A sectoral environmental audit of livestock production systems in Migori district, Nyanza province
Wamalwa, Joel M
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This study was carried out within the VicRes project scope in Uriri, Nyatike and Karungu divisions in Migori District as a second phase objective of the project (Trends in livestock production systems and their impact on environment and livelihoods in the Lake Victoria basin). The objective was to undertake an environmental audit of livestock production practices with their related factors causing environmental degradation with emphasis on soil, water and vegetation. The livestock industry in Kenya accounts for about 10% of the country's GDP and for 93.8% of the households in Migori District occupation is Agro-based of which livestock industry accounts for about 35% ofthe household income earnings. Other than fiscal value of the livestock sector, small holder households in the district depend on as a medium of exchange in local trade besides the livestock roles in traditional and other customs such as dowry payments. However there are concerns in the sustainability of the natural resource base in supporting livestock production in Migori District emanating from utilizing the available vast communal land and ungazzeted areas that are ecologically fragile such as hills slopes and riparian area. The livestock production systems in the district are of concern especially in the manner in which available communal grazing lands and watering points are utilized. Lack of stipulated rules and regulation for free range grazing and fodder harvesting within riparian areas has for a long time resulted into high erosion within grazing lands and with no vegetation adequate vegetation cover within riparian areas to hold storm water. Soil sediments and livestock feacal materials find their way into surface water sources that serves over 20,000 households predisposing the population to water borne related disease caused by pathogenic Cryptosporidium parvum, Salmonella enterica, Shigella dysenteriae and Escherichia coli. Household surveys were done randomly among 135 livestock keeping households to assess the rearing system and how it impacts on the environmental components. Rapid field assessment parameters in grazing fields and assessment of the state of riparian environment attributes based on responds own perception. 38 water samples were collected at livestock watering point and water quality parameters assessed in accordance to the Kenya National Environment Management Authority guidelines at University of Nairobi, department water engineering laboratory. 54 soil samples were collected for analysis of soil fertility parameters such as bulk Density, soil pH, soil and soil structure at various bare ground patches were analyzed at the Kenya Agricultural research institute (KARl) laboratory in Nairobi. Woody and non-woody vegetation species was counted within Line transects and point centered quadrants (PCQ) and by construction of plot line transects and spatial sampling using point centered quadrants (PCQ) the number of individual woody species identified and recorded. Sampling points were established along transect line at regular interval subject to vegetation density variation. The study established that the Livestock respondents in the study area have adopted different livestock systems for their livestock with 92% of the household rearing poultry birds, cattle and sheep. The livestock are reared under different grazing systems where in Uriri division respondents adopt intensive livestock grazing systems with 26.1 % of the respondents practice zero grazing. As for Nyatike and Karungu divisions farmers have adopted communal grazing and free range grazing system respectively. The problem of managing communal grazing fields among users in Nyatike who maximize on the benefits by keeping large herds of Livestock overgraze increasing the degree of soil compaction which in turn increases soil bulk density. The study established an (adjusted _R2 of 0.7308) between soil bilk density and number of livestock over a grazing field. Compacted soils affect water infiltration rates into the soil profile thus accelerating the rates of storm water runoff. Overgrazing affects vegetation composition by accelerating the emergence of non-palatable grass species and woody species in the grazing land e.g. Acacia nilotica, Acacia brevis pica, Euphorbia tirucali and non palatable grass species like Bothriochloa insculpta and Melinis minutejlora. The Shannon diversity index indicated a low species diversity of 1.143942 and 0.867603 in Transect 4 and 5 constructed in Karungu and Nyatike grazing fields respectively a pointer to over grazing on the palatable grass species in the area. The study further established significant water pollution emerging from livestock production that is characterized with bacterial contamination with pathogens such as Cryptosporidium parvum, Salmonella enterica, Shigella dysenteriae and Escherichia coli resulting from watering livestock directly in the available water sources with livestock wastes finding way in to available water source affecting over 20,000 households access to clean drinking water in the study area. To address the impacts of livestock sector on the environment and at the same time realize significant sustainable benefits at household. Livestock farmers have to be encouraged to allocate land for pasture production at household level as this would mitigate against fodder harvesting from riparian areas that eventually degrades and reduces its ecological functioning. Households have to be encouraged to adopt rain water harvesting technology by constructing rain water harvesting tanks within their households as well as construction of watering points a long major river banks. This would mitigate against driving livestock and watering them directly in the available surface water thereby polluting it.
University of Nairobi, Kenya