The Utility of Crotalaria juncea as a Cover Crop in a Temperate Climate

The Utility of Crotalaria juncea as a Cover Crop in a Temperate Climate

Summary

Field experimental plots were established with the assistance of two farmer cooperators in Hampshire County WV to evaluate several cover crops in a young peach orchard and in vegetable cropping. This is a multi-year project to determine how sunn hemp (Crotalaria juncea), compares to other cover crops in weed control, soil fertility, and nematode populations. Because of drought in the first summer season (2009), field plots were re-seeded with the same cover crops according to the experimental design. During the 2010 growing season, the area was under extreme drought with less than 7.6 cm. of rainfall from June to mid-October at the vegetable crop location, and less than 18 cm. rainfall at the orchard location. The greater amount of rainfall at the orchard location was due to a single thunderstorm on July 9th that produced 12.7 cm. of rain within a 2 hr. period. Results of the 2009 cover crop growth, peach tree growth, and weed infestation in the orchard research plots were presented as a seminar to the Hampshire County Fruit Growers Association. The orchard research area was part of a Fruit Growers Demonstration Tour in June.

Objectives/Performance Targets

We will measure the overall production of buckwheat, hairy vetch, and sunn hemp to compare their suitability as a cover crop in orchard and vegetable farming systems.

We will determine by soil sampling if there are differences among the cover crops and farming systems on total soil nitrogen, inorganic N, P, K, and nematode populations.

We will evaluate the weed populations in all systems during each growing season and in seasons following cover crop plantings.

Production of vegetables planted in the cover crop residues will be determined by weight at harvest. Trunk circumference increase will be used to determine growth of the young peach trees.

Accomplishments/Milestones

Sunn hemp grew well during the 2010 growing season with extreme heat and drought. At the vegetable crop farm, sunn hemp grew to a height of 1.2 m. and impacted weed growth to a greater extent than buckwheat (Fagopyrum sagittatum). At the orchard area, sunn hemp grew to a height of 2 m. and inhibited weed growth by 90%. Hairy vetch (Vicia villosa) grew well during early spring and, after flowering, the mulched crop provided excellent early season weed control. Buckwheat was severely impacted by the drought and heat at both sites. Observed but not numerically evaluated was a low level of nodulation on the roots of sunn hemp plants at the end of the growing season.

Impacts and Contributions/Outcomes

Sunn hemp grows well under extreme heat and drought in West Virginia highlands. Because of the weather conditions, soil sampling was delayed until mid-November for adequate soil moisture to assess nematode populations. Plans are to repeat the orchard experiments at a different site and hopefully under more normal weather conditions.

Collaborators: