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Archive | Soil Fertility

Grasping the True Value of Cover Cropping

cover crop

Photo by USDA NRCS

Planting cover crops in rotation between cash crops is even more valuable than previously thought, according to a team of agronomists, entomologists, agroecologists, horticulturists and biogeochemists from Penn State’s College of Agricultural Sciences. Research, published in Agricultural Systems, quantified the benefits offered by cover crops across more than 10 ecosystem services. Benefits included increased carbon and nitrogen in soils, erosion prevention, more mycorrhizal colonization and weed suppression. Researchers simulated a three-year, soybean-wheat-corn rotation with and without cover crops in central Pennsylvania, which presented agroecological conditions broadly representative of the Northeast and mid- Atlantic regions. The cover crop rotation included red clover, frost-seeded into winter wheat in March, and winter rye, planted after corn was harvested in the fall. The research, funded by the U.S. Department of Agriculture, used simulated management practices, including tillage, synthetic fertilizer use and mechanical weed control.

This report appears in the May 2014 issue of Acres U.S.A.

Vetch Cover Crop Recommended for Organic Zucchini

Illustration_Vicia_sativa0In a new study, the popular cover crop vetch (Vicia sativa L.) was used in a two-year field experiment designed to determine the effects on organic zucchini yield and quality of vetch residue management strategies incorporating green manure using a roller-crimper (RC) and organic fertilizers.

To allow for timely crop rotation in organic farming, the growing cycle of cover crops is often terminated before natural maturity using mechanical chopping and/or plowing, field disking, mowing or crushing with a roller-crimper. Innovative conservation tillage production systems using RC technology to end cover crops are gaining popularity. The technique uses one or two passes of the RC to flatten the cover crops, leaving a thick mulch layer into which the next crop is sown or transplanted. The thick mulch hinders the development of weeds during the critical growing period, contributes to reduced soil erosion and increases soil moisture and fertility.

Researchers used municipal solid waste compost, anaerobic digestate and a commercial organic fertilizer in the field experiments designed to determine yield, yield components, crop quality, and soil nutritional status in organic zucchini fields in southern Italy.

“Our results showed that zucchini yield was influenced positively by the vetch residue management strategy, although the response was significantly different between years,” the scientists said. “The vetch cover crop increased marketable zucchini yield in the first year by 46.6 percent compared with the fallow treatment, indicating that this fertility-building crop could reduce off-farm nitrogen (N) fertilizer input for subsequent crops. Averaging over two years of the experiment, marketable zucchini yield increased by 15.2 and 38 percent with the roller-crimper mulch and green manure plow-down, respectively, compared with the fallow treatment, although differences were significant only in the first year.”

The application of organic fertilizers in vetch management plots increased marketable zucchini yield by 21.8 percent in the first year compared with the unfertilized control.

This article appears in the December 2013 issue of Acres U.S.A.

Three-Year Rotations Best For Potatoes

Potatoes being harvested in the San Luis Valley of south-central Colorado. Rotating potatoes with cover crops provides many benefits, including nitrogen management, improved soil and water quality, and bigger potatoes and higher yields.

Potatoes being harvested in the San Luis Valley of south-central Colorado. Rotating potatoes with cover crops provides many benefits, including nitrogen management, improved soil and water quality, and bigger potatoes and higher yields.

Agricultural Research Service (ARS) scientists have been investigating new cost-efficient options for increasing yields of potatoes and improving production sustainability. The researchers determined that three-year crop rotations generally helped break the host-pathogen cycle more effectively than two-year rotations. The three-year rotations provided better disease control and resulted in higher crop yields. These rotations also supported beneficial soil microbes that improve soil quality by increasing soil organic matter or by inhibiting plant pathogens. After weighing the costs and benefits of different management systems, researchers concluded that using a combination of Brassica and sudangrass green manures, fall cover crops and crop rotations can reduce soilborne diseases by up to 58 percent, and adding compost to the mix increases tuber yields up to 42 percent.

This report appears in the November 2013 issue of Acres U.S.A.