Labor requirements and profitability of alternative soil fertility replenishment technologies in Zambia

Low soil fertility is a major concern in agricultural productivity and development policy discourse in sub-saharan Africa. The problem is exacerbated by government withdrawal from fertilizer input markets and the inability of private sector operators to fill the gap. This warranted a search for other nutrient sources to supplement chemical fertilizers. Based on field data collected in Zambia, this study assessed the labor inputs implications of “improved tree fallows”, continuous maize cropping with and without mineral fertilizer and, evaluated the financial profitability of the different land use systems. Results show that agroforestry-based land use systems are more profitable (NPV between $233 and$309 per ha) than farmers’ practice of continuous maize production without external fertilization ($130/ha) but, they are less profitable than mineral fertilizer ($499). When the effects of the 50% government subsidy on fertilizers are taken into account, the differences in the profitability of fertilizers over improved tree fallows falls from 61% to 13%. The returns per person labor-day is $3.20 for fertilizer and$2.50, $2.40, and$1.90 respectively, for the three agroforestry options evaluated and only $1.10 for unfertilized maize. These returns compare with a daily agricultural wage of$0.50 in the study area. Key determinants of financial attractiveness and by extension, potential adoptability of the land use systems were identified. Given the low rate (20%) of farmers in Zambia who have access to fertilizers, there is a large niche to integrate other soil nutrient replenishing options with fertilizer to improve food security and reduce poverty among resource-poor smallholder farmers in Africa.Agroforestry, improved tree fallows, financial analysis, Production economics, Southern Africa, Sustainable agriculture, Agricultural and Food Policy, Community/Rural/Urban Development, Consumer/Household Economics, Environmental Economics and Policy, Farm Management, Food Consumption/Nutrition/Food Safety, Food Security and Poverty, Land Economics/Use, Production Economics, Research and Development/Tech Change/Emerging Technologies,

The Role of Food from Natural Resources in Reducing Vulnerability to Poverty: A Case Study from Zimbabwe

Vulnerability to poverty is a major problem in the rural areas of Sub Saharan Africa. Rural Households are confronted with various covariate and idiosyncratic shocks and are often severely constrained in coping with such events. They frequently resort to food from natural resources such as indigenous fruits during times of crisis. The availability of such food sources is increasingly at risk due to deforestation and biodiversity loss. The objective of this paper is to quantify the contribution of indigenous fruit trees towards reducing vulnerability to food insecurity and poverty. The methodology used is a multi-period stochastic household income model. The data were collected in a case study in Zimbabwe using detailed monthly income and expenditure records of a sample of 39 rural households in two areas. The two regions differ in their agricultural system. In one area horticulture, off-farm activities and exotic fruits are a major source of income while in the other area indigenous fruits are a more important source of income. This paper concentrates on the latter area. Model calculations show that rural households in Zimbabwe are highly vulnerable to seasonal fluctuations in income and therefore a critical period where households run high risk of being food insecure can be identified. While indigenous fruits, as a low cost 1 International Centre of Insect Physiology and Ecology (ICIPE), Nairobi, Kenya, [email protected] (for merly 2 & 3). 2 Development and Agricultural Economics, Faculty of Econo mics and Business Administration, Hannover University, Germany. 3 World Agrofore stry Centre (ICRAF), Lilongwe, Malawi. natural resource, can facilitate income-smoothing, the role of other sources of income must not be neglected. The paper concludes that diversified season-specific income generating portfolios must be designed of which indigenous fruit trees have a role to play.Vulnerability, poverty, food security, seasonal fluctuations, wild food resources, Zimbabwe, Food Security and Poverty,

Can integration of legume trees increase yield stability in rain-fed maize cropping systems in Southern Africa?

Growing maize (Zea mays) in association with legume tree in agroforestry arrangements has been shown to increase yields in many parts of sub-Saharan Africa (SSA). However, the stability of crop yields has not been critically analyzed in the various cropping systems that integrate leguminous trees. The objective of this analysis was to compare yield stability in improved cropping systems, namely maize-Gliricidia (Gliricidia sepium) intercropping and fertilized monoculture maize, with the de facto practice of resource-poor farmers who grow maize continuously without any external input. Yield stability was determined for three long-term field trials (12-13 consecutive years) conducted at Makoka Research Station in southern Malawi and Msekera Research Station in eastern Zambia. At Makoka, the most stable yield was recorded in maize-Gliricidia intercrops. Average yield was highest in maize-Gliricidia intercropping amended with 50% of the recommended N and P fertilizer, and this was comparable with yield recorded in monoculture maize that received inorganic fertilizer. On the two sites at Msekera, the highest yield was recorded in fertilized monoculture maize followed by maize-Gliricidia intercrops. However, yields were more stable in maize- Gliricidia intercropping compared to fertilized maize on both sites at Msekera. It is concluded that maize yields remain more stable in maize-Gliricidia intercropping than in fertilized maize monoculture in the longterm although average yields may be higher with full fertilization.The government of Ireland through the Irish Aid and Irish Embassy in Malawi to the World Agroforestry Centre.https://www.agronomy.org/publications/a

Phenotypic variation in fruit and seed morphology of Adansonia digitata L (Baobab) in five selected wild populations in Malawi

Adansonia digitata L (Baobab) is widely distributed throughout Sub-Saharan Africa stretching from Senegal to Sudan, and from Ethiopia to Natal. Information of phenotypic and genetic variation is a prerequisite for the domestication and improvement of baobab fruits from the wild. A study was done to determine within and between provenance variability in fruit and seed characteristics of five populations selected from four silvicultural zones and assess whether morphometric traits could delineate populations from different zones into land races. Fruits were characterized from 55 trees representing a wide geographical range. Six fruit traits and three individual seed traits were assessed. Results showed highly significant differences (P≤0.001) in fruit, pulp, and seed weight, fruit length and width, number of seed, individual seed weight, seed length and width within and between populations. Mean fruit weight ranged from 125.8 ± 3.25 g to 162.9 ± 3.25 g, seed weight ranged from 38.6 ± 2.5 g to 66 ± 2.01g and pulp weight ranged from 28.7 ± 1.33 g to 41.4 ± 1.33 g. Single seed weight showed pronounced evidence of divergence of populations into ecotypes. The rich diversity found between and within populations is important for domestication purposes and tree improvement through selection and breeding. All populations could be used for seed source but distribution should be consciously done recognizing existence of races.Universities of Mzuzu and Stellenbosch and University of Pretoria.http://www.springer.com/life+sci/forestry/journal/1045

Genetic variation among and within provenances of Adansonia digitata L. (Baobab) in seed germination and seedling growth from selected natural populations in Malawi

Baobab (Adansonia digitata L) trees have a wide variety of subsistence and economic values across sub-Saharan Africa. Knowledge of the genetic variation within and between the species is essential for management and designing domestication, improvement and conservation strategies. Fifty-nine half-sib families were evaluated in the nursery to determine the genetic variation and control within and between the populations from four silvicultural zones. Seed germination and seven seedling growth parameters were assessed. Total phenotypic variance, family variance, within family variance, individual narrow sense heritability, and additive genetic coefficient of variation (AGCV) were derived from observed and expected mean squares. There were highly significant differences in seed germination, plant height, root collar diameter, number of leaves, shoot height and diameter, tuber diameter and weight. Provenance variation in germination ranged from 46.7 ±3.3% to 68.7±3.3% while tree –to- tree variation ranged from 6.3±8.6% to 95.5±8.6%. Coefficient of variation in seedling growth variables ranged from 18.6% to 43.6%. Individual narrow sense heritabilities (h2) ranged from 0.07 to 0.71. AGCV ranged from 3.21% to 14.67%. Morphological traits showed that mainland populations were genetically distant from the island one. High and moderate additive genetic control of traits and AGCV show the potential that Baobab can also respond well to tree improvement. High phenotypic variation found in the study offers an opportunity to effect selection of superior attributes at both provenance and individual tree-to-tree level.Universities of Mzuzu and Stellenbosch.http://www.agronomy-journal.org/hb201

Genetic differentiation and diversity of Adansonia digitata L (baobab) in Malawi using microsatellite markers

Baobab (Adansonia digitata L) belonging to Bombacaceae family, is one of the most widely used indigenous priority tree species in sub-Saharan Africa, valued in the cosmetic industry for its seed oil, and powdery fruit pulp for juice making. Baobab has high potential for domestication in southern Africa, therefore understanding its genetic diversity and population structuring is warranted. The study investigated the level of genetic diversity and differentiation of five populations of A. digitata L. sampled from four diverse silvicultural zones in Malawi. Variation at nine microsatellite loci were examined in 150 individual trees. Low mean genetic diversity was expressed through genetic diversity indices: Nei’s genetic diversity (h, 0.18 ± 0.03), Shannon Information Index (I, 0.21 ± 0.07), observed number of alleles (na, 1.47 ± 0.10), effective number of alleles (na, 1.23 ± 0.04) and percentage polymorphic loci (pp, 48%). The low genetic variation found is attributed to the population growing in marginal areas of genetic centre of diversity of the species, anthropogenic factors and founder effects. Moderate genetic differentiation was observed among populations (Gst = 0.13) indicating the presence of a large number of common alleles resulting in a homogenisation effect. Clustering of individual trees by genetic similarity coefficients indicated that mainland trees were genetically closer than the trees on Likoma Island. Mantel’s test showed a weak positive insignificant correlation (Z = 0.12; P = 0.64) between genetic distance among populations and actual distance on the ground implying that geneflow was not directly influenced by isolation by distance. The results suggest that seed distribution and tree improvement should recognise the presence of ecotypes and conservation measures should protect all the populations due to existence of private alleles which are of adaptive importance.Mzuzu University and Stellenbosch University.http://www.springer.com/life+sci/forestry/journal/1045

Economic framework for integrating environmental stewardship into food security strategies in low-income countries: case of agroforestry in southern African region

One of the greatest challenges in many Sub-Saharan Africa countries especially where seasonal food deficits occur frequently, is how best to achieve a balance between the goals of food security and agricultural production on the one hand, and the concerns for the conservation of environmental quality and natural resources capital on the other. A number of agricultural production technologies (based on natural resource management principles) exist that offer opportunities for achieving the two seemingly divergent goals because they have the characteristics to produce joint multiple outputs, i.e, they produce food and provide environmental services. However, farmer adoption of these technologies has generally been limited. Drawing from natural resource economics, this study presents a conceptual framework that provide environmental-economic logic for establishing incentives that internalize the environmental services produced by multiple-outputs land use technologies. Using a land use practice based on agroforestry principles (that is, “improved tree fallows”) as a case study, this paper synthesizes studies carried out in southern Africa region for over a decade. It then discusses how the potential impacts of the technological advances made in research and development are affected by policy and institutional constraints, among other challenges. With particular emphasis on the socio-economic context in southern Africa, the paper identifies options for addressing these institutional and policy constraints in order to facilitate adoption of multi-output land use practices by farmers and unlock their potential to meet food production goals for individual households and environmental services for the wider society.Keywords: Adoption, Agri-Environmental quality, Environmental services, Natural resource economics, Payment for environmental services, Science-policy linkage

Blanching and drying period affect moisture loss and vitamin C content in Ziziphus mauritiana (Lamk.)

Wider utilization of Ziziphus mauritania (Lamk) Ber fruits in sub-Saharan Africa is hindered by the rapid deterioration of the fresh fruits and darkening of sun-dried fruits. This study was undertaken to determine the effect of pre-drying treatment, drying method and the subsequent duration of storage on the quality attributes of Z. mauritiana fruits harvested from the Zambezi Valley. The vitamin C content was high at the beginning of the drying period and progressively decreased as the drying increased, and was lowest at three weeks for all drying methods. Effect of drying method was not significant (P > 0.05). The purity (chroma) and lightness (value) of fruit colour decreased (P < 0.001) with increasing drying duration irrespective of the drying method. Blanching fruits before drying significantly (P< 0.001) decreased the colour chroma of the fruits (6.4) in comparison with non-blanched fruits (6.6). Further work to determine the causes of darkening in drying Z. mauritiana fruits and sensory evaluations to determine the level of darkening that is acceptable to consumers is warranted

Accurate crop yield predictions from modelling tree-crop interactions in gliricidia-maize agroforestry

Agroforestry systems, containing mixtures of trees and crops, are often promoted because the net effect of interactions between woody and herbaceous components is thought to be positive if evaluated over the long term. From a modelling perspective, agroforestry has received much less attention than monocultures. However, for the potential of agroforestry to impact food security in Africa to be fully evaluated, models are required that accurately predict crop yields in the presence of trees. The positive effects of the fertiliser tree gliricidia (Gliricidia sepium) on maize (Zea mays) are well documented and use of this tree-crop combination to increase crop production is expanding in several African countries. Simulation of gliricidia-maize interactions can complement field trials by predicting crop response across a broader range of contexts than can be achieved by experimentation alone. We tested a model developed within the APSIM framework. APSIM models are widely used for one dimensional (1D), process-based simulation of crops such as maize and wheat in monoculture. The Next Generation version of APSIM was used here to test a 2D agroforestry model where maize growth and yield varied spatially in response to interactions with gliricidia. The simulations were done using data for gliricidia-maize interactions over two years (short-term) in Kenya and 11 years (long-term) in Malawi, with differing proportions of trees and crops and contrasting management. Predictions were compared with observations for maize grain yield, and soil water content. Simulations in Kenya were in agreement with observed yields reflecting lower observed maize germination in rows close to gliricidia. Soil water content was also adequately simulated, except for a tendency for slower simulated drying of the soil profile each season. Simulated maize yields in Malawi were also in agreement with observations. Trends in soil carbon over a decade were similar to those measured, but could not be statistically evaluated. These results show that the agroforestry model in APSIM Next Generation adequately represented tree-crop interactions in these two contrasting agro-ecological conditions and agroforestry practices. Further testing of the model is warranted to explore tree-crop interactions under a wider range of environmental conditions