THE WATER DEFICIENCY EFFECT OVER MAIZE YIELD CULTIVATED FOR GRAIN WITHOUT IRRIGATION IN THE REGION OF SOUTH-CENTRAL BULGARIA

I. Gospodinov, V. Кoteva, V. Bazitov, R. Bazitov

Abstract: This study aims at pointing out parameters of water deficit during the critical for the maize moths, also, to follow the relations between yield and water deficit, provoked by the lack of rains, to establish the possibility of obtaining good yield in conditions without irrigation for the region of Central South Bulgaria. It has been analyzed 40 years data from monthly rain falls (mm), average monthly temperature of the air (°C) during the critical for this culture period (June, July, August) and the yield of maize grain, cultivated without irrigation and irrigated for the period 1972–2012. The soil of the two experimental fields was of the type vertisoil. For the purpose of the study are followed the yield of maize grain from two hybrids – middle late Knezha 530 and late H – 708, cultivated without irrigation (kg/da having 14% moisture) and optimal irrigation. The experimental studies were done by means of block method by four repetitions. The hybrids were cultivated by common agrotechnology for this country. A fertilizing was done by N P K. It was established that the average agroecological potential of the late hybrids maize in Central South Bulgaria in optimal irrigation, established experimentally in risky years was 12 230 kg.ha–1 and without irrigation – 5530 kg.ha–1. In middle late hybrids the yield was respectively 6670 kg.ha–1 and 3990 kg.ha–1. The parameters of the factor “water deficit” and establishment of the lost of grain when cultivated without irrigation could serve for decision making and planning in region of the Central South Bulgaria, as well as for formation of the state policy concerning compensations of the farmers during dry years. The established lost of grain in dry years and the role of irrigation can be used for further economical analysis for planning in risky, dry years and defining the cost and market price in such a meteorological situation.

Keywords: maize; optimal irrigation; water deficit; without irrigation; yield

Date published: 2017-08-18