Sensitivity and uncertainty propagation in coupled models for assessing smallholder farmer food security in the Olifants River Basins, South Africa

Using family balance (i.e., combined net farm and non-farm incomes less family expenses), an output from an integrated model, which couples water resource, agronomic and socio-economic models, its sensitivity and uncertainty are evaluated for five smallholder farming groups (AeE) in the Olifants Basin. The crop management practiced included conventional rainfed, untied ridges, planting basins and supplemental irrigation. Scatter plots inferred the most sensitive variables affecting family balance, while the Monte Carlo method, using random sampling, was used to propagate the uncertainty in the model inputs to produce family balance probability distributions. A non-linear correlation between in-season rainfall and family balance arises from several factors that affect crop yield, indicating the complexity of farm family finance resource-base in relation to climate, crop management practices and environ- mental resources of soil and water. Stronger relationships between family balance and evapotranspira- tion than with in-season rainfall were obtained. Sensitivity analysis results suggest more targeted investment effort in data monitoring of yield, in-season rainfall, supplemental irrigation and maize price to reduce family balance uncertainty that varied from 42% to 54% at 90% confidence level. While sup- plemental irrigation offers the most marginal increase in yields, its wide adoption is limited by avail- ability of water and infrastructure cost

Revisiting the stream-aquifer flow problem with a flux-based Green element model

This revisit of the stream-aquifer problem is based on a recent flux-based Green element formulation which offers more accurate solutions than previous formulations presented in Taigbenu (2003). Its accuracy also surpasses those provided by finite element and finite difference methods using grids that are coarser. As in all Green element formulations, the current formulation is predicated on the singular boundary integral theory that is implemented in an element-by-element fashion. What is new in the current formulation is that it calculates the fluxes at all nodes and not only at external nodes. While this approach exhibits much improved accuracy, its drawback lies with handling an increased number of unknowns. This drawback is, however, compensated for by the fewer elements required to achieve accuracies comparable to other conventional numerical methods. In this paper, it is demonstrated that with between 20% and 30% of elements used in finite element and finite difference models, comparable accuracy is achieved with this formulation. The main significance of the current computational technique is that it preserves the flux calculations in a manner that is consistent with the stream-aquifer interaction problem. Keywords: stream-aquifer interaction, The Green element metho

Food insecurity of smallholder farming systems in B72A catchment in the Olifants River Basin, South Africa

Traditional smallholder farming systems are characterized by low yields and high risks of crop failure and food insecurity. Through a biophysical model, PARCHED-THIRST and a socio-economic farming systems simulation model, OLYMPE, we evaluated the performance of farming practices based on maize yield, gross margin and total family balance over a 10-year period in semi-arid Olifants River Basin of South Africa. Farm profitability under scenarios of different maize productions, maize grain and fertiliser price variations were explored for the identified farming systems. Farm types (A to E) were identified from farm surveys, and validated with farmers and extension officers. The order of vulnerability to severe droughts and food insecurity, starting with the most vulnerable is farm Type B, C, D, A and E. Severe drought or flood shock resulted in highest farm gross margin and total family balance reductions, partly due to loss of production for family consumption. Labour returns ranged from US$62/capita.year for crop-based farm types to US$ 363/capita.year for livestock-based farm Type E. Results revealed that livestock and crop diversification are most proficient strategies to ensure stable income and food security for smallholder farmers. Thus, smallholder farming technology innovations and policies should engage in solutions to poor yields and livestock farming

Rural poverty and Food insecurity mapping at district level for improved agricultural water management in the Limpopo River Basin

The Challenge Program on Water and Food (CPWF) Phase II for the Limpopo Basin Development Challenge (LBDC) project aims to develop methods, processes, and technologies to help resource- constrained smallholder farmers mitigate poverty and food insecurity through improved agricultural water management (AWM) strategies. The purposes of this paper are to: 1) Identify areas in the Limpopo River Basin with high levels of rural poverty and food insecurity; 2) Identify areas where AWM interventions are taking place; and 3) Check whether current activities of the CPWF in the Limpopo Basin are located in areas of need as per poverty profiles and geographical location of smallholder farms. The generated poverty and food insecurity maps were based on food security surveys and estimates of consumption or income-based welfare outcomes at the district level from 2003–2013. Based on existing district level poverty and other relevant data in the basin, the study shows that the LBDC study sites are located in poor areas in the Limpopo Basin, and poverty reduction efforts should prioritize vulnerable female and child-headed households as they are the most negatively impacted by poverty and food insecurity in the four countries. Hence, with the overall aim of CPWF under LBDC to reduce poverty and food insecurity, and improve livelihoods, poverty indices should rank highly as one of the factors for project site selection. Poverty and food insecurity mapping plays an important role in identifying areas lagging behind in social and economic development, and also in facilitating targeted developmental programs such as education, health, access to credit, agricultural production support and food aid. However, it should be recognized that using district-level information often masks the existence of poverty pockets in otherwise relatively well-off districts, which could lead to poorly targeted AWM schemes. In addition, the poverty index is limited by the subjective nature of community-level and household-level factors that influence it, and this is reflected by the responses from research participants. Whereas a common poverty line for a particular time frame enables poverty comparisons across countries, local level poverty assessments, however, usually require more in-depth and diverse information that can be used in designing cost-effective and efficient anti-poverty programs and livelihoods enhancement opportunities. In order to achieve the research project’s goals of poverty and food insecurity reduction, and livelihood enhancement of smallholder farmers in the Limpopo Basin, it is of greater significance to understand trends in poverty rates rather than 1-year values at CPWF-LBDC study sites. Poverty maps that highlight areas marginalized by resource constraints help in setting priorities for developing technologies and in deploying resources where they are most needed and likely to alleviate poverty and food insecurity. This work provides background information on the Limpopo Basin

Small and medium-sized entrepreneur development within public and private collaborations

It is widely recognised that the development of SMEs results in multiple positive outcomes, including job creation and economic growth. These outcomes benefit both the public sector and private sector. Considering these benefits to the public sector and private sector, this study aimed to determine whether the collaboration of the two sectors through PPCs could enhance the development of SMEs. A qualitative exploratory research method founded on an inductive reasoning approach was used. 12 semi-structured interviews were held with senior experts in the fields of PPCs and SME development. These experts were members of the C-suite, executive director team and senior management in their respective organisations. Thematic analysis was used to analyse the data. The key findings confirmed that PPCs had both the incentive and characteristics necessary to develop SMEs. They further suggested that PPCs would enhance the development of SMEs through greater interaction with other SME development programs and with the assistance of certain elements present within the macro environment. Further research to determine the effectiveness of PPCs in developing SMEs is needed. This study enhances how the public sector, the private sector and SMEs view the concept of collaborating with one another to enhance the development of SMEs to the benefit of all parties. Given how complex such an undertaking can be, the PPS model was presented as an illustration of how this collaborative advantaged could be attained.Mini Dissertation (MBA)--University of Pretoria, 2019.Gordon Institute of Business Science (GIBS)MBAUnrestricte

Effectiveness of agricultural water management technologies on rainfed cereals crop yield and runoff in semi-arid catchment: a meta-analysis

Multiple agricultural water management (AWM) technologies are being promoted worldwide in rainfed agro-ecological production systems, such as the Limpopo River Basin, to close the yield gap, enhance food security and reduce poverty, but evidences on yield gains and environmental impacts are varied. This paper conducts a review of the performance of AWM technologies against conventional farmer practices to produce adequate evidence on cereal yield and field runoff changes. With the interrogation of literature from 1980 to 2013 using seven AWM groupings, enough evidence was found that AWM technologies can deliver substantial benefits of increased crop yield and water productivity with reduced environmental impacts. Using random effects model, the standardized mean difference (SMD) of yield between AWM and control was 0.27, while SMD of water productivity was 0.46, indicating the effectiveness of the technologies (SMD > 0). Subgroup analyses showed greatest yield responses on silty-clay-loam, clay-loam and sandy soils compared to clay and loam-sandy soils, and higher yield increase under low rainfall regime (200–500 mm) than under high rainfall regime (500–800 mm). Large yield change variations for different AWM technologies present a huge opportunity for meeting the existing yield gaps and enhancing coping capacity in dry years and under climate change

Numerics of boundary-domain integral and integro-differential equations for BVP with variable coefficient in 3D

This is the post-print version of the article. The official published version can be accessed from the links below - Copyright @ 2013 Springer-VerlagA numerical implementation of the direct boundary-domain integral and integro-differential equations, BDIDEs, for treatment of the Dirichlet problem for a scalar elliptic PDE with variable coefficient in a three-dimensional domain is discussed. The mesh-based discretisation of the BDIEs with tetrahedron domain elements in conjunction with collocation method leads to a system of linear algebraic equations (discretised BDIE). The involved fully populated matrices are approximated by means of the H-Matrix/adaptive cross approximation technique. Convergence of the method is investigated.This study is partially supported by the EPSRC grant EP/H020497/1:"Mathematical Analysis of Localised-Boundary-Domain Integral Equations for Variable-Coefficients Boundary Value Problems"