Semi-arid West Africa Research Articles

Rapid assessment of post-dispersal seed removal in an agricultural landscape of semi-arid West Africa

Rapid assessment of post-dispersal seed removal in an agricultural landscape of semi-arid West Africa

Potential of Unconventional Seed Oils and Fats from West African Trees: A Review of Fatty Acid Composition and Perspectives

Seed oils sourced from West Africa are generally not well-characterized, but likely to have an untapped potential. This review aims to make an overview of fatty acid (FA) composition of unconventional seed oils from semi-arid West African trees and evaluate potential for new and enhanced uses and for improving local livelihoods and biodiversity conservation. A total of 111 studies on FA composition were found, covering 31 species. Only 69 of the studies (62%) were included in the review, as 38% had unreliable or incomplete results. There was a clear link between taxonomic kinship and FA composition. Over 20 potentially interesting and underexploited oils were found, including oils with properties similar to palm oil, olive oil, coconut oil, shea butter, and cotton seed oil. About half of the oils have promising potential for cosmetics. One third of the oils were relatively saturated, indicating properties for structuring food and heat resistance. Most of the species had multiple uses and oil production could be profitable in co-production with other non-timber forest products. Furthermore, establishment of sustainable oil production and domestication of oil trees could promote biodiversity conservation. Enhanced oil production in semi-arid West Africa is promising, but several practical constraints remain to be overcome.

Climate resilience of irrigated quinoa in semi-arid West Africa

Quinoa (Chenopodium quinoa Willd.) is a herbaceous C3 crop that has demonstrated resilience in regions concurrently affected by climate change and food insecurity, such as sub-Saharan Africa (SSA). The photosynthetic rate and productivity of C3 crops are enhanced under increasing CO2 concentrations. We looked at future climate trends in SSA to estimate their impacts on quinoa yields in Burkina Faso. Climate projections show a temperature increase of 1.67-4.90°C under Representative Concentration Pathways (RCP) 4.5 and 8.5, respectively by the end of the century. We demonstrate that any further climate disturbances can either be beneficial or harmful for quinoa, and modulating climate risks will depend on the decisions made at the farm level (e.g. planting date and crop choice). Crop modelling supports the identification of the most suitable transplanting dates based on future climate conditions (RCP 4.5 and 8.5), agroclimatic zones (Sahel, Soudano-Sahelian and Soudanian) and time-horizons (2020, 2025, 2050 and 2075). We show that quinoa yields can improve—when grown under irrigated conditions and transplanted in November—by about 14-20% under RCP 4.5 and by 24-33% under RCP 8.5 by 2075 across the Sahel and Soudanian agroclimatic zones, respectively. For the Soudano-Sahelian zone, the highest yield improvements (19%) are obtained when transplanting is assumed in December under RCP 8.5 by 2075. Overall, the findings of this work encourage policymakers and agricultural extension officers to further promote climate-resilient and highly nutritious crops. Such possibilities are of much interest in SSA, thought to be highly vulnerable to climate change impacts where millions of people are already experiencing food insecurity.

Agromorphological Characterization of Introgression Lines Derived from Wild and Exotic Sorghum Germplasm to Climate Change Challenges

Sorghum (Sorghum bicolor (L.) Moench) is vitally important for food security in semi-arid West Africa. The introgression of wild- and high transpiration efficiency genotypes may contribute genes for abiotic stress tolerance or novel traits. Characterizing the introgressed lines can help researchers in the process of varietal improvement. The objectives of this study are (i) To learn if introgression of wild sorghum (CWR) and high transpiration efficiency (HTE) lines into a very early maturing (photoperiod insensitive) local land-race variety can create useful variation for grain yield in drought-prone Sahelian environments, (ii) To determine if grain yield advantages (and putative drought tolerance traits) obtained from introgression of CWR and HTE germplasm are expressed differently in moderately to highly moisture-limited environments, and (iii) To understand the relationship between putative drought tolerance traits. These populations were developed from crosses between the CSM63E (Jakumbe, a high grains quality variety) and two wild parents (accessions) and five high transpiration efficiency (TE) sorghum accessions. Phenotyping was conducted using an alpha lattice design with three replications in two environments for agronomic traits (grain yield and components), flowering time and physiological traits (stay-green, chlorophyll content and lodging). A total of 669 BC1F5 progenies were developed. Genetic variation for grain yield and putative drought tolerant traits were evaluated. Both populations derived from wild parents exhibited in Cinzana a grain yield (>300 g/m2) greater than CSM63E (245 g/m2). In Bema, more than 75% of the progenies of all populations indicated a chlorophyll content at physiological maturity (>30 SPAD) higher than CSM63E (20 SPAD) chlorophyll content. The estimated broad sense heritability was generally high (≥0.50) for all traits. The results also showed a very significant interaction between genotype and environment for grain yield, flowering time, chlorophyll content, stay green and lodging. There was a strong correlation between stay green and chlorophyll content (0.60) on the one hand and between stay green and lodging (0.48) on the other. This great variability could help improve the grain yield of sorghum for farmers in the Sahelian zone.

Analysis of main factors affecting silage fermentation of sorghum prepared with whole crop and stover in semiarid West Africa

Sorghum (Sorghum bicolor L.) is widely cultivated in semiarid West Africa as a combined crop for human consumption and animal feed. In order to address the shortage of ruminant feed in Burkina Faso, we studied the potential of preparing silage from sorghum at various growth stages and analysed the main factors affecting silage fermentation, including the microbial population, chemical composition and ensiling characteristics of sorghum prepared with and without microbial additives at three stages of development (soft dough; hard dough; physiological mature stover). After 90 d of ensiling, lactic acid bacteria (LAB) became the dominant microorganisms in silages. The silage from soft dough sorghum exhibited the highest LAB counts, water-soluble carbohydrate (WSC) and crude protein content. In addition, silage presented greater quality with higher (p < 0.05) lactic acid content and lower (p < 0.05) pH and ammonia nitrogen levels than those at hard dough stage and stover. The WSC and LAB were the important factors affecting silage fermentation and the addition of LAB and cellulase improved fermentation quality. The combined additives displayed a synergistic effect and when silage is prepared with sorghum at soft dough stage, it has best potential for controlling spoilage microorganisms and preserving the silage quality for animal feed.

On-farm trials identify adaptive management options for rainfed agriculture in West Africa

Rainfed crop production is the primary means of food security and income generation for rural households in semi-arid West Africa, which contains a high level of agro-ecological and socio-economic heterogeneity. Official management recommendations currently focus on the use of purchased certified seed and inorganic fertilizers, but are based primarily on highly controlled on-station trials that do not capture this heterogeneity and complexity of production systems. This study established hundreds of on-farm research trials across Senegal and The Gambia to test the agronomic benefit of multiple integrated practices related to seeds, inorganic fertilizers, and locally available organic amendments. All management practice were found to reliably increase yield across both the heterogeneity of this region and the diversity of the partnering farmers, and multiple integrated practices had greater effect than the currently recommended “best” practice. These alternative practices therefore offer an immediate pragmatic replacement to the existing recommendations and demonstrate the research and extension value of supervised on-farm trials. These findings also suggest that agronomic recommendations should focus on multiple “better” options rather than singular “best” practices, and farmers encouraged to select among these options based on their individual knowledge, circumstances, and preferences.

“Every day it’s tuo zaafi”: considering food preference in a food insecure region of Ghana

This study takes the role of food preference in food insecurity analysis seriously. Guided by feminist political ecology, I do so by underscoring bodily relationships to tuo zaafi a cereal based porridge upheld as a culturally important meal across semi-arid West Africa. Drawing from 12 months of mixed methods fieldwork in Upper West Ghana, I look at perceptions of this salient meal as well as rates of consumption of it to uncover how food preference features in food insecurity. I use the refrain routinely evoked by my interlocutors during the height of the food insecure season—“Every day it’s tuo zaafi” as an anchoring datum point, an affectively effective statement. In this examination, I argue that when effectively acknowledged and assessed, food preference is a facet of food security that helps to not only identify hunger, but also articulate the experience with it. This articulation is important because it provides a necessarily broader perspective on the relationship between culture, food and health that challenge neo-liberal hued solutions to hunger.

Chemical composition, characteristics concerned with fermentative quality and microbial population of ensiled pearl millet and sorghum stover in semi-arid West Africa.

To effectively utilize crop by‐product resources for ruminant feed in semi‐arid West Africa, we studied the chemical composition, characteristics concerned with fermentative quality, and microbial population of ensiled pearl millet stover (PMS) and sorghum stover (SS) in Mozambique. After panicle harvest, the PMS and SS were exposed in the field for 7, 21, 35, 49, 63, 77, 91, and 120 days under natural weather conditions. The fresh stover silages were prepared and stored for 120 days. With increased exposure time, the dry matter, neutral detergent fiber, acid detergent lignin, and neutral detergent insoluble nitrogen contents increased, whereas the crude protein, ether extract, gross energy, digestible energy, metabolizable energy, and true protein contents decreased. After 120 days of field exposure, aerobic bacteria dominated both stovers, and lactic acid bacteria (LAB) decreased to below detectable levels. After 120 days of ensiling, LAB dominated the silage of both crops, while the harmful microorganisms as aerobic bacteria, coliform bacteria, yeast, and mold were reduced or below detectable levels. Both silages did not produce more lactic acid to reduce the pH value, but they preserved nutrients well during ensiling. Therefore, PMS and SS can be prepared as silage for ruminant feed in semi‐arid West Africa.

Management and socioeconomic determinants of woody species diversity in parkland agroforestry in Tembaro District, Southern Ethiopia

Parkland agroforestry farming system is widely practiced by smallholder farmers in semi-arid West and East Africa. Parkland agroforestry plays an important role in product diversification and biodiversity conservation. The study carried out to examine the management and socioeconomic determinants of woody species diversity in parkland agroforestry in Tembaro district, Southern Ethiopia with objectives (i) assess woody species diversity, (ii) identifying farmers management practices and (iii) socioeconomic determinants of woody species diversity in parkland agroforestry. Two administrative kebeles were selected purposively. A total of 120 households were randomly selected for socioeconomic data and woody species inventory. Based on the analysis, 90% of households are males, and 54.2% are in medium wealth class. A total of 27 woody species were recorded in the study area. The Shannon, Simpson and evenness were1.83±0.18, 0.78±0.046 and 0.77±0.07, respectively. Woody species density per quadrate at Waro site (15.58±5.47) was significantly higher than Bechira site (13.47±5.77) (p<0.05). The mean basal area of woody species at Waro was slightly higher (2.52±1.38ha-1) than at Bechira (2.2±1.36ha-1), the difference not statistically significant (p>0.05). At the study sites, farmers retained (planted) woody species in their parkland agroforestry for the purpose of fuel wood, improving soil fertility, fodder, timber, shade, construction, etc. The important socioeconomic determinants influencing woody species richness in the study area were family size, farm size, wealth, education level, access to extension services, and access to the road. The diversity of woody species in parkland agroforestry plays a great role in provisioning and regulation functions.

Multidimensional Poverty Assessment among Adolescent Children in the Mouhoun Region of Burkina Faso, West Africa

Poverty is complex and multidimensional and particularly pronounced in children living in semi-arid West Africa. Unfortunately, few studies have addressed multidimensional child poverty in this region. Using novel data generated from 431 randomly selected households in the Boucle du Mouhoun region in Burkina Faso, the Alkire–Foster methodology was applied to estimate and decompose multidimensional poverty among adolescent children. Ten dimensions guided by the child poverty literature, data availability and the country’s SDGs were used. While deprivations in water and sanitation (89%), health (75%), nutrition (82%), and child labour (48.7%) were found to be more prevalent in the rural areas, child subjective well-being (73%) and child protection (61%) were more pronounced in the urban areas. Analysis of multiple overlaps in dimensions shows that all of the children suffer from deprivations in three or more dimensions simultaneously. Furthermore, when the poverty cut-off values were set at k = 20% (“Vulnerable to Poverty”), k = 30% (“Multidimensionally Poor”) and k = 50% (“Poverty Severity”), close to 95% of children are categorized as being in “Severe Poverty”, 68% as “Multidimensionally Poor”, and 38% as being “Vulnerable to Poverty”. Using binary logistic regressions, household size, age and marital status of household head, locality of child, income source, debt status, education, number of siblings, gender of child, adults and maternal health condition were found to be significantly correlated to poverty vulnerability, multidimensionally poor and poverty severity in the region. The implications of these findings for multidimensional child poverty targeted policies and interventions are discussed.

English

Cowpea (Vigna unguiculata (L.) Walp) is important in semi-arid West Africa. Yields are low due to inadequate water and nutrient availability and other constraints. Grain and fodder yield responses to nutrient application were determined from 21 site-years of research conducted in the Sahel and Sudan Savanna. The incomplete factorial treatment arrangement varied by country but included: Four levels each of P and K in 7.5 and 10.0 kg ha-1 increments, respectively; Mg-S-Zn-B package (Mg-S-Zn-B); and comparable with and without manure treatments. Yield increases due to P application always occurred with curvilinear to plateau or linear responses. The overall mean grain yield increase was 0.35 Mg ha-1 and 47% due to application of 22.5 kg ha-1 P. Application of K resulted in a linear negative effect in 2014 and positive effect in 2015 for on-station trials in Niger, but had no effect in Burkina Faso and for on-farm trials in Niger. Yield was not affected by Mg-S-Zn-B in Burkina Faso but was increased by a mean of 0.085 Mg ha-1 in Niger. Manure application resulted in a mean yield increase of 0.1 Mg ha-1 in Niger but only with fertilizer P applied, and had no effect in Burkina Faso. Cowpea grain and fodder yields were responsive to fertilizer P up to 22.5 kg ha-1 but little affected by other applied nutrients. Key words: Fertilizer, fodder, grain, manure, micronutrient, phosphorus, secondary nutrient,&nbsp; Sahel, Sudan Savanna. &nbsp

Hydrogeochemical and multi-tracer investigations of arsenic-affected aquifers in semi-arid West Africa

The semi-arid Sahel regions of West Africa rely heavily on groundwater from shallow to moderately deep (<100 m b.g.l.) crystalline bedrock aquifers for drinking water production. Groundwater quality may be affected by high geogenic arsenic (As) concentrations (>10 μg/L) stemming from the oxidation of sulphide minerals (pyrite, arsenopyrite) in mineralised zones. These aquifers are still little investigated, especially concerning groundwater residence times and the influence of the annual monsoon season on groundwater chemistry. To gain insights on the temporal aspects of As contamination, we have used isotope tracers (noble gases, 3H, stable water isotopes (2H, 18O)) and performed hydrochemical analyses on groundwater abstracted from tube wells and dug wells in a small study area in southwestern Burkina Faso. Results revealed a great variability in groundwater properties (e.g. redox conditions, As concentrations, water level, residence time) over spatial scales of only a few hundred metres, characteristic of the highly heterogeneous fractured underground. Elevated As levels are found in oxic groundwater of circum-neutral pH and show little relation with any of the measured parameters. Arsenic concentrations are relatively stable over the course of the year, with little effect seen by the monsoon. Groundwater residence time does not seem to have an influence on As concentrations, as elevated As can be found both in groundwater with short (<50 a) and long (>103 a) residence times as indicated by 3He/4He ratios spanning three orders of magnitude. These results support the hypothesis that the proximity to mineralised zones is the most crucial factor controlling As concentrations in the observed redox/pH conditions. The existence of very old water portions with residence times >103 years already at depths of <50 m b.g.l. is a new finding for the shallow fractured bedrock aquifers of Burkina Faso, suggesting that overexploitation of these relatively low-yielding aquifers may be an issue in the future.

Crop response to manure and fertilizer in Burkina Faso and Niger

Farmyard manure (FYM) is valuable for soil management, especially for soils with < 10 g kg−1 organic C in semi-arid West Africa. This study determined short-term FYM effects on yield and on response to N, P and K fertilizer for 20 trials in Niger and 28 trials in Burkina Faso involving six crops. The comparisons were of 0 and 2.5 Mg ha−1 yr−1 FYM applied in Niger, and of 0 and 5 Mg ha−1 FYM applied once in 2 years in Burkina Faso. Fertilizer and FYM application alone had little effect on yield in Niger but there was a synergistic effect of fertilizer P with FYM which included increased mean responses to P of, respectively: 0.22 and 0.43 Mg ha−1 for sorghum grain and fodder (Sorghum bicolor L.); 0.15 and 0.27 Mg ha−1 for cowpea grain and fodder; 0.16 Mg ha−1 grain for pearl millet (Pennisetum glaucum L.) when intercropped with cowpea (Vigna unguiculata L.); and 0.39 Mg ha−1 for groundnut fodder (Arachis hypogea L.). Application of FYM increased pearl millet response to N but decreased legume response to K fertilizer. In Burkina Faso, there was a mean grain yield increase of 0.29 Mg ha−1 yr−1 due to FYM and the effect of applying both FYM and fertilizer was additive except for a synergy of N fertilizer plus manure application for maize (Zea mays L.). Therefore, farmers should apply FYM and fertilizer together in Niger but these can be applied alone or together in Burkina Faso with mostly similar effects.

Maize Sole Crop and Intercrop Response to Fertilizer in Mali and Niger

Core Ideas Applying N for maize production in semi‐arid west Africa can be profitable.The profit potential of N application is great for maize–groundnut intercrop.Application of P and K has low and inconsistent profit potential for maize production in semi‐arid west Africa.Nutrient response functions can be determined for maize–groundnut intercrop from maize sole crop data. Maize (Zea mays L.) is important in semiarid West Africa where the increase in demand exceeds the increase in production. Yield is often constrained by inadequate nutrient availability even though the occurrence of soil water deficits may overall be more constraining. Research was conducted in semiarid Mali and Niger to determine the yield and profit responses of maize sole crop (MzSC) to N, P, and K and to develop a procedure for determining maize–groundnut (Arachis hypogaea L.) intercrop (MzGnI) nutrient response functions from MzSC functions. Trials were conducted in 2014 and 2015 at five locations spanning 14 degrees of longitude and two degrees of latitude. Mean MzSC grain yield increase due to 50 kg ha−1 N was 0.69 Mg ha−1 in Mali and 0.42 Mg ha−1 in Niger, and due to 10 kg ha−1 P was 0.14 Mg ha−1 in Niger with inconsistent P effects in Mali. Responses to K were negligible. Productivity and profit potential with N application was more with MzGnI compared with MzSC, but profit potential for applied P and K were not improved with MzGnI. Considering the fodder value of stover added to production value but did not have much effect on profits from fertilizer use. The procedure for determining MzGnI nutrient response functions by adapting MzSC functions was developed, providing a means to improve fertilizer use efficiency for MzGnI. Productivity and returns to applied N, on a maize grain value equivalent, are greater with MzGnI compared to MzSC.

Understanding farmers’ perceptions and the effects of shea (Vitellaria paradoxa) tree distribution in agroforestry parklands of Upper West Region, Ghana

Agroforestry parklands, characterized by scattered trees growing within cultivated crop fields, are the most widespread agricultural system in semi-arid West Africa. Agroforestry trees offer many ecological and socioeconomic benefits, such as added income, food, and medicine. They are currently under threat in this region due to recent changes in agricultural and land use practices. For example, a reduction in traditional fallow rotation periods has led to decreased regeneration of a common agroforestry tree, shea (Vitellaria paradoxa), which has been an important economic resource for women. The aims of this study were to determine beneficial spatial distributions of shea to maintain high yields of staple crops and to better understand male and female farmer perceptions of shea maintenance. We compared maize (Zea mays) vegetative growth, grain yield, soil moisture, and light availability associated with individual shea trees and clumps of trees on five farms in Ghanaian agroforestry parklands. We also interviewed local farmers to better understand their management perspectives. Maize vegetative growth increased with light availability, but was not limited by soil moisture. Conversely and contrary to farmer perceptions, grain yield was not influenced by light availability, but increased with increasing soil moisture. Also contrary to common beliefs of local farmers, grain yield was greater under clumps of shea compared to scattered distributions of individual trees. We therefore recommend the maintenance of clumped distributions of shea, as they provide beneficial microclimates for staple crops, and could assist in improving the productivity of shea products that are considered the domain of women farmers.

Evaporation from cultivated and semi-wild Sudanian Savanna in west Africa

Abstract. Rain-fed farming is the primary livelihood of semi-arid west Africa. Changes in land cover have the potential to affect precipitation, the critical resource for production. Turbulent flux measurements from two eddy-covariance towers and additional observations from a dense network of small, wireless meteorological stations combine to relate land cover (savanna forest and agriculture) to evaporation in a small (3.5 km2) catchment in Burkina Faso, west Africa. We observe larger sensible and latent heat fluxes over the savanna forest in the headwater area relative to the agricultural section of the watershed all year. Higher fluxes above the savanna forest are attributed to the greater number of exposed rocks and trees and the higher productivity of the forest compared to rain-fed, hand-farmed agricultural fields. Vegetation cover and soil moisture are found to be primary controls of the evaporative fraction. Satellite-derived vegetation index (NDVI) and soil moisture are determined to be good predictors of evaporative fraction, as indicators of the physical basis of evaporation. Our measurements provide an estimator that can be used to derive evaporative fraction when only NDVI is available. Such large-scale estimates of evaporative fraction from remotely sensed data are valuable where ground-based measurements are lacking, which is the case across the African continent and many other semi-arid areas. Evaporative fraction estimates can be combined, for example, with sensible heat from measurements of temperature variance, to provide an estimate of evaporation when only minimal meteorological measurements are available in remote regions of the world. These findings reinforce local cultural beliefs of the importance of forest fragments for climate regulation and may provide support to local decision makers and rural farmers in the maintenance of the forest areas.

Precision farming for increased land and labour productivity in semi-arid West Africa. A review

Farmers in the semi-arid regions of West Africa face challenges related to poor crop establishment, variable rainfall, low soil fertility and a shortage of labour at times of peak demand. Farmers are generally low on resources. Given these conditions, it is important to develop farming practices that make efficient use of the available resources and reduce risks. Here, we review agricultural intensification in semi-arid West Africa using the principles of precision farming to assess the possibilities they offer. The basic idea is to create a favourable micro-environment in the planting pocket and to ensure timely sowing and weeding. In the context of precision farming in the semi-arid West Africa, this means (1) large seeds are selected, primed and treated with a mix of pesticides/fungicides. Seed priming increases yields in the order of 20 to 30%, while seed treatment increases yields by 15%. (2) Mineral fertilizers are applied; at doses as low as 0.3 g of fertilizer per pocket, they have been found to increase yields by half or more. (3) Seeds and fertilizers are distributed accurately by means of a combined planter-weeder, which can be motorized. (4) Mechanized sowing and weeding enable timely farm operations and reduce the workload. (5) Water loss is prevented by using zai and stone bunds on soils with high run-off rates. (6) Care is taken to make use of farm resources in a targeted and efficient way. This can imply adjusting micro-doses of manure and fertilizer to crops (sorghum needs less than millet) and soil types, sequenced sowing of crops according to their vulnerability to delayed sowing and applying organic input to soils. This paper is the first to review agricultural intensification in semi-arid West Africa within the context of precision farming. It shows how a low-cost package for precision farming can be developed, which can help to increase land and labour productivity, and works with all the major field crops in the region.

Strategies trees use to overcome seasonal water limitation in an agroforestry system in semiarid West Africa

AbstractAgroforestry parklands, in which annual crops are grown under scattered mature trees, constitute the most prevalent farming system in semiarid West Africa, covering vast areas of land. The most dominant tree species in these systems is Vitellaria paradoxa, an indigenous tree to West Africa. Despite the importance of this tree in the region, no study to our knowledge has examined its sources and patterns of water uptake. In this study, we used oxygen stable isotopes at natural abundance levels to investigate water sources used by V. paradoxa both in the dry and wet season in an agroforestry parkland in Burkina Faso. We found that during the wet season soil moisture was highest near the soil surface (&lt;10 cm depth), yet during this time V. paradoxa preferentially accessed water from slightly deeper soil depths, obtaining ca. 90% of its water from 10 to 50 cm depth. In contrast, soil moisture in the upper soil layers was significantly lower during the dry season and as a result V. paradoxa shifted to deeper water sources, obtaining ca. 30% of its water from groundwater and ca. 50% from 30 to 600 cm depth. We also found a negative relationship between tree size and the contribution of groundwater during the dry season, whereas during the wet season V. paradoxa predominantly used water near the soil surface regardless of tree size. Knowledge about the sources and patterns of tree water uptake provides crucial information to better understand how trees influence the local water balance.

Impact of tillage and fertility management options on selected soil physical properties and sorghum yield

Water and soil fertility are the most limiting biophysical factors affecting crop production in semi-arid West Africa. . This study was conducted in Nadion (south Sudan zone of Burkina Faso) to assess the impact of tillage practices (no-till, tied ridging; ripping and conventional tillage) combined with soil fertility management options (compost, NPK + Urea, crop residues, Compost+ NPK + Urea and a control) on soil moisture content and sorghum yield. The soil moisture was monitored weekly using the Time Domain Reflectometer (TDR) method and the soil bulk density was evaluated 30 days after planting. Zero tillage increased the soil water storage capacity compared to the other tillage practices at 0-30 cm depth. Sorghum straw residues application improved soil water content by 20%. Conventional tillage decreased surface soil (0-10 cm) bulk density. Compost + NPK + Urea application increased sorghum yield by 74% over the control while, NPK + urea and compost increased sorghum grain yield by 50% and 29%, respectively relative to the control (no soil amendment). Conventional tillage led to decrease in yield compared to zero tillage after two years of experimentation. The zero tillage combined with compost, NPK and urea increased sorghum yield by 28% compared to tied-ridging regardless of the fertility management options. Zero tillage is a promising option for sorghum production in the South Sudan agro-ecological zone of Burkina Faso. Keywords : Bulk density, fertility management, sorghum yield, South Sudan zone, tillage, water conservation.

Effects of farmer managed natural regeneration on livelihoods in semi-arid West Africa

This paper used a multivalued treatment framework to assess the effects of farmer managed natural regeneration (FMNR) on selected outcomes among 1080 rural household farmers in the Sahelian and Sudano-Sahelian ecozone of West Africa Sahel. The results indicate that keeping, protecting and managing trees in the farmland have significant effects on the livelihoods of the rural poor in the Sahelian countries. If 1000 households in a community decide to practice the FMNR continuously, it results in an increase in the gross income by US$ 72,000 per year. Noticeable changes are also observed on the value of tree products, with an observed significant increase in the value of the products harvested from tree by about 34–38 % among those actively practicing FMNR as compared to their counterparts. The results also lend support to the household resilience hypothesis of FMNR in that it leads to a significant increase of the dietary diversity by about 12–14 %. However, it also appeared that several factors impeded the regeneration of trees on farms. To foster the widespread dissemination and enhance the capacity of farmers to increase, diversify and sustain tree-based production systems, an enabling institutional, technical and policy environment needs to be promoted.