S. PANDELIEV, B. STALEV and L. ANGELOV
Agricultural University, Department of Viticulture, BG - 4000 Plovdiv, Bulgaria
PANDELIEV, S., B. STALEV and L. ANGELOV, 2013. Effect of soil surface maintenance methods on the yield and quality of grapes of the Velika variety. Bulg. J. Agric. Sci., 19: 1231-1235
During the period 2009-2012 was carried out research on the yield and quality of grapes of the Velika variety, depending on the method of maintaining the soil surface. Application of manure and mulching with straw for a few years leads to an increase in the productivity of grapevines, which is due to an intensified mineralization of the organic mass by microorganisms in the soil (ammonifying, nitrifying bacteria, etc.). In terms of yield, the plantation grown by organic farming is no worse than that grown by conventional technology. The factors which characterize the yield of grapes (number of bunches of grapes, weight of bunches and berries) in the case of grapevines grown in natural grass stand conditions are good. The percentage of developed buds, the weight of bunches and berries, the shape, the firmness of bunches and coloration of the skins of the berries are all better expressed in those originating from knots compared to those from fruiting canes. This is an indication that the percentage of Extra class grapes would be higher if loading is limited to two buds per knot at the time of pruning. The quality of grapes of the Velika variety is directly dependent on the loading of vines. On restricting the number of bunches to 8-10 per grapevine the yield obtained is 10990-12470 kg.ha-1, containing 150-160 g.kg-1 sugars and above 800 g.kg-1 of it Extra class grapes. Increasing the load to 11-20 bunches per grapevine leads to an increase in the yield to reach 20 tons per hectare, but the quantity of “Extra” class grapes drops down to 12-14 g.kg-1.