Production expenses for high-value organic crops like lettuce and broccoli can exceed $7,000 per acre, so producers often try to streamline costs with an annual two- to three-crop rotation. Agricultural Research Service (ARS) horticulturalist Eric Brennan designed a long-term investigation that examined several different cover cropping strategies for an annual organic lettuce-broccoli production system. ARS is USDA's chief intramural scientific research agency, and this work supports the USDA priority of promoting international food security.
The researcher selected three winter cover crops often grown in the Salinas, Calif., area—rye, mustard, and a legume-rye mix—and planted each cover crop using either a typical seeding rate or a seeding rate that was three times higher. Seeding rates can influence a cover crop's ability to smother weeds.
During lettuce and broccoli production, Brennan ensured all systems received the same fertilizer and irrigation inputs and pest management. The harvest and sale of the crops, which met all USDA organic standards, were conducted by a commercial harvester.
Brennan's results indicated that all three cover crops yielded more dry matter than the two tons of crop residue per acre often recommended for maintaining soil organic matter. The legume-rye and rye cover crops produced approximately 25 percent more dry matter biomass than the mustard crops. But effectively suppressing weeds with the legume-rye crops required seeding at three times the typical rate, while rye and mustard crops appeared to suppress weeds adequately with typical seeding rates.
The long-term study also provided Brennan with more data about year-to-year yield variations in the legume-rye mix, including why legumes, which make up most of the seed costs, are not consistently abundant. Brennan thinks cooler early-season weather helps legumes compete with the rye. So when a hot and dry autumn is expected, producers might want to use a rye cover crop and skip spending the money on a cover crop with legumes.
Brennan, who works at the ARS Crop Improvement and Protection Research Unit in Salinas, has published some his findings in Agronomy Journal and Applied Soil Ecology.
Read more about this research in the February 2013 issue of Agricultural Research magazine.
Ann Perry | Source: EurekAlert!
Further information: www.ars.usda.gov
More articles from Agricultural and Forestry Science:
Crop Rotation with Nematode-Resistant Wheat Can Protect Tomatoes
15.05.2013 | Crop Science Society of America (CSSA)
Less O2 Triggers Grasshopper Molting, Farmers Could Benefit
14.05.2013 | Union College
A fried breakfast food popular in Spain provided the inspiration for the development of doughnut-shaped droplets that may provide scientists with a new approach for studying fundamental issues in physics, mathematics and materials.
The doughnut-shaped droplets, a shape known as toroidal, are formed from two dissimilar liquids using a simple rotating stage and an injection needle. About a millimeter in overall size, the droplets are produced individually, their shapes maintained by a surrounding springy material made of polymers.
Droplets in this toroidal shape made ...
Frauhofer FEP will present a novel roll-to-roll manufacturing process for high-barriers and functional films for flexible displays at the SID DisplayWeek 2013 in Vancouver – the International showcase for the Display Industry.
Displays that are flexible and paper thin at the same time?! What might still seem like science fiction will be a major topic at the SID Display Week 2013 that currently takes place in Vancouver in Canada.
High manufacturing cost and a short lifetime are still a major obstacle on ...
University of Würzburg physicists have succeeded in creating a new type of laser.
Its operation principle is completely different from conventional devices, which opens up the possibility of a significantly reduced energy input requirement. The researchers report their work in the current issue of Nature.
It also emits light the waves of which are in phase with one another: the polariton laser, developed ...
Innsbruck physicists led by Rainer Blatt and Peter Zoller experimentally gained a deep insight into the nature of quantum mechanical phase transitions.
They are the first scientists that simulated the competition between two rival dynamical processes at a novel type of transition between two quantum mechanical orders. They have published the results of their work in the journal Nature Physics.
“When water boils, its molecules are released as vapor. We call this ...
Researchers have shown that, by using global positioning systems (GPS) to measure ground deformation caused by a large underwater earthquake, they can provide accurate warning of the resulting tsunami in just a few minutes after the earthquake onset.
For the devastating Japan 2011 event, the team reveals that the analysis of the GPS data and issue of a detailed tsunami alert would have taken no more than three minutes. The results are published on 17 May in Natural Hazards and Earth System Sciences, an open access journal of ...
22.05.2013 | Life Sciences
22.05.2013 | Ecology, The Environment and Conservation
22.05.2013 | Earth Sciences
17.05.2013 | Event News
15.05.2013 | Event News
08.05.2013 | Event News