In 2002, the annual precipitation was 799 mm, while in 2003 and 2004 it was 536 mm and 861 mm, respectively. In 2003, statistically significant differences occurred in the relative change of the cross-sectional area of the ridge (the ridge area made with the RTC cultivator/ridger (14.7%) was larger than the one made with the STC (7.4%) and RC (6.4%) cultivators/ridgers), while in the other years there were none (Table 4)