Soil texture and crop management affect switchgrass (Panicum virgatum L.) productivity in the Mediterranean

Switchgrass is a promising perennial energy crop with a good potential under environmental limiting conditions. Although some studies have highlighted the different yields of lowland and upland cultivars in Mediterranean environments, only a few have explored the role of soil and different crop managements on switchgrass productive performances. For this reason, two field trials were carried out in central Italy to investigate the effect of soil texture (silty-clay-loam vs. sandy-loam soils), irrigation (rainfed vs. 75% restitution of the potential evapotranspiration) and nitrogen fertilization (0, 50 and 100 kg N ha−1) on the yield of two switchgrass (Panicum virgatum L.) cultivars: Alamo and Blackwell. Crop aboveground dry yields were monitored from the first to the fourth year of growth. Results highlighted cultivar as the most significant factor affecting crop yield. In fact, excluding the establishment year, aboveground dry yields in Alamo and Blackwell exceeded 30 and 15 Mg ha−1 respectively. Our results highlighted switchgrass to be able to achieve good yields under limiting conditions (i.e. sandy-loam soil, rainfed) as well. In addition, through the appropriate choice of the nitrogen fertilization, crop yields increased by 30%, while a supplementary water supply of about 300 mm of water per year, during the dry summer period, was less effective in determining a significant increase in the harvestable dry yield.