Adaptive Nutrient Supply and Soil Cultivation Methods in the Upper Zone of Hillside Vineyards

Abstract

Somló-hill is Hungary's smallest wine district; however, it produces some of the best white wines. Viticulture dates back about 2000 years in the district, and the climate is balanced. Former volcanic activity was an important factor in the development of the brown forest soils (Cambisols). Experiments were conducted in 2006–2008 in vineyards located in the upper zone (above 200 m sea level) of Somló-hill for studying the most adaptive and environmentally friendly soil cultivation and nutrient-supply methods. The following treatments were applied in four replicates: (soil cultivation experiment) SC1, natural grass cover; SC2, mechanical soil cultivation; and SC3, organic mulch (crop residues), and (nutrient supply experiment) NS1, unfertilized control, NS2, nitrogen (N) fertilizer (NH4NO3) 50 kg ha−1; and NS3, farmyard manure (34 tons ha−1). Main chemical soil characteristics were determined in the 0- to 30-cm and 31- to 60-cm soil layers at blossoming and grape ripening. Yield parameters (kg per m2, soluble solids g per 100 g juice, and titratable acidity, g L−1) were assessed at harvest. The experimental results suggested that covering the soil with crop residues resulted in the greatest yields, explained by the more favorable soil water conditions. Differences in yield parameters were significant in 2 of 3 years. Soil mineral N content also showed significant differences among treatments. Increased N requirement of crop residues and natural crop cover were suggested. Results of the experiments showed that both ammonium nitrate and farmyard manure resulted in increased grape yield compared to the unfertilized control. Maintaining adequate soil moisture levels (containing basalt debris with low humus content and shallow fertile layer with poor water management) and soil organic matter content is of great importance because other nutrients may be ensured by the weathering of basalt.