Search

This study documented use of wild food and medicinal plants in areas around five biodiversity hot spots in Zimbabwe. Data was collected using semi-structured interviews and focus group discussions in representative communities. About 89 wild food plants were used by the communities. Trees, shrubs, tubers/herbs, lianas/climbers and succulents constituted 65%, 11%, 12%, 8% and 4% respectively. Fruits were mostly harvested (52%) then leaves (28%), and others (roots/rhizomes/tubers, sap and fibres) (20%). Fruits were commonly consumed raw (96%) whilst others are processed into juices (4%), mostly collected by women and children. Fruits of Adansonia digitata L., Vangueria infausta Burch., Uapacca kirkiana Mull. Arg., Berchemia discolour/zeyheri (Klotzsch) Hemsl., Vitex doniana Sweet and leaves of A. digitata were most preferred plant species because of their taste and availability. However, some fruits such as Vitex spp. and U. kirkiana caused constipation and diahorrea respectively if consumed in excess. About 149 medicinal plant species belonging to 115 genera and 61 families were used for treating about 32 diseases and disorders. These were dominated by families; Fabaceae(16%), Meliaceae(5%), Apocenaceae(3%), Anacadaceae(3%) and Solanaceae (4%). About 45, 30, 25, 23, 13 species treat abdominal pains, toothache, women and gynaecological issues, sexually transmitted diseases and paediatric remedies respectively. Other species are used as aphrodisiacs (4) and treatment of cancer (4). Leaves (28%), roots(27%) bark(24%) and fruits(12%) were main parts used to prepare remedies. Cultural/Traditional knowledge plays an important role in valuing species in particular areas and associated conservation of food and medicinal plants.

We determined fall armyworm abundance, infestation and damage on maize in smallholder farmers’ fields in the Zambezi Valley in northern Zimbabwe. Data were collected through field measureme...

Although the ecosystem engineering role of termites has long been recognized, understanding the distribution and properties of their nests that affect ecosystem heterogeneity continues to be a priority. Studies have investigated soil properties like clay and organic matter (OM) composition of mounds belonging to fungus growing termites, however, little is known for southern African savanna soil feeding termites. Indeed, studies on the spatial distribution of termite mounds in savannas have been carried out with a focus mainly on the genus Macrotermes in savanna woodlands, leaving us with little information on other species that often occur on grasslands, for example soil feeding Cubitermes. Therefore, in this study we aimed to understand the effect of rainfall on Cubitermes breviceps mounds structure, soil properties and spatial point patterning at three sites. At each site two 25 m × 25 m plots were marked for spatial analysis. Mound height and basal diameter were recorded. Two soil properties (clay and OM) from mound and savanna matrix soil were investigated. A decreasing trend in mound height and diameter was observed from the more arid to the wettest site. Mound height was positively influenced by the amount of both clay and OM. However, both clay and OM had a negative relationship with numerical density of mounds, and we suggest other factors such as grass cover and the prevailing conditions such as moisture and competition at early colony establishment also influence mound density. Cubitermes breviceps mounds were generally completely spatially random across sites, except for Ripley’s L summary function that showed clustering, which we attribute to its cumulative nature. In conclusion, soil feeding C. breviceps incorporate more OM in their mounds and do not show competition between colonies probably due to them not feeding on limited food resources in the savanna such as grass and wood.

Flood–recession cropping improves smallholder farmers' household food security. The objective of this study was to determine the fertility status of cultivated Zambezi Valley floodplain soils, in northern Zimbabwe. The study was conducted at three sites, along tributaries of Musengezi River. Soil samples were taken at 0.20 m depth increments to 0.60 m from hydromorphologically stratified fields, during the cropping season. Sampling points were replicated twice in each stratum at points equidistant from river edges. Relative elevations of sampling points were measured using levelling equipment. Soil was analysed using: core method for bulk density, hydrometer method for texture, loss on ignition for soil organic carbon (SOC), Kjeldahl procedure for total nitrogen (N), 0.01 M CaCl 2 for pH, and Inductively Coupled Plasma (ICP) for Mehlich 3 extractable elements. Data from soil analyses were subjected to One Way Analysis of Variance and Pearson's correlation analysis. Bulk density ranged from 1.2 to 1.4 g cm −3 and it was negatively related to distance from river; and positively related to elevation at two sites. Highest values for SOC and total N were 2.04% and 0.36% respectively. Soil pH ranged from 7.70 to 8.60. Soil organic carbon and N were positively related to distance from river but negatively related to elevation. Threshold concentrations for deficiency

Revegetation accelerates soil fertility improvement and enhances biodiversity on mine dumps. The objective of the study was to determine the status of edaphic conditions; aboveground carbon stocks; and plant diversity. The study was conducted on nickel tailings dump revegetated with Senegalia polyacantha aged 8, 9, 10 and 11 years in Zimbabwe. Results showed high bulk densities and pH values; low organic carbon; deficiency in K; and toxic levels for Ni and As implying that the tailings materials are still marginal for vegetation establishment. Limited presence of woody species suggests that the substrate is not yet suitable for colonization by such species. Copyright © 2017 John Wiley & Sons, Ltd.

Forest plantations composed of pines, eucalypts and wattle are threatened by wildfires that are responsible for an average annual loss of 700 ha. Communities neighbouring forest plantations and illegal settlers (estimated at >3000) occupying some areas within plantations are the major sources of wildfires that enter into plantations. Strategies to tackle fire problems in plantations should focus on (1) improving law enforcement to deter illegal starting of fires; (2) address illegal settlement; (3) explore possibilities of community shareholding and out-grower schemes and, (4) institute and increase fire awareness campaigns.

The miombo ecoregion is one of the five global wilderness areas with high levels of endemicity and is habitat to several species, spanning over seven countries in central and southern Africa. This ecoregion is threatened by tobacco production that accounts for 15% of deforestation in Zimbabwe and 26% in Malawi. For every kg of tobacco, as much as 31 kg of firewood is used for curing. If left unabated, tobacco production will significantly contribute to the disappearance of the miombo woodlands. This therefore calls for governments in the ecoregion to come up with interventions that help conserve these forests.

Food security in Sub-Saharan Africa, particularly in semi-arid tropics (41% of the region; 6 months of dry season) is threatened by droughts, dry spells and infertile soils. In Zimbabwe, 74% of smallholder farming areas are located in semi-arid areas mostly in areas with soils of low fertility and water holding capacity. The dominant crop in these areas, maize (Zea mays L.), is susceptible to drought. Under smallholder farming in Zimbabwe, conventional tillage entails cutting and turning the soil with a mouldboard plough thereby burying weeds and crop residues. Seed is planted by hand into a furrow made by the plough, ensuring that crops germinate in relatively weed free seedbeds. Inter-row weed control is performed using the plough or ox-drawn cultivators and hand hoes. Conventional tillage has been criticised for failure to alleviate negative effects of long dry spells on crops and to combat soil loss caused by water erosion estimated at 50 to 80 t ha-1 yr-1. Therefore, conservation tillage has been explored for improving soil and water conservation and crop yields. Our objective was to determine the maize yield advantage of the introduced technology (conservation tillage) over conventional tillage (farmers’ practice) based on a review of experiments in semi-arid Zimbabwe. We use a broad definition of conservation tillage instead of the common definition of =30% cover after planting. Eight tillage experiments conducted between 1984 and 2008 were evaluated. Conventional tillage included ploughing using the mouldboard plough and digging using a hand hoe. Conservation tillage included tied ridging (furrow diking), mulch ripping, clean ripping and planting pits. Field-edge methods included bench terraces (fanya juus) and infiltration pits. Results showed small yield advantages of conservation tillage methods below 500 mm rainfall. For grain yields =2.5 t ha-1 and rainfall =500 mm, 1.0 m tied ridging produced 144 kg ha-1 and mulch ripping 344 kg ha-1 more than conventional tillage. Above 2.5 t ha-1 and for rainfall >500 mm, conventional tillage had =640 kg ha-1 yield advantage. Planting pits had similar performance to ripping and conventional tillage but faced digging labour constraints. Experiments and modelling are required to test conservation tillage seasonal rainfall thresholds. Constraints to adoption of conservation tillage by smallholder farmers necessitate best agronomic practices under conventional tillage while work on adoption of alternative tillage methods continues.

Southern Africa rainfall station network is suffering from an unfortunate serious decline while climate-related food insecurity is worsening. In the current work, we demonstrate the possibility of exploiting the complementary roles that remote sensing, modeling, and geospatial data analysis can play in forecasting maize yield using data for the growing seasons from 1996/1997 to 2003/2004. Satellite-derived point-specific rainfall estimates were input into a crop water balance model to calculate the Water Requirement Satisfaction Index (WRSI). When these WRSI values were regressed with historical yield data, the results showed that relatively high skill yield forecasts can be made even when the crops are at their early stages of growth and in areas with sparse or without any ground rainfall measurements. Inferences about the yield at national level and small-scale commercial farming sector (SSCF) sector can be made at confidence levels above 99% from the second dekad of February. However, the most unstable models are those for the communal farming sectors whose inferences for yield forecast can only be made above the 95% confidence level from the end of February, after having recovered from a state of complete breakdown two dekads earlier. The large-scale commercial farming (LSCF) sector has generally the weakest fitting, but it is usable from the first dekad of February to the end of the rainy season. Validation of the national yield models using independent data set shows that an early estimation of maize yield is quite feasible by the use of the WRSI.

Maize ( Zea mays L.), the dominant and staple food crop in Southern and Eastern Africa, is preferred to the drought-tolerant sorghum and pearl millet even in semi-arid areas. In semi-arid areas production of maize is constrained by droughts and poor rainfall distribution. The best way to grow crops in these areas is through irrigation, but limited areal extent, increasing water scarcity, and prohibitive development costs limit the feasibility of irrigation. Therefore, there is need for a policy shift towards other viable options. This paper presents daily rainfall analysis from Rushinga district, a semi-arid location in Northern Zimbabwe. The purpose of the rainfall analysis was to assess opportunities and limitations for rainfed maize production using 25 years of data. Data was analysed using a variety of statistical methods that include trend analysis, t -test for independent samples, rank-based frequency analysis, Spearman's correlation coefficient and Mann–Whitney's U test. The results showed no evidence of change in rainfall pattern. The mean seasonal rainfall was 631 mm with a standard deviation (SD) of 175 mm. December, January and February consistently remained the major rainfall months. The results depicted high inter-annual variability for both annual and seasonal rainfall totals, a high incidence of droughts ≥3 out of every 10 years and ≥1 wet year in 10 years. Using the planting criteria recommended in Zimbabwe, most of the plantings would occur from the third decade of November with the mode being the first decade of December. This predisposes the rainfall to high evaporation and runoff losses especially in December when the crop is still in its initial stage of growth. On average 5 to more than 20 days dry spells occupy 56% of the rainy season. Seasonal rainfall exhibited negative correlation ( P R = −0.746) with cumulative dry spell length, and wet years were free from dry spells exceeding 20 days. The most common dry spells (6–10 days), are in the range in which irrigated crops survive on available soil water. Therefore, they can be mitigated by in situ rainwater harvesting (RWH) and water conservation. The potential evapotranspiration of a 140-day maize crop was estimated to be 540 mm. Consequently, short season maize cultivars that mature in less than 140 days could be grown successfully in this area in all but drought years. However, sustainable maize production can only be achieved with careful management of the soil as a medium for storing water, which is essential for buffering against dry spells. To this end soil restorative farming systems are recommended such as conservation farming, in situ RWH techniques for dry spell mitigation and a cropping system that includes drought-tolerant cereal crops as for example sorghum and pearl millet, and perennial carbohydrate sources as for example cassava to provide stable crop yields.

An estimated 25% of the adults in urban areas of Zimbabwe are living as HIV-positive. In HIV-affected households the need for income increases with the demand for medicines, food and funeral costs. One way to mitigate this effect of the epidemic is by expanding micro enterprises that can enhance the livelihoods of urban households affected by HIV. To identify viable income-generating projects for such households, five possible projects facilitated by two HIV/AIDS support organisations were selected for assessment. These were: selling second-hand clothing, poultry-keeping and nutritional/herbal gardens, freezit-making, mobile kitchens, and payphone set-ups. A case study of 200 households benefiting from one of these projects was done in two high-density suburbs in the town of Bindura, northern Zimbabwe. Information was collected from each household four times per year, over four years (2001–2004). Information on the income generated from the micro enterprises was collected monthly during the period. Descriptive statistics were used to analyse household demographic data; income data was analysed using cost-benefit analysis and analysis of variance. The results show that all five income-generating projects were viable for these households, although some were not feasible for the most vulnerable HIV-affected households. Making more efficient use of micro enterprises can be a valuable part of mainstreaming HIV-affected people and households in urban areas, and so allow people living with HIV to have longer and more meaningful lives. Keywords: Africa, feasibility, micro finance, poverty, small-scale enterprises, urban, viabilityAfrican Journal of AIDS Research 2007, 6(1): 9–15

Under low and poorly distributed rainfall higher food production can be achieved by increasing crop water use efficiency (WUE) through optimum soil fertility management and selection of deep-rooting cultivars, appropriate plant density and planting dates. We explored AquaCrop's applicability in selecting adaptive practices for improving maize yield and WUE under rainfed smallholder farming in semi-arid Zimbabwe. AquaCrop was first tested using field measurements without calibration. The model was subsequently applied to estimate the effect of effective rooting depth (ERD), plant density and planting date on maize yield. Simulations were done with daily rainfall data for 25 seasons. During model testing AquaCrop simulated canopy cover development well and simulated biomass accumulation showed good agreement with measured values. The model overestimated soil water, and observed final biomass and grain yield were 96 and 92% of simulated values, respectively. Model application showed that increasing ERD from 0.40 m at 32,500 plants ha−1 to 0.60 m at 44,400 plants ha−1 increased grain yield from 6.0 to 7.8 t ha−1, biomass water use efficiency by 20.5%, grain water use efficiency by 23.6% and transpiration water use efficiency by 26.8%. At 0.60 and 0.80 m ERD and 44,400 plants ha−1, biomass and grain yield, and WUE, were similar. Drainage below the rootzone was ≥40% of non-productive water losses in normal and wet seasons whilst soil evaporation contributed 47% in dry seasons at 0.80 m ERD. To improve yield and WUE, we recommend: incorporation of deep-rooting legumes, deeper-rooting cultivars (≥0.60 m effective rooting depth) and practices that improve ERD, a plant density of 44,400 plants ha−1; and practices that reduce soil evaporation e.g. mulching and addition of organic fertilisers to improve soils’ available water capacity and enhance response to mineral fertilisers. Further research should include field testing of results from this study with farmers.

Realising that rainwater harvesting (RWH) improves crop productivity, smallholder farmers in semi-arid Zimbabwe modified contour ridges traditionally used for rainwater management by digging infiltration pits inside contour ridge channels in order to retain more water in crop fields. However, scientific studies on crop yield benefits of infiltration pits have not been conclusive. Combining field-edge RWH methods such as contour ridges with infiltration pits with in-field practices may enhance crop yield benefits. Thus, the objective of the study was to assess soil moisture and maize yield improvement of combining infiltration and planting pits. Field experiments were conducted in Rushinga, Zimbabwe for three seasons at three sites using a split-plot design: main-plot factor, field-edge rainwater management method (RWMM); and split-plot factor, tillage method. Soil moisture content was measured weekly using gravimetric and Time Domain Reflectometry (TDR) methods. A household and field survey to establish farmers’ perceptions, typology and availability of field-edge RWMM was conducted. In order to share experiences and enhance stakeholders’ learning, field days were held. Lateral movement of soil water was measured up to 2 m downslope from infiltration pits, hence infiltration pits did not improve maize yield and soil moisture content in the cropping area. Maize yield (kg ha−1) was 45% higher under conventional tillage (2697) than planting pits (1852) but the yield gap decreased from 90 to 30% in the first and third year respectively. The value of infiltration pits is in reducing soil erosion by water and growing high value horticultural crops inside and close to pits, a view shared by host farmers and other stakeholders. Planting pits are an option for farmers without access to draught power and a fall-back method. Research is required to determine soil moisture, maize yield benefits and waterlogging risk in fields with underlying impermeable layers that enhance lateral flow of water.

In order to reduce the negative effects of conventional tillage there is need to develop or adopt alternative tillage systems. A comparative study on the effects of three tillage methods on the yield performance of a maize cultivar SC633 was conducted in Musiiwa ward of Musana Communal Area, Mashonaland Central Province in Zimbabwe. The experiment was conducted on existing farmers’ fields. A randomized complete block design with three treatments (direct seeding, ripping and conventional mouldboard ploughing) replicated four times was used. The data were subjected to analysis of variance using SPSS for Windows, Version 15.0 (2006). Results showed that there was no significant difference (P>0.05) in maize grain yield mouldboard ploughing and ripping. Mouldboard ploughing out-yielded (P 0.05). It was concluded that ripping can perform perfectly well just like the conventional mouldboard ploughing. In view of the comparative advantages of conservation tillage in terms of carbon sequestration and the subsequent soil quality improvement, mitigation of greenhouse gas emissions, and reduced soil erosion, adoption of conservation tillage is recommended. Key words: Tillage, maize, communal area, conservation farming, grain yield.

The objective of the study was to compare the performance of exotic ( Eucalyptus grandis and Acacia saligna ) and indigenous ( Acacia polyacantha and Bauhinia thonningii ) tree species in rehabilitating active gold mine tailings dump. The seedlings were produced in a nursery and transplanted onto the tailings dumps during the rainy season in the years 2000, 2001 and 2002. The saplings were monitored for survival rates one year after transplanting and growth performances by measuring root collar diameters and heights. There was no significant difference among the species in survival. The mean height increment of the exotics significantly surpassed indigenous tree species. E. grandis performed best followed by A. saligna. Bauhinia thoningii showed the lowest height increment. Root collar diameters were highest for A. polyacantha , followed by the exotics. There was no significant difference for the mean root collar diameter and height between the exotics. It was concluded that both exotic and indigenous tree species could be used for the rehabilitation of mine tailings. Journal of Applied Sciences and Environmental Management Vol 9(2) 2005: 57-59