Martens said.

Cover crop mixes are good for this, and Martens said that this year Austrian Winter pea had tolerated the heat and done well for them.

Continuing the emphasis on the importance of understanding the physical aspects and biology of the soil, Bianca Moebius-Clune, an Extension associate from Cornell University’s Department of Crop and Soil Sciences, talked about the publicly available Cornell Soil health program and some of its features (http://soilhealth.cals.cornell.edu/).

Aaron Ristow from the Upper Susquehanna Coalition discussed the importance of cover cropping in New York to make progress toward the 2025 EPA requirements for the total maximum daily load for the Chesapeake Bay.

“If the progress isn’t made, EPA will impose backstops which will be things most farmers will not like or want,” Ristow said.

The workshop was sponsored by the USDA-NRCS, Upper Susquehanna Coalition, Empire Chapter of Soil and Water Conservation and Cornell Cooperative Extension.<\c> Photos by Helen Margaret Griffiths

Cover-Crops-2

Using a soil slaking demonstration for two soil types, agronomist Ray Archuleta showed how no-till samples on left and right maintained soil aggregates, compared to the conventionally tilled samples in the middle. Aggregates, or clusters of particles, help prevent erosion and improve the soil’s ability to absorb and hold water.

 

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