María Dolores Curt

The potential of Cynara cardunculus L. for seed oil production in a perennial cultivation system

Cynara cardunculus L. has been recognised as an energy crop for rainfed lands with Mediterranean climates. For energy purposes, it is grown as a permanent crop and the whole aerial biomass produced over the annual growth cycle is harvested every year. In this work, the potential of C. cardunculus L. as an oil crop is studied in a perennial cultivation system. The degree of variation of seed oil content and fatty acid oil composition is assessed in two experiments designed to study the effect of the factors: plant population, crop year and experiment location. The range of values of seed oil content was greater for the multilocal experiment (20.0–31.6%) than for the experiment on populations (22.0–28.8%), but the effect of the agricultural year was noticed in both experiments. There were significant differences in the 18 populations experiment and a group of 5 populations was identified as rich in seed oil (>26%). Seed presscake was analysed and as a result the use of this material as fertiliser or as animal feed was proposed. Finally, the degree of variation of fatty acid oil composition—studied for the factors population, location and year—turned out to be rather small. Cynara oil profile was characterised in terms of major fatty acids as: 10.7% palmitic, 3.7% stearic, 25.0% oleic and 59.7% linoleic.

Productivity and water use efficiency of sweet sorghum (Sorghum bicolor (L.) Moench) cv. "Keller" in relation to water regime

Abstract Sweet sorghum (Sorghum bicolor (L.) Moench) has been recognized as an alternative crop for energy purposes. In the central area of the Iberian Peninsula, its main growth period coincides with the dry season and irrigation is needed for reasonable sorghum productivity. Knowledge of irrigation-yield relationships is fundamental, since water is a scarce resource there. Our objectives in this work were to study the effect of water regime on the productivity and water use efficiency (WUE) in a sweet sorghum cultivar “Keller” grown in lysimeters in Madrid. Experiments were carried out during three crop cycles. Three irrigation regimes: H1, H2 and H3, corresponding to a water supply of 5.7, 11.4 and 17.1 dm3 m−2 day−1 were experimented with during the main growth period. Maximum aerial biomass production was 4.0 103g DM m−2 in the H3 regime. WUE was quite similar for every irrigation regime but varied between sorghum seasons. 4.6 g aerial biomass DM dm−3 was obtained as the average for a crop cycle length of approximately 130 days. The water regime did not clearly affect the sugar content in stalk sections. The mean value of sugar content in whole stalks was 41.4% w/w on a dry-weight basis. The ratio of ethanol production to evapotranspired crop water was estimated at 0.63 g dm−3 (mean value).

Approach to the potential production of giant reed in surplus saline lands of Spain

Growing energy crops on marginal land has been promoted as a way of ensuring that biomass production involves an acceptable and sustainable use of land. Saline and saline‐prone agricultural lands represent an opportunity for growing energy crops avoiding the displacement of food production and contributing to restoration of degraded land. Giant reed (Arundo donax L.) is a perennial grass that has been proposed as a promising energy crop for lignocellulosic biomass production while its tolerance to salinity has been proved. In this work, the identification of surplus saline lands that could be irrigated with saline waters for growing tolerant‐energy crops (giant reed) in the mainland of Spain and the assessment of the agronomically attainable yield in these limiting growing conditions were undertaken. To this purpose, a GIS analysis was conducted using geodatabases related to saline areas, agro‐climatic conditions, irrigation water requirements, agricultural land availability, restrictions regarding the range of electrical conductivity tolerated by the crop, competition with agro‐food crops and irrigation water provisions. According to the approach developed, the irrigated and saline agricultural area available and suitable for biomass production from giant reed amounted up to 34 412 ha. The agronomically attainable yield in these limiting conditions was estimated at 12.7 – 22.2 t dm ha−1 yr−1 and the potential production of lignocellulosic biomass, 597 338 t dm yr−1. The methodology followed in this study can be applied to other target regions; it allows the identification of this type of marginal lands, where salinity‐tolerant plant species could be grown for bioenergy purposes, avoiding competition with agro‐food crops, and where soil restoration measurements should be undertaken.

Production of Nicotiana glauca R.C. Graham aerial biomass in relation to irrigation regime

Nicotiana glauca R. C. Graham is a member of the Solanaceae, naturalized in the areas of warm-arid climates of the Iberian Peninsula. This species could have a great importance as a possible energy crop, because of its drought hardiness, sprouting capacity, large biomass productivity and high content of non-structural carbohydrates. In this work the production of the above-ground biomass of Nicotiana glauca was studied in relation to the irrigation regime in a cycle of cultivation. Primary values — leaf area, leaf dry weight and stem dry weight — were determined by non-destructive methods, in order to follow individually the development of each plant. From these primary values, growth indexes were calculated, and the behaviour of the species is discussed in relation to the environment. From the results obtained, it is deduced that Nicotiana glauca is a species adapted to conditions of water deficit and high temperatures. It is concluded that Nicotiana glauca could be cultivated in marginal lands of warm-arid climates; and a production of above-ground biomass of 3·9 t d.m. ha−1 year−1 was estimated, from which it would be possible to extract about 900 kg of easily fermentable carbohydrates.

Assessment of the bioethanol potential of prickly pear (Opuntia ficus-indica (L.) Mill.) biomass obtained from regular crops in the province of Almeria (SE Spain)

Prickly pear is a widely-known crop in the SE of Spain, where it is currently used for forage, fodder and fruit. Now it is being considered as a potential crop for bioethanol production from its whole biomass. In order to estimate the potential bioethanol production in the province of Almeria (SE-Spain) and the optimal location of bioethanol processing plants, a GIS analysis involving a predictive yield model of prickly pear biomass was undertaken following specific restriction criteria. According to this analysis, the total potential bioethanol production in Almeria would be up to 502,927.8 t dm·year-1 from 100,616 ha maximum that could be cultivated with prickly pear, with a calculated yield ranging between 4.2 and 9.4 t dm·ha-1·year-1. An exclusive suitability analysis and a preferable suitability analysis based on the Analytic Hierarchy Process were performed in order to estimate the optimal location of the subsequent processing plants within Almerias road network by a discrete location-allocation model.

Trends in Land Use in Spain and their Meaning to Bioenergy Production

The availability of land for biomass production has become a growing concern worldwide. Principles of sustainability indicate that the bioenergy chain, from biomass production to bioenergy end-uses, should be locally addressed. Thus, regardless of the possibilities that the international biomass trade could offer, each country should assess the size of the land resource that might be available for biomass production in order to establish realistic national targets for bioenergy. This work addresses two key challenges for bioenergy implementation: (i) ‘Do we have land available to accommodate future biomass production?, (ii) ‘What would be the choice of energy crops from the knowledge gained in field experiments?’. Focusing on Spain, an analysis of the evolution of land use is made and changes occurred in the last years are discussed to assess the size of land resource for bioenergy. Subsequently, the suitability of a selection of lignocellulosic energy crops is studied with a view to the potential available lands.