MAIZE GROWTH AND DEVELOPMENT AS AFFECTED BY TILLAGE SYSTEMS UNDER MEDITERRANEAN CONDITIONS

Conservation tillage has proven to be very effective in reducing runoff, and in increasing soil water storage. In semi-arid cropping situations, the later fact should result in a greater yield potential for conservation than for conventional tillage. The objective this study was to determine the influence of tillage on growth and yield of maize (Zea mays L.) under semi-arid Mediterranean conditions in the western Turkey. The experiment was conducted from 2005 through 2009 on a clay loam soil under shallow rototiller, chisel and mouldboard plough tillage systems. Results indicated that root biomass was higher in rototiller than in plough and chisel. Rototiller also provided higher plant biomass in all days after planting in three of the five years. The highest root dry matter by soil depth found at the 0 to 10 cm compared with the 10 to 20 cm and the 20 to 30 cm for all study years in three tillage systems. Rototiller also increased the plant height during the early part of the growing season when compared with plough and chisel, with the exception of the last part of the growing season that they showed similar. On the other hand, the highest root dry matter by soil depth found at the 0 to 10 cm compared with the 10 to 20 cm and the 20 to 30 cm for all study years in three tillage systems. Considering the tillage systems, the lowest root dry matter was found in plough, especially in 2008 of the 20 to 30 cm depth when compared with rototiller and chisel. Grain yield was also found higher in rototiller than in plough and chisel in two of the five years..