I. Tringovska, V. Yankova, D. Markova

Maritsa Vegetable Crops Research Institute, 32 Brezovsko shosse, 4003 Plovdiv, Bulgaria (Manuscript received 22 August 2016; accepted for publication 27 September 2016)

Abstract. Cover crops are an important component in sustainable vegetable production with main purpose to reduce the use of synthetic inputs, especially nitrogen fertilizers. The aim of the current study was to evaluate the effect of cover crops as hairy vetch (Vicia villosa Roth), winter pea (Pisum sativum L.) and white mustard (Sinapis alba L.) on (i) greenhouse tomato yield and fruit quality and (ii) root-knot nematodes infestation. The experiment was carried out during two consecutive years (2014 – 2015) in an unheated greenhouse at Maritsa Vegetable Crops Research Institute. Cover crops were grown before the main crop and plowed under and incorporated into the soil a week before transplanting the tomato plants. Control plots did not receive green manures. Two variants of fertigation were applied – optimal and 50% reduced amount of nitrogen fertilizer. Green manures did not change significantly the yield of tomato plants as well as did not influence on fruit quality parameters as brix, total sugars and titrable acidity. A slight negative effect was observed on Vitamin C content in tomato fruits. By green manuring with hairy vetch a reduction of the amount of nitrogen fertilizer used for fertigation could be achieved. Hairy vetch and white mustard as green manures suppressed to some extent the development of Meloidogyne spp.