• Energy Research

Over the past 70 years, the world has witnessed extraordinary growth in crop productivity, enabled by a suite of technological advances, including higher yielding crop varieties, improved farm management, synthetic agrochemicals, and agricultural mechanization. While this “Green Revolution” intensified crop production, and is credited with reducing famine and malnutrition, its benefits were accompanied by several undesirable collateral effects (Pingali, 2012). These include a narrowing of agricultural biodiversity, stemming from increased monoculture and greater reliance on a smaller number of crops and crop varieties for the majority of our calories. This reduction in diversity has created vulnerabilities to pest and disease epidemics, climate variation, and ultimately to human health (Harlan, 1972). The value of crop diversity has long been recognized (Vavilov, 1992). A global system of genebanks (e.g., www.genebanks.org/genebanks/) was established in the 1970s to conserve the abundant genetic variation found in traditional “landrace” varieties of crops and in crop wild relatives (Harlan, 1972). While preserving crop variation is a critical first step, the time has come to make use of this variation to breed more resilient crops. The DivSeek International Network (https://divseekintl.org/) is a scientific, not-for-profit organization that aims to accelerate such efforts.

Pyrolysis bio-oil (PBO), a renewable and sustainable alternative energy source, is gaining significant importance. PBOs are polar, viscous, and acidic in nature, which restrict their direct utilization. The blending of PBOs with fossil-based fuels in combustion processes can potentially reduce net carbon emissions. The utilization of PBOs in combustion systems warrants an understanding of their combustion chemistry, which serves as the motivation for this study. In this study, pyrolysis of a saltwater halophyte, Salicornia bigelovii, was performed to obtain PBO. Based on the PBO composition, a blend of pyrrole, furfural, and toluene was prepared as a surrogate. The combustion chemistry of a three-component surrogate comprising oxygen- and nitrogen-containing compounds is studied for the first time. To understand the gas-phase combustion chemistry of the PBO surrogate, experiments were performed in a jet-stirred reactor (JSR) at atmospheric pressure and a residence time of 2 s in the temperature range of 780–960 K (ϕ = 0.25). Also, the PBO surrogate was blended in the ratios of 10 and 20% (by wt) with a toluene/iso-octane (80/20 mol/mol) mixture and investigated to mimic the combustion of PBO with hydrocarbons. A detailed chemical kinetic mechanism was compiled using different sub-mechanisms for surrogate components. NUIGMech1.2 was used as the base mechanism. Fuel-reactant species and 17 product species were identified to understand the combustion chemistry of PBO surrogate and its blends. Furthermore, rate of production analysis was performed to understand the pathways vital for forming intermediates. In addition, the thermal stability of PBO was studied in a thermogravimetric analyzer in the temperature range of 105–750 °C in oxygen and nitrogen atmospheres. The mass loss and derivative mass loss profiles were acquired, different stages of the reactions were identified under the oxygen atmosphere, and the apparent kinetic parameters were determined via the Friedman method. ; The authors acknowledge the ...

Abstract. Control of indoor temperature and humidity is of critical concern for controlled environment agriculture systems in hot, arid regions. Evaporative cooling is a technology utilized for energy-efficient cooling and humidification of these systems. However, the evaporative cooling process consumes considerable amounts of water, as much as 80-90% of the water footprint for indoor food production in these regions. The use of saline water in place of fresh water in evaporative cooling systems offers a potential solution for greatly improving the sustainability of these systems. However, the use of saline water in industry-standard cellulose pad systems can cause premature clogging of the porous medium, leading to system failure and the need for porous media replacement. A new evaporative cooling technology consisting of crushed pozzolan volcanic rock formed into porous bricks was evaluated for use in controlled environment agriculture systems using saline water. Two brick designs were tested for proof of concept cooling of commercial-scale greenhouses. Temperature-based cooling efficiencies of the bricks were achieved that are comparable to cellulose pads. In addition, the pozzolan-based bricks showed impressive resistance to saline water and harsh environments, requiring no replacement over the duration of the experimental trials. The integration of the pozzolan evaporative cooling systems using sea or brackish water with a water-saving growing technology, such as recirculating aquaponics or hydroponics, shows promise for reducing the fresh water footprint of food raised indoors in hot, dry environments by as much as 80%-90%. Keywords: Controlled environment, Evaporative cooling, Pozzolan, Salt, Water conservation.

SummaryCereal varieties with improved salinity tolerance are needed to achieve profitable grain yields in saline soils. The expression of AVP1, an Arabidopsis gene encoding a vacuolar proton pumping pyrophosphatase (H+‐PPase), has been shown to improve the salinity tolerance of transgenic plants in greenhouse conditions. However, the potential for this gene to improve the grain yield of cereal crops in a saline field has yet to be evaluated. Recent advances in high‐throughput nondestructive phenotyping technologies also offer an opportunity to quantitatively evaluate the growth of transgenic plants under abiotic stress through time. In this study, the growth of transgenic barley expressing AVP1 was evaluated under saline conditions in a pot experiment using nondestructive plant imaging and in a saline field trial. Greenhouse‐grown transgenic barley expressing AVP1 produced a larger shoot biomass compared to null segregants, as determined by an increase in projected shoot area, when grown in soil with 150 mm NaCl. This increase in shoot biomass of transgenic AVP1 barley occurred from an early growth stage and also in nonsaline conditions. In a saline field, the transgenic barley expressing AVP1 also showed an increase in shoot biomass and, importantly, produced a greater grain yield per plant compared to wild‐type plants. Interestingly, the expression of AVP1 did not alter barley leaf sodium concentrations in either greenhouse‐ or field‐grown plants. This study validates our greenhouse‐based experiments and indicates that transgenic barley expressing AVP1 is a promising option for increasing cereal crop productivity in saline fields.

Greenhouse gas (GHG) emissions have created a global climate crisis which requires immediate interventions to mitigate the negative effects on all aspects of life on this planet. As current agriculture and land use contributes up to 25% of total GHG emissions, plant scientists take center stage in finding possible solutions for a transition to sustainable agriculture and land use. In this article, the PlantACT! (Plants for climate ACTion!) initiative of plant scientists lays out a road map of how and in which areas plant scientists can contribute to finding immediate, mid-term, and long-term solutions, and what changes are necessary to implement these solutions at the personal, institutional, and funding levels.

ABSTRACTWheat is the most important crop grown on many of world's saline and sodic soils, and breeding for improved salinity tolerance (ST) is the only feasible way of improving yield and yield stability under these conditions. There are a number of possible mechanisms by which cereals can tolerate high levels of salinity, but these can be considered in terms of Na+ exclusion and tissue tolerance. Na+ exclusion has been the focus of much of the recent work in wheat, but with relatively little progress to date in developing high‐yielding, salt‐tolerant genotypes. Using a diverse collection of bread wheat germplasm, the present study was conducted to assess the value of tissue Na+ concentration as a criterion for ST, and to determine whether ST differs with growth stage. Two experiments were conducted, the first with 38 genotypes and the second with 21 genotypes.A wide range of Na+ concentrations within the roots and shoots as well as in ST were observed in both experiments. However, maintenance of growth and yield when grown with 100 mm NaCl was not correlated with the ability of a genotype to exclude Na+ either from an individual leaf blade or from the whole shoot. The K+ : Na+ ratio also showed a wide range among the genotypes, but it did not explain the variation in ST among the genotypes. The results suggested that Na+ exclusion and tissue tolerance varied independently, and there was no significant relationship between Na+ exclusion and ST in bread wheat. Consequently, similar levels of ST may be achieved through different combinations of exclusion and tissue tolerance. Breeding for improved ST in bread wheat needs to select for traits related to both exclusion and tissue tolerance.

This study focuses on understanding the effects of a CO$_2$ atmosphere on the pyrolysis of $\textit{Salicornia bigelovii}$ by performing a detailed kinetic analysis and investigating the pyrolysis products. In comparison to N$_2$ pyrolysis, CO$_2$ pyrolysis increased the amounts of acids, phenols, amines/amides and N-aromatics in the bio-oil. Biochar showed a 6.5% increase in carbon and a 5.8% decrease in oxygen due to the presence of CO$_2$ in the pyrolysis atmosphere. CO$_2$ also inhibited the volatilization of certain functional groups, such as phenols, tertiary alcohols and aromatics from the biochar, and the surface area of the biochar was 12 times larger than pyrolysis in N$_2$ atmosphere. Pyrolysis in CO$_2$ led to an increase in the average apparent activation energy from 146.5 kJ mol$^{−1}$ in N$_2$ to 163.4 kJ mol$^{−1}$. The kinetic equation was found to conform to a three dimensional diffusion mechanism. Finally, the pre-exponential factor was determined for each reaction. ; Dinara Utarbayeva and Hongwei Ren from KAUST are acknowledged for their help in growing plants and threshing the seeds. This work was sponsored by King Abdullah University of Science and Technology (KAUST). The authors thank the Clean Combustion Research Center (CCRC) at KAUST for funding and allowing access to their experimental facilities. The authors would also like to thank the Core Labs at KAUST for access to their instruments.