Switchgrass biomass partitioning and growth characteristics under different management practices

Biomass dry matter partitioning and growth characteristics are important selection criteria for energy crops. The objective of the study was to examine the response of switchgrass (cv. Alamo) to irrigation (2 levels: rainfed and irrigated with 250 mm) and N-fertilization (4 levels: 0, 80, 160 and 240 kg N ha−1) under two different soil-climatic conditions for two growing seasons 2011 and 2012. The results demonstrated a significant effect (P &lt; 0.05) of irrigation, fertilization and their interaction on crop growth and biomass productivity. Biomass yield ranged from 14 to 27 Mg ha−1 for the calcareous, clay loam to clay, fertile soil (Velestino; Greece) and for the deep, calcareous sandy loam to loam, semi-fertile soil (Palamas; Greece), respectively. In both sites, switchgrass accumulated a high amount of biomass in stems. Dry stem/total biomass ratio was stabilized in the 3rd growing year and it was rather constant throughout the growing period (range 68–71%). The maximum growth rates were similar for both sites with value of 390 kg ha−1 day−1, whereas the highest leaf area index observed was 7.59, indicating that switchgrass has high growth rate independently of the site and its microclimate. Therefore switchgrass should be included in future cropping systems as an important energy crop for solid bio-fuel production.<p>Biomass dry matter partitioning and growth characteristics are important selection criteria for energy crops. The objective of the study was to examine the response of switchgrass (cv. Alamo) to irrigation (2 levels: rainfed and irrigated with 250 mm) and N-fertilization (4 levels: 0, 80, 160 and 240 kg N ha⁻¹) under two different soil-climatic conditions for two growing seasons 2011 and 2012. The results demonstrated a significant effect (P &lt;0.05) of irrigation, fertilization and their interaction on crop growth and biomass productivity. Biomass yield ranged from 14 to 27 Mg ha⁻¹ for the calcareous, clay loam to clay, fertile soil (Velestino; Greece) and for the deep, calcareous sandy loam to loam, semi-fertile soil (Palamas; Greece), respectively. In both sites, switchgrass accumulated a high amount of biomass in stems. Dry stem/total biomass ratio was stabilized in the 3rd growing year and it was rather constant throughout the growing period (range 68–71%). The maximum growth rates were similar for both sites with value of 390 kg ha⁻¹ day⁻¹, whereas the highest leaf area index observed was 7.59, indicating that switchgrass has high growth rate independently of the site and its microclimate. Therefore switchgrass should be included in future cropping systems as an important energy crop for solid bio-fuel production.