Intensification Options Research Articles

Manufacture of n-Propyl Propionate Using Ion Exchange Resins: Reaction Kinetics and Feasibility of Reactive Distillation

Reaction kinetics of esterification of propionic acid with 1-propanol to produce n-propyl propionate using Amberlyst-15 as a catalyst was investigated in this work. Effect of various parameters was studied. Initially, the efficacy of different catalysts was investigated which revealed that Amberlyst-15 can be suitably used for the reaction. This was followed by mass transfer exclusion which included effect of agitation speed, catalyst size and calculation of Weisz-Prater Criterion. Parameters selected for kinetic study were mole ratio of propionic acid to 1-propanol, temperature, catalyst loading and initial water concentration. Catalyst reusability was also verified. Aspen Custom Modeler (ACM) was used to regress kinetic parameters and a good match was obtained. Reactive Distillation (RD) runs in the batch mode were performed which showed that RD is a better option for process intensification (PI) for this reaction. Copyright © 2022 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Features of root rot development in the spring wheat agrophytocenosis under various agricultural technologies in the forest-steppe of Western Siberia

Crop infection is a stress factor for plants. The development and spread of fungal phytopathogens (Fusarium, Bipolaris, Alternaria, etc.) of the root system leads to a significant decrease in both quantitative, and qualitative parameters of grain crop productivity. The current paper has presented the data (2011–2018) on the study of subsoil parts of spring wheat plants when they are damaged by root rots of various etiologies, depending on the forecrops, agricultural technology and plant protection products. In the conditions of the Omsk region, the introduction of rapeseed into field crop rotations is justified. The grain crop has a positive effect on improving the phytosanitary condition of the soil and crops. There has been established that the greatest spread of infection on the root system of plants is identified on wheat sown in fallow (35–46 %), the minimum spread after rapeseed (7–16 %). Seeds of bluegrass weeds during protective tillage are concentrated in an uppermost (0–10 cm) soil layer. The increased weed infestation of agrophytocenosis reduces the competitiveness of cultivated plants and, as a result, the population of B. sorokiniana conidia in soil increases, creating unfavorable conditions for spring wheat development, especially during the initial period of growth. The highest crop productivity, regardless of a forecrop, mean for intensification options, was provided by moldboard tillage with 3.02 t/ha (wheat sown in fallow); 2.60 t/ha (wheat sown after wheat) and 2.15 t/ha (wheat sown\ after rapeseed). With a protective tillage, there was grain productivity decrease on 0.20 t/ha (wheat sown in fallow); 0.22 t/ha (wheat sown after wheat) and 0.12 t/ha (wheat sown after rapeseed) t/ha, respectively, in comparison with a moldboard technology. When fertilizing and herbicidal-fungicidal treatment of sowings during a vegetation period of plants, there is a slight difference between agricultural technologies. The complex use of chemicals reduces the infection of agrophytocenosis on 7–11 % and increases spring wheat productivity upto 4.14 t/ha (on 98 %) relative to extensive agricultural technology.

Determining the role of land resource, cropping and management practices in soil organic carbon status of rice-based cropping systems

Rice-based cropping systems (RBCS) cover the majority of cultivated land in Bangladesh and are the country's primary source of food security. To bolster food security, cropping intensity has increased by 192% in the last 30 years. Concerns have been raised about the sustainability of such cropping increases, particularly for soil productivity and resilience, with many areas reporting low soil organic carbon (SOC). The research assessed the levels of SOC, total nitrogen (TN) and soil pH in RBCS to identify relative importance of the land resource, cropping and management settings on these soil properties and to determine options for sustainable land use intensification. Soil samples (0–30 cm) were collected following stratified random design from a range of RBCS and analyzed for SOC, TN and soil pH. These soil properties were interpreted against previously developed farming system typology of Soil Carbon Improvement Likelihood (SCIL) and the legacy soil datasets. SOC was recorded higher in the stop-go triple cropping (12.00–16.33 g/kg) compared to the triple and double cropping intensities (6.90–8.30 g/kg). The crop-diversified and mustard-rice cropping systems of High SCIL, where there is crop rotational diversity and high residue retention, recorded a higher SOC. However these systems were also located on inherently fertile soil (Floodplain medium highland) compared to the less diverse cropping systems (wheat-rice, veg.-rice and rice-rice) of Medium and Low SCIL. The wheat-rice system had the lowest SOC (5.46 g/kg), which is considered to be a consequence of low crop residue retention and reduced periods of inundation in highland on the Piedmont plain or Terrace. However, the build up of SOC and TN was linked to soil acidification associated with altered fertilizer regime and crop residue removal. Cropping intensity, and in particular, the associated cropping systems and management, were determinants of SOC, depending on which land resource setting and cropping systems were practiced by the smallholders. The types of cropping systems and management options in land resource settings were identified that have the potential for sustainable land use intensification. The implications would be to ensure these cropping systems are conserved, and trade offs contemplated to meet the rising food demand and carbon sequestration goals to counteract smallholder vulnerability to climate change in Bangladesh and South Asian countries.

Novelty in fossil fuel carbon abatement technologies in the 21st Century: post‐combustion carbon capture

AbstractA global net zero target by mid‐century and keeping the maximum global temperature rise to below 1.5 °C was agreed by nearly 200 nations at the 26th UN Climate Change Conference of the Parties. The Intergovernmental Panel on Climate Change advises that emission cuts by 45% are needed by 2030 in order to maintain the global temperature rise below the 1.5 °C target. To achieve this target, it is necessary to investigate technological options that are economically viable and globally acceptable for commercial deployment. This review paper looks at the new technologies needed to reduce CO2 emission and to motivate commercial deployment, considering that the commercial deployment of CO2 has been slowed down as a result of high capital and operating expenses which invariably increase the cost of energy. The paper presents a review on early years of process intensification technologies as well as a discussion on potential new process intensification options for CO2 capture, with suggestions on how to modify those technologies for suitable application to solvent‐based carbon capture. The work further discusses current process intensification technologies used for CO2 capture applications. Solvent developments for enhancing CO2 capture also are discussed as they contribute to cutting down the sizes of the units as well as decreasing the cost of regeneration which leads to reduction in capital and operating costs. A process flow diagram using a mop fan for capture of CO2 from buildings is proposed. In addition, a new flow diagram is proposed for using loop reactor technology to capture CO2 from large point sources, and finally a new process diagram using rotating packed bed absorber combined with sono‐assisted regenerator is presented for improved performance of CO2 capture technology. Recommendations on these diagrams are made to help ensure transition toward the net zero target. © 2022 The Authors. Journal of Chemical Technology and Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry (SCI).

Use of iGlarLixi for Management of Type 2 Diabetes in Japanese Clinical Practice: SPARTA Japan, a Retrospective Observational Study.

Many individuals with type 2 diabetes (T2D) experience suboptimal glycemic control. Treatment intensification options include fixed-ratio combination products containing a basal insulin and a glucagon-like peptide-1 receptor agonist, such as iGlarLixi (insulin glargine 100U/mL and lixisenatide). This study aimed to provide real-world evidence of the effect of iGlarLixi in Japanese clinical practice. SPARTA Japan was a non-comparative, observational study conducted at 27 institutions in Japan. Anonymized individual-level data from adults with T2D receiving iGlarLixi in routine clinical practice were retrospectively collected. The primary study objective was to assess the impact of iGlarLixi on the change in glycated hemoglobin (HbA1c) at 6months' post-treatment initiation, with preplanned subanalyses to determine the influence of baseline characteristics. Secondary and exploratory endpoints included assessment of the proportion of individuals achieving HbA1c targets, change in body weight, and incidence and severity of hypoglycemia and gastrointestinal events. The full analysis set included 432 individuals, with data available at 6months for 426. Of the 432 individuals, the mean (SD) age at baseline was 61.6 (12.8) years and the majority had a T2D duration of ≥ 10years [mean (SD) 13.3 (10.4) years]. At 6months, HbA1c had significantly decreased versus baseline ( -0.85%; P < 0.0001), with a greater decrease in those aged < 65years, with a shorter duration of T2D and higher baseline HbA1c. A significant increase in the proportion of participants achieving age-specific HbA1c versus baseline was observed. Mean body weight decreased by 0.5kg (P = 0.0034 versus baseline). There were few hypoglycemia and gastrointestinal events (in individuals with HbA1c data); no severe hypoglycemic events were reported. The results of this real-world study indicate that iGlarLixi may improve glycemic control without serious adverse events in Japanese individuals with T2D who have suboptimal glycemic control on current treatment regimens and switch to iGlarLixi. UMIN-CTR Trials Registry, UMIN000044126; registered 10 May 2021.

Integrated water availability modelling to assess sustainable agricultural intensification options in the Meki catchment, Central Rift Valley, Ethiopia

ABSTRACT The Meki catchment in the Central Rift Valley basin of Ethiopia is currently experiencing irrigation expansion and water scarcity challenges. The objective of this study is to understand the basin’s current and future water availability for agricultural intensification. This was done by simulating scenarios through an integrated SWAT-MODFLOW model to assess the water balance. The scenarios were co-developed with communities who expressed their aspirations for agricultural intensification in conjunction with projected climate change. The results show that with the present land use and climate, the catchment is already water stressed and communities cannot meet their irrigation water demand, particularly in the first irrigation season (October–January). However, in the second irrigation season (February–May) water resource availability is better and increasing irrigated area by 50% from the present extent is possible. With a climate change scenario that favours more rainfall and shallow groundwater use, agricultural intensification is feasible to some extent.

The potential of conservation agriculture to improve nitrogen fixation in cowpea under the semi-arid conditions of Kenya

Low-cost but productive crop intensification options are needed to assist smallholder farmers in the tropics to move away from poverty. This study assessed the capacity of cowpea (Vigna unguiculata (L.) Walp.) to perform biological N fixation (BNF) under no-tillage practices, crop residue cover and intercropping with maize (Zea mays L.). The study was performed during the long rains of 2017 at Kiboko experimental station, located in semi-arid eastern Kenya. The research field trials had been running for three years (6 cropping seasons) by the time the sampling took place. The experimental set up was a split-plot design: main plots being tillage system (no till + maize stover retention (CA), and conventional tillage to 15 cm depth without mulch retention (CT)), sub-plot being cropping system (maize-cowpea intercrop, maize monocrop, and cowpea monocrop). Cowpea plants were sampled at 50% flowering stage and at physiological maturity to investigate biomass production and %N derived from the atmosphere (%Ndfa) through the 15N natural abundance technique, using maize as a reference control. Results showed that the number of nodules per plant was higher in CA treatments rather than in CT although not significant (p&amp;gt;0.05). Mean cowpea grain yield at harvest varied between 472 – 590 kg ha‐1 in intercrops whereas grain yield in monocrops was between 1465 - 1618 kg ha-1. Significant differences were however recorded between treatments with CT monocropped cowpea at flowering recording the highest mean %Ndfa (62%) and CT intercrop the lowest (52%). At harvest stage CA inter recorded the highest %Ndfa (54%) while CT intercrop the lowest (41%). The %Ndfa was higher (p&amp;lt;0.05) at flowering (between 57- 69%) compared with 45 - 64 % at harvest stage. Overall cowpeas in intercrops derived between 17.8 - 22.8 kg ha-1 of their total N from atmospheric dinitrogen fixation while monocrops between 54.9 - 55.2 kg ha-1. The effect of CA on BNF was positive but not significantly different from CT. These results suggest that CA has the potential to enhance the BNF process but there is a need to explore in future alternative spatial arrangement and variety choice in intercropping of cowpea and maize to optimize the BNF process.

Combining sustainable livelihood and farm sustainability approaches to identify relevant intensification options: Implications for households with crop-based and gathering-based livelihoods in Tanzania

In low-income countries, the livelihoods of smallholders are affected to different extent by multiple issues, such as food insecurity or low soil fertility, depending on their multiple assets and farming characteristics. In this study, we aim at assessing the current sustainability of households in Tanzania to suggest potential changes in farming system to increase the household́ sustainability. Household survey data from 891 households in two regions of Tanzania (dry Dodoma and humid Morogoro) were used to build composite sustainability indices representing the three pillars of sustainability (economic, environmental and social), based on 46 basic indicators. Then, a household typology was developed through principal component analysis and hierarchical clustering analysis of descriptive variables, and regression analysis linked the sustainability of farms with household characteristics. The analysis revealed significant differences in household types that relied on different livelihood strategies including particularly a “Gathering-based” type in Dodoma and two “Crop-based” types in both regions. These livelihoods significantly influenced the level of farming system sustainability. Particularly, the households in the “Gathering-based” type performed worst on all three pillars of sustainability. By examining the level of capitals from the different household types, we identified that the “Gathering-based” type and “Crop-based” types could improve their livelihood and be better off if they adopt various upgrading solutions. Such solutions include intercropping and optimised weeding to increase productivity and resource-use efficiency, for which these households have sufficient labour resources. Additionally, livestock rearing and use of fertilisers coupled with rainwater harvesting can increase soil fertility and water use efficiency, and hence food security, without compromising the environmental component of sustainability. To facilitate the adoption of these sustainable intensification options, agricultural policies and appropriate training need to be implemented to fit the local context and diversity of household types.

Optimizing maize–bean cropping systems for sustainable intensification in southern Ethiopia

AbstractDeclining productivity and scarcity of cultivable land in smallholder systems call for exploring sustainable intensification options to increase productivity. Field experiments were conducted at five sites (Sites 1–5) of the Sidama region, southern Ethiopia, in 2018 and 2019 to determine the effects of cropping systems on maize (Zea mays L.) and common bean (Phaseolus vulgaris L.) productivity. The intercropping of common bean with maize at varying planting times (simultaneous, relay) and number (frequency) of legume intercropping (once or twice) per growing season were compared with monocultures of the components in randomized complete block design with four replications. Cropping system affected the agronomic parameters (pod number plant−1 and 100‐seed weight) of common bean, more so than maize. Specifically, the results revealed that cropping systems affected both maize and bean yields, although the magnitude of the effect varied with sites. The highest maize yield was recorded in fertilized monoculture maize at Sites 1, 2, and 5, and in relay and sequential bean intercropping at Sites 3 and 4, respectively. Moreover, the highest bean yields were obtained in double common bean monoculture whereas, the lowest yields were recorded in relay intercropping. The total land equivalent ratio (LER) ranged from 1.2 to 1.8 and partial LER of maize was higher than that of the common bean. Sequential intercropping (Sites 1, 2, and 5) and relay intercropping (Sites 3 and 4) were economically more beneficial than the other cropping systems. Therefore, farmers could benefit more from maize–bean intercropping systems than monocultures in areas where maize is a staple crop.

Modeling intensification decisions in the Kilombero Valley floodplain: A Bayesian belief network approach

AbstractThe Kilombero Valley floodplain in Tanzania is a major agricultural area. Government initiatives and projects supported by international funding have long sought to boost productivity. Due to increasing population pressure, smallholder farmers are forced to increase their output. Nevertheless, the level of intensification is still lower than what is considered necessary to increase production and support smallholder livelihoods significantly. This article aims to better understand farmers’ intensification choices and their interdependent determinants. We propose a novel modeling approach for identifying determinants of intensification and their interrelationships by combining a Bayesian belief network (BBN), experimental design, and multivariate regression trees. Our approach complements existing lower‐dimensional statistical models by considering uncertainty and providing an easily updatable model structure. The BBN is constructed and calibrated using data from a survey of 304 farm households. Our findings show how the data‐driven BBN approach can be used to identify variables that influence farmers’ decision to choose one technique over another. Furthermore, the most important drivers vary widely, depending on the intensification options being considered.

Contextualisation of salinisation and adaptation preferences in the coastal areas of Bangladesh: Bringing together farmers' salinity perspectives into place‐based policy initiatives

AbstractThe salinisation of coastal areas in Bangladesh reduces livelihood options for rice intensification but offers a more suitable environment for shrimp and salt farming. Thus, farmers' salinity perspectives might vary resulting in contested land use settings that may create uncertainties for policymakers in planning adaptation initiatives to address salinisation. The aim of this study was to examine co‐located farmers' salinisation perspectives (e.g., trends, causes, impacts), and to demonstrate its potential for place‐based policy initiatives and research prioritisation for sustainable agricultural development in the coastal areas. Primary data were collected from randomly selected rice, shrimp and salt prodcrs/farmers in two coastal sub‐districts through semi‐structured interviews at the household level. Furthermore, key informant interviews were conducted with personnel from research and extension organisations at national and local levels to complement the survey results. Perceptions of the salinity extent contrasted starkly among the various types of farmers. While the majority of rice farmers (87%) perceived increased salinity, just over half of the salt and shrimp farmers perceived that salinity had decreased over the last 20 years. There was also a lack of agreement on the causes of salinity, with most rice farmers (62%) indicating anthropogenic factors as the main causes, while the majority of shrimp and salt farmers focused more on natural factors. Rice farmers (42%) also perceived a reduction in yield followed by less income (30%) under saline conditions, while shrimp farmers (70%) and salt farmers (55%) perceived production gains when high salinity prevailed. The adaptation preferences to combat salinity were also at odds between different types of farmers, with rice farmers having adaptation preferences for the development of salinity‐tolerant rice varieties that should have greater tolerance at the reproductive stages, while shrimp and salt farmers' preferences were for engineering‐based solutions to prevent seawater inundation during cyclones. Thus, research and extension services on integrated coastal resources management need to consider tailoring their approach to accommodate varied livelihood perspectives of salinity, as this place‐based approach could accelerate the pace of achieving the sustainable development goals (SDGs), such as SDG‐1, SDG‐2 and SDG‐3 due to a more strategic targeting of farmer types and their context.

Modeling sorghum-cowpea intercropping for a site in the savannah zone of Mali: Strengths and weaknesses of the Stics model

Intercropping is a key entry point for sustainable intensification of cropping systems in sub-Saharan Africa where variable rainfall conditions prevail. Crop simulation models can complement field experiments to assess the agronomic and environmental performances of intercropping systems under diverse climatic conditions, including hypothetical future climate. So far, crop models that can handle intercropping, such as STICS, have not often been extensively evaluated for tropical conditions and for species grown by farmers in sub-Saharan Africa. The objective of this study was to evaluate the performance of the calibrated STICS model to simulate sorghum-cowpea intercropping systems in rainfed conditions in West Africa. We used data from field experiments conducted at the N'Tarla Agronomic Station in Mali in 2017 and 2018. Two varieties of sorghum (local and improved) with contrasting photoperiod sensitivities were grown as sole crop and intercropped with cowpea, with additive design. Two sowing dates and two levels of mineral fertilization were also investigated. Model simulations were evaluated with observed data for phenology, leaf area index (LAI), aboveground biomass, grain yield and in-season soil moisture. Large variations in aboveground biomass of sorghum and cowpea was observed in the experiment (i.e. 3.5 – 9.6 t/ha for sorghum and 0.4–2.5 t/ha for cowpea), owing to the treatments (i.e. sole vs intercrop, early vs late sowing, no fertilizer input vs fertilizer input). Such variations were satisfactorily reproduced by the model, with EF of 0.81 in calibration and 0.58 in evaluation (with relative rRMSE of 23 % and 43 %) across crops. Sorghum AGB simulations were more accurate (rRMSE of 21 % and EF of 0.54) than cowpea AGB simulations (rRMSE of 25 % and EF of −0.09). The two main observed features of the intercropping system were well reproduced by the model. Firstly, cowpea and sorghum aboveground biomass decreased with intercropping compared with sole cropping, and the decrease in cowpea biomass was greater than the decrease in sorghum biomass. Secondly, despite a reduction in sorghum and cowpea yield, Land Equivalent Ratio of the intercropping for aboveground biomass was always above one. With regard to grain yield, observed LER was above one only in the non-fertilized treatment. The model failed at reproducing this behavior, probably because of insufficiently accurate calibration of the process leading to grain yield formation: rRMSE for grain yield was 49 % in calibration and 41 % in evaluation. Based on these findings, we discuss avenues to improve model calibration and use the model to explore options for sustainable intensification in land constrained sub-Saharan Africa. • Accurate STICS simulations of intercropped sorghum and cowpea aboveground biomass. • Inaccurate STICS simulations of intercropped sorghum and cowpea grain yield. • The model can be used to start exploring inter-annual performance of intercropping. • Experiments looking at N dynamics in intercropping needed to refine calibration.

Scalable diversification options delivers sustainable and nutritious food in Indo-Gangetic plains

Indo-Gangetic plains (IGP) of South Asia have supported bulk of human and bovine population in the region since ages, and a spectacular progress has been made in food production. However, malnutrition, diminishing total factor productivity, and natural resource degradation continue to plague this cereal-dominated region, which is also vulnerable to climate change. Addressing these challenges would require a transition towards diversifying cereal rotations with agroecological cropping systems. A study was, therefore, conducted at the experimental farm of ICAR-CSSRI, Karnal on crop diversification and sustainable intensification options using agro-ecological approaches such as Conservation Agriculture (CA) and diversified cropping systems to ensure food and nutritional security while sustaining the natural resources. On 2 years mean basis, CA-based cropping system management scenarios (mean of Sc2–Sc7) using diversified crop rotations; increased the system yield by 15.4%, net return by 28.7%, protein yield by 29.7%, while using 53.0% less irrigation water compared to conventional tillage (CT)-based rice–wheat system (Sc1). Maize-mustard-mungbean on permanent beds (PBs) (Sc4) recorded the highest productivity (+ 40.7%), profitability (+ 60.1%), and saved 81.8% irrigation water compared to Sc1 (11.8 Mg ha−1; 2190 USD ha−1; 2514 mm ha−1). Similarly, Sc5 (maize-wheat-mungbean on PBs) improved productivity (+ 32.2%), profitability (+ 57.4%) and saved irrigation water (75.5%) compared to Sc1. In terms of nutritional value, Sc5 was more balanced than other scenarios, and produced 43.8, 27.5 and 259.8% higher protein, carbohydrate and fat yields, respectively, compared to Sc1 (0.93, 8.55 and 0.14 Mg ha−1). Scenario 5 was able to meet the nutrient demand of 19, 23 and 32 additional persons ha−1 year−1 with respect to protein, carbohydrate and fat, respectively, compared to Sc1. The highest protein water productivity (~ 0.31 kg protein m−3 water) was recorded with CA-based soybean-wheat-mungbean (Sc6) system followed by maize-mustard-mungbean on PBs (Sc4) system (~ 0.29 kg protein m−3) and lowest under Sc1. Integration of short duration legume (mungbean) improved the system productivity by 17.2% and profitability by 32.1%, while triple gains in irrigation water productivity compared to CT-based systems. In western IGP, maize-wheat-mungbean on PBs was found most productive, profitable and nutritionally rich and efficient system compared to other systems. Therefore, diversification of water intensive cereal rotations with inclusion of legumes and CA-based management optimization can be potential option to ensure nutritious food for the dwelling communities and sustainability of natural resources in the region.

Techno-economic and environmental assessment of bioenergy and livestock integrated systems in Brazil

Bioenergy-livestock integrated systems (BLI) are a promising land-based option to meet future agricultural demands, while also alleviating pressure on land use and mitigating greenhouse gas (GHG) emission. However, their techno-economic feasibility and environmental implications are still unclear. This study performs a life cycle assessment and techno-economic assessment of key BLI systems in Brazil from a land management perspective. We considered pasture intensification options and use of biofuels by-products as animal feed supplement to release pasture area for additional crop production. BLI presents higher techno-economic feasibility compared to conventional systems, reducing payback time by almost half, and resulting in a five-fold increased net present value to initial investment ratio. The potential to avoid GHG emissions per hectare (replacing fossil fuels) is about two times higher in BLI than conventional system, mostly due to the possibility of producing more outputs using less area. Sugarcane ethanol produced under BLI scenarios outperformed conventional systems in eight out of nine addressed Sustainable Development Goals (SDGs), mainly because of the use of manure on sugarcane fields and use of bagasse as animal feed. Crops production to feed cattle in feedlots can increase acidification and eutrophication impacts, negatively influencing the meat production scores on SDG 2: Zero Hunger, 6: Clean Water and Sanitation, and 14: Life Below Water, for example. Conversely, meat produced in feedlots resulted in lower impacts on air quality and increased GHG mitigation, mostly due to shorter cycle duration, with better scores in SDG 11: Sustainable Cities and Communities and 13: Climate Action. These results might help to guide an enhanced integration of biofuels and livestock sectors in Brazil. BLI systems are expected to contribute to the achievement of climate mitigation targets while also reaching many of the SDGs and remaining techno-economically feasible. • Bioenergy-livestock integrated systems (BLI) reduced payback time in half. • BLI potential to mitigate GHG emissions was twice higher than conventional systems. • BLI do not reduce meat production compared to conventional systems. • Integrated systems can contribute to Sustainable Development Goals. • Inclusion of feed production in biorefineries can be techno-economically feasible.

Sustainable Intensification and Climate-Smart Yam Production for Improved Food Security in West Africa: A Review

Intensification of staple food crops such as Yam (Dioscorea spp.) while sustaining the environment is imperative in providing food for the expected 9.6 billion global population by 2050. In West Africa, amid the threat posed by climate change on food security, yam production is associated with deforestation and land degradation. Integrated soil fertility management and improved staking options for intensification and sustainable yam production on continuously cropped fields hold the key to addressing this challenge. This review evaluates the last decade's yam production trends in West Africa and in three leading yam-producing countries, Nigeria, Ghana, and Côte d'Ivoire, using the Food and Agriculture Organization Corporate Statistical Database (FAOSTAT) data. A production increase of 1.72, 1.43, and 1.35 times resulted in an area harvest increase of 2.25, 1.23, and 1.59 times in Nigeria, Ghana, and Côte d'Ivoire, respectively. Nigeria and Côte d'Ivoire had the worst yam productivity across the decade by producing at an average yield 17.3 and 12.5%, respectively, of the estimated potential yam yield (50 t ha−1). Even in Ghana, where the productivity increased across the decade, the average productivity was 33% of the estimated potential yield. Thus, it can be observed that the primary reason for the increase in yam production across the globe and in West Africa is mainly because of the increase in area under cultivation in the major yam-producing countries. The projected future erratic rainfall and elevated daily mean temperature as a result of climate change would cause declining tuber yields. Meanwhile, the importation of food such as rice as a strategy to improve food availability cannot be accessed by poor rural households due to the strong correlation between international food price hikes and prices of these foods. However, there is less relationship between international yam price hikes and yam prices in West Africa. Therefore, yam production and sustenance could be vital for food security for the increasing population of West Africa. This study reviews current research on soil fertility and staking options for sustaining yam production on continuously cropped fields. Promotion and adoption of these improved technologies would enhance food security and contribute to achieving Sustainable Development Goals 1 (No poverty), 2 (Zero hunger), 13 (Climate action), and 15 (Life on land).

Experimental evaluation of the thermal and hydrodynamic performance of nanofluids in a coiled flow inverter

In this study, water-based nanofluids are thermally and hydrodynamically evaluated in a coiled flow inverter as the heat exchanger (CFI-HE). Aluminum oxide (Al2O3) and titanium dioxide (TiO2) nanoparticles are used to prepare samples with 1%–3% volume concentrations. An experimental analysis is performed at a steady state under laminar and turbulent flow conditions (2000 < Re < 19,000). Nusselt number and friction factor correlations were developed. The performance evaluation criterion (PEC) based on the Nusselt number, and the Fanning friction factor is used to evaluate the CFI-HE. The results show that all nanofluids demonstrate an improved PEC compared with the base fluid. The Al2O3/H2O and TiO2/H2O water-based nanofluids at 3%vol under the turbulent flow conditions achieved maximum increases of 53% and 59%, respectively, illustrating that using nanofluids in a CFI-HE is a feasible option for the process intensification in thermal applications.

Energy Balance, Productivity and Resource-Use Efficiency of Diverse Sustainable Intensification Options of Rainfed Lowland Rice Systems under Different Fertility Scenarios

Rice-based cropping systems (RBCS) are a kingpin of global food security and rice fallow is one of the largest (&gt;14 m ha) RBCS. A three-year study was carried out to develop sustainable intensification options and efficient nutrient management protocols of RBCS with greater water and energy productivity and more profits. Rice-lentil, rice-linseed and rice-rapeseed systems were tested in a split-plot design with nutrient management practices involving fertilizer levels (50%, 75% and 100% recommended fertilizer dose; RDF), green manuring with Sesbania (SGM) and rice residue incorporation (RRI). The results indicated that SGM produced significantly better rice productivity, enhanced 6.4–22.7% yield of succeeding crops and increased profits by ~20%. Application of 75 or 100% of RDF produced 24.5–30.3% higher grain yield of rabi crops. System intensification resulted in an additional rice equivalent yield (REY) of ~1–1.6 t ha−1. SGM consumed relatively more energy (76,793 MJ ha−1) but at the same time, resulted in higher energy output (182,657 MJ ha−1), net energy (105,864 MJ ha−1), energy intensity (1.68 MJ INR−1) and human energy profitability (787) than the RRI. However, RRI recorded a higher energy ratio (2.42), energy productivity (0.082 kg MJ−1) and energy profitability (1.42 kg MJ−1). The rice-linseed cropping system resulted in greater system productivity, higher energy output (186,305 MJ ha−1) and net energy (112,029 MJ ha−1) than other systems. Overall, considering energy productivity, resource-use efficiency and profits, a rice-linseed system coupled with SGM and 75% RDF may be recommended as a sustainable intensification option in RBCS.

Narrowing crop yield gaps in Ethiopia under current and future climate: A model-based exploration of intensification options and their trade-offs with the water balance

In the Central Rift Valley of Ethiopia (CRV), actual productivity of most cereals is less than 3 t ha −1 associated with low input use and poor crop management. After calibrating and validating the Agricultural Production System Simulator (APSIM) using experimental data, we explored and prioritized promising intensification options for rainfed maize and wheat that enable to narrow prevailing yield gaps in the CRV, and quantified trade-offs with the water balance and gross margins. We set up a factorial simulation experiment combining Genetic x Environment x Management factors that influence crop yield and water use at field scale to simulate yield and water balance components under current and future climate scenarios (pessimistic scenario for mid-century). Varietal selection and nitrogen (N) fertilization were the most important factors contributing to yield gap closure. Although yields were maximized with N application rates up to 250 kg −1 in most soils and varieties, maximum gross margin and maximum water use efficiency (WUE) were attained at lower N rates, associated with a small yield reduction compared to the maximum. There was a trade-off between intensification and increased absolute water use through transpiration, while the water use per kg product was decreased. However, location-specific N application rates that allow producing at least 80% of the water-limited potential yield (Yw) of maize and wheat resulted in high water use efficiencies as well as favorable cost-benefit ratios. Climate change was projected to lower yield as it advanced maturity, and to result in decreased drainage and increased soil evaporation across all variety, location and management combinations for both crops. Climate change reduced crop yield by 15–25% for wheat and 2–30% for maize. We conclude that the locally-calibrated APSIM model could be used to derive key lessons from the genetic, environment and management interactions, and generate information on sustainable intensification pathways that combine narrowing yield gaps with maximizing WUE and gross margins. • Variety selection and N fertilization contribute most to closing yield gaps (Yg) • Yg can be narrowed at N rates that maximize water use efficiency and gross margin • The potential for yield gap closure is crop, variety, soil and climate specific • Crop intensification increases total water use but decreases water per kg product • Climate change reduces land productivity by 15–25% for wheat and 2–30% for maize

Assessing the impact of high-input management for reducing soybean yield gaps on high-productivity farms

To increase soybean actual yields (Ya), modern farmers are interested in exploring novel intensification options. We hypothesize that the inclusion of a high-input treatment in high-productivity systems may potentially reduce yield gaps (Yg), representing additional profits for farmers. Our objectives were to: (i) estimate Ya, water-limited yield potential (Ywlim), and Yg; (ii) evaluate a high-input treatment as a management option for reducing Yg; (iii) identify management and environmental factors associated to yield response to inputs and, (iv) determine the economic outcome of this high-input management on high-productivity soybean crops. We carried out 27 on-farm field experiments comparing a conventional management system versus a novel high-input treatment across the Central Pampas of Argentina. The conventional treatment was the most common management prescribed by farmers in the region. The high-input treatment included a set of inputs that were not usually applied and involved soil fertilizers with S and Zn, seeds treated with insecticides, fungicides, and inoculants, stress-reducing product, Ca and B foliar fertilizers and preventive insecticide. The Ywlim was estimated using crop simulation models. Yield gaps were calculated as the difference between Ywlim and Ya. Average Ya and Ywlim were 4571 and 5100 kg ha−1, respectively, with a Yg lower than 30%. High-input treatments promoted a yield response of 131 kg ha−1 across sites (p < 0.001), reducing Yg by 2.6%. Yield response to high-input treatment was positively correlated with Yg and soil pH, but negatively correlated with soil P. No positive economic outcomes were obtained with the high-input treatment. This study showed low benefits of the high-input treatments for reducing Yg in high-yielding soybeans managed by high-productivity farmers. Future yield increases in this type of systems would rely on genetic improvement of soybean yield potential and exploiting genotype x management x environment interactions.

Mapping spatial distribution and geographic shifts of East African highland banana (Musa spp.) in Uganda.

East African highland banana (Musa acuminata genome group AAA-EA; hereafter referred to as banana) is critical for Uganda’s food supply, hence our aim to map current distribution and to understand changes in banana production areas over the past five decades. We collected banana presence/absence data through an online survey based on high-resolution satellite images and coupled this data with independent covariates as inputs for ensemble machine learning prediction of current banana distribution. We assessed geographic shifts of production areas using spatially explicit differences between the 1958 and 2016 banana distribution maps. The biophysical factors associated with banana spatial distribution and geographic shift were determined using a logistic regression model and classification and regression tree, respectively. Ensemble models were superior (AUC = 0.895; 0.907) compared to their constituent algorithms trained with 12 and 17 covariates, respectively: random forests (AUC = 0.883; 0.901), gradient boosting machines (AUC = 0.878; 0.903), and neural networks (AUC = 0.870; 0.890). The logistic regression model (AUC = 0.879) performance was similar to that for the ensemble model and its constituent algorithms. In 2016, banana cultivation was concentrated in the western (44%) and central (36%) regions, while only a small proportion was in the eastern (18%) and northern (2%) regions. About 60% of increased cultivation since 1958 was in the western region; 50% of decreased cultivation in the eastern region; and 44% of continued cultivation in the central region. Soil organic carbon, soil pH, annual precipitation, slope gradient, bulk density and blue reflectance were associated with increased banana cultivation while precipitation seasonality and mean annual temperature were associated with decreased banana cultivation over the past 50 years. The maps of spatial distribution and geographic shift of banana can support targeting of context-specific intensification options and policy advocacy to avert agriculture driven environmental degradation.