Influence of Tea Plantations, Forest and Mixed Farming on Stream Flow and Sediment Loads, Case of Sondu Miriu River Basin, Kenya

The changing patterns of land cover and land use in the tropical river basin over time are critical. The hydrological phenomena at basin and sub basin scale are affected positively or negatively by dynamics of the land cover and land use patterns. Hence identifying causes and driving factors aid in taking appropriate measures to avert the impacts. This study determined the influences of sub basins dominated by tea plantations, forests and agricultural land uses in terms of streamflow and sediment flux variability in Sondu Miriu River Basin in Kenya, East Africa. Field-based investigations were conducted through sampling of flow velocities, turbidity and TSSC obtained from existing River Gauging Stations established within the three sub basins. The sub basin dominated by mixed farming land cover exhibits high turbidity approximately 620 NTU and high levels of total suspended sediment concentration (TSSC) of the order of 630 mg/l in wet seasons. The turbidity levels and TSSC were low in sub basins dominated by forest and tea plantations with approximately mean value of 17 - 29 NTU and 0.019 g/l. The sediment loads in sub basin dominated by mixed farming in the pre planting season in January to February were about 900 tonnes/day higher than that in crop growing season. In sub basins dominated by forest cover and tea plantations, sediment loads were low ranging between 2 - 7 tonnes/day. The relationship between stream flows and area under tea plantations, forests and mixed farming ranged between R2 of 0.025 and 0.16. Tea plantations and forests influence the stream flows and sediment yields in long term duration while in mixed farming variations were observed seasonally. The strong relationships between rainfall and stream flows at the sub basins ranging between R2 of 0.84 and 0.97 revealed the significance of rainfall in hydrologic response of the Sondu Miriu River Basin.

The emergence, development and regional differences of mixed farming of rice and millet in the upper and middle Huai River Valley, China

Mixed farming of rice and millet is one of the basic agricultural modes in the upper and middle Huai River Valley(HRV). According to the latest data, this agricultural mode appeared during the middle and late Peiligang Culture(7.8–7.0 ka BP) in the upper HRV, and then became a common subsistence economy in the end of the Neolithic(5.0–4.0 ka BP) in both the upper and middle HRV. However, it is still not clear how this mixed farming developed in the upper HRV after its occurrence, nor are the regional differences in the development of mixed farming between the upper and middle HRV during the Neolithic completely understood. In this paper, flotation and starch analyses were conducted on samples from eight archaeological sites in the upper and middle HRV. The results indicate that the mixed farming of rice and millet first appeared in the later phase of the middle Neolithic in the regions of the Peiligang Culture, then developed quite rapidly in the late Neolithic(6.8–5.0 ka BP), finally becoming the main subsistence economy at the end of the Neolithic in the upper HRV. However, there are obvious differences in the emergence and development of agriculture between the middle and upper HRV. Rice farming was the only agricultural system during the middle Neolithic, lasting until the end of the Neolithic, when mixed farming appeared in the middle HRV. Furthermore, although mixed farming appeared in both the upper and middle HRV during the end of the Neolithic, the roles of rice, foxtail millet and broomcorn millet in the subsistence economy were not the same. In general, millet was more widely cultivated than rice in the upper HRV, but rice occupied the same or a slightly more prominent position in the middle HRV at the end of the Neolithic. These results are significant for understanding the process of agricultural development and transformation, as well as human adaptation to climatic and cultural variability duringthe Neolithic.

REINTEGRATION OF CROP-LIVESTOCK SYSTEMS IN EUROPE:AN OVERVIEW

Ongoing specialization of crop and livestock systems provides socioeconomic benefits to the farmer but has led to greater externalization of environmental costs when compared to mixed farming systems.Better integration of crop and livestock systems offers great potential to rebalance the economic and environmental trade-offs in both systems.The aims of this study were to analyze changes in farm structure and review and evaluate the potential for reintegrating specialized intensive crop and livestock systems,with specific emphasis on identifying the co-benefits and barriers to reintegration.Historically,animals were essential to recycle nutrients in the farming system but this became less important with the availability of synthetic fertilisers.Although mixed farm systems can be economically attractive,benefits of scale combined with socio-economic factors have resulted in on-farm and regional specialization with negative environmental impacts.Reintegration is therefore needed to reduce nutrient surpluses at farm,regional and national levels,and to improve soil quality in intensive cropping systems.Reintegration offers practical and cost-effective options to widen crop rotations and promotes the use of organic inputs and associated benefits,reducing dependency on synthetic fertilisers,biocides and manure processing costs.Circular agriculture goes beyond manure management and requires adaptation of both food production and consumption patterns,matching local capacity to produce with food demand.Consequently,feed transport,greenhouse gas emissions,nutrient surpluses and nutrient losses to the environment can be reduced.It is concluded that reintegration of specialized farms within a region can provide benefits to farmers but may also lead to further intensification of land use.New approaches within a food system context offer alternatives for reintegration,but require strong policy incentives which show clear,tangible and lasting benefits for farmers,the environment and the wider community.