High-Grade Chemicals and Biofuels Produced from Marginal Lands Using an Integrated Approach of Alcoholic Fermentation and Pyrolysis of Sweet Sorghum Biomass Residues

New global directions align agricultural land resources towards food production; therefore, marginal lands could provide opportunities for second-generation energy crops, assuming that in the difficult conditions of plant development, productivity can be maintained at relatively high levels. Sustainable bioenergy production on marginal lands represents an ambitious objective, offering high-quality biofuels without competing with the agri-food industry, since it allows successful feedstock production to be performed on unmanaged areas. However, marginal land feedstock production generally shows several agronomic, techno-economic, and methodological challenges, leading to decreases in the obtained quantities of biomass and profitability. Sweet Sorghum is a technical plant that has the needed qualities to produce large amounts of biofuels on marginal lands. It is a high biomass- and sugar-yielding crop, characterized by a high photosynthetic efficiency and low fertilizer requirement, is resistant to drought, and adapts well to different climate areas. Marginal lands and contaminated soils provide a favorable development environment for plants such as sweet sorghum; however, in-depth research studies on biomass productivity must be carried out, as well as advanced quality evaluation of the products, in order to develop combined technologies that use resources efficiently. The present study starts with a comparative evaluation of two sweet sorghum crops established on both marginal and regular lands, assessing plant development characteristics and juice production, and an evaluation of bioethanol generation potential. The vegetal wastes resulting from the processing were treated by pyrolysis, with the aim of maximizing the productivity of high-quality liquid biofuels and chemicals. The charcoal obtained in the thermal processes was considered as an amendment of the soil so that marginal land quality could be improved over time.

Spatial Assessment of Jerusalem Artichoke’s Potential as an Energy Crop in the Marginal Land of the Shaanxi Province, China

As a foodstuff crop, Jerusalem artichoke has a promising prospect for providing sustainable feed-stock sources for bioenergy development. Due to relatively limited cultivated land resources in China, it is crucial to evaluate Jerusalem artichoke’s potential production capacity in marginal land. Based on Jerusalem artichoke’s growth and photosynthetic characteristics, the agricultural production systems simulator model (APSIM) and multi-factor integrated assessment method were integrated to provide an operational method for comprehensively evaluating the marginal land resources suitable for developing the plantation of Jerusalem artichoke in the Shaanxi province, China. The results showed that 0.73 million ha of marginal land was suitable for Jerusalem artichoke cultivation in the Shaanxi province, and 5.4 million ha of marginal land was fairly suitable for Jerusalem artichoke cultivation, with the yield reaching 44,289 kg/ha and 38,861 kg/ha, respectively. The suitable land resources are mainly located in Yan’an (0.18 million ha), Hanzhong (0.13 million ha), and Baoji (0.08 million ha), most of which are moderate dense grassland (accounting for 50.6% of suitable land), dense grassland (accounting for 16.2% of suitable land), shrubland (accounting for 14.7% of suitable land), and sparse forest land (accounting for 9.18% of suitable land). The findings of this study can be used to establish targeted policies for Jerusalem artichoke development in China and other countries, particularly those along the Silk Road.

A Critical Review on Lignocellulosic Biomass Yield Modeling and the Bioenergy Potential from Marginal Land

Lignocellulosic biomass from marginal land is needed for a social–ecologically sustainable bioeconomy transition. However, how much biomass can be expected? This study addresses this question by reviewing the limitations of current biomass yield modeling for lignocellulosic crops on marginal land and deriving recommendations to overcome these limitations. It was found that on the input side of biomass yield models, geographically limited research and the lack of universally understood definitions impose challenges on data collection. The unrecognized complexity of marginal land, the use of generic crop growth models together with data from small-scale field trials and limited resolution further reduce the comparability of modeling results. On the output side of yield models, the resistance of modeled yields to future variations is highly limited by the missing incorporation of the risk of land use changes and climatic change. Moreover, several limitations come with the translation of modeled yields into bioenergy yields: the non-specification of conversion factors, a lack of conversion capacities, feedstock yield–quality tradeoffs, as well as slow progress in breeding and the difficulty of sustainability criteria integration into models. Intensified political support and enhancement of research on a broad range of issues might increase the consistency of future yield modeling.

Optimization of curcumin temulawak (Curcuma xanthorrizha Roxb.) on calcareous marginal land under teak

Temulawak produces bioactive compounds that have antioxidant activity and changes in its chemical composition are caused by environmental pH. Sulphur is an essential nutrient for plants and a constituent of several coenzymes and vitamins that play a role in plant metabolism. Marginal calcareous land in Tuban is generally used as teak production forest, because food crops cannot grow optimally in this land. Temulawak is a shade-tolerant plant that can grow well in conditions of low light intensity. The objective of this research is to obtain the appropriate goat manure and sulphur fertilizer dosages for temulawak planted beneath teak stands on calcareous marginal soil in order to maximize its yield and quality. The field experiment was RCBD with three replications and two factors: manure level (10, 15 and 20 t ha-1) and ZA level (0, 40, 80 and 120 kg ha-1). The results showed that a higher fresh weight of rhizomes per clump was obtained in combination of 10 and 15 ha-1 manures and 40 kg ha-1 sulphur fertilizer. Similar high yield is obtained when 20 t ha-1 of manure is applied in combination with 80 kg ha-1 of sulphur. In addition, a higher curcumin content and antioxidant activity were obtained in plant treated with 10 t ha-1 manure without S fertilizer. Similar high curcumin content and antioxidant activity of the rhizome were also obtained from rhizome treated with 15 t ha-1 of manure in combination with 40 kg ha-1 sulphur fertilizer and 20 t ha-1 manure without sulphur fertilizer.

Biomass Potential of the Marginal Land of the Polish Sudetes Mountain Range

Marginal land is the area remaining in agricultural use, which is not suitable for food production because of its unfavorable ecological, anthropological, and economic conditions. A certain amount of such land exists in mountainous areas. An analysis was undertaken on the example of the Polish Sudeten mountain range of energy use. The study aimed to estimate the biomass potential for the efficient use of agricultural land in mountain areas. The characteristics of the Polish Sudeten Mountains mountain range were characterized using Geographic Information System (GIS) methods. The Polish Sudeten Mountains covers an area of 370,392 ha, 95,341 ha of which is arable land, 35,726 ha of which is class 5 bonitation land with a northern exposure of 19,030 ha and southern exposure of 16,696 ha. Depending on the sowing structure, we can obtain 331,639 tons/year of dry biomass (Miscanthus sacchariflorus on the southern and Helianthus tuberoses on northern exposure). Fertilization levels will significantly affect low yielding plants, and water stress significantly reduced yields in all cases. Due to the steep slope of the 5th-grade halves and intensive rainfall in the mountain region, the establishment of perennial plantations is recommended. The research shows that after the first year of cultivation, yields of 9.27 tons/ha of dry matter can be obtained with a low yield of trees, shrubs and perennials.

Pongamia: A Possible Option for Degraded Land Restoration and Bioenergy Production in Indonesia

Indonesia has 14 million ha of degraded and marginal land, which provides very few benefits for human wellbeing or biodiversity. This degraded land may require restoration. The leguminous tree Pongamia pinnata syn. Milettia pinnata (pongamia) has potential for producing biofuel while simultaneously restoring degraded land. However, there is limited information on this potential for consideration. This paper aims to address the scientific knowledge gap on pongamia by exploring its potential as a biofuel and for restoring degraded land in Indonesia. We applied a literature review to collect relevant information of pongamia, which we analyzed through narrative qualitative and narrative comparative methods with careful compilation and scientific interpretation of retrieved information. The review revealed that pongamia occurs naturally across Indonesia, in Sumatra, Java, Bali, Nusa Tenggara and Maluku. It can grow to a height of 15–20 m and thrive in a range of harsh environmental conditions. Its seeds can generate up to 40% crude pongamia oil by weight. It is a nitrogen-fixing tree that can help restore degraded land and improve soil properties. Pongamia also provides wood, fodder, medicine, fertilizer and biogas. As a multipurpose species, pongamia holds great potential for combating Indonesia’s energy demand and restoring much of the degraded land. However, the potential competition for land and for raw material with other biomass uses must be carefully managed.