Double row spacing and drip irrigation as technical options in energy sorghum management

Abstract

The effect of two row spacing configurations and four water supply levels was investigated on sweet and fibre sorghum in Central Italy for two consecutive years. Results highlighted the influence of both irrigation and row spatial configuration on crop productivity. Indeed, several studies have pointed out the positive response of sorghum to irrigation in Mediterranean climate, as in this environment water stress represents one of the main limiting factors on crop productivity. On the other hand, few attempts have been made to explore the role of row spacing on energy sorghum productivity. Results outlined an average increase in sorghum dry biomass yield ranging from +23% to +79% at variable rates of water supply as compared to rainfed control. The positive effect of irrigation was also observed on leaf area index and radiation use efficiency. Moreover, we observed a crop yield increase, from 9% to 20%, under double row spacing compared to the standard planting pattern (i.e. single row spacing). Finally, it was confirmed the efficient use of water by sorghum and the great ability of sorghum to increase its biomass yield in response to increasing volumes of water supplied. Therefore, this work suggests how row spacing configuration and drip irrigation could be feasible technical options to increase sorghum biomass yields in Mediterranean environments. These techniques should be experienced by farmers towards a sustainable intensification of current cropping systems.

Giant reed (Arundo donax L.) for biogas production: land use saving and nitrogen utilisation efficiency compared with arable crops

“…For these reasons, maize was cultivated under a high input regime; at opposite, the other crops took advantage of much lower fertilisation levels (250 vs 100 kgN ha −1 ) and they were rainfed. Biomass yields of maize, fibre and forage sorghum were in line with those observed by other authors under similar conditions (Barbanti et al, 2014), while the yield of sorghum could be substantially increased by irrigation (Roncucci et al, 2014). Regarding the growth of giant reed as assessed by cutting at different times, a modest yield increase was recorded from June to early August, since the crop was presumably limited by water deficit, while the growth was intense afterwards.…”

Field-scale calibration of crop-yield parameters in the Soil and Water Assessment Tool (SWAT)

“…Empirical values of BIO_E from field data, subject to various environmental limitations, would be expected to be less than theoretical maximum BIO_E (for ideal growing conditions) used for crop modeling, such as the 50 x 10 -1 g/MJ found in this study (table 3). Roncucci et al (2014) also found BLAI of 2.1 to 4.7, which also increased with increasing irrigation amounts. Sakellariou-Makrantonaki et al (2007) found BLAI ranging from 7.5 to 8.0 under a range of irrigation conditions in Central Greece, compared to 2.5 for no irrigation.…”

“…Other experimental studies on sweet sorghum have found wide ranges of measured BIO_E and BLAI values. Roncucci et al (2014), for a range of irrigation treatments over 2 years of study in Pisa, Italy, found BIO_E ranging from 20 to 42 x 10 -1 g/MJ, which generally increased with increasing irrigation amounts. Empirical values of BIO_E from field data, subject to various environmental limitations, would be expected to be less than theoretical maximum BIO_E (for ideal growing conditions) used for crop modeling, such as the 50 x 10 -1 g/MJ found in this study (table 3).…”

Screening for Cold Tolerance during Germination within Sweet and Fiber Sorghums [Sorghum bicolor (L.) Moench] for Energy Biomass

“…Sweet and fiber sorghums [Sorghum bicolor (L.) Moench], as fast growing and highyielding species under a wide range of soil and environmental conditions [1,2], are considered promising industrial crops for the European Community, for the bioethanol (sweet types) and the combustion (fiber types) chains [3]. Moreover, both types of sorghums produce lignocellulose that could serve as feedstock for second generation biofuel [4].…”

“…As a drought resistant plant, sorghum well adapts to cultivation in arid and semi-arid regions. However, increasingly extensive drought or prolonged drought periods due to climate change are becoming major concerns even for sweet and fiber sorghums, in those areas where the irrigation water scarcity is the most important factor that limits summer crops' productivity [3,7].…”