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Cassava utilisation in Malawi is negatively affected by rapid deterioration of fresh roots, primarily caused by postharvest physiological deterioration (PPD). A study was conducted to assess farmers’ knowledge and approaches used to minimize losses from PPD. Multi-stage sampling was used to identify districts, Extension Planning Areas (EPA’s) and farmers. Data were collected from 519 farmers using a structured questionnaire. Results revealed that PPD (74.0%) was the major post-harvest constraint followed by pests and diseases (62.1%). Farmers had varying knowledge levels on signs and causes of PPD. They were knowledgeable on PPD signs with 91.5% ably identifying PPD through change of pulp colour. The farmers also had moderate knowledge on causes of PPD, citing high temperature (57.6%) and over-staying of roots (56.2%) as main causes of PPD. Key methods for preventing PPD are: storage (43.0%) and piece-meal harvesting (40.4%). Only 2.6% of the farmers exploited varietal difference in dealing with PPD as some varieties (Sauti, Mpuma, Ching’amba, and Kalasa) take three to five days before showing PPD signs. Farmers’ knowledge levels and PPD preventive methods could be strengthened through: provision of training on post-harvest handling, improvement in storage and processing technologies; and application of advanced breeding techniques to exploit genetic variation in cassava germplasm.

SummaryConservation agriculture (CA) practices such as zero tillage (ZT) and permanent raised beds (PB) accelerate deposition of soil organic matter and augment associated biological properties of soil through enhanced inputs of organic carbon. However, the potential benefit of CA under intensive cereal‐based systems for key soil health indicators (such as carbon pools and biological activities) is only partially known. Therefore, we analysed the effect of three medium‐term tillage practices and four intensive crop rotations on selected soil organic carbon pools and microbial properties. The tillage practices consist of ZT, PB and conventional tillage (CT) in main plots and four crop rotations (MWMb, maize–wheat–mungbean; MCS, maize–chickpea–Sesbania; MMuMb, maize–mustard–mungbean; MMS, maize–maize–Sesbania) in subplots. The experimental design was split‐plot with three replications. After 6 years, we observed a significant positive effect of CA practices on soil organic carbon (SOC) content, labile SOC fractions, soil microbial biomass carbon (MBC) and dehydrogenase activity (DHA). The total organic carbon (TOC) was greatly affected by medium‐term tillage and diversified cropping systems; it was larger for CA and MCS and MWMb systems. The interaction effect between tillage and cropping systems for SOC content was not significant at all soil depths. Significantly larger contributions (8.5–25.5%) of labile SOC pools to TOC at various soil depths were recorded in PB and ZT. There was a significant positive effect of CA practices and diversified crop rotations on MBC and DHA at all the soil depths and sampling times, but the interaction effect between tillage and cropping systems was not significant. Thus, our medium‐term (≥ 5‐years) study showed that the combination of CA (PB and ZT) practices and appropriate choice of rotations (MCS and MWMb) appears to be the most appropriate option for restoration and improvement of the soil health of light‐textured Inceptisols through the accumulation of soil organic matter (SOM) and improvement in soil biological properties.Highlights Effect of conservation agriculture (CA) on soil labile carbon inputs and biological properties. Observed changes in SOC stock and C‐pools at different soil depths after 6 years. Significant effects of tillage and crop rotations observed for labile‐C pools. Adoption of ZT and PB enhanced SOC stock, C‐pools and microbial activity compared to CT.

Spodoptera eridania (Stoll), a polyphagous lepidopteran pest from the Americas, has recently invaded western and central Africa. Like its congeners, S. eridania has developed pesticide resistance. The rapid global spread and impacts of Spodoptera frugiperda (J.E. Smith) has raised concerns about whether S. eridania is set to do the same. Here we fit a CLIMEX niche model for S. eridania and apply a climate change scenario for 2050 to investigate the sensitivity of the pest threat. We find that S. eridania can potentially expand its range throughout the tropics and into the sub-tropics, threatening a range of important commercial and subsistence crops. An important feature of the pest threat posed by S. eridania is the extent of its ephemeral habitat during warmer months. Modelled climatic changes will mostly expand this species potential range poleward by around 200 km by 2050, indicating a moderate sensitivity. These areas of emerging potential expansion are mostly into subtropical climates, supporting diverse cropping systems, including at risk crops beans, groundnut, potato, soybeans, tomato and sweet potato. The potential distribution of S. eridania in the Amazon basin and the southern boundary of the Sahara Desert appear set to contract substantially due to increasing heat stress. While it may not be as invasive as some of its congeners, nor acquire pesticide resistance as readily, S. eridania does have some of these traits, and the current and emerging pest threat posed by this moth deserves closer attention, especially in relation to intercontinental phytosanitary measures to slow its spread.

In Mabhaudhi, Tafadzwanashe; Senzanje, A.; Modi, A.; Jewitt, G.; Massawe, F. (Eds.). Water - energy - food nexus narratives and resource securities: a global south perspective. Amsterdam, Netherlands: Elsevier ; The currently used water–energy–food (WEF) nexus philosophy and frameworks integrate the interconnections across the water, energy, food-agricultural sectors using a systems perspective. There are many challenges to model the interdependencies and trade-offs using a WEF nexus approach. Many tools and indices have been developed and used at the regional and national levels. However, there are few attempts to apply tools at a local and/or catchment level as described in this chapter for the Inkomati-Usuthu catchment in South Africa. The available tools were described according to inputs required and outputs produced together with both spatial and temporal scales and potential users. The data requirements for each sector were unpacked, and potential sources for local information are listed despite the wide set of data necessary. The way forward to applying these tools in the Crocodile and lower Komati river basins was considered in light of the facilitated stakeholder engagement to promote understanding of the scope of the WEF nexus and economic and policy implications.

En este taller, realizado en el Territorio Sostenible Adaptado al Clima (TeSAC) en El Tuma - La Dalia, en Nicaragua, familias rurales dedicadas a la agricultura realizaron un análisis de vulnerabilidad al cambio climático de los principales recursos productivos y fuentes de agua de sus fincas, con el propósito de fortalecer sus conocimientos en vulnerabilidad, variabilidad y cambio climático y de esta manera disminuir los impactos negativos de la variabilidad climática en sus territorios y comunidades. Durante esta sesión los participantes elaboraron un calendario estacional, construido de forma colectiva, que marca las principales variables climáticas que se presentan en la zona durante el año, de esta manera los agricultores se encuentran más preparados pues disponen de más información y habilidades para hacer análisis de vulnerabilidad de sus sistemas de producción y recursos de la comunidad ante el cambio climático. Los agricultores también reconocieron la importancia de la implementación de prácticas de agricultura climáticamente inteligente (ACI) para reducir su vulnerabilidad frente al cambio climático. ; In this workshop, held in the climate-smart village (CSV) in El Tuma - La Dalia, in Nicaragua, rural families conducted an analysis of vulnerability to climate change of the main productive resources and water sources of their farms, with the purpose of strengthening their knowledge on vulnerability, variability and climate change and thus reduce the negative impacts of climate variability on their territories and communities. During this session the participants prepared a seasonal calendar, built collectively, which marks the main climatic variables that occur in the area during the year, in this way farmers are more prepared because they have more information and skills to do analysis of vulnerability of their production systems and community resources in the face of climate change. Farmers also recognized the importance of implementing climate-smart agriculture (CSA) practices to reduce their ...

This rapid climate risk assessment for the Southern Africa Development Community (SADC) uses the Intergovernmental Panel on Climate Change (IPCC) 2014 risk analysis framework to assess the distribution of climate hazards and social and biophysical vulnerability to those hazards in order to identify climate risk hotspots. The assessment uses regional climate models from CORDEX-Africa to map rainfall extremes and drought hazards to 2031–2059. Ten social and biophysical vulnerability indicators are identified from across the capital assets (human, physical, social, financial, natural), using data from the Global Multidimensional Poverty Index (MPI), to develop a vulnerability index. The vulnerability index and distribution of climate hazards are mapped to identify hotspots. Hotspots of vulnerability to and risk of extreme rainfall are shown in northern Madagascar and in south west Tanzania, under both the RCP4.5 and 8.5 scenarios. These hotspots also correspond to the hotspots for drought risk under RCP4.5 and 8.5. However, it is clear that medium-high climate risk (high vulnerability, medium-high climate hazard) is widespread across Angola, Democratic Republic of the Congo (DRC), Tanzania, Mozambique, and Madagascar.

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.

AbstractAgroforestry systems are thought to reconcile biodiversity protection with food production and as a means of climate change adaptation and mitigation options. The contribution of a coffee-based agroforestry system to tree diversity and carbon stock along altitudinal gradients in Western Ethiopia was assessed. At 500-m intervals, six transect lines were methodically set up throughout the altitudinal gradient. There were made a total of 60 sample plots, each measuring 40 m by 40 m. A total of 34 woody species were identified. Biomass carbon stocks and tree diversity were quantified across altitudinal gradients. In the middle altitude, there were more woody species (28) than in the top altitude, where there were only a few species (16). The tree plants stored around 40.6 t ha−1 of biomass carbon on average. Aboveground biomass had a carbon stock of 32.22 C t ha−1, whereas belowground biomass had a carbon stock of 8.38 C t ha−1. The lower altitude biomass carbon stocks were substantially bigger than the upper altitude, which were 48.4 C t ha−1 and 25.67 C t ha−1, respectively. With increasing altitude, the study found a statistically significant negative link between tree diversity and biomass carbon storage (P < 0.05). The negative link between biomass carbon stock and altitude was that tree parameters that determine the amount of biomass carbon sequestered in a plant, such as basal area, tree diversity, and density, decreased as altitude increased. Despite differences along altitudinal gradients, the systems supported a diverse range of tree species and biomass carbon stocks.