Your search found 17 records
1 Mabhaudhi, T.; Mpandeli, S.; Chimonyo, V. G. P.; Nhamo, Luxon; Backeberg, G.; Modi, A. T. 2016. Prospects for improving irrigated agriculture in southern Africa – linking water, energy and food. Paper presented at the 2nd World Irrigation Forum, Chiang Mai, Thailand, 6-8 November 2016. 10p.
Farming systems ; Small scale farming ; Irrigated farming ; Agriculture ; Rainfed farming ; Cultivated land ; Food security ; Food insecurity ; Food production ; Water productivity ; Water scarcity ; Water use efficiency ; Nutritional losses ; Energy demand ; Energy consumption ; Infrastructure ; Dam construction ; Smallholders ; Farmers ; Capacity building / Southern Africa / Africa South of Sahara
(Location: IWMI HQ Call no: e-copy only Record No: H047846)
(0.63 MB)
Sub-Saharan Africa (SSA) faces high incidence of food and nutrition insecurity. Consequently, increasing agricultural productivity has always featured prominently on regional agenda. The Comprehensive Africa Agriculture Development Programme’s (CAADP) set a target to expand the area under irrigation by at least 5 million ha by 2025. This review assessed the current status of irrigated agriculture in SSA from a water–energy–food nexus perspective, focusing on southern Africa. Gaps and opportunities for improving irrigated agriculture were also assessed in terms of the feasible limits to which they can be exploited. Sub-Saharan Africa faces water scarcity and projections show that countries in SSA will face increased physical and / or economic water scarcity by 2025. However, with agriculture already accounting for more than 60% of water withdrawals, increasing area under irrigation could worsen the problem of water scarcity. Recurrent droughts experienced across SSA reaffirm the sensitive issue of food insecurity and water scarcity. The region also faces energy insecurity with most countries experiencing chronic power outages. Increasing area under irrigation will place additional demand on the already strained energy grids. Projections of an increasing population within SSA indicate increased food and energy demand; a growing middle class also adds to increasing food demand. This poses the question - is increasing irrigated agriculture a solution to water scarcity, food insecurity and energy shortages? This review recommends that, whilst there are prospects for increasing area under irrigation and subsequent agricultural productivity, technical planning should adopt a water–energy–food nexus approach to setting targets. Improving water productivity in irrigated agriculture could reduce water and energy use while increasing yield output.
2 Mabhaudhi, T.; Mpandeli, S.; Nhamo, Luxon; Chimonyo, V. G. P.; Nhemachena, Charles; Senzanje, A.; Naidoo, D.; Modi, A. T. 2018. Prospects for improving irrigated agriculture in Southern Africa: linking water, energy and food. Water, 10(12):1-16. [doi: https://doi.org/10.3390/w10121881]
Farming systems ; Small scale farming ; Irrigated farming ; Agriculture ; Food security ; Food insecurity ; Food production ; Water productivity ; Water accounting ; Energy resources ; Nexus ; Infrastructure ; Dams ; Smallholders ; Farmers ; Capacity building / Southern Africa / Africa South of Sahara
(Location: IWMI HQ Call no: e-copy only Record No: H049042)
(1.74 MB)
Increasing agricultural productivity has always been a prominent feature on the regional agenda due to a high incidence of food and nutrition insecurity. This review assessed the current status of irrigated agriculture in southern Africa from a water–energy–food (WEF) nexus perspective. Gaps and opportunities for improving irrigated agriculture within the context of the WEF nexus were also assessed in terms of the feasible limits to which they can be exploited. Southern Africa faces water scarcity, and climate projections show that member states will face increased physical and/or economic water scarcity by as early as 2025, which will have negative impacts on water, energy and food production. Recurrent droughts experienced across the region reaffirm the sensitive issues of food and energy insecurity as well as water scarcity. Projections of an increasing population within the region indicate increased water, energy and food demand. With agriculture already accounting for about 70% of water withdrawals, increasing the area under irrigation will place additional demand on already strained energy grids and scarce water resources. This poses the question—is increasing irrigated agriculture a solution to improving water access, food security and energy supply? While there are prospects for increasing the area under irrigation and subsequent improvement in agricultural productivity, adopting a WEF nexus approach in doing so would mitigate trade-offs and unintended consequences. Consideration of the WEF nexus in integrated resources planning and management eliminates the possibilities of transferring problems from one sector to other, as it manages synergies and trade-offs. While it is acknowledged that improving water productivity in irrigated agriculture could reduce water and energy use while increasing yield output, there is a need to decide how such savings would then be reallocated. Any intervention to increase the irrigated area should be done in the context of a WEF nexus analytical framework to guide policy and decision-making. Technical planning should evolve around the WEF nexus approach in setting targets, as WEF nexus indicators would reveal the performance and impact of proposed interventions on any of the three WEF nexus components.
3 Mabhaudhi, T.; Chimonyo, V. G. P.; Hlahla, S.; Massawe, F.; Mayes, S.; Nhamo, Luxon; Modi, A. T. 2019. Prospects of orphan crops in climate change. Planta, 250(3):695-708. [doi: https://doi.org/10.1007/s00425-019-03129-y]
Climate change adaptation ; Food security ; Food insecurity ; Food systems ; Nutrition ; Genetic diversity ; Sustainability ; Cropping systems ; Water scarcity ; Water use efficiency ; Greenhouse gas emissions ; Agroecosystems ; Agrobiodiversity ; Socioeconomic environment ; Research and development ; Diversification ; Land use
(Location: IWMI HQ Call no: e-copy only Record No: H049145)
https://link.springer.com/content/pdf/10.1007%2Fs00425-019-03129-y.pdf
https://vlibrary.iwmi.org/pdf/H049145.pdf
https://vlibrary.iwmi.org/pdf/H049145.pdf
(0.97 MB) (988 KB)
Orphan crops play an important role in global food and nutrition security, and may have potential to contribute to sustainable food systems under climate change. Owing to reports of their potential under water scarcity, there is an argument to promote them to sustainably address challenges such as increasing drought and water scarcity, food and nutrition insecurity, environmental degradation, and employment creation under climate change. We conducted a scoping review using online databases to identify the prospects of orphan crops to contribute to (1) sustainable and healthy food systems, (2) genetic resources for future crop improvement, and (3) improving agricultural sustainability under climate change. The review found that, as a product of generations of landrace agriculture, several orphan crops are nutritious, resilient, and adapted to niche marginal agricultural environments. Including such orphan crops in the existing monocultural cropping systems could support more sustainable, nutritious, and diverse food systems in marginalised agricultural environments. Orphan crops also represent a broad gene pool for future crop improvement. The reduction in arable land due to climate change offers opportunities to expand the area under their production. Their suitability to marginal niche and low-input environments offers opportunities for low greenhouse gas (GHG) emissions from an agro-ecosystems, production, and processing perspective. This, together with their status as a sub-set of agro-biodiversity, offers opportunities to address socio-economic and environmental challenges under climate change. With research and development, and policy to support them, orphan crops could play an important role in climate-change adaptation, especially in the global south.
4 Mabhaudhi, T.; Mpandeli, S.; Nhamo, Luxon; Senzanje, A.; Chimonyo, V. G. P.; Modi, A.T. 2019. Options for improving agricultural water productivity under increasing water scarcity in South Africa. Paper presented at the 3rd World Irrigation Forum (WIF3) on Development for Water, Food and Nutrition Security in a Competitive Environment, Bali, Indonesia, 1-7 September 2019. 14p.
Agricultural production ; Water productivity ; Water scarcity ; Climate change ; Risks ; Drought ; Rainwater harvesting ; Smallholders ; Farmers ; Water management ; Strategies ; Irrigation methods ; Water use / South Africa
(Location: IWMI HQ Call no: e-copy only Record No: H049340)
(0.35 MB)
South Africa is ranked among the thirty driest countries in the world, a challenge that is negatively affecting agricultural production. Other challenges such as population growth, rural-urban migration, changing food preferences and drought exacerbate pressure on agricultural water productivity. The review critically assessed the different considerations for increasing agricultural water productivity under water scarce conditions in South Africa. While under these conditions, irrigation may seem an obvious solution to increasing agricultural water productivity as a response to frequent droughts and mid-season dry spells. However, considerations on the availability of water and energy for irrigation expansion and the accessibility of irrigation services to different farming groups in the country. It is generally argued that irrigation is an expensive option and not necessarily readily accessible to most farmers.
There are prospects for tapping into South Africa’s groundwater resources but the extent to which they can contribute to expanding area under irrigation is contested given the challenges of quantifying and pumping the water. Most smallholder farmers currently lack access to water, energy, infrastructure and technical skills to irrigate thus making irrigation a challenging option in this sector. An alternative would be to explore rainwater harvesting and soil water conservation technologies, which involve inducing, collecting, storing and conserving runoff water for agriculture. The drawbacks to this are that, apart from scale issues, rainfall is becoming more erratic and droughts more frequent and hence the feasibility of this approach under frequent drought could be challenged.
There are prospects for tapping into South Africa’s groundwater resources but the extent to which they can contribute to expanding area under irrigation is contested given the challenges of quantifying and pumping the water. Most smallholder farmers currently lack access to water, energy, infrastructure and technical skills to irrigate thus making irrigation a challenging option in this sector. An alternative would be to explore rainwater harvesting and soil water conservation technologies, which involve inducing, collecting, storing and conserving runoff water for agriculture. The drawbacks to this are that, apart from scale issues, rainfall is becoming more erratic and droughts more frequent and hence the feasibility of this approach under frequent drought could be challenged.
5 Nhamo, Luxon; Magidi, J.; Nyamugama, A.; Clulow, A. D.; Sibanda, M.; Chimonyo, V. G. P.; Mabhaudhi, T. 2020. Prospects of improving agricultural and water productivity through unmanned aerial vehicles. Agriculture, 10(7):256. [doi: https://doi.org/10.3390/agriculture10070256]
Agricultural productivity ; Water productivity ; Unmanned aerial vehicles ; Water management ; Plant health ; Crop yield ; Monitoring ; Vegetation index ; Remote sensing ; Evapotranspiration ; Water stress ; Irrigation scheduling ; Mapping ; Smallholders ; Farmers ; Models ; Disaster risk reduction ; Resilience ; Satellite imagery ; Cost benefit analysis
(Location: IWMI HQ Call no: e-copy only Record No: H049892)
(1.05 MB) (1.05 MB)
Unmanned Aerial Vehicles (UAVs) are an alternative to costly and time-consuming traditional methods to improve agricultural water management and crop productivity through the acquisition, processing, and analyses of high-resolution spatial and temporal crop data at field scale. UAVs mounted with multispectral and thermal cameras facilitate the monitoring of crops throughout the crop growing cycle, allowing for timely detection and intervention in case of any anomalies. The use of UAVs in smallholder agriculture is poised to ensure food security at household level and improve agricultural water management in developing countries. This review synthesises the use of UAVs in smallholder agriculture in the smallholder agriculture sector in developing countries. The review highlights the role of UAV derived normalised difference vegetation index (NDVI) in assessing crop health, evapotranspiration, water stress and disaster risk reduction. The focus is to provide more accurate statistics on irrigated areas, crop water requirements and to improve water productivity and crop yield. UAVs facilitate access to agro-meteorological information at field scale and in near real-time, important information for irrigation scheduling and other on-field decision-making. The technology improves smallholder agriculture by facilitating access to information on crop biophysical parameters in near real-time for improved preparedness and operational decision-making. Coupled with accurate meteorological data, the technology allows for precise estimations of crop water requirements and crop evapotranspiration at high spatial resolution. Timely access to crop health information helps inform operational decisions at the farm level, and thus, enhancing rural livelihoods and wellbeing.
6 Mudau, F. N.; Chimonyo, V. G. P.; Modi, A. T.; Mabhaudhi, Tafadzwanashe. 2022. Neglected and underutilised crops: a systematic review of their potential as food and herbal medicinal crops in South Africa. Frontiers in Pharmacology, 12:809866. [doi: https://doi.org/10.3389/fphar.2021.809866]
Medicinal plants ; Food crops ; Underutilized species ; Food security ; Nutrition security ; Nutraceuticals ; Pharmaceuticals ; Sustainability ; Diets ; Food supplements ; Capacity development / South Africa
(Location: IWMI HQ Call no: e-copy only Record No: H050904)
https://www.frontiersin.org/articles/10.3389/fphar.2021.809866/pdf
https://vlibrary.iwmi.org/pdf/H050904.pdf
https://vlibrary.iwmi.org/pdf/H050904.pdf
(1.93 MB) (1.93 MB)
The African continent harbours many native species with nutraceutical and pharmaceutical potential. This study reviewed underutilised crops in South Africa to determine their potential as food and herbal medicinal crops. Over 5,000 species have been identified and earmarked for their medical attributes in formal and informal setups. Researchers, plant breeders and policymakers have mostly ignored the development potential of these crops. Consequently, their value chains are poorly developed. In South Africa, there is a wide range of neglected and underutilised crops, which were historically popular and used by communities; however, over the years, they have lost their status within farming systems and been relegated to the status of neglected and underutilised. Recently, driven by the need to transition to more sustainable and resilient food systems, there has been renewed interest in their potential as food and herbal medicinal crops to establish new value chains that include vulnerable groups. They are now gaining global attention, and their conservation and sustainable utilisation are now being prioritized. The review confirmed that several of these crops possess nutraceutical and pharmaceutical properties, highlighting their potential for development as food and herbal medicines. However, current production levels are too low to meet the requirements for industrial development; research and development should focus on all aspects of their value chain, from crop improvement to utilisation. A transdisciplinary approach involving a wide range of actors is needed to develop the identified neglected and underutilised crops’ potential as food and herbal medicinal crops and support the development of new and inclusive value chains.
7 Mabhaudhi, Tafadzwanashe; Hlahla, S.; Chimonyo, V. G. P.; Henriksson, R.; Chibarabada, T. P.; Murugani, V. G.; Groner, V. P.; Tadele, Z.; Sobratee, N.; Slotow, R.; Modi, A. T.; Baudron, F.; Chivenge, P. 2022. Diversity and diversification: ecosystem services derived from underutilized crops and their co-benefits for sustainable agricultural landscapes and resilient food systems in Africa. Frontiers in Agronomy, 4:859223. [doi: https://doi.org/10.3389/fagro.2022.859223]
Biodiversity ; Ecosystem services ; Underutilized species ; Crops ; Diversification ; Sustainable agriculture ; Food security ; Nutrition security ; Poverty alleviation ; Sustainable livelihoods ; Agricultural landscape ; Food systems ; Resilience ; Gender equality ; Role of women ; Income ; Socioeconomic development ; Sustainable Development Goals ; Climate change ; Ecological factors ; Habitats ; Cultural services ; Policies ; Systematic reviews / Africa
(Location: IWMI HQ Call no: e-copy only Record No: H051093)
https://www.frontiersin.org/articles/10.3389/fagro.2022.859223/pdf
https://vlibrary.iwmi.org/pdf/H051093.pdf
https://vlibrary.iwmi.org/pdf/H051093.pdf
(2.48 MB) (2.48 MB)
There are growing calls to adopt more sustainable forms of agriculture that balance the need to increase production with environmental, human health, and wellbeing concerns. Part of this conversation has included a debate on promoting and mainstreaming neglected and underutilized crop species (NUS) because they represent a more ecologically friendly type of agriculture. We conducted a systematic review to determine the ecosystem services derived from NUS and assess their potential to promote functional ecological diversity, food and nutritional security, and transition to more equitable, inclusive, sustainable and resilient agricultural landscapes and food systems in Africa. Our literature search yielded 35 articles for further analysis. The review showed that NUS provide various provisioning, regulating, cultural, and supporting ecosystem services and several environmental and health co-benefits, dietary diversity, income, sustainable livelihood outcomes, and economic empowerment, especially for women. Importantly, NUS address the three pillars of sustainable development- ecological, social, and economic. Thus, NUS may provide a sustainable, fit-for-purpose transformative ecosystem-based adaptation solution for Africa to transition to more sustainable, healthy, equitable, and resilient agricultural landscapes and food systems.
8 Brewer, K.; Clulow, A.; Sibanda, M.; Gokool, S.; Odindi, J.; Mutanga, O.; Naiken, V.; Chimonyo, V. G. P.; Mabhaudhi, Tafadzwanashe. 2022. Estimation of maize foliar temperature and stomatal conductance as indicators of water stress based on optical and thermal imagery acquired using an Unmanned Aerial Vehicle (UAV) platform. Drones, 6(7):169. [doi: https://doi.org/10.3390/drones6070169]
Crop growth stage ; Maize ; Temperature measurement ; Stomatal conductance ; Estimation ; Water stress ; Thermal infrared imagery ; Unmanned aerial vehicles ; Machine learning ; Forecasting ; Models ; Precision agriculture ; Smallholders ; Small-scale farming ; Crop water use ; Indicators / South Africa / KwaZulu-Natal / Swayimani
(Location: IWMI HQ Call no: e-copy only Record No: H051298)
https://www.mdpi.com/2504-446X/6/7/169/pdf?version=1657704795
https://vlibrary.iwmi.org/pdf/H051298.pdf
https://vlibrary.iwmi.org/pdf/H051298.pdf
(7.44 MB) (7.44 MB)
Climatic variability and extreme weather events impact agricultural production, especially in sub-Saharan smallholder cropping systems, which are commonly rainfed. Hence, the development of early warning systems regarding moisture availability can facilitate planning, mitigate losses and optimise yields through moisture augmentation. Precision agricultural practices, facilitated by unmanned aerial vehicles (UAVs) with very high-resolution cameras, are useful for monitoring farm-scale dynamics at near-real-time and have become an important agricultural management tool. Considering these developments, we evaluated the utility of optical and thermal infrared UAV imagery, in combination with a random forest machine-learning algorithm, to estimate the maize foliar temperature and stomatal conductance as indicators of potential crop water stress and moisture content over the entire phenological cycle. The results illustrated that the thermal infrared waveband was the most influential variable during vegetative growth stages, whereas the red-edge and near-infrared derived vegetation indices were fundamental during the reproductive growth stages for both temperature and stomatal conductance. The results also suggested mild water stress during vegetative growth stages and after a hailstorm during the mid-reproductive stage. Furthermore, the random forest model optimally estimated the maize crop temperature and stomatal conductance over the various phenological stages. Specifically, maize foliar temperature was best predicted during the mid-vegetative growth stage and stomatal conductance was best predicted during the early reproductive growth stage. Resultant maps of the modelled maize growth stages captured the spatial heterogeneity of maize foliar temperature and stomatal conductance within the maize field. Overall, the findings of the study demonstrated that the use of UAV optical and thermal imagery, in concert with prediction-based machine learning, is a useful tool, available to smallholder farmers to help them make informed management decisions that include the optimal implementation of irrigation schedules.
9 Mugiyo, H.; Chimonyo, V. G. P.; Kunz, R.; Sibanda, M.; Nhamo, L.; Masemola, C. R.; Modi, A. T.; Mabhaudhi, Tafadzwanashe. 2022. Mapping the spatial distribution of underutilised crop species under climate change using the MaxEnt model: a case of KwaZulu-Natal, South Africa. Climate Services, 28:100330. [doi: https://doi.org/10.1016/j.cliser.2022.100330]
Crop production ; Underutilized species ; Spatial distribution ; Climate change adaptation ; Food security ; Nutrition security ; Sorghum ; Cowpeas ; Amaranthus ; Taro ; Machine learning ; Models ; Forecasting / South Africa / KwaZulu-Natal
(Location: IWMI HQ Call no: e-copy only Record No: H051487)
https://www.sciencedirect.com/science/article/pii/S2405880722000486/pdfft?md5=6c4991c59d70a740431da7b2b337a330&pid=1-s2.0-S2405880722000486-main.pdf
https://vlibrary.iwmi.org/pdf/H051487.pdf
https://vlibrary.iwmi.org/pdf/H051487.pdf
(9.38 MB) (9.38 MB)
Knowing the spatial and temporal suitability of neglected and underutilised crop species (NUS) is important for fitting them into marginal production areas and cropping systems under climate change. The current study used climate change scenarios to map the future distribution of selected NUS, namely, sorghum (Sorghum bicolor), cowpea (Vigna unguiculata), amaranth (Amaranthus) and taro (Colocasia esculenta) in the KwaZulu-Natal (KZN) province, South Africa. The future distribution of NUS was simulated using a maximum entropy (MaxEnt) model using regional circulation models (RCMs) from the CORDEX archive, each driven by a different global circulation model (GCM), for the years 2030 to 2070. The study showed an increase of 0.1–11.8% under highly suitable (S1), moderately suitable (S2), and marginally suitable (S3) for sorghum, cowpea, and amaranth growing areas from 2030 to 2070 across all RCPs. In contrast, the total highly suitable area for taro production is projected to decrease by 0.3–9.78% across all RCPs. The jack-knife tests of the MaxEnt model performed efficiently, with areas under the curve being more significant than 0.8. The study identified annual precipitation, length of the growing period, and minimum and maximum temperature as variables contributing significantly to model predictions. The developed maps indicate possible changes in the future suitability of NUS within the KZN province. Understanding the future distribution of NUS is useful for developing transformative climate change adaptation strategies that consider future crop distribution. It is recommended to develop regionally differentiated climate-smart agriculture production guidelines matched to spatial and temporal variability in crop suitability.
10 Chimonyo, V. G. P.; Chibarabada, T. P.; Choruma, D. J.; Kunz, R.; Walker, S.; Massawe, F.; Modi, A. T.; Mabhaudhi, Tafadzwanashe. 2022. Modelling neglected and underutilised crops: a systematic review of progress, challenges, and opportunities. Sustainability, 14(21):13931. (Special issue: Interdisciplinary Approaches to Mainstreaming Underutilized Crops) [doi: https://doi.org/10.3390/su142113931]
(Location: IWMI HQ Call no: e-copy only Record No: H051496)
https://www.mdpi.com/2071-1050/14/21/13931/pdf?version=1666790014
https://vlibrary.iwmi.org/pdf/H051496.pdf
https://vlibrary.iwmi.org/pdf/H051496.pdf
(0.91 MB) (930 KB)
Developing and promoting neglected and underutilised crops (NUS) is essential to building resilience and strengthening food systems. However, a lack of robust, reliable, and scalable evidence impedes the mainstreaming of NUS into policies and strategies to improve food and nutrition security. Well-calibrated and validated crop models can be useful in closing the gap by generating evidence at several spatiotemporal scales needed to inform policy and practice. We, therefore, assessed progress, opportunities, and challenges for modelling NUS using a systematic review. While several models have been calibrated for a range of NUS, few models have been applied to evaluate the growth, yield, and resource use efficiencies of NUS. The low progress in modelling NUS is due, in part, to the vast diversity found within NUS that available models cannot adequately capture. A general lack of research compounds this focus on modelling NUS, which is made even more difficult by a deficiency of robust and accurate ecophysiological data needed to parameterise crop models. Furthermore, opportunities exist for advancing crop model databases and knowledge by tapping into big data and machine learning.
11 Chimonyo, V. G. P.; Govender, L.; Nyathi, M.; Scheelbeek, P. F. D.; Choruma, D. J.; Mustafa, M.; Massawe, F.; Slotow, R.; Modi, A. T.; Mabhaudhi, Tafadzwanashe. 2023. Can cereal-legume intercrop systems contribute to household nutrition in semi-arid environments: a systematic review and meta-analysis. Frontiers in Nutrition, 10:1060246. [doi: https://doi.org/10.3389/fnut.2023.1060246]
Intercropping ; Cereal crops ; Legumes ; Multiple cropping ; Water use efficiency ; Water productivity ; Nutrition ; Sustainable Development Goals ; Goal 2 Zero hunger ; Goal 3 Good health and well-being ; Goal 12 Responsible production and consumption
(Location: IWMI HQ Call no: e-copy only Record No: H051672)
https://www.frontiersin.org/articles/10.3389/fnut.2023.1060246/pdf
https://vlibrary.iwmi.org/pdf/H051672.pdf
https://vlibrary.iwmi.org/pdf/H051672.pdf
(1.35 MB) (1.35 MB)
Introduction: Intercropping cereals with legumes can intensify rainfed cereal monocropping for improved household food and nutritional security. However, there is scant literature confirming the associated nutritional benefits.
Methodology: A systematic review and meta-analysis of nutritional water productivity (NWP) and nutrient contribution (NC) of selected cereal-legume intercrop systems was conducted through literature searches in Scopus, Web of Science and ScienceDirect databases. After the assessment, only nine articles written in English that were field experiments comprising grain cereal and legume intercrop systems were retained. Using the R statistical software (version 3.6.0), paired t-tests were used to determine if differences existed between the intercrop system and the corresponding cereal monocrop for yield (Y), water productivity (WP), NC, and NWP.
Results: The intercropped cereal or legume yield was 10 to 35% lower than that for the corresponding monocrop system. In most instances, intercropping cereals with legumes improved NY, NWP, and NC due to their added nutrients. Substantial improvements were observed for calcium (Ca), where NY, NWP, and NC improved by 658, 82, and 256%, respectively.
Discussion: Results showed that cereal-legume intercrop systems could improve nutrient yield in water-limited environments. Promoting cereal legume intercrops that feature nutrient-dense legume component crops could contribute toward addressing the SDGs of Zero Hunger (SDG 3), Good Health and Well-3 (SDG 2) and Responsible consumption and production (SDG 12).
Methodology: A systematic review and meta-analysis of nutritional water productivity (NWP) and nutrient contribution (NC) of selected cereal-legume intercrop systems was conducted through literature searches in Scopus, Web of Science and ScienceDirect databases. After the assessment, only nine articles written in English that were field experiments comprising grain cereal and legume intercrop systems were retained. Using the R statistical software (version 3.6.0), paired t-tests were used to determine if differences existed between the intercrop system and the corresponding cereal monocrop for yield (Y), water productivity (WP), NC, and NWP.
Results: The intercropped cereal or legume yield was 10 to 35% lower than that for the corresponding monocrop system. In most instances, intercropping cereals with legumes improved NY, NWP, and NC due to their added nutrients. Substantial improvements were observed for calcium (Ca), where NY, NWP, and NC improved by 658, 82, and 256%, respectively.
Discussion: Results showed that cereal-legume intercrop systems could improve nutrient yield in water-limited environments. Promoting cereal legume intercrops that feature nutrient-dense legume component crops could contribute toward addressing the SDGs of Zero Hunger (SDG 3), Good Health and Well-3 (SDG 2) and Responsible consumption and production (SDG 12).
12 Ramphinwa, M. L.; Mchau, G. R. A.; Mashau, M. E.; Madala, N. E.; Chimonyo, V. G. P.; Modi, T. A.; Mabhaudhi, T.; Thibane, V. S.; Mudau, F. N. 2023. Eco-physiological response of secondary metabolites of teas: review of quality attributes of herbal tea. Frontiers in Sustainable Food Systems, 7:990334. [doi: https://doi.org/10.3389/fsufs.2023.990334]
Herbal teas ; Physiological response ; Secondary metabolites ; Medicinal properties ; Phenolic compounds ; Environmental factors ; Abiotic stress ; Biotic stress ; Antioxidants ; Antidiabetic properties ; Antimicrobial properties ; Water stress ; Temperature
(Location: IWMI HQ Call no: e-copy only Record No: H051765)
https://www.frontiersin.org/articles/10.3389/fsufs.2023.990334/pdf
https://vlibrary.iwmi.org/pdf/H051765.pdf
https://vlibrary.iwmi.org/pdf/H051765.pdf
(0.42 MB) (429 KB)
Herbal tea is a rich source of secondary metabolites which are reputed to have medicinal and nutritional efficacy. These secondary metabolites are influenced by the abiotic and biotic stresses that improve the production of herbal teas in terms of biomass production, accumulation and partitioning of assimilates of compounds. In this study, various examples of herbal teas have been shown to respond differently to secondary metabolites affected by environmental factors. Thus, the meta-analysis of this study confirms that different herbal teas' response to environmental factors depends on the type of species, cultivar, and the degree of shade that the plant is exposed. It is also evident that the metabolic processes are also known to optimize the production of secondary metabolites which can thus be achieved by manipulating agronomic practices on herbal teas. The different phenolic compound in herbal teas possesses the antioxidant, antimicrobial, antiatherosclerosis, anti-inflammatory, antimutagenic, antitumor, antidiabetic and antiviral activities that are important in managing chronic diseases associated with lifestyle. It can be precluded that more studies should be conducted to establish interactive responses of biotic and abiotic environmental factors on quality attributes of herbal teas.
13 Buthelezi, S.; Mutanga, O.; Sibanda, M.; Odindi, J.; Clulow, A. D.; Chimonyo, V. G. P.; Mabhaudhi, Tafadzwanashe. 2023. Assessing the prospects of remote sensing maize leaf area index using UAV-derived multi-spectral data in smallholder farms across the growing season. Remote Sensing, 15(6):1597. (Special issue: Retrieving Leaf Area Index Using Remote Sensing) [doi: https://doi.org/10.3390/rs15061597]
Maize ; Leaf area index ; Vegetation index ; Remote sensing ; Unmanned aerial vehicles ; Multispectral imagery ; Small-scale farming ; Smallholders ; Growth stages ; Monitoring ; Forecasting ; Models ; Machine learning ; Agricultural productivity ; Crop yield / South Africa / KwaZulu-Natal / Swayimane
(Location: IWMI HQ Call no: e-copy only Record No: H051818)
https://www.mdpi.com/2072-4292/15/6/1597/pdf?version=1678869485
https://vlibrary.iwmi.org/pdf/H051818.pdf
https://vlibrary.iwmi.org/pdf/H051818.pdf
(3.96 MB) (3.96 MB)
Maize (Zea Mays) is one of the most valuable food crops in sub-Saharan Africa and is a critical component of local, national and regional economies. Whereas over 50% of maize production in the region is produced by smallholder farmers, spatially explicit information on smallholder farm maize production, which is necessary for optimizing productivity, remains scarce due to a lack of appropriate technologies. Maize leaf area index (LAI) is closely related to and influences its canopy physiological processes, which closely relate to its productivity. Hence, understanding maize LAI is critical in assessing maize crop productivity. Unmanned Aerial Vehicle (UAV) imagery in concert with vegetation indices (VIs) obtained at high spatial resolution provides appropriate technologies for determining maize LAI at a farm scale. Five DJI Matrice 300 UAV images were acquired during the maize growing season, and 57 vegetation indices (VIs) were generated from the derived images. Maize LAI samples were collected across the growing season, a Random Forest (RF) regression ensemble based on UAV spectral data and the collected maize LAI samples was used to estimate maize LAI. The results showed that the optimal stage for estimating maize LAI using UAV-derived VIs in concert with the RF ensemble was during the vegetative stage (V8–V10) with an RMSE of 0.15 and an R2 of 0.91 (RRMSE = 8%). The findings also showed that UAV-derived traditional, red edge-based and new VIs could reliably predict maize LAI across the growing season with an R2 of 0.89–0.93, an RMSE of 0.15–0.65 m2/m2 and an RRMSE of 8.13–19.61%. The blue, red edge and NIR sections of the electromagnetic spectrum were critical in predicting maize LAI. Furthermore, combining traditional, red edge-based and new VIs was useful in attaining high LAI estimation accuracies. These results are a step towards achieving robust, efficient and spatially explicit monitoring frameworks for sub-Saharan African smallholder farm productivity.
14 Abrahams, M.; Sibanda, M.; Dube, T.; Chimonyo, V. G. P.; Mabhaudhi, Tafadzwanashe. 2023. A systematic review of UAV applications for mapping neglected and underutilised crop species’ spatial distribution and health. Remote Sensing, 15(19):4672. (Special issue: Crops and Vegetation Monitoring with Remote/Proximal Sensing II) [doi: https://doi.org/10.3390/rs15194672]
Underutilized species ; Mapping ; Unmanned aerial vehicles ; Plant health ; Crop production ; Remote sensing ; Machine learning ; Food security ; Precision agriculture ; Spatial distribution ; Stomatal conductance ; Smallholders ; Farmland ; Vegetation index ; Systematic reviews
(Location: IWMI HQ Call no: e-copy only Record No: H052234)
https://www.mdpi.com/2072-4292/15/19/4672/pdf?version=1695462413
https://vlibrary.iwmi.org/pdf/H052234.pdf
https://vlibrary.iwmi.org/pdf/H052234.pdf
(11.70 MB) (11.7 MB)
Timely, accurate spatial information on the health of neglected and underutilised crop species (NUS) is critical for optimising their production and food and nutrition in developing countries. Unmanned aerial vehicles (UAVs) equipped with multispectral sensors have significantly advanced remote sensing, enabling the provision of near-real-time data for crop analysis at the plot level in small, fragmented croplands where NUS are often grown. The objective of this study was to systematically review the literature on the remote sensing (RS) of the spatial distribution and health of NUS, evaluating the progress, opportunities, challenges, and associated research gaps. This study systematically reviewed 171 peer-reviewed articles from Google Scholar, Scopus, and Web of Science using the PRISMA approach. The findings of this study showed that the United States (n = 18) and China (n = 17) were the primary study locations, with some contributions from the Global South, including southern Africa. The observed NUS crop attributes included crop yield, growth, leaf area index (LAI), above-ground biomass (AGB), and chlorophyll content. Only 29% of studies explored stomatal conductance and the spatial distribution of NUS. Twenty-one studies employed satellite-borne sensors, while only eighteen utilised UAV-borne sensors in conjunction with machine learning (ML), multivariate, and generic GIS classification techniques for mapping the spatial extent and health of NUS. The use of UAVs in mapping NUS is progressing slowly, particularly in the Global South, due to exorbitant purchasing and operational costs, as well as restrictive regulations. Subsequently, research efforts must be directed toward combining ML techniques and UAV-acquired data to monitor NUS’ spatial distribution and health to provide necessary information for optimising food production in smallholder croplands in the Global South.
15 Sibanda, M.; Ndlovu, H. S.; Brewer, K.; Buthelezi, S.; Matongera, T. N.; Mutanga, O.; Odidndi, J.; Clulow, A. D.; Chimonyo, V. G. P.; Mabhaudhi, Tafadzwanashe. 2023. Remote sensing hail damage on maize crops in smallholder farms using data acquired by remotely piloted aircraft system. Smart Agricultural Technology, 6:100325. [doi: https://doi.org/10.1016/j.atech.2023.100325]
Crop damage ; Hail damage ; Maize ; Remote sensing ; Smallholders ; Farmers ; Farmland ; Small-scale farming ; Unmanned aerial vehicles ; Plant health ; Leaf area index ; Vegetation index ; Agricultural productivity ; Climate change / South Africa / KwaZulu Natal / Swayimane
(Location: IWMI HQ Call no: e-copy only Record No: H052320)
https://www.sciencedirect.com/science/article/pii/S2772375523001545/pdfft?md5=79fa6611a7221a58090e695d915834b8&pid=1-s2.0-S2772375523001545-main.pdf
https://vlibrary.iwmi.org/pdf/H052320.pdf
https://vlibrary.iwmi.org/pdf/H052320.pdf
(17.40 MB) (17.4 MB)
Smallholder farmers reside in marginal environments typified by dryland maize-based farming systems. Despite the significant contribution of smallholder farmers to food production, they are vulnerable to extreme weather events such as hailstorms, floods and drought. Extreme weather events are expected to increase in frequency and intensity under climate change, threatening the sustainability of smallholder farming systems. Access to climate services and information, as well as digital advisories such as Robust spatially explicit monitoring techniques from remotely piloted aircraft systems (RPAS), could be instrumental in understanding the impact and extent of crop damage. It could assist in providing adequate response mechanisms suitable for bolstering crop productivity in a spatially explicit manner. This study, therefore, sought to evaluate the utility of drone-derived multispectral data in estimating crop productivity elements (Equivalent water thickness (EWT), Chlorophyll content, and leaf area index (LAI)) in maize smallholder croplands based on the random forest regression algorithm. A hailstorm occurred in the study area during the reproductive stages 2 to 3 and 3 to 4. EWT, Chlorophyll content, and LAI were measured before and after the storm. Results of this study showed that EWT, Chlorophyll content, and LAI could be optimally estimated based on the red edge and its spectral derivatives. Specifically, EWT was estimated to a rRMEs 2.7% and 59%, RMSEs of 5.31 gm- 2 and 27.35 gm-2, R2 of 0.88 and 0.77, while chlorophyll exhibited rRMSE of 28% and 25%, RMSEs of 87.4 µmol m- 2 and 76.2 µmol m- 2 and R2 of 0.89 and 0.80 and LAI yielded a rRMSE of 10.9% and 15.2%, RMSEs of 0.6 m2 /m2 and 0.19 m2 /m2 before and after the hail damage, respectively. Overall, the study underscores the potential of RPAS-based remote sensing as a valuable resource for assessing crop damage and responding to the impact of hailstorms on crop productivity in smallholder croplands. This offers a means to enhance agricultural resilience and adaptability under climate change.
16 Mugiyo, H.; Magadzire, T.; Choruma, D. J.; Chimonyo, V. G. P.; Manzou, R.; Jiri, O.; Mabhaudhi, Tafadzwanashe. 2023. El Niño’s effects on southern African agriculture in 2023/24 and anticipatory action strategies to reduce the impacts in Zimbabwe. Atmosphere, 14(11):1692. (Special issue: Joint Disasters of High Temperature and Drought) [doi: https://doi.org/10.3390/atmos14111692]
El Nino ; Early warning systems ; Strategies ; Disaster risk reduction ; Climate services ; Weather ; Rainfall ; Drought ; Heat stress ; Mitigation ; Crop production ; Crop yield ; Agricultural sector ; Farmers / Southern Africa / Zimbabwe
(Location: IWMI HQ Call no: e-copy only Record No: H052405)
https://www.mdpi.com/2073-4433/14/11/1692/pdf?version=1700139089
https://vlibrary.iwmi.org/pdf/H052405.pdf
https://vlibrary.iwmi.org/pdf/H052405.pdf
(1.79 MB) (1.79 MB)
The frequency of El Niño occurrences in southern Africa surpasses the norm, resulting in erratic weather patterns that significantly impact food security, particularly in Zimbabwe. The effects of these weather patterns posit that El Niño occurrences have contributed to the diminished maize yields. The objective is to give guidelines to policymakers, researchers, and agricultural stakeholders for taking proactive actions to address the immediate and lasting impacts of El Niño and enhance the resilience of the agricultural industry. This brief paper provides prospective strategies for farmers to anticipate and counteract the El Niño-influenced dry season projected for 2023/24 and beyond. The coefficient of determination R2 between yield and ENSO was low; 11 of the 13 El Niño seasons had a negative detrended yield anomaly, indicating the strong association between El Nino’s effects and the reduced maize yields in Zimbabwe. The R2 between the Oceanic Nino Index (ONI) and rainfall (43%) and between rainfall and yield (39%) indirectly affects the association between ONI and yield. To safeguard farmers’ livelihoods and improve their preparedness for droughts in future agricultural seasons, this paper proposes a set of strategic, tactical, and operational decision-making guidelines that the agriculture industry should follow. The importance of equipping farmers with weather and climate information and guidance on drought and heat stress was underscored, encompassing strategies such as planting resilient crop varieties, choosing resilient livestock, and implementing adequate fire safety measures.
17 Sibanda, M.; Buthelezi, S.; Mutanga, O.; Odindi, J.; Clulow, A. D.; Chimonyo, V. G. P.; Gokool, S.; Naiken, V.; Magidi, J.; Mabhaudhi, Tafadzwanashe. 2023. Exploring the prospects of UAV-remotely sensed data in estimating productivity of maize crops in typical smallholder farms of Southern Africa. ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences, X-1/W1-2023:1143-1150. (ISPRS Geospatial Week 2023, Cairo, Egypt, 2-7 September 2023) [doi: https://doi.org/10.5194/isprs-annals-X-1-W1-2023-1143-2023]
Agricultural productivity ; Small farms ; Smallholders ; Maize ; Yield forecasting ; Models ; Remote sensing ; Unmanned aerial vehicles ; Vegetation index / Southern Africa / South Africa / KwaZulu-Natal
(Location: IWMI HQ Call no: e-copy only Record No: H052490)
https://isprs-annals.copernicus.org/articles/X-1-W1-2023/1143/2023/isprs-annals-X-1-W1-2023-1143-2023.pdf
https://vlibrary.iwmi.org/pdf/H052490.pdf
https://vlibrary.iwmi.org/pdf/H052490.pdf
(1.59 MB) (1.59 MB)
This study estimated maize grain biomass, and grain biomass as a proportion of the absolute maize plant biomass using UAV-derived multispectral data. Results showed that UAV-derived data could accurately predict yield with R2 ranging from 0.80 - 0.95, RMSE ranging from 0.03 - 0.94 kg/m2 and RRMSE ranging from 2.21% - 39.91% based on the spectral datasets combined. Results of this study further revealed that the VT-R1 (56-63 days after emergence) vegetative growth stage was the most optimal stage for the early prediction of maize grain yield (R2 = 0.85, RMSE = 0.1, RRMSE = 5.08%) and proportional yield (R2 = 0.92, RMSE = 0.06, RRMSE = 17.56%), with the Normalized Difference Vegetation Index (NDVI), Enhanced Normalized Difference Vegetation Index (ENDVI), Soil Adjusted Vegetation Index (SAVI) and the red edge band being the most optimal prediction variables. The grain yield models produced more accurate results in estimating maize yield when compared to the biomass and proportional yield models. The results demonstrate the value of UAV-derived data in predicting maize yield on smallholder farms – a previously challenging task with coarse spatial resolution satellite sensors.
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