Row spacing affects grain yield and other agronomic characters of proso millet

Proso millet (Panicum miliaceum L.), a short-season summer annual with excellent water-use efficiency, is well adapted to crop production systems in semi-arid environments. It is used as an emergency crop or as a rotation crop in a three-year rotation with winter wheat (Triticum aestivum L.). Row spacing and cultivar may impact the success of proso millet in the semi-arid Great Plains. Six row spacings; 15, 19, 23, 30, 38, and 46 cm, were compared in three environments; conventional tillage irrigated, conventional tillage dryland, and no-tillage dryland. These plots were evaluated at two different weed density levels: weedy (allowed all weeds to grow in the plots during the growing period) and weed-free (did not allow any weeds during the growing period). These trials were conducted in 1995 at the High Plains Agriculture Lab, Sidney, Nebraska (latitude 41 degrees 16' North and longitude 103 degrees 00' West) at an elevation of 1250 m. Proso millet responded to changes in row spacing. Grain yield, tiller number, and straw weight decreased as row spacing increased while seed weight and plant height increased with row spacing. Seed weight increased with row spacing at all row spacings in the irrigated treatment while in the dryland sites, the increase was only at the narrower row spacing. The relatively light weed pressure in all but the no-till treatment reduced the effect of weeds in the response of grain yield to row spacing. Even in the no-till treatment, row spacing had little influence on weed weight. Narrow rows were superior for grain yield and weed control. In areas of limited moisture, however, 15 cm appears to be too narrow. Thus, 19 cm would appear to be a better choice of row spacing for areas where drought is likely.