I. Saldzhiev, A. Muhova
Abstract. Field trial on cotton (Vega cultivar) was carried out during 2007–2011 on leached vertisols under irrigation regime of sprinkling – 75 % of the field moisture capacity (FMC) for the soil layer of 0 – 40 cm. The trial included the following variants: factor A) Irrigation with lower rates:1). Single irrigation of 600 mm/ha at the interphase period blooming-boll formations; 2). Two irrigations of 450 mm/ha – the first one at the blooming stage and the second – in the boll formations period; 3).Two irrigations of 600 mm/ha – the first one at the blooming and the second – in the boll formations period; 4). Non-irrigated variant – for standard. Factor B) Width of inter-row space: 1). 60 cm. 2).80 cm. It was established that the best results were obtained for the variant where cotton cultivated at 80 cm of inter-row space and with second irrigation with 600 mm – 939 kg/ha more than the non-irrigated control and 11.9 % more than the variant with irrigated norm 600 mm/ha. In reference of net profit of 1000 m3 irrigated water the best results were achieved after single irrigation norm of 600 mm/ha. In respect to width of inter-row space the yield from a unit of area with inter-row space 0.80 cm we receive 4.6 % more than sowing at 0.60 cm inter-row space.