Surface water monitoring is essential for ecological security and water management. Owing to the limitations in the spatial and temporal resolution of commonly used remote sensing data, it is challenging to achieve accurate water monitoring relying on individual data, especially for small water bodies. This study integrated Planet-NICFI images with long-term Landsat images to monitor surface water dynamics in Zimbabwe. A deep learning segmentation model was developed to generate high-resolution binary water maps from Planet-NICFI images, which were linked to Landsat spectral features to construct a random forest regression model for producing water fraction series. The fraction series was evaluated by Global Surface Water product and applied to analyze the dynamics of the water area. Results showed that the segmentation model achieved an IoU of 0.91, while the random forest regression model attained an R2 of 0.89 and an RMSE of 0.09. In Zimbabwe, a total of 58246 water bodies were identified, showing a superior detection capability than global surface water products. 26.23% of regions exhibited a significant increasing trend, while 15.37% showed a decreasing trend from 1994 to 2024. This study indicated that integrating high-resolution binary maps with long-term fraction series can better monitor the spatial and temporal dynamics of surface water.

Purpose: This study explored the potential of aluminium water treatment residuals (Al-WTR), a by-product of drinking water purification, to improve soil quality and maize productivity on a degraded sandy soil. Methods: A field experiment was conducted over two cropping seasons (2019/20 and 2020/21), with treatments including sole applications of cattle manure (CM), maize stover (MS), Al-WTR, their co-amendments (Al-WTR + CM and Al-WTR + MS), NPK fertiliser, and an unamended control. Soil samples collected during the 2020/21 season (at 0–10 and 10–20 cm depths, and 3 and 6 weeks after planting) were analysed for soil organic carbon (SOC), total nitrogen (TN), microbial biomass carbon (MBC) and nitrogen (MBN), and basal respiration. Maize grain and biomass yields were recorded at physiological maturity for both seasons. Results: Co-amended treatments significantly increased SOC (> 4.90 g kg⁻¹) and TN (> 0.60 g kg⁻¹), compared to single amendments (< 4.80 g kg⁻¹ SOC; 0.50 g kg⁻¹ TN). At 6 WAP and 0–10 cm depth, Al-WTR + CM recorded the highest MBC (190 ± 1.14 mg C kg⁻¹) and MBN (35.80 ± 0.51 mg N kg⁻¹), while the control recorded the lowest (120 ± 1.58 mg C kg⁻¹; 18.72 ± 0.35 mg N kg⁻¹). Basal respiration also increased with co-amendments. Al-WTR + CM yielded 5.61 ± 0.05 t ha⁻¹ maize grain (2020/21), while the control yielded below 1 t ha⁻¹ in both seasons. Conclusion: The findings demonstrate that Al-WTR co-amendments can effectively restore soil function and support resilient maize production in degraded agroecosystems.

A key parameter influencing crop growth is the availability of water and its spatial distribution within agricultural soils. The strong electrical response associated with variations in water content means that electrical geophysical methods such as Electrical Resistivity Tomography ( ERT ) are ideally suited for studying soil moisture dynamics. While relative changes in electrical resistivity allow conclusions to be drawn on the temporal variability of soil moisture in the subsurface, they do not provide quantitative estimates of soil moisture. Laboratory measurements of soil moisture and electrical resistivity - together with the fitting of a model to these data (e.g. Waxman-Smits) - enable the estimation of soil moisture from ERT models. While this method is established, examples are limited for Alfisols in general, and from African sites in particular. We present laboratory data on agricultural Alfisols from three sites in southern Africa, to define relationships between electrical resistivity and volumetric water content. We fit the data to several widely used models, and utilise the novel application of Akaike’s Information Criterion to identify the best model for each dataset. In addition to identifying which model is most suitable for each site, our findings also allow us to make conclusions on whether a single or multiple models are required per site, or even whether heterogeneities make the utilisation of a model inadvisable. We then compare our results against complementary laboratory datasets to explain which soil physical parameters are the main causes of variability in electrical response at each site.

Africa is one of the most rapidly urbanizing regions in the 21st century. Understanding the development of Urban Green Spaces (UGS) is crucial for ecological environmental protection and the well-being of urban populations. However, high-resolution, long-term remote sensing data for monitoring and analyzing urban green spaces in Africa remains lacking. To address this gap, this study conducts a precise and comprehensive analysis of the longterm UGS dynamics in major African cities during the 21st century using Landsat images. An improved vegetation index, KNDVI_c, is proposed to estimate Fractional Vegetation Cover (FVC) for assessing UGS conditions. Additionally, six natural and anthropogenic driving factors are identified to quantify their impacts on UGS across Africa. The results indicate that from 2000 to 2024, although UGS development in Africa has improved to a certain extent, overall volatility remains relatively high, accompanied by significant differentiation and complex spatiotemporal changes. African UGS is influenced by the interaction and coupling between natural environmental and socioeconomic factors, with the role of socioeconomic factors becoming increasingly prominent over the study period. The corresponding driving mechanisms vary across regions due to differences in local climatic conditions and socioeconomic development levels. In summary, this study fills a critical gap in the long-term, high-resolution systematic investigation of African UGS and provides a scientific foundation for formulating sustainable urban development policies in African cities.

There are hidden health-related threats associated with the use of organic nutrient resources (ONRs) in farming systems which may affect plant, livestock, and human health and survival. Culturing and DNA-based sequencing (Illumina and Pacbio) methods were used to examine fungal and bacteria communities in Crotalaria juncea L., Calliandra calothyrsus Meissn., cattle manure, Zea mays L. stover and Pinus patula Schiede & Schltdl. & Cham sawdust biomass from Domboshawa Training Centre in Zimbabwe. Results were complemented with a review to: (1) identify handling and utilization strategies for ONRs in cropping systems; (2) establish potential plant and livestock health risks associated with the utilization of organic resources and (3) determine potential public health risks associated with handling organic resources, consumption and/or handling of affected crops or livestock. Pathogenic fungi and bacteria were identified through culturing (Aspergillus niger and Alternaria species) and DNA sequencing (Pantoea agglomerans, Aureobasidium pullulans, Aspergillus penicillioides, Scopulariopsis brevicaulis, Cladosporium spp., and Alternaria alternata). The identified microorganisms are potentially harmful to crops, livestock and humans as they could be transmittable during handling, processing, through water or inhalation. Good hygiene practices and farmer training on proper handling of organic material are recommended. Routine sampling and testing of ONR for culturable potentially pathogenic organisms and further nation-wide studies are recommended. A policy for handling and utilization of ONRs regarding the One Health can reduce the risks of exposure, transferability and transmission.

Surface water resources are widely distributed and undergo rapid fluctuations, necessitating large-scale, highfrequency monitoring. Remote sensing technologies provide critical data for this purpose, but challenges such as data gaps and contamination hinder the effective observation of surface water dynamics at fine temporal scales. This limitation can obscure the recording of short-term water variations, ultimately leading to misclassified inundation extents. This study aims to develop a framework for large-scale and short-interval surface water dynamic monitoring using Sentinel-1/2 data, and generate surface water dynamic product for detailed analysis of water distribution and changes in East Africa (EA). Specifically, we proposed a novel water mapping algorithm including water extraction, integration and filtering techniques for Sentinel-1/2 data to map semimonthly surface water dynamic across EA. We then used a simple similarity-based gap-filling method to fill the data gaps in these water maps. Using this framework, we generated semimonthly and seamless surface water dynamic product covering EA from 2017 to 2023. A comprehensive spatiotemporal analysis of surface water distribution and dynamics in EA was then conducted using the product. The results showed that the water mapping algorithm achieved an overall accuracy of 0.9746, with precision (0.9815) higher than recall (0.9706). The gap-filling algorithm proved highly robust, with overall accuracy exceeding 0.98 under different scenarios. The spatial distribution of surface water in EA is heterogeneous, with dominant permanent water area (66.57 %), followed by temporary water area (22.04 %), and seasonal water area (11.39 %). The overall surface water area in EA shows fluctuation, with an increase from 2017 to 2021, followed by a decrease from 2021 to 2023. By incorporating SAR data and increasing observation frequency, our product revealed finer-scale surface water dynamics than previous product. This large-scale, short-interval mapping framework provides new insights for regional and global water resource monitoring, while the EA dataset serves as a key reference for water management in the region.

Abstract Novel climate conditions are posing a serious threat to humanity and ecological systems, presenting and aggravating social injustices at different levels. African agriculture-based livelihood systems will be invariably the most affected because of their reliance on climate-sensitive agriculture and limited adaptive capacity due to low economic development linked primarily to historical contingency. Just transition pathways for Africa’s agriculture are urgently required for sustainable production systems that enhance food security and poverty reduction, while optimising mitigation co-benefits. We critically reviewed and synthesised literature from relevant scientific reports and peer-reviewed articles to develop a framework for just transition pathways for Africa’s agriculture towards low emission and climate resilient development under a 1.5°C global warming. We first characterise current and future climate hazards and assess climate risks underpinning African agriculture-based livelihoods. Our results demonstrated that a 1.5°C global warming will be approached by 2040 in all five subregions of Africa, even under low emission scenarios. This is despite Africa emitting <4% concentration of greenhouse gas emissions in the atmosphere. The African agriculture-based livelihood systems have experienced considerable losses and damages from climate change and this will worsen with increasing intensity of climate hazards. Neither the existing or planned incremental adaptation mechanisms nor the anticipated benefits of mitigatory measures are sufficiently comprehensive to match the pending novel climate conditions. We argue that the just transition pathways for Africa’s agriculture should be anchored on reprogramming of the cropping, livestock and fishery systems for climate-proofing with a specific focus on the following underpinnings: financing the advancement of science, technology and innovation; restoring neglected or underulitised crops and livestock genetic pools; regenerating soil fertility and advancing soil health; restoring degraded land; protecting natural ecosystems and biodiversity; accessing quality education training and information technologies; and developing markets and creating novel distribution and trade opportunities. Such efforts should also focus on mechanising and greening Africa’s agriculture as driven by a deliberate ‘Green Industrial Revolution’ for the new normal induced by climate change. The sustainability of climate change response and a just transition pathway framework for Africa also lies in the corresponding transformation of education systems and research capacities tailored to drive economic development for Africa. In conclusion, the developed just transition framework offers opportunities for social inclusion, equity, building capacity for self-mobilisation and self-organisation of communities for climate action, and investments in the transition pathways for building a climate resilient agriculture towards zero poverty and meaningful contribution towards zero carbon.

Background: Simultaneous breeding of grain yield and desirable agronomic traits are effective when the traits are positively correlated and heritability is high. Knowledge of the magnitude of trait contribution is essential in hastening crop breeding progress. Aim: This study aimed to investigate the correlations and path analysis of yield traits in grain sorghum. Setting: The experiment was conducted in three different agro-ecological regions in Zimbabwe. Methods: A total of 20 experimental sorghum genotypes were evaluated during the 2021–2022 and 2022–2023 cropping seasons across five sites representing primary sorghum production areas in Zimbabwe. A randomised complete block design replicated thrice was used. Correlation and path analysis were performed. Results: Correlation analysis showed significant (p ≤ 0.05) and positive correlation between grain yield and days to 50% flowering (phenotypic correlation [rp] = 0.48; genotypic correlation [rg] = 0.53), days to 95% physiological maturity (rp = 0.59; rg = 0.31) and panicle length (rp = 0.61; rg = 0.57) over the two seasons at both phenotypic and genotypic level. The path analysis revealed that days to 50% flowering (Pp = 0.185; Pg = 0.280), days to 95% physiological maturity (phenotypic path coefficient [Pp] = 0.169; genotypic path coefficient [Pg] = 0.201) and panicle length (Pp = 0.354; Pg = 0.194), had significant (p ≤ 0.05) positive direct effects on sorghum grain yield at both phenotypic and genotypic level. Days to 50% flowering and panicle length had high heritability of 0.72 and 0.86, respectively. Conclusion: Breeders are recommended to select high sorghum grain yielding genotypes through days to 50% flowering and panicle length making effective indirect selection for sorghum grain improvement. Contribution: Identification and use of correlated traits for grain yield saves resources and increases breeding efficiency.

Knowledge on the fuel consumption of agricultural tractors helps in the management and planning of farm operations. Fuel consumption data are also important in calculating the cost of using machinery to carry out operations and to estimate the contribution of agricultural machinery to greenhouse gas emissions. Various factors, including operating speed, soil type and tractor load affect the fuel consumption rate. Promotion of two‐wheel tractors (2WTs) as an appropriate power‐source for smallholder farmers has been on the rise in Zimbabwe. However, the fuel consumption performance of these tractors for some operations has not been established. Our study focused on evaluating the fuel consumption performance of a 2WT–based direct seeding system for sorghum and pearl millet crops in clayey and sandy soils at varying speeds of operation. Results showed that crop type, soil type and speed of operation affect fuel consumption rate. Increasing the operating speed resulted in a decrease in fuel consumption rate. For the same soil type, the fuel consumption rates for pearl millet seeding were higher than those of planting sorghum. At the recommended planting speeds, the fuel consumption rates when planting sorghum were 6.42 L/ha and 7.34 L/ha for clayey and sandy soils, respectively. For pearl millet planting, the fuel consumption rates were 10.93 L/ha and 11.90 L/ha for clayey and sandy soils, respectively. This information on fuel consumption rate can be used by farmers and other operators of 2WTs for planning the fuel quantity and budgetary requirements.

Climate change and variability is affecting the production of maize, a staple food in Zimbabwe, leading to the advocacy for production of traditional grains (sorghum, pearl millet and finger millet) as complementary crops for food and nutrition security; mainly because of their drought tolerance. Adoption of traditional grains as a climate change adaptation strategy is, however, limited by lack of appropriate field mechanisation technologies, inter alia. The specific objective of this review was to examine the field mechanisation technologies being used in different farming systems across the globe for their appropriateness in smallholder traditional grain production systems in developing countries, using Zimbabwe as an example, and focusing on the prevailing technical, socio-economic and environmental factors which influence sustainable adoption. The review was conducted by searching ScienceDirect, Researchgate, JSTOR, Springer, AGORA and Google Scholar databases for mechanisation strategies, policies, machinery and equipment used in cereal production systems across the globe. The review revealed that the mechanisation of traditional grain production operations is lagging behind that of other cereals and that there is need to work on developing appropriate mechanisation systems for smallholder farmers in developing countries. Various farm power options were analysed and the use of two-wheel tractors under service-provision was identified as the most suitable option. Conservation agriculture-based direct seeders and use of mowers or bio-pesticides are the best-suited technologies for crop establishment and weed control, respectively. In terms of harvesting, no available equipment can be recommended for smallholder use as yet. Further research is required to optimize the practical application of mowers and bio-pesticides as well as develop scale-based direct seeders and harvesting equipment. Policy issues were identified and recommendations for improvement made. The findings of the current study can be adapted by other sub-Sahara Africa countries where farming systems, priorities and challenges are similar to that of Zimbabwe.

Traditional cereal crops are important for food and nutrition security in rural communities of southern Africa, but their productivity is often constrained by low soil water largely linked to low seasonal rainfall and long intra-seasonal dry spells. Planting basins (PB), tied ridges (TR), and conventional ploughing (CP) were evaluated, over two cropping seasons (2020/2021 and 2021/2022), for their effects on sorghum [Sorghum bicolor (L.), Moench], pearl millet [Pennisetum glaucum (L.) R.Br.], and finger millet [Eleusine coracana (L.) Gaertn] productivity on degraded (<0.4% soil organic carbon) and productive (>0.6% soil organic carbon) fields under rainfed conditions in Mbire (<450 mm rainfall year−1) and Mutasa (>800 mm rainfall year−1) districts in Zimbabwe. Field trials were established on degraded and productive field sites in each district, with sorghum, pearl millet, and finger millet either sown as monocrops or intercropped with cowpea. The experiments were laid out in a 2 × 3 × 3 factorial in a randomized complete block design (RCBD). The highest sorghum grain yield response of 2100 kg ha−1 was attained under PB on productive soils. Overall, PB and TR increased sorghum, finger millet, and pearl millet grain yields by 43% to 58% compared with CP. Growing sorghum, finger millet, and pearl millet on productive soils increased grain yields by 64%, 33%, and 43%, respectively, compared with degraded soils. Intercropping sorghum, pearl millet, and finger millet with cowpea increased cereal yields by between 23% and 42% over the sole crops. Rainwater use efficiency averaged 1 kg grain mm−1 on productive fields and 0.4 kg grain mm−1 on degraded fields. PB produced the highest net profit of $US408 on a productive field. Overall, production of sorghum and millets on productive soils gave positive economic returns irrespective of rainwater management option and cropping system. Conversely, 63% of the treatments on degraded soils recorded negative economic returns in both districts. We conclude that in-field rainwater management technologies combined with other agronomic practices like intercropping increase the productivity of sorghum and millets under rainfed conditions. However, degraded soils remain a challenge for the increased productivity of traditional cereal crops.

Characterising groundwater recharge is fundamental for sustainable groundwater management. This study focuses on assessing recharge in drylands using four experimental plots under different land-use practices in crystalline basement aquifers in three southern African countries (Chitedze in Malawi, Kabeleka and Liempe in Zambia, and Domboshawa in Zimbabwe). Several methods, including water-table fluctuation (WTF), chloride mass balance (CMB), water stable isotopes (δ18O and δ2H) and dissolved gases, were used to quantify annual recharge rates, recharge sources and groundwater residence times. This informed the development of a conceptual model of groundwater recharge in unpumped basement aquifers. Using WTF, across all sites/years, the range of annual median recharge was found to be in the range of 2.8–14.1

Sorghum and pearl millet contain anti-nutritional factors such as tannins and phytic acid, which limits their use in processed food products. Pre-treatment processes of these traditional grains such as dehulling, roasting, and fermentation, have potential to reduce the anti-nutritional factors. However, there is death in data on their efficacy. Therefore, this study aimed to evaluate the effect of dehulling, fermenting and roasting on the proximate, micronutrient and anti-nutritional content of sorghum and pearl millet flour from Zimbabwe. The grains were roasted, dehulled, fermented, and milled into flour. Four treatments namely, (1) unprocessed sorghum (control 1), (2) processed sorghum, (3) unprocessed pearl millet (control 2) and (4) processed pearl millet were prepared. The treatment samples were evaluated for proximate and mineral content using standard methods of analysis (AOAC, 2000) and inductively coupled plasma atomic emission spectrophotometry (ICP-OES) method, respectively. Phytates and tannins were measured using the UV Spectrophotometer method. The alkaloid content was determined gravimetrically. Data were analysed statistically using ANOVA at 95% probability. Sorghum processing i.e. dehulling, fermenting, roasting and milling significantly increased the protein content (from 15.0±0.08 to 20.0±3.98%) and ash content (from 3.6±0.05 to 4.2±0.52%) (p<0.05). No significant difference in fat content was observed between the processed and unprocessed sorghum and pearl millet (p>0.05). Similarly, the protein content of pearl millet significantly increased after processing (from 20.0 ±0.07 to 25±2.875) (p<0.05), while carbohydrate and ash content reduced significantly after processing (p<0.05). The processed pearl millet had significantly higher moisture content than the unprocessed (p<0.05). No significant difference in the calcium, iron and sodium content was recorded between the processed and unprocessed sorghum (p>0.05). The magnesium content decreased significantly after processing sorghum (p<0.05). However, potassium and zinc content increased significantly after processing (p<0.05). Processing pearl millet significantly increased in the calcium, potassium and zinc content (p<0.001). No significant difference in the iron content was observed between the two treatments (p>0.05). The magnesium and sodium content decreased significantly after processing (p<0.001). Processing pearl millet and sorghum significantly reduced the phytic acid content and tannin levels (p<0.05). The alkaloid content of the processed sorghum decreased significantly, while no significant difference in alkaloid content was recorded between processed and unprocessed pearl millet (p>0.05). Processing of sorghum and pearl millet is recommended since it improves the nutritional composition and lowers anti-nutritional factors.

Africa’s potential for scientific research is not yet being realized, for various reasons including a lack of researchers in many fields and insufficient funding. Strengthened research capacity through doctoral training programmes in higher education institutes (HEIs) in Africa, to include collaboration with national, regional and international research institutions, can facilitate self-reliant and sustainable research to support socio-economic development. In 2012, the Royal Society and the UK’s Department for International Development (now the Foreign, Commonwealth and Development Office) launched the Africa Capacity Building Initiative (ACBI) Doctoral Training Network which aimed to strengthen research capacity and training across sub-Saharan Africa. The ACBI supported 30 core PhD scholarships, all registered/supervised within African HEIs with advisory support from the UK-based institutes. Our ‘Soil geochemistry to inform agriculture and health policies’ consortium project, which was part of the ACBI doctoral training programme network, was implemented in Malawi, Zambia and Zimbabwe between 2014 and 2020. The aims of our consortium were to explore linkages between soil geochemistry, agriculture and public health for increased crop productivity, nutrition and safety of food systems and support wider training and research activities in soil science. Highlights from our consortium included: (i) the generation of new scientific evidence on linkages between soils, crops and human nutrition; (ii) securing new projects to translate science into policy and practice; and (iii) maintaining sustainable collaborative learning across the consortium. Our consortium delivered high-quality science outputs and secured new research and doctoral training funding from a variety of sources to ensure the continuation of research and training activities. For example, follow-on Global Challenges Research Funded Translation Award provided a strong evidence base on the prevalence of deficiencies in children under 5 years of age and women of reproductive age in Zimbabwe. This new evidence will contribute towards the design and implementation of a nationally representative micronutrient survey as an integral part of the Zimbabwe Demographic and Health Surveys conducted by the Ministry of Health and Child Care. The award also generated new evidence and a road map for creating quality innovative doctorates through a doctoral training landscape activity led by the Zimbabwe Council for Higher Education. Although our project and the wider ACBI has contributed to increasing the self-reliance and sustainability of research within the region, many challenges remain and ongoing investment is required.

Pasta is one of the most consumed staples worldwide. New formulations incorporating novel nutritious ingredients are now common in its production. The purpose of this study was to formulate, optimise and evaluate the sensory properties of sorghum-based extruded gluten-free pasta. Sorghum flour, pearl millet flour, high-iron bean flour (Biofortified NUA 45 beans) and Hermes potato flour were evaluated for proximate and micronutrient composition, formulated to produce pasta through the extrusion process. Three sorghum-based pastas, namely sorghum high bean pasta (SHBP), sorghum bean pasta (SBP) and sorghum high potato pasta (SHPP) were produced and evaluated for sensorial properties (visual, palpatory and gustatory qualities). The Box-Benhken Design (BBD) in conjunction with Response Surface Methodology (RSM) was used to select the best formulation by evaluating cooking quality parameters and sensory parameters. The protein content in the four flours ranged from 10.52% to 22.00%. NUA 45 bean flour had significantly (p<0.05) higher protein content than the other flours. Potato flour had significantly higher carbohydrate content (73.82%) than other flours. SHPP had a significantly (p<0.001) higher optimum cooking time (7 minutes) than SHBP (5 minutes) and SBP (6.2 minutes). SHPP had significantly (p<0.001) higher water absorption (WA) capacity (238%) than pasta SHBP (190%) and SBP (210%). A significant (p<0.001) difference in the swelling index (SI) of the three pasta samples was observed, with pasta SHBP having a significantly lower SI (1.02%) than pasta SBP (1.15%) and pasta SHPP (1.24%). The cooking loss (CL) for pasta SHPP (11%) was significantly higher (P<0.001) than for pastas SHBP and SBP, with pasta SHBP having the lowest CL. There was no significant (p>0.05) difference in the cross-sectional area, surface appearance and surface property of the three cooked pastas. A significant (p<0.05) difference in shape between SHBP and SBP samples was noted. The gluten-free pasta was developed and produced successfully. Sorghum high bean pasta treatment (SHBP) was found to be superior in terms of sensory, nutritional and physical properties as compared to the other pasta samples, making it good for commercialisation.

An in vitro study was conducted to assess the effects of phytase and tannase enzyme supplementation on nutrient digestibility and tannin degradability in sorghum-based broiler diets. A two-stage in vitro experiment involving simulation of gastric and ileal digestion in vivo was used. Data were analysed using Statistical Analysis System (SAS, 2011). The data were analysed for descriptive statistics and Chi-square tests were performed to check for possible associations among variables. Analysis of variance were performed to determine the effects of sorghum inclusion level as well as the effects of exogenous phytase and tannase supplementation on nutrients digestibility and tannin degradability using the GLM procedure. All tests were done at p<0.05 level of significance. The results of this study indicated that phytase and tannase supplementation significantly influenced calcium, phosphorus, fat and crude protein digestibility (p< 0.01). Sorghum inclusion level had no significant effect on calcium, phosphorus, fat and crude protein digestibility. Sorghum inclusion level significantly influenced tannin degradability (p<0.01). Chi-square test showed that there was an association between sorghum inclusion level and tannin hence increasing sorghum level increased tannin degradability. Both enzyme supplementation and sorghum inclusion level had significant effect on crude fibre and tannin degradability.

The effects of phytase and tannase enzyme treatment of sorghum-based broiler diets on ileal villi characteristics were evaluated in Cobb 500 broilers. A total of three sorghum levels, 0, 50, and 100%, with 4 enzyme levels; 0, 5% phytase, 5% tannase and 5% phytase+tannase combination were used to develop 12 different dietary treatments. Three hundred and sixty broilers were randomly allocated to the 12 dietary treatments in a completely randomized design experiment. On day 42, two birds from each replicate were randomly selected and slaughtered for ileal villi morphometry analyses. A 2cm tissue sample of the ileum was cut and prepared for histological analyses. Villus height and width, muscularis externa thickness, and crypt depth were measured on a light microscope using a calibrated eyepiece graticule. The total villi surface area was calculated, which indicates the digestive and absorptive capacity of the ileum. The General Linear Models (GLM) procedure of the Statistical Analysis System ver 9.4 (SAS Institute Inc., 2011) was used to analyse the data. All tests were performed at p < 0.05 significance. Villus height, width, and muscularis externa thickness significantly increased with increasing levels of sorghum in the diet (p<0.001). Birds fed complete sorghum diets supplemented with phytase enzyme had the longest villi (p<0.001). The 0% and 100% sorghum levels exhibited comparable crypt depth. Treatment significantly affected the apparent villi surface area (p<0.0001). The apparent villi surface area increased with increasing sorghum inclusion. Birds fed a complete sorghum diet supplemented with phytase had the highest villi surface area (15.48±0.241 mm). It can be concluded that phytase and tannase can be added to complete sorghum broiler diets without compromising ileal villi integrity. Hence, we recommend the addition of phytase and tannase in sorghum-based broiler diets to counteract the effects of sorghum antinutrients.

IntroductionSoil degradation coupled with poor access to organic nutrient resources remains a major constraint in increased crop productivity in sub-Saharan Africa, thus hindering the continent's efforts in achieving the United Nations' Sustainable Development Goals, particularly goals 1 (end poverty), 2 (zero hunger) and 3 (improve human health). Water treatment residual (WTR), a by-product of clean water treatment, has been identified as an alternative organic nutrient resource for crop production. However, there are some inconsistences in soil phosphorus (P) dynamics following aluminium WTR (Al-WTR) application.Materials & MethodsA laboratory experiment was conducted to evaluate the P sorption of a sandy soil amended with 10% Al-WTR, 10% compost (C) as a quasi-control, 10% C + 10% Al-WTR (10% coamendment) and 5% C + 5% Al-WTR (5% coamendment) under varying levels of pH, particle size and P concentration. We calculated crop P fertilizer requirements under different amendments.ResultsThe results demonstrated that all amendments exceeded the minimum of 0.2 mg P L-1 needed in soil solution at equilibrium to maintain plant growth. However, the maximum P sorption capacity was higher for 10% Al-WTR single amendment, ranging from 770 to 1000 mg P Kg-1, and from 714 to 1000 mg P Kg-1 and 555 to 909 mg P Kg-1 for 10% and 5% coamendments, respectively, across a range of pH and soil particle size fractions. The coamendments showed a reduction in crop P fertilizer requirements by ranges of 30-60% and 60-70% for the 10% and 5% coamendment levels, respectively, across different pH and particle sizes, relative to 10% Al-WTR.ConclusionResults show that the use of 5% coamendment in sandy soils increases P availability sufficiently to improve crop yields. The results provide scope for using Al-WTR coamendments to rebuild soil health in sandy soils in urban agriculture and increase macronutrient provision in crops to support human health.

Soil phosphorus (P) deficiency is a major challenge to food security in most parts of sub-Saharan Africa, including Zimbabwe, where farmers largely depend on local organic nutrient resources as fertilizer in the production of crops. Soil microorganisms can contribute to synchronous availability of soil P to plants through regulating immobilization and mineralization cycles of soil P pools but their activity may be influenced by antecedent soil P, P fertilizer application regimes and P uptake by plants. Using soils collected from plots where Crotalaria juncea (high quality), Calliandra calothyrsus (medium quality), cattle manure (variable quality), maize stover and Pinus patula sawdust (both low quality) were applied at the rate of 4 t C ha -1 with 16 kg P ha -1 at the start of every season over 16 seasons. A pot study was conducted to evaluate the influence of increasing inorganic P fertilizer rates (26 and 36 kg P ha -1 ) on soil microbial dynamics, soil P pools, and maize P uptake. Results indicated that nineteen (19) fungal and forty-two (42) bacterial colonies were identified over the study period. Fungi dominated bacteria on day one, with Aspergillus niger showing a 30–98% abundance that depends on organic resource quality. Overall, microbial diversity peaked activity characterized succession on day 29, which coincided with a significant (P<0.05) increase in P availability. Increasing P rate to 26 kg P ha -1 amplified the microbial diverse peak activity under medium-high quality resources while under the control the peak emerged earlier on day 15. Mucor and Bacillus had peak abundances on day 43 and 57, respectively, across treatments regardless of P rates. Treatment and P rate had a significant (P<0.01) effect on microbial P. Bacteria were more responsive to added P than fungi. Increasing P to 36 kg P ha -1 also stimulated an earlier microbial diverse peak activity under maize stover on day 15. Addition of P alone, without supplying complementary nutrients such as N, did not have a positive effect on maize P uptake. Farmers need to co-apply medium-high quality organic resources with high fertilizer P rates to increase microbial diversity, plant available P and maize growth on sandy soils (Lixisols). Our results suggest that there is a need to reconsider existing P fertilizer recommendations, currently pegged at between 26 and 30 kg P ha -1 , for maize production on sandy soils as well as develop new fertilizer formulations to intensify crop production in Zimbabwe.

Finger millet (Eleucine coracana), cowpea (Vigna unguiculata), and bio-fortified vitamin A “orange” maize (Zea mays) are three nutrient dense crops currently being promoted in Zimbabwe. The effect on nutrient content of processing these specific crop varieties has not been investigated. Therefore, this study was designed to determine the effects of germination and roasting on the proximate, mineral, and anti-nutritional factors in finger millet, cowpeas and orange maize. Finger millet grains were germinated for 48hrs, cowpeas and orange maize for 24hrs, at room temperature (20-23oC). Both raw and processed samples were dried and milled into flour for the determination of proximate and mineral and anti-nutritional composition. Protein content of finger millet increased significantly after processing from 6.53±0.25 mg/100 g to 11.27±0.15 mg/100 g in germinated finger millet flour (P<0.05). Germination of finger millet resulted in significantly increased minerals (mg/100 g); calcium from 345.53±0.55 to 352.63±0.21, zinc from 3.59±0.15 to 8.71±0.01, sodium from 49.89±0.16 to 57.78±1.20 and iron content from 3.75±0.05 to 4.52±0.01 whilst magnesium and potassium decreased significantly from 198.09±0.07 to 69.08±0.06 and 487.08±0.03 to 144.78±0.27 respectively. Processing of cowpeas resulted in slight but significant increase in protein content (20.47±0.21 to 28.50±0.10), increased calcium (138.18±0.12 to 148.18±0.12 mg/100 g), magnesium (14.23±2.00 to 19.18±0.31 mg/100 g), potassium (232±4.00 to 443.41±0.02 mg/100 g) and iron (4.85±0.03 to 4.86±0.04 mg/100 g). Conversely zinc and sodium decreased from 4.5±0.30 to 2.9±0.10 mg/100 g and 31.85±0.03 to 11.64±0.02 mg/100 g, respectively. Notably for orange maize, protein content did not change from 10.06±0.04 to 10.04±0.04 g/100 g before and after processing. Calcium increased from 47.02±2.82 to 57.99±8.85 (mg/100 g), magnesium from 90.91±0.11 to 108.30±0.53 (mg/100 g), potassium from 2.13±0.04 to 4.33±0.25 (mg/100 g), sodium from 0.50±0.02 to 0.70±0.02 (mg/100 g) and iron from 0.50±0.02 to 1.25±0.05 (mg/100 g). Zinc decreased from 6.2±0.2 to 3.53±0.55 (mg/100 g). Tannins, oxalates and phytates decreased significantly after processing of all three crops. Results showed that germination and roasting increased the nutritional profile and decreased anti-nutrient content in finger millet, cowpeas and orange maize. Therefore, it is important to consider germinating and roasting these grains during processing to increase the nutritional potential of the end food product. Further studies are required to investigate the decrease in some nutrients after germination and roasting and possibly establish optimum processing parameters for improved nutrient profile of these food crops. Key words: Traditional grains, millet, orange maize, biofortification, germination, roasting, nutrients, anti-nutrients