Effects of Nitrogen Fertilization and Plant Density on Proso Millet (Panicum miliaceum L.) Growth and Yield under Mediterranean Pedoclimatic Conditions

In recent years, the dry-land cereal proso millet has become an interesting crop for cultivation in the Mediterranean environment due to the consequences of climate change. It can be considered a resilient crop because it is particularly successful in extreme drought and high-temperature conditions. The goals of this research study were to compare different plant densities (D) and nitrogen fertilization rates (N) in millet (Panicum miliaceum), evaluating morphological, productive, and phenological traits. A 2-year field experiment was carried out in Italy, and millet (var. Sunrise) was subjected to four nitrogen fertilization rates (0, 50, 100, and 150 kg N ha−1) in interaction with three plant densities (55, 111, and 222 plants m2). Significant differences were found in all the investigated plant traits. The highest grain yield data (i.e., 3.211 kg ha−1 and 3.263 kg ha−1) and total biomass (i.e., 11.464 kg ha−1 and 11.760 kg ha−1) were obtained with the N rate of 150 kg ha−1 and density of 222 plants m2. Regarding protein content, the highest values were observed using N50, N100, and N150 (ranging from 10.03% to 10.14%) and with D55 (10.43%). Phenological parameters were affected by both plant density and nitrogen amount and decreased when higher levels of these two factors were employed.