Effects of Cover Crops on Yield and Quality of Organically Grown Greenhouse Tomatoes

This research was conducted in order to determine the effects of cover crops on yield and fruit quality of organic greenhouse tomatoes during spring and autumn growing seasons of 2009 and 2010. The tested cover crops were lupine (Lupinus albus L.), cowpea (Vigna sinensis L.), crimson clover (Trifolium incarnatum L.), scarlet pimpernel (Dichondra repens L.), vetch (Vicia sativa L.) and alfalfa (Medicago sativa L.). They were used as no-till and/or living mulch. In autumn the treatments were (1) lupine (no-till mulch), (2) lupine (living mulch), (3) cowpea, (4) crimson clover, (5) scarlet pimpernel, (6) black PE mulch and (7) control; in the spring season they were (1) lupine, (2) vetch (no-till mulch), (3) vetch (living mulch), (4) alfalfa, (5) scarlet pimpernel (living mulch), (6) black PE mulch and (7) control. Total yield changed between 9.4 and 5.9 kg m(-2) in autumn. The highest yield was obtained from lupine (no-till mulch) and followed by cowpea and scarlet pimpernel. In spring growing cycle, yield was between 13.26 and 8.50 kg m(-2). Vetch and lupine applied as no-till mulch resulted in the highest yields. The changes in fruit quality parameters excluding total soluble solids were found significant in autumn whereas no significant difference was determined in spring growing season. According to overall results, it was concluded that among the tested cover crops lupine could be appropriate for organic tomato growing in unheated greenhouse conditions.