The use of scientific and indigenous knowledge in agricultural land evaluation and soil fertility studies of Ezigeni and Ogagwini villages in KwaZulu-Natal, South Africa.

Abstract

In the past, the indigenous knowledge of soils of small-scale farmers in South Africa has been largely ignored in scientific research. Hence the use of scientific approaches to land evaluation has often failed to improve land use in rural areas where understanding of the prescriptive scientific logic is lacking. Despite this, it is clear that local people and smallscale farmers have knowledge of their lands based on soil and land characteristics that remain largely unknown to the scientific community. It is therefore important for researchers to understand farmers’ knowledge of soil classification and management. To address this issue, a study was conducted in the uMbumbulu area of KwaZulu-Natal to investigate the use of indigenous knowledge as well as farmers’ perceptions and assessments of soil fertility. A preliminary questionnaire was designed to explore indigenous knowledge in a group interview that was conducted prior to the study. Another questionnaire was used to elicit indigenous knowledge from 59 randomly chosen homesteads representative of the population of Ezigeni and Ogagwini villages. Six homesteads were chosen for further detailed information on the cropping history, knowledge specific to the cultivated lands, detailed soil description and fertility. Soil samples were taken from these homesteads under different land uses (taro, fallow, veld and vegetable) at 0-30 and 30-60 cm depth for laboratory analysis. This was done to determine the effect of land use on soil physical and chemical properties and soil microbial activity. For scientific evaluation a general purpose free soil survey was conducted to produce land capability and suitability maps. Farmers identified ten soil types using soil morphological characteristics, mainly soil colour and texture. These soil properties were also used in the farmers’ land suitability assessment. In addition, slope position, natural vegetation and village location were used to indicate land suitability. The amount of topsoil was also used in land evaluation. However, slope position was considered the most important factor as it affects the pattern of soils and hence their suitability. Soils on the footslope were considered more suitable for crops than those found on the midslope and upslope. The yield difference observed between villages, which were higher in Ogagwini than Ezigeni, was also used as a criterion for evaluation. Farmers attributed these yield differences for various crops to the effect of soil type on productivity. In support, scientific evaluation found that Ezigeni village had a number of soils with a heavy textured, pedocutanic B horizon and hence a relatively shallow effective rooting depth. Moreover, the Ezigeni village land suitability was limited in places by poor drainage and stoniness. These limitations were rarely found for the Ogagwini village soils. Farmers had a total of six comprehensive and well defined soil fertility indicators, namely crop yield, crop appearance, natural vegetation, soil texture, soil colour and presence of mesofauna. Results showed that farmers’ fertility perceptions are more holistic than those of researchers. However, despite this, their assessment correlated with soil analysis. There was a close relationship between scientific and indigenous suitability evaluation for three commonly cultivated crops (taro, maize and dry beans). This was further substantiated by yield measurements which were significantly higher for Ogagwini as rated by both farmers and scientific evaluation as the more suitable. The significant agreements between the scientific and indigenous approaches imply that there are fundamental similarities between them. Recognizing this and subsequently integrating the two approaches will produce land use plans relevant and profitable for both small-scale farmers and scientists.