A methodology for assessing irrigation practice in small scale community gardening.

Abstract

The challenges facing small scale irrigation development in South Africa are varied and complex. This complexity is exacerbated by the many years of systematic neglect, in tandem with material and intellectual impoverishment of the majority of participants in this agricultural sector. Attempting to juggle sustainable development of small scale agriculture and environmental and socio-economic advancement is difficult, but there is sufficient evidence in the literature to suggest that small scale agriculture is increasing not only in South Africa but in Sub-Saharan Africa (Collier and Field, 1998) There is no doubt that this observed increase in irrigated communal gardens result from their increasingly important role of providing food security and as means of augmenting family income. Hence the government,NGO' s and other private sector organisations have increased their support for these small scale agricultural initiatives. Small scale agriculture is therefore increasingly becoming a common land use, and with this increased support, it is likely to become a major water user, particularly as it is located in close proximity to the water source. Hence both practices and processes for small scale agriculture require careful study. Irrigation practices have been studied in KwaZulu-Natal where small scale community gardens are continuously developing. The study included two locations near Pietermaritzburg. The first, at Willowfontein, involved irrigation by furrow , and the second, at Taylors Halt, involved irrigation by hand, using containers. The dynamics of the subsurface flow was monitored using tensiometry and modelled in detail using a two dimensional, soil physics model, Hydrus-2D, to evaluate the application efficiency. This study consisted of three parts viz: socio-economic system appraisal, technical measurement and monitoring, and modelling. Important findings obtained include the following: The highlighting of pertinent socio-economic issues governing water use and allocation and other operations in developing small scale agricultural conditions, including constraints to the development of this sector under the conditions described. The demonstration of the use of reasonably inexpensive, but sophisticated measuring techniques to observe the soil water processes in small scale community gardening practices. Accurate simulations of soil water infiltration,redistribution and uptake using the Hydrus2D model. With these successful simulations, together with the results of the social system appraisal, more efficient irrigation scenarios are proposed and evaluated. The development of a methodology that could be used to assess small scale irrigation efficiencies, with computer simulation models used as tools to conduct such an assessment.