SOYBEAN PLANTING PATTERNS IN RELATION TO YIELD AND YIELD COMPONENTS

Research on the effect of soybean [Glycine max (L.) Merr.] planting patterns on yield have produced variable conclusions; some indicated that high yield was produced by equidistant patterns, but others indicated that clear differences in yield were not found. Therefore, the objective of this study was to determine whether different planting patterns effect soybean yield, and to determine which planting patterns produce the highest yield. These experiments were conducted in the field at Niigata University, Niigata, Japan for 3 yr on a loamy sand soil at a plant population of 25 plants/m2, using the cultivar Enrei (Group VII). Planting patterns varied across years and included wide rows (70 or 80 cm), square and rectangular patterns, and twin row arrangements with two narrow rows 10 or 20 cm apart with 50 or 60 cm between the twin rows. The results indicated that (i) yield tended to decrease with wider row widths and narrower within row spacings. Thus, it should be possible to increase yield with square patterns, (ii) A constant 70-cm width with the twin-zigzag patterns (plants in the twin rows offset from each other) yielded higher than twin-rectangular ones (plants in the twin rows across from each other). In all cases, the increased yields came from an increase in seeds per plant; weight per seed was not affected.