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

Proso millet (Panicum miliaceum L.), a short-season summer annual with exce llent water-use efficiency, is well adapted to crop production systems in s emi-arid environments. It is used as an emergency crop or as a rotation cro p in a three-year rotation with winter wheat (Triticum aestivum L.). Row sp acing 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 compare d in three environments; conventional tillage irrigated, conventional tilla ge dryland, and no-tillage dryland. These plots were evaluated at two diffe rent weed density levels: weedy (allowed all weeds to grow in the plots dur ing the growing period) and weed-free (did not allow any weeds during the g rowing period). These trials were conducted in 1995 at the High Plains Agri culture 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 decrea sed as row spacing increased while seed weight and plant height increased w ith row spacing. Seed weight increased with row spacing at all row spacings in the irrigated treatment while in the dryland sites, the increase was on ly at the narrower row spacing. The relatively light weed pressure in all b ut the no-till treatment reduced the effect of weeds in the response of gra in yield to row spacing. Even in the no-till treatment, row spacing had lit tle 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 t oo narrow. Thus, 19 cm would appear to be a better choice of row spacing fo r areas where drought is likely.