Effect of Ridge Top Width on the Soil Cover of Tubers in a Ridge

Green tubers are often a problem in a modern potato production system. They can lead to a substantial reduction in marketable yield and potato quality. This study examined the effects of ridge top width on reduction of green potatoes, ridge geometry, soil cover of tubers, tuber position in the ridge and potato yield. Three different ridge top widths were analysed in the trial, i.e. 10, 28 and 38 cm. Final trapezoid-shaped ridges were formed simultaneously with planting. By increasing the width of the ridge top, especially to 38 cm, the horizontal distance between the tubers and the ridge side was increased. In the ridges with a 28- and 38-cm top width, a larger area between tuber cluster and ridge sides was achieved than in ridges with a 10-cm ridge top width. A 38-cm ridge top width led to the largest area of empty space between the tubers and the ridge sides. The increase in the ridge top width increased the cross-sectional area 0-5 cm below top of the ridge. The above-mentioned factors helped to decrease the weight and percentage of green tubers in the ridges with top widths of 28 and 38 cm compared to 10 cm, particularly by reducing greening of tubers at the ridge sides. The increase in ridge top width also increased the theoretical area of the ellipse that represents the largest possible area for the growth of tubers in a ridge. The area of the tuber clusters in the ridge was 220-360 cm(2).