The effects of tillage methods and plant density on growth, development and yield of soybean [Glycine max (L.) Merrill] grown under main and second cropping system

The aim of this study was to compare tillage methods and plant density on growth, development and yield of soybean [Glycine max (L.) Merrill] grown under main and second cropping systems. The field experiments were carried out at the experimental area of Agricultural Faculty, Dicle University during 2013 and 2014. The experiments were conducted as split-split plot design based on randomized complete blocks with two sowing dates (normal and late) as the main plot, three tillage methods (no-tillage, reduced and conventional) as sub-plot, and three between row spacing (35, 55 and 70 cm) sub-sub plot factor. The experiments were performed in three replications and soybean cultivar Nova (MG III) was used. The combined analysis of the data showed that yield means of reduced (2015.4 kg/ha) or conventional tillage (2036.1 kg/ha) were significantly different (P>0.01) compared with no-tillage (1881.1 kg/ha). Comparison of means indicated that seed yield of early sowing didn't significantly different (1932.0 kg/ha) compared with late sowing (2021.0 kg/ha). Yield means of 70x5 cm plant density (2023.1 kg/ha) didn't significantly different compared to 35x5 or 55x5 cm plant density (1951.2 kg/ha and 1958.2 kg/ha, respectively). Significant interaction among experimental factors was observed. Yield means of early sowing x conventional tillage x 70x5 cm had highest value of 2206.1 kg/ha. Results of this study showed that reduced or conventional tillage, and 70x5 cm plant spacing under main crop condition (early sowing) for soybean are the best planting methods for growth, development and seed yield of soybean.