Improved soil and water conservatory managements for cotton-maize rotation system in the western cotton area of Burkina Faso

Integrated soil fertility management combining additions of organic and mineral fertilizers and reduced ploughing frequencies is a prospective option for sustainable cropping systems. In the cotton cultivation area of Burkina Faso the agricultural land is gradually degrading due (at least in part) to increases in mechanization and the use of mineral fertilizers, herbicides and pesticides. The objective of the work underlying this thesis was to test soil management techniques to improve soil fertility, and the productivity of cotton (Gossypium hirsutum) and maize (Zea mays). For this purpose, a research program was initiated in 2003 at Bondoukuy in the western cotton growing zone of the country. On-farm experiments combining two tillage regimes - annual ox-ploughing (AP) and ox-ploughing/hand hoe scarifying in alternate years, referred to as reduced tillage (RT) - with or without compost addition in a cotton-maize rotation were carried out on two common soil types (a Ferric Lixisol and a Ferric Luvisol). We investigated the effects of the treatments on: (i) soil aggregate stability, (ii) soil infiltrability, and (iii) crops nutrient uptakes and yields. Reduced tillage resulted in greater macroaggregate stability than annual ploughing in both soil types. The compost addition treatments (in combination with annual ploughing or reduced tillage) increased soil saturated hydraulic conductivity (Ks) compared to the annual ploughing without compost addition (control). The soil nutrient status was related to organic and mineral fertilizer inputs, and soil carbon and nitrogen contents were highest (ca 0.6% C and 0.05% N) in plots where compost was applied, after the third year of the experiment. Reducing tillage had no clear effect on cotton and maize nutrient uptake, but compost applications increased N and P uptake by cotton in both soil types. On both soil types, the cotton fibre yields under the reduced tillage regime with compost additions were higher than those obtained under the control, although the differences were not always statistically significant. The trend of maize production was: higher production under the annual ploughing with compost addition than the control on the Lixisol, while it was the reduced tillage with compost addition, on the Luvisol. The results supported earlier conclusion that the effects of soil management techniques on crop production depend on the seasonal rainfall pattern. In spite of the short term of the experiment, reduced tillage with compost addition seems to be a suitable option for the smallholder farmers. As recommendation; soil fertility management regimes in the cotton maize rotation system should mix compost application or other organic matter source with mineral fertilizer, and should consider ploughing frequency

Soil moisture in forest island and adjacent ecosystems in Sub-Saharan Region

Forest islands are widely distributed throughout West Africa savanna landscape. Stated as direct outcome of anthropogenic activity, these mosaics are often found around villages and are known for their unique and luxuriant characteristics of tropical rainforest. Althought significant studies focus on their ecology, works on edaphic factors that govern their establishment are very scare. The objective of the current study was to evaluate soil moisture dynamics in forest islands compared to that of surrounding savannas and farmlands at five sites located along a precipation gradient in Burkina Faso. For two years, from 2016 to 2017, soil moisture was monitored at a depth of 0-80 cm using a neutron probe. The results highlighted a seasonal pattern ranging from 42±2% during the heavy rainy month (August) to 16±1% during the dry season (October-November). Significant differences in soil moisture content soil water profile and water stock at depth 0 to 80 cm were recorded between locations and land use patterns. In general, soil moisture was on average 58% less in forest island than in croplands across sites. Soil moisture content was lower in topsoil (0-20 cm) compared to deeper soil (40-80 cm). The Study demonstrated evident link of soil moisture dynamic with rainfall and the vegetation pattern

Improvement of sorghum productivity through introducing integrated soil fertility management options in the Northern Sudanian zone of Burkina Faso

Agricultural intensification is a necessity to ensure food security in the Sahel countries. This study aimed at assessing the effects of technological packages of integrated soil fertility management on sorghum productivity. An experiment was set up in dispersed blocks design where each producer constituted a repetition. Fertilizers were applied using the microdose technique. The results showed that the best grain yields of sorghum are obtained with the technology combining stone bunds + zaï + NPK + urea with respectively 1428.70 kg / ha in 2018 and 1158.40 kg / ha in 2019. The grain yield gaps between the current farmers’ practice under stone bunds and ISFM packages varied from 5.66% to 44.45% in 2018 and from 25.15% to 53.80% in 2019. In the context of climate variability and climate change, these results show that water harvesting techniques such as stone bunds and the zaï, associated with microdose are viable and sustainable alternative for improving agricultural productivity. L’intensification agricole est une nécessité pour assurer la sécurité alimentaire dans les pays du sahel. Cette étude avait pour objectif d’évaluer les effets de paquets technologiques de gestion intégrée de la fertilité des sols sur la productivité du sorgho. Pour ce faire, un dispositif en blocs dispersés a été mis en place en milieu paysan où chaque producteur constituait une répétition. Les paquets technologiques se composent des formules de fumures et/ou des techniques de conservation des eaux et des sols (CES). Les engrais ont été apportés selon la technique de la microdose. Les résultats ont montré que les meilleurs rendements grains du sorgho ont été obtenus avec la technologie cordons pierreux + zaï + NPK + urée avec respectivement 1428,70 kg/ha en 2018 et 1158,40 kg/ha en 2019. Les gaps de rendement grains entre la pratique actuelle des producteurs sous cordons pierreux et les paquets technologiques ont varié de 5,66% à 44,45% en 2018 et de 25,15% à 53,80% en 2019. Dans le contexte de la variabilité et des changements climatiques, ces résultats montrent que la collecte et la valorisation de l’eau à la parcelle à travers les cordons pierreux et le zaï, associée à la microdose est une alternative viable et durable d’amélioration de la productivité agricole

Vegetation improvement and soil biological quality in the Sahel of Burkina Faso

Soil living environment contains macro-fauna that play important role in the soil structure and chemical composition, the degradation process of organic matter and in the resilience of ecosystems. Few studies evaluated the impact of the “re-greening” trend observed in the Sahel on soil biological quality. The objective of this study is to assess the impact of the “re-greening” of the Sahel on soil macro-fauna population and diversity. The method of Tropical Soil Biology and Fertility (TSBF) was used to assess macro-fauna abundance and diversity in different land use types (cropland, shallow land, degraded land and forest). Four sites were selected, in the Sahelian zone of Burkina Faso, with contrasted Normalized Difference Vegetation Index (NDVI). In each site, four repetitions were taken for each land use type. In total, 64 plots samples were used to assess the abundance of macro-fauna. Results showed that there were more individuals (64.92%) and higher macro-fauna density in re-greening zones compared to the degrading zones. There was dominance of Arthropoda phylum (60.85%), Insecta class (59.03%) and Isoptera order (46.97%) in macro-fauna population. There were more species in the shallow land and cropland in re-greening zones and all trophic groups are represented in all sites. Despite this abundance, composition and diversity, it was observed that the re-greening processes have not significantly improved soil biological quality. It is concluded that vegetation improvement might be at the beginning stage in the Sahel, especially in croplands, and clear change of soil biological quality is not perceptible but may be tangible in the future.Keywords: Macro-fauna, ecosystem, soil quality, re-greening, degradation

Water efficiency and productivity concepts. A review.

Water efficiency and productivity indicators are used in many scientific disciplines, usually to account for water losses that occur during its use, or products generated per unit of water consumed. The interpretation of these indicators is very diverse in the literature. However, the majority of definitions consider water efficiency as a measure of the effectiveness of irrigation, and view water productivity as a measure of the effectiveness of the physiological processes of both biomass production and crop yield formation, linked to the actual consumption of water by the crops. Thus, the consensus seems to be for water application efficiency (Ea) to be considered as the ratio of actual evapotranspiration to the water applied and productivity as the ratio of yield to actual evapotranspiration. The point of divergence relates fundamentally to the understanding of the constituent expressions of productivity (PE, product/“water consumed”) and efficiency of water application (Ea, “water consumed”/“applied water”). Indeed, the term “water consumed” is referred to variously by several authors as “actual evapotranspiration”, “gross irrigation plus rainfall”, “evapotranspiration plus water lost at the plot but beneficial to other users”, etc. Furthermore, while providing more details on the concepts of efficiency and water productivity, this review shows that the factors affecting these indicators have not yet been sufficiently elucidated. Thus, one of the axes of investigation could be to model the application efficiency of water firstly, according to water management practices and secondly, in terms of productivity levels in relation to the crop establishment period

Soil tillage practices and crops rotations effects on yields and chemical properties of a lixisol in Burkina Faso

Objective: To improve soil chemical properties and crops productivity, this study was conducted from 2008 to 2015, on lixisoil in a research station, using reduced soil tillage and leguminous plant cover.Methodology and Results: Three soil tillage practices in main plot (T1 = no tillage with direct sowing, T2 = minimum tillage by soil scarifying with IR12 tool and T3 = conventional tillage with animals drawn plough) were compared and combined to four crops rotation systems, in a split-plot experimental design. Soil chemical characteristics and crops yields were evaluated. The results showed that tillage practices did not influence significantly the soil chemical properties, but soil organic matter contents, nitrogen, phosphorus and potassium were lower in conventional tillage plots (T3) compared to minimum tillage (T2) and no tillage (direct sowing). Rotations did not significantly influence nitrogen and soil organic matter contents, even the leguminous mucuna insertion in the rotation during three years. After 8 years, crops rotations improved significantly cotton (Gossypium hirsutum L.) and maize (Zea mays L.) yields. The yield increases were respectively +7, +23 and +43%, with one, two and three years of mucuna insertion into rotations. No tillage (direct sowing) and minimum tillage (scarifying with IR12) were as efficacy as conventional tillage on Mucuna and maize yields whereas cotton yield, with minimum tillage (T2) was significantly higher than no tillage (T1).Conclusion and application of results: The study showed that conventional tillage with mouldboard plough, appear to be the soil tillage practice, which led to soil properties degradation. Crops rotations with the use of leguminous mucuna allowed reducing soil N contents decreases. No tillage (direct sowing) and minimum tillage (scarifying with IR12) showed same efficacy with conventional tillage on cotton, maize and mucuna yields, which were improved after mucuna insertion into crops rotations. Therefore, tillage suppression or its reduction combined to one year leguminous cover plant insertion in rotation (mucuna-cotton-maize) could be used for crops diversification and sustainable productivity in cotton and cereals based production systems.Keywords: Tillage practices, crops rotations, plant cover, soil fertility, yields, Burkina Fas

Effet de micronutriments et de nutriments secondaires sur la production du mil et du sorgho en Zone nord soudanienne du Burkina Faso: Effect of micronutrients and secondary nutrients on millet and sorghum production in the North Sudan Zone of Burkina Faso

L’inadéquation de la fertilisation minérale est une contrainte qui limite la production du sorgho et du mil au Burkina Faso. Cette étude vise à déterminer l’effet des nutriments secondaires et des micronutriments (NSM) dans la production du sorgho et du mil sur des sols ferrugineux tropicaux lessivés du Burkina Faso. Elle a été conduite en station expérimentale à Saria de 2018 à 2019. Le dispositif expérimental est constitué d’un bloc de Fisher avec trois répétitions. Sept traitements ont été comparés : Témoin (0), NPK (60-15-20), NPK+S (60-15-20-15S), NPK+Mg (60-15-20-10Mg), NPK+Zn (60-15-20-2,5Zn), NPK+B (60-15-20-0,5B) et Complet (60-15-20-15S-10Mg-2,5Zn-0,5B). Le rendement grain du sorgho a été significativement augmenté avec les traitements combinant les NSM au macronutriment. Contrairement au sorgho, cette combinaison a entraîné une baisse des rendements grain du mil. Les rendements grains du sorgho ont augmenté de 40% en 2018 avec les traitements Complet, NPK+S, NPK+Zn et NPK+Mg. En 2019, ces augmentations ont été de 53%, 23% et 16% respectivement avec les traitements Complet, NPK+B et NPK+S par rapport au NPK. L’apport d’engrais composé de NPK combiné au NSM et à la matière organique est une alternative pour accroître durablement les rendements des céréales. The inadequacy of mineral fertilization is a constraint that limits the production of sorghum and millet in Burkina Faso. This study aimed at determining the effect of secondary nutrients and micronutrients (NSM) in the production of cereals on leached tropical ferruginous soils from Burkina Faso. It was conducted in the Saria experimental station from 2018 to 2019. The experimental design consisted of a Fisher block with three repetitions. Seven treatments were compared: Control without fertilizers (0), NPK (60-15-20), NPK + S (60-15-20-15S), NPK + Mg (60-15-20-10Mg), NPK + Zn (60-15-20-2,5Zn), NPK + B (60-15-20-0,5B) and Complete (60-15-20-15S-10Mg-2,5 Zn-0,5B). The grain yield of sorghum was significantly increased with the addition of NSM to the NPK. However, millet grain yield was decline with NSM addition to NPK treatment. The Complete, NPK + S, NPK + Zn and NPK + Mg treatments showed 40% increasing in grain yield of sorghum compared to NPK in 2018. Complete, NPK + B and NPK + S treatments which increased the grain yield of sorghum by 53%, 23% and 16% respectively in 2019. Adding NPK fertilizer combined with NSM and organic matter is an alternative to achieve sustainable increasing of grains yields

Site-specific responses of lowland rice to acidulated and calcined phosphate rock fertilizers in the Center-West region of Burkina Faso.

Soil phosphorus (P) deficiency is a major constraint of crop production in Sub-Saharan Africa. In particular, in the Sudano-Sahelian zone of Burkina Faso, P is rarely replenished as fertilizer supplies are limited in rural areas and because of the socio-economic situation of farmers. There is however, an abundance of local phosphate rock resource in the country. The development of local inorganic P fertilizers to improve crop production and replace the nutrients removed after harvesting, as well as to promote to sustainable agriculture, is desired. This study evaluated the efficiency of low-grade Burkina Faso phosphate rock (BPR)-based P fertilizers, produced by acidulation and calcination-the major fertilizer processing methods, on lowland rice production and the soil factors influencing their effectiveness. The results showed that the acidulated P fertilizers were as effective as conventional commercial P fertilizers on various soil types, textures, and fertility. Calcined P fertilizers were consistently effective on fine-textured soils with high basic fertility. It was found that fine soil texture and basic fertility of the initial soils were important factors in agronomic efficiency of BPR-based fertilizers and the resilience of rice production to climatic variability. It is recommended that soil type, with respect to soil texture, soil properties, inherent fertility, and water availability, should be considered when using BPR-based fertilizers for rice cultivation

Structure, composition spécifique et diversité des ligneux dans deux zones contrastées en zone Sahélienne du Burkina Faso

This study conducted in the Sahel of Burkina Faso presents the current state of woody vegetation in this region so as to establish the link between the reality on the ground and satellite observations in two sites within each of the two contrasted zones ; one presenting a certain rate of re-greening and the other of degradation. It also analyzes the specific composition, the structure, ligneous diversity and the similarities between four sites (two sites by two zones). The study used a stratified random sampling method analyzing 104 plots of 20 x 20 sqm. Statistical analysis showed significant differences in density, number of species, height class, diameter class and Simpson and Shannon indices between the two zones. The highest values were observed in the re-greening zone. We also noted a significant difference in density, diameters and heights according to land use. The fields in the re-greening zone have the highest values of density and height, but the lowest diameters. The re-greening in the Sahel is more apparent in the fields