Effect of Tillage System and Soil Conditioner Application on Soybean (Glycine Max (L.) Merrill.) and Its Crop Management Economic Indicators

Experiments with soybean on heavy soils of East Slovak Lowlands were established in the years 2010–2012. The effect of mineral fertilisers and soil conditioner application on soybean’s yield using three tillage systems (minimum tillage (MT), conventional tillage (CT) and no tillage (NT)) was studied. Production costs and economic efficiency of crop management practices were evaluated. The influence of production year on soybean crop was significant in the order of 2011, 2010 and 2012. Statistical evaluation confirmed that the effects of CT and MT systems were more significant compared with NT system. No significant differences were found between the variants of the mineral fertiliser and conditioner application. Differences in the total cost of soybean cultivation, as measured between years, were not significant. Fertilisation variants with application of HUMAC agro and NPK generated the highest costs. On the other hand, the lowest costs were achieved at fertilisation variants with application of NPK alone. Comparing tillage variants, the CT system had the highest costs each year. Significant savings were achieved on MT and NT variants. During the experimental period, a profit was reached on all variants. Applying NPK alone, the highest profit was achieved in 2010 and 2012 using MT system and in 2011 with CT tillage. The variant b₂ with PRP sol in the years 2010 and 2011 was the most profitable using NT system and in 2012 using MT. Variant with HUMAC agro was the most profitable in each year using MT. The lowest income threshold for zero profitability was calculated in 2012. Using CT farming techniques at NPK fertilisation variant b₁ in 2012, the income threshold was 1.85 t/ha, at variant b₂ PRP sol it was 2.10 t/ha and at variant b₃ HUMAC agro it was 2.42 t/ha. At MT and NT systems, the income threshold values for zero profitability were lower.