The need for sustainable intensification in Eastern and Southern Africa (ESA) is widely recognized as a requirement to achieve food security with minimum negative social and environmental consequences. In current Research & Development programs, much emphasis is placed on increasing the efficiency with which land, water and nutrients are used, whereas farm power appears to be a 'forgotten resource'. This is a major concern when farm power in ESA countries is declining due to the collapse of most tractor hire schemes, the decline in number of draught animals and the growing shortage of human labour. A consequence of low levels of farm mechanization is high labour drudgery, which makes farming unattractive to the youth and disproportionally affects women. Undoubtedly, sustainable intensification in ESA will require an improvement in access to farm power. In this paper, we suggest this can be achieved through the use of small, multipurpose and inexpensive power sources such as two-wheel tractors (2WTs) coupled with the promotion of energy saving technologies such as conservation agriculture (CA), whilst ensuring the profitability for farmers, service providers and other private sector actors in the supply chain. We argue that appropriate mechanization in Africa, a paradigm largely abandoned three decades ago, may be re-examined through the combination of these three elements.

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The bark of Commiphora tenuis Vollensen exudes a translucent, free-flowing odoriferous liquid upon wounding which was analysed by capillary GLC and GLC-MS. 42 mono- and sesquiterpenes were detected and 37 identified. The main components of the monoterpenoid fraction were alpha-pinene (60.8%), beta-pinene (8.8%), sabinene (6.3%), alpha-thujene (8.9%), limonene (5.5%), 3-carene (3.7%), beta-myrcene (1.8%), and beta-elemene (1.1%) constituting 97% of the oil. Identified sesquiterpenoid components constituted approximately 1.6% of the oil. Oleanolic acid acetate was isolated and identified as the main triterpene from the resin by 1H- and 13C-NMR. Three other triterpenes of the olean-12-ene group were also detected using GC-MS. The essential oil exhibited antibacterial activities against Staphylococcus aureus. Proteus mirabilis and E. coli with MIC between 0.5 and 1%.

Major morphometric parameters of Goro watershed were derived from Aster Global Digital Elevation Model (GDEM) using ArcGIS10.1 extension, Arc Hydro Tool 2.0 in order to characterize it quantitatively. The study also assessed the relation of stream orders to selected channel hydraulic parameters (width, depth, channel bed slope, velocity and discharge) at bankfull flow condition. Channel geometry data and grain size samples collected from 14 representative cross-sections used as input to compute hydraulic parameters using equations appropriate for ungauged streams. The analysis of morphometric parameters indicate that pattern of stream networks is less controlled by structural condition though the area is situated in the rim of the great east African rift valley; and its geomorphic development is at late youth stage. Though hydraulic components of the channel do have a positive relation with stream orders, only channel cross-section area and discharge well related to stream orders [each increased at the rate of 0.86 and 1 on average with R 2 of 0.92 and 0.8 respectively with increasing in stream orders]. However, depth, velocity and bed slope of the channel are less explained by stream order, which may indicate us these hydraulic parameters are rather affected by other local channel factors.