An empirical framework for modelling transpiration use efficiency and radiation use efficiency of biomass sorghum in Mediterranean environment

摘要

In this experimental-modelling research, the potential biomass achievable by sorghum to be converted in bioethanol was assessed and then formalized into the radiation use efficiency (RUE) and transpiration use efficiency (TUE). Dry aboveground biomass (harvested at the flowering stage) ranged between 22.6 t ha(-1) and 28.34 t ha(-1) over two growing seasons with a total water consumption of 382 mm and 504 mm, respectively. Starting from sampling measurements, the empirical framework allowed to reproduce daily data of dry biomass, canopy development, intercepted photosynthetically active radiation and transpiration related efficiencies. RUE and TUE resulted 4.98 g MJ(-1) and 7.45 kg m(-3), respectively. Their robustness (as stable parameters) was assessed through the validation process. Finally, the multiple linear regression approach, was applied to screen among limiting factors. It was pointed out that although sorghum was grown under irrigated regime, water demand resulted not fully fulfilled to achieve the full performance of the crop.