Grasses and Legumes in Mixture: An Energy Intercropping System Intended for Anaerobic Digestion

Abstract

Batch testing of biomethanization was conducted on organic matrices from a mixture of grasses (triticale and barley) and legumes (field bean -Vicia faba L. var. minor). These tests were performed in mesophylic conditions (35°C) on previously chopped and ensiled biomass.The three crops have been cultivated in Southern Italy (Puglia region), both as single-crops and intercropping between triticale or barley and field bean, in different mixture combinations, during the season 2009-2010. Emphasis was placed on the determination of the chemical composition of feedstock from the three single species and their different intercropping ratios, mowed at two subsequent stages (milk and dough development of grasses), also assessing their consequent biogas and methane potential yields after silage. Seven overall treatments have been compared: the three species in monoculture (triticale, barley and field bean, respectively); two mixtures between triticale and field bean (with triticale at 70 and 50%, respectively); two mixtures between barley and field bean (again with barley at 70 and 50%, respectively). Immediately after cutting and for the next 90 days, biomass samples were closed into plastic mini-silos, each having a 5-L capacity, in order to simulate the silage process. Thereafter, the batch testing was performed and biogas and methane production have been determined, with respect to the main chemical characteristics of the chopped and ensiled biomass samples, able to affect biogas and methane yield. Considering the single-crop treatments the highest biogas per hectare production has been found with respect to triticale (8737.1 nm 3 ha -1 ) and barley (8837.6 nm 3 ha -1 ), at the first and second harvesting stage, respectively. Concerning grass-legume intercropping, the highest biogas yield (8635.0 nm 3 ha -1 ) was observed with reference to the 70:30 mixing ratio, specifically on barley mowed at the milk development stage. The methane content in the biogas ranged from 61.1% (on a 50:50 mixing ratio of barley at the milk stage) to 53.7% (on a barley monoculture at the dough stage).

Valorising faba bean residual biomass: Effect of farming system and planting time on the potential for biofuel production

“…In our research, the residual biomass composition showed statistically significant differences between greenhouse and open field as well as among planting times. Consistently with our findings, Mahmood et al [14] reported a decrease in biomass lignin and hemicellulose content with the planting delay in spring grown sorghum, and Gatta et al [12] found similar hemicellulose values to those recorded in the present work. Additionally, compared to Pakarinen et al reports [9], the composition of faba bean residual biomass detected in our analyses shows a higher amount of lignin and hemicellulose, but the same prevalence of glucans and arabinoxylans in hemicellulose.…”

“…In Australia, Loss and Siddique [11] reported a decreasing trend of faba bean yield as a function of planting delay, conversely to the increase described in the present work from the first to the fourth planting time in open field. Lower Vicia faba biomass yields than the values recorded in the best treatments of our trial have been previously published, showing that our trial covers near optimal growth conditions [12,13]. Moreover, we observed a higher residual biomass production in open field than in greenhouse, with a maximum in the third and fourth transplant for greenhouse and in the fourth planting time for open field; the latter experimental treatment also resulted in the highest harvest index value.…”

From oil spills to barley growth – oil‐degrading soil bacteria and their promoting effects

“…On the one hand the plants are used as fertilizers, since they enhance the transport of oxygen to greater depths in the soil, stimulate oil-degrading microorganisms and provide microbial access to soil micropores for better degradation [142]. However, on the other hand the barley grown on contaminated sites can be used for biomass based bioprocesses such as the production of biogas or biofuels, since barley is known as substrate for biogas [143][144][145] and biofuel [146][147][148] production. Whether barley grown in these conditions would be fit for human consumption or for use as animal feed is a matter which will require further investigation.…”

Ecological evaluation of biogas from catch crops with Sustainable Process Index (SPI)

“…It includes dates of soil coverage, soil cultivation, and seeding and harvest of summer catch crop (s-cc) and winter wheat for the calculation of erosion with BoBB. 3 In cropping systems with ploughing, it is common to combine rotary harrow and seeding in one pass. Separation as indicated below was due to requirements of BoBB.…”

“…However, additional cropping potential can be developed when some farming techniques and sequences are changed [3]. One example which could play a role in this debate is shown in the work where summer and winter catch crops are sown in field experiments during the projects Syn-Energy I [4] and II [5].…”