P. Yankov*, M. Drumeva
Department of Plant Production, Faculty of Shipbuilding, Technical University Varna, 1 Studentska, 9010 Varna, Bulgaria
(Manuscript received 6 March 2017; accepted for publication 15 May 2017)
Abstract. The investigation was carried out in the trial field of Dobrudzha Agricultural Institute on slightly leached chernozem soil. In order to clarify the effect of some types of pre-sowing soil tillage for wheat on the crop structure and certain yield components, the following variants of a stationary field experiment were analyzed: double disking at depth 10-12 cm (check variant); ploughing at 14-16 cm + disking; no-tillage (direct sowing) – pre-sowing treatment of the area with total herbicides. Wheat was sown after previous crop grain maize and was fertilized with N140P120K80. Wheat cultivar Enola was planted at norm 550 germinating seeds/m2. The number of emerging wheat plants was read using square sampling frames sized 50 cm x 50 cm. Using the same sampling frames, the tillering in autumn prior to the wintering of the crops was followed, and in spring – prior to booting stage. The number of productive tillers was also read using these sampling frames. To determine the length of spike, the number of grains in it, and their weight, 30 spikes from 8 replications of each variant were analyzed. The emerging of the wheat plants, under the conditions of slightly leached chernozem soil in Dobrudzha region, was more uniform after sowing following disking, and after direct sowing. The minimal pre-sowing tillage and no-tillage for wheat ensured better autumn development of the crop and the plants. In these variants, higher number of overwintering plants and productive tillers per unit area were registered. Spike length was the highest after ploughing as pre-sowing tillage. Significant variations in the number of grains per spike of the investigated variants were not found. Grain weight per spike was the lowest under direct sowing.