Soil and nutrient losses and the role of gender in land degradation in Southwestern Uganda

Abstract

Land degradation is rapidly increasing in Southwestern Uganda, leading to the loss of soil productivity, increased water-body pollution and reduced vegetation and wetland cover. Soil erosion is a leading observable indicator of land degradation. This study evaluated runoff, soil, and nutrient losses under the various land uses and landscape positions within the L. Bunyonyi catchment, which covers approximately 334 km2 in the Kabale District in Southwestern Uganda. Erosion plots were established for the four major land uses: perennial crops, annual crops, woodlots, and grazing. Erosion trap plots measuring 15 m × 2 m were established for each land use and were replicated four times at each of the landscape positions of summit, shoulder, mid-slope, and foot slope. A pipe sampler was used to collect approximately 1 % of the plot runoff. Runoff was measured using a measuring cylinder the day after a rain event. All the runoff with its soil sediments was collected in plastic bottles and delivered to a laboratory for analysis of soil and nutrient losses. The role of women in land management and degradation was assessed using a social survey questionnaire administered to 120 adult female respondents. The most runoff was observed in the annuals (175 m3 ha-1 year-1), followed by woodlots and perennials (159 m3 ha-1 year-1) and (141 m3 ha-1 year-1), respectively, and, finally, grazing land (136 m3 ha-1 year-1). However, the most soil loss was observed in the woodlots (431 kg ha-1 year-1), followed, in decreasing order, by grazing land (143 kg ha-1 year-1), perennials (78 kg ha-1 year-1), and annuals (72 kg ha-1 year-1). The mid-slope had significantly more soil loss (274 kg ha-1 year-1) than foot slopes (152 kg ha-1 year-1). Soil loss was lowest at the summit shoulders (144 kg ha-1 year-1). Runoff did not follow a similar pattern to that of soil loss. Although the variations were not statistically significant, more runoff was observed at the foot slopes (163 m3 ha-1 year-1) than the summit shoulder (157 m3 ha-1 year-1) and mid slope (138 m3 ha-1 year-1). The significantly high nutrient losses recorded in woodlots were more than for all other land uses. Women do not own land in Uganda but are primarily responsible for domestic food security and contribute more than 70 % of domestic labor. On average, women spend more than 8 h daily in the field providing manual labor. Occasionally, they engage in hired labor to supplement domestic agricultural activities and access other necessities. Most soil-conservation and soil-fertility improvement practices are too laborious and costly for women to undertake. This results in inevitable environmental and resource depletion problems and, subsequently, land degradation. The heavy burden of sustaining a rapidly increasing population on a diminishing resource base is accelerating land degradation, for which women share ample blame. If men fully participated in land management, especially contributing much-needed labor and resources, the state of land degradation in southwestern Uganda would be much better.