Soil water regime under rotational fallow and alternating hedgerows on an Ultisol in southern Cameroon

Article purchasedSoil moisture depletion during dry seasons by planted hedgerows to lower levels than under natural fallow, would reduce drainage and nutrient losses in the following rainy season when food crops are grown. The volumetric water content of the 0–150 cm soil profile was measured under planted hedgerows (alternating Leucaena leucocephala and Gliricidia sepium) and natural fallow, both either annually cropped to sole maize or in a two-year crop/two-year fallow rotation, in the humid forest zone (annual rainfall 1700 mm) of southern Cameroon during the 1995–1996 and 1996–1997 dry seasons. Hedgerows were cut to 0.05 m height, largely eliminating trees’ water consumption during cropping phases. Differences in total soil water content at 0–150 cm depth, between systems, occurred only in the early phases of the 1996–1997 dry season. In both dry seasons, differences between systems in water content were found in some soil layers, all within 0–60 cm depth, yet, without consistent advantage of any system in exploiting the topsoil water resources. Soil water content was lower under L. leucocephala than G. sepium at 20–40 cm depth only. Below 60 cm depth, no differences in water regimes between systems were found. Under southern Cameroonian conditions it is unlikely that any of the systems has an advantage in accessing or recovering water and thus, if available, nutrients from the sub-soil. None of the systems examined was capable of delaying drainage and thus it appears unlikely that downward displacement of nutrients is delayed after the start of the rains

From Tree Planting to Tree Growing: Rethinking Ecosystem Restoration Through Tree

Every year, millions of dollars are spent on tree-based landscape restoration activities. Over the last five decades, there are few success stories of such interventions and even those do not match the anticipated objectives for which the resources were spent. News articles that announce planting campaigns of millions of seedlings are common. Despite all this, in many countries, vegetation cover has not improved due to poor seedling survival rate. This makes the return on investment low. The objective of this paper is to highlight the main underlying challenges that need to be tackled to make restoration through tree-based interventions successful. Numerous challenges hamper the success of project-supported public tree growing schemes. 1) Often tree planting is stated as the ultimate objective of the intervention; when that objective should instead be tree growing. Performance indicators are often the number of trees planted or area planted, not the number of trees grown, or the area of land covered with grown trees. 2) Most projects operate on a short time frame (1-3 years) while many tree species (e.g. native trees in many African countries) need more time to sufficiently grow. 3) Emphasis on the right trees, for the right place and the right purposes, is very weak. 4) Even in projects of adequate duration emphasis on after-planting management is often limited. 5) There is lack of tree tenure to formally transfer the management of planted trees to local communities who reside in the landscapes over a long period of time. Tackling these challenges and changing mindsets is crucial if restoration through tree-based interventions is to yield the intended outcomes of reversing ecosystem degradation

Biophysical interactions in tropical agroforestry systems

sequential systems, simultaneous systems Abstract. The rate and extent to which biophysical resources are captured and utilized by the components of an agroforestry system are determined by the nature and intensity of interac-tions between the components. The net effect of these interactions is often determined by the influence of the tree component on the other component(s) and/or on the overall system, and is expressed in terms of such quantifiable responses as soil fertility changes, microclimate modification, resource (water, nutrients, and light) availability and utilization, pest and disease incidence, and allelopathy. The paper reviews such manifestations of biophysical interactions in major simultaneous (e.g., hedgerow intercropping and trees on croplands) and sequential (e.g., planted tree fallows) agroforestry systems. In hedgerow intercropping (HI), the hedge/crop interactions are dominated by soil fertility improvement and competition for growth resources. Higher crop yields in HI than in sole cropping are noted mostly in inherently fertile soils in humid and subhumid tropics, and are caused by large fertility improvement relative to the effects of competition. But, yield increases are rare in semiarid tropics and infertile acid soils because fertility improvement does not offse

Assessment of the effect of season and location on microbiological and physicochemical quality of livestock drinking water in Ginchi watershed, Ethiopia

This study was conducted at Ginchi watershed in Oromia Regional State, Ethiopia to evaluate the physical, chemical and microbiological quality of livestock drinking waters during dry, short rain and wet seasons. Purposive sampling technique was used to obtain samples. Data were collected and analyzed using descriptive statistics. The analysis showed that the overall mean concentrations (mg/l) were 298.33 TDS, 8.0 pH, 15.78 Na, 2.9 K,128.22 CaCO , 40.89 Ca, 6.32 Mg, 0.26 F, 5.38 Cl, 0.03 NO , 5.68 NO , 2.67 CO 146 alkalinity, 3 2 3 3, 172.83 HCO , 3.42 SO and 0.07 boron. The pH of the water was basic, ranging from 7.8 to 8.2, which is within 34 the normal range for pH in surface water systems (6.5 to 8.5). The waters exhibited a general ionic dominance pattern of Ca > Na > Mg > K. The water was moderately hard to hard (range of hardness 80–170 mg/l CaCO3) with high turbidity due to traditional farming practices, which resulted in large quantities of topsoil runoff ending up in the river after rains. Trace metal levels were low suggesting low metal contamination of the rivers. The dominance of chloride over sulphate could probably be due to domestic activities resulting from fertilizer use, household effluents and other anthropogenic point sources. The TDS varied (P0.05) was observed between locations. From results of this study, the microbial quality of water was observed to be poor due to direct contamination by animal and human excreta and other activities such as washing of clothes. From both livestock and human health point view, consumption of this coli- form polluted water should be avoided