POSSIBILITIES FOR COTTON GROWING UNDER CONDITIONS OF ORGANIC FARMING IN BULGARIA

The purpose of this study was to investigate the possibilities for cotton varieties growing under conditions of organic farming. The research was carried out in the certificated field of the Field Crops Institute, Chirpan, Bulgaria in cotton-durum wheat crop-rotation under non-irrigated conditions. The results demonstrated that at organic production the new Bulgarian varieties realized good seed-cotton yield. The average total cotton yield was 1328 kg/ha, ranging from 1279 kg/ha fоr cultivar Boyana to 1372 kg/ha for Chirpan-539. Varieties Chirpan-539, Boyana and Darmi were identified as a high-yielding and adaptable to biological conditions. As a result of two-fold foliar application with “ALGA 300” in dose of 1l/ha the yield increased with 7.3 to 14.6 % compared to the untreated. Under the influence of field conditions and foliar application the variety Natalia formed most bolls per plant - 3.48, and the boll weight was the highest in cultivar Helius - 4.00 g

RESPONSE OF DURUM WHEAT (TRITICUM DURUM DESF.) CULTIVAR PROGRESS TO FOLIAR FEEDING

During the period 2008-2010 the response of durum wheat cultivar Progress, grown on Pellic Vertisols at the field of the Field Crops Institute, Chirpan, Bulgaria, to foliar feeding was studied. The new organic, systematic and complex fertilizers - Icyactive, Icyamin, Start-up, Fertileader Alfa, Fertileader BPK and Fertileader Vital 954 were tested. Fertilizers were applied twice during tillering - begining of stem elongation, alone and in combination with N120 fertilization. The results showed that the products influenced the durum wheat growth, productivity and grain quality. Additional grain yield after foliar application ranged from 122 to 430 kg.ha-1, which is 4.4-15.4 % above the control. Differences were stronger after a combination of foliar spraying and N fertilization - yields were in excess of 53.7-54.1 % and reached 4.30 t.ha-1 after fertilization with Icyactive + N120. The test weight of the grain was in the range of 79.70-80.23 kg/hl and was formed mainly under influence of the weather conditions. The 1000 kernel weight reached 57.7 g after Fertileader Vital 954 - 3 l/ha, which is 2.5 % above control. Vitreousness increased with 36.4-43.9 %, content of crude protein - with 22.0-30.7 % and wet gluten – with 17.9-25.7 % compared to control. From agronomic point of view liquid fertilizers can be successfully used for foliar feeding of durum wheat. Icyactive - 1 l/ha, Fertileader Alfa - 3 l/ha and Start-up - 3 l/ha manifested a very good effect