• Energy Research
• 2. Zero hunger close
• GB close
• PK close

Agriculture is the largest sector of Pakistan’s economy, contributing almost 22% to the GDP and employing almost 45% of the total labor force. The two largest food crops, wheat and rice, contribute 3.1% and 1.4% to the GDP, respectively. The objective of this research was to calculate the energy return on investment (EROI) of these crops on a national scale from 1999 to 2009 to understand the size of various energy inputs and to discuss their contributions to the energy output. Energy inputs accounted for within the cropping systems included seed, fertilizer, pesticide, human labor, tractor diesel, irrigation pump electricity and diesel, the transport of fertilizer and pesticide, and the embodied energy of tractors and irrigation pumps. The largest per-hectare energy inputs to wheat were nitrogen fertilizer (52.6%), seed (17.9%), and tractor diesel (9.1%). For rice, the largest per-hectare energy inputs were nitrogen fertilizer (32%), tube well diesel (19.8%), and pesticide (17.6%). The EROI of wheat showed a gradual downward trend between 2000 and 2006 of 21.3%. The trend was erratic thereafter. Overall, it ranged from 2.7 to 3.4 with an average of 2.9 over the 11-year study period. The overall trend was fairly consistent compared to that of rice which ranged between 3.1 and 4.9, and averaged 3.9. Rice’s EROI dipped sharply in 2002, was erratic, and remained below four until 2007. It rose sharply after that. As energy inputs increased, wheat outputs increased, but rice outputs decreased slightly. Rice responded to inputs with greater output and an increase in EROI. The same was not true for wheat, which showed little change in EROI in the face of increasing inputs. This suggests that additional investments of energy in rice production are not improving yields but for wheat, these investments are still generating benefits. The analysis shows quantitatively how fossil energy is a key driver of the Pakistani agricultural system as it traces direct and indirect energy inputs to two major food crops.

Oil palm plantations have expanded rapidly in recent decades, and are causing substantial impacts on tropical habitats and biodiversity. However, owing to its long lifespan (25-30 years), oil palm forms a much more varied and structurally-complex habitat than many other crops. This can include abundant understory vegetation and also epiphytes on palm trunks. However, the diversity of this plantation vegetation has been poorly studied, and there has been little consideration of the impacts of common plantation vegetation management practices on plant communities. We conducted a long-term vegetation management experiment that forms part of the Biodiversity and Ecosystem Function in Tropical Agriculture (BEFTA) Programme in Riau, Indonesia. We manipulated herbicide and manual cutting regimes within mature oil palm plantations to create three different understory complexity treatments (Reduced, Normal, and Enhanced vegetation) across replicated sets of plots. Plant communities were surveyed before and after experimental understory vegetation treatments began in three different microhabitats: within the middle of the plantation block (core), on the road edge (edge) and on oil palm trunks (trunk). Part of the sampling was also conducted during a drought event. We recorded 120 plant species, which comprised a mixture of native, non-native, ‘beneficial’, and ‘problem’ species. We found substantial variation in plant communities between edge, core, and trunk microhabitats, indicating high levels of heterogeneity within the plantation. There were significant effects of varying understory treatment within both core and edge microhabitats, but no spillover of impacts into the trunk microhabitat. We also observed substantial impacts of drought on plant communities, with declines in either biomass, percentage cover, or richness seen across core, edge, and trunk microhabitats during low-rainfall periods. Our findings highlight the diversity of plant communities that can be supported within oil palm plantations, and the substantial impacts that management decisions, and also drought, can have on them. Given the role that diverse plant communities can have in supporting species in other groups, this is likely to have a significant impact on the wider plantation biodiversity. We suggest that plantation management strategies give greater consideration to within-plantation understory plant communities and choose more wildlife-friendly options where possible.

Microalgae are considered to be a potential alternative to terrestrial crops for bio-energy production due to their relatively high productivity per unit area of land. In this work we examined the amount of dissolved organic matter exuded by algal cells cultured in photobioreactors, to examine whether a significant fraction of the photoassimilated biomass could potentially be lost from the harvestable biomass. We found that the mean maximum amount of dissolved organic carbon (DOC) released measured 6.4% and 17.3% of the total organic carbon in cultures of Chlorellavulgaris and Dunaliella tertiolecta, respectively. This DOM in turn supported a significant growth of bacterial biomass, representing a further loss of the algal assimilated carbon. The release of these levels of DOC indicates that a significant fraction of the photosynthetically fixed organic matter could be lost into the surrounding water, suggesting that the actual biomass yield per hectare for industrial purposes could be somewhat less than expected. A simple and inexpensive optical technique, based on chromophoric dissolved organic matter (CDOM) measurements, to monitor such losses in commercial PBRs is discussed.

As the effects of global climate change become more apparent, animal species will become increasingly affected by extreme climate and its effect on the environment. There is a pressing need to understand animal physiological and behavioural responses to climatic stressors. We used the reactive scope model as a framework to investigate the influence of drought conditions on vervet monkey ( Chlorocebus pygerythrus ) behaviour, physiological stress and survival across 2.5 years in South Africa. Data were collected on climatic, environmental and behavioural variables and physiological stress via faecal glucocorticoid metabolites (fGCMs). There was a meaningful interaction between water availability and resource abundance: when food availability was high but standing water was unavailable, fGCM concentrations were higher compared to when food was abundant and water was available. Vervet monkeys adapted their behaviour during a drought period by spending a greater proportion of time resting at the expense of feeding, moving and social behaviour. As food availability decreased, vervet mortality increased. Peak mortality occurred when food availability was at its lowest and there was no standing water. A survival analysis revealed that higher fGCM concentrations were associated with an increased probability of mortality. Our results suggest that with continued climate change, the increasing prevalence of drought will negatively affect vervet abundance and distribution in our population. Our study contributes to knowledge of the limits and scope of behavioural and physiological plasticity among vervet monkeys in the face of rapid environmental change.

La combinaison de différents systèmes de culture et de travail du sol avec différents génotypes au cours de plusieurs saisons de culture peut révéler des opportunités d'intensification durable (IS). L'objectif de cette étude était d'évaluer la performance de six génotypes de maïs en culture intercalaire avec labour de conservation (sans labour) - deux options prometteuses pour le SI. L'expérience a été menée sur trois ans (ou six saisons de culture) à la station de recherche de Kiboko, au Kenya, avec la culture de la sole et le labour des plaques de moulage comme systèmes de production de base. Les résultats ont montré que les génotypes et les systèmes de culture du maïs avaient un effet significatif sur le rendement, mais que l'effet du travail du sol n'était pas significatif. De plus, il n'y avait pas d'effets interactifs significatifs des facteurs testés sur le rendement du maïs. Le génotype de maïs CKH10085 avait le rendement le plus élevé de 7,7 t ha-1 en culture en solitaire, mais il a également enregistré la plus grande pénalité de rendement en raison de la culture intercalaire de 1,1 t ha-1. D'autre part, le génotype CKH10717 a maintenu le même rendement moyen de 7,1 t ha-1 dans les systèmes de travail du sol conventionnels et de conservation. Les génotypes commerciaux CKH10080 et CKH08051 étaient plus stables que les autres génotypes expérimentaux dans les conditions variables de croissance et de gestion. Ces deux génotypes sont de maturité intermédiaire et de tolérance à la sécheresse, deux attributs essentiels à l'amélioration de la production de maïs. Les cultures intercalaires ont réduit les rendements de maïs en raison de la concurrence accrue, par exemple, le rendement global de la culture de la sole était de 7,1 t ha-1 par rapport à 6,4 t ha-1 en cultures intercalaires ; ce qui représente une pénalité de rendement global de 0,7 t ha-1. Les différences de performance des génotypes de maïs ont révélé des possibilités de déploiement de génotypes pour réduire les risques ou maximiser le rendement, en fonction des circonstances biophysiques et de l'objectif de production de l'agriculteur. La combinación de diferentes sistemas de cultivo y labranza con diferentes genotipos a lo largo de varias temporadas de cultivo puede revelar oportunidades para la intensificación sostenible (IS). El objetivo de este estudio fue evaluar el rendimiento de seis genotipos de maíz en cultivos intercalados con labranza conservadora (sin labranza), dos opciones prometedoras para SI. El experimento se llevó a cabo durante tres años (o seis temporadas de cultivo) en la Estación de Investigación de Kiboko, Kenia, con el cultivo de lenguado y el arado de vertederos como sistemas de producción de referencia. Los resultados mostraron que los genotipos de maíz y los sistemas de cultivo tuvieron un efecto significativo en el rendimiento, pero el efecto de la labranza no fue significativo. Además, no hubo efectos interactivos significativos de los factores probados en el rendimiento del maíz. El genotipo de maíz CKH10085 tuvo el mayor rendimiento de 7,7 t ha-1 en el cultivo de lenguado, pero también registró la mayor penalización de rendimiento debido al cultivo intercalado de 1,1 t ha-1. Por otro lado, el genotipo CKH10717 mantuvo el mismo rendimiento medio de 7,1 t ha-1 tanto en sistemas de labranza convencional como conservadora. Los genotipos comerciales CKH10080 y CKH08051 fueron más estables que los otros genotipos experimentales en las condiciones variables de crecimiento y manejo. Estos dos genotipos son de madurez intermedia y tolerancia a la sequía, dos atributos críticos para mejorar la producción de maíz. Los cultivos intercalados redujeron los rendimientos de maíz debido a una mayor competencia, por ejemplo, el rendimiento general del cultivo de lenguado fue de 7,1 t ha-1 en comparación con 6,4 t ha-1 en cultivos intercalados; lo que representa una penalización de rendimiento general de 0,7 t ha-1. Las diferencias en el rendimiento de los genotipos de maíz revelaron oportunidades para desplegar genotipos para reducir el riesgo o maximizar el rendimiento, dependiendo de las circunstancias biofísicas y el objetivo de producción del agricultor. Combining different cropping and tillage systems with different genotypes across several cropping seasons can reveal opportunities for sustainable intensification (SI). The objective of this study was to assess the performance of six maize genotypes under intercropping with conservation tillage (no-till) - two promising options for SI. The experiment was carried out over three years (or six cropping seasons) at Kiboko Research Station, Kenya with sole cropping and mouldboard ploughing as baseline production systems. Results showed that maize genotypes and cropping systems had a significant effect on yield, but the effect of tillage was not significant. Moreover, there was no significant interactive effects of the tested factors on maize yield. The maize genotype CKH10085 had the highest yield of 7.7 t ha-1 under sole cropping yet it also recorded the largest yield penalty due to intercropping of 1.1 t ha-1. On the other hand, genotype CKH10717 maintained the same average yield of 7.1 t ha-1 in both conventional and conservation tillage systems. The commercial genotype genotype CKH10080 and CKH08051 were more stable than the other experimental genotypes under the variable growing and management conditions. These two genotypes are of intermediate maturity and drought tolerance, two critical attributes to improved maize production. Intercropping reduced maize yields due to increased competition, for example the overall yield of sole cropping was 7.1 t ha-1 compared with 6.4 t ha-1 under intercropping; representing an overall yield penalty of 0.7 t ha-1. The differences in performance of maize genotypes revealed opportunities to deploy genotypes to reduce risk or maximize yield, depending on the biophysical circumstances and the production objective of the farmer. يمكن أن يكشف الجمع بين أنظمة المحاصيل والحراثة المختلفة والأنماط الجينية المختلفة عبر العديد من مواسم المحاصيل عن فرص للتكثيف المستدام (SI). كان الهدف من هذه الدراسة هو تقييم أداء ستة أنماط جينية للذرة تحت الزراعة البينية مع حراثة الحفظ (بدون حراثة) - وهما خياران واعدان لـ SI. تم إجراء التجربة على مدى ثلاث سنوات (أو ستة مواسم زراعة) في محطة أبحاث كيبوكو، كينيا باستخدام الزراعة الوحيدة وحرث ألواح القوالب كنظم إنتاج أساسية. أظهرت النتائج أن الأنماط الجينية للذرة وأنظمة المحاصيل كان لها تأثير كبير على المحصول، لكن تأثير الحراثة لم يكن كبيرًا. علاوة على ذلك، لم تكن هناك آثار تفاعلية كبيرة للعوامل التي تم اختبارها على محصول الذرة. كان للنمط الجيني للذرة CKH10085 أعلى إنتاجية تبلغ 7.7 طن هكتار -1 تحت المحصول الوحيد، ومع ذلك فقد سجل أيضًا أكبر عقوبة على المحصول بسبب المحصول البيني البالغ 1.1 طن هكتار -1. من ناحية أخرى، حافظ النمط الجيني CKH10717 على نفس متوسط العائد البالغ 7.1 طن هكتار -1 في كل من أنظمة الحراثة التقليدية وأنظمة الحفظ. كان النمط الجيني التجاري CKH10080 و CKH08051 أكثر استقرارًا من الأنماط الجينية التجريبية الأخرى في ظل ظروف النمو والإدارة المتغيرة. هذان النمطان الوراثيان لهما نضج متوسط وتحمل للجفاف، وهما سمتان حاسمتان لتحسين إنتاج الذرة. قللت الزراعة البينية من غلة الذرة بسبب زيادة المنافسة، على سبيل المثال، كان العائد الإجمالي للمحصول الوحيد 7.1 طن هكتار -1 مقارنة بـ 6.4 طن هكتار -1 تحت الزراعة البينية ؛ مما يمثل عقوبة إنتاجية إجمالية قدرها 0.7 طن هكتار -1. كشفت الاختلافات في أداء الأنماط الجينية للذرة عن فرص لنشر الأنماط الجينية لتقليل المخاطر أو زيادة الغلة، اعتمادًا على الظروف الفيزيائية الحيوية وهدف الإنتاج للمزارع.

Abstract Background The African continent is known for high entrepreneurial activity, especially in the agricultural sector. Despite this, the continent's economic development is below expectations, due to numerous factors constraining the growth and sustainability of agricultural SMEs. These constraints have been exacerbated by the COVID-19 pandemic. The purpose of this study was to understand the pathways through which the pandemic affected agri-SMEs, with specific focus on assessing the differentiated effects arising from the size of the agri-SME and the gender of the owner-manager. Methods Data was collected from over 100 agri-SMEs, ranging in size from sole proprietorships with one employee to agri-SMEs employing up to 100 people, in six African countries. Mixed methods were used to analyse the data with changes in business operations arising from changing market access, regimented health and safety guidelines and constrained labour supply assessed using visualisations and descriptive statistics. Logistic regression modelling was employed to determine the set of variables contributing to agri-SME business downturn during the COVID-19 pandemic. Results All surveyed agri-SMEs were negatively affected by COVID-19-associated restrictions with the size of the firm and gender of the owner-managers resulting in differentiated impacts. The smallest agri-SMEs, mainly owner-managed by women, were more likely to experience disruptions in marketing their goods and maintaining their labour supply. Larger agri-SMEs made changes to their business operations to comply with government guidelines during the pandemic and made investments to manage their labour supply, thus sustaining their business operations. In addition, logistic regression modelling results show that financing prior to the pandemic, engaging in primary agricultural production, and being further from urban centres significantly influenced the likelihood of a firm incurring business losses. Conclusions These findings necessitate engendered multi-faceted agri-SME support packages that are tailored for smaller-sized agri-SMEs. Any such support package should include support for agri-SMEs to develop sustainable marketing strategies and help them secure flexible financing that considers payment deferrals and debt moratorium during bona fide market shocks such as the COVID-19 pandemic.

In a number of African countries, the trophy hunting of large felids is an important revenue generator for landholders, governments and in some cases communities. The hunting of large felids is especially profitable but they are sensitive to harvest, as the killing of prime-aged, dominant males can lead to infanticide and lowered reproductive success. In an attempt to limit the negative impacts of trophy hunting on large felids, the scientific community has proposed a number of interventions, including age restrictions on the animals that may be hunted. Such interventions are theoretically complementary to trophy hunting, as hunters typically seek large trophies, and older animals are normally larger than younger ones in large felids. If trophy size results in an increase in trophy price, then interventions that improve average trophy size could confer elevated earnings. This is particularly true if such interventions increased the number of failed hunts such that the same tag can be sold more than once. However, if trophy size is not one of the most important factors determining the desirability of a hunt (which we judge by the price paid for a trophy hunt package), it may be more difficult to implement such schemes. It is therefore important to evaluate potential determinants of trophy hunt package price; and we examine that here for leopards (Panthera pardus) in Africa, at both the country and outfitter level. We show that Tanzania and Botswana have the most expensive package prices while South Africa has the cheapest packages. At the country level, we found no statistical relationships between package price and leopard trophy size (either through advertised website or Safari Club International (SCI) leopard trophy size), country GDP, relative hunt success, or quota size. Contrastingly, the number of charismatic species offered within a package and an index of outfitter reputation (as measured by total SCI trophy records) were positively associated with package price. Interestingly, SCI leopard trophy size was inversely correlated with package price. Our results suggest that hunters do not value leopard trophy size above other factors, which could hinder the implementation of more sustainable, age-based leopard hunting regulations.