Summer Cover Crop Screenings for Fall Vegetable Production in the Gulf States.

We have conducted two consecutive years of cover crop screening at the Truck Crops Branch in Crystal Springs, MS. The cover crops tested are for summer production in fallow vegetable land, with the intention of improving the soil prior to growing fall planted vegetables in organic or non-organic systems. The focus of the screening is production of above ground biomass under hot conditions with natural summer rainfall after using irrigation for germination and stand establishment. None of the screening trials received fertilizers, pesticides, or soil amendments. Each year included three replications of small plots of 30 or more entries.  Entries were seeded in early summer and biomass sampled from a 0.25 m² quadrat at early flowering or near 90 days after seeding if the entrie did not flower by that time.  After two years, seedling emergence and deer predation have proven to limit the production of most Vigna selections tested. Pigeon pea has been an exception. Although it did not produce as much biomass as many of the grasses tested, its solid stands resulted in minimal weed growth, another valuable contribution we screened for. Most large seeded legumes have not fared well under these conditions, due to both poor emergence and deer predation.  Several millets have produced excellent stands, with modest biomass production. Sorghums and sorghum-sudans have done very well in the trials. Sunn hemp has performed well for us, although some deer feeding has been noted.