The zai system is a traditional agricultural practice used for crops production for water and nutrients management. A study was conducted in Burkina Faso at Kamboinsin to evaluate the profitability of the zai use in cowpea cultivation. Treatments consisted of three levels of drought stress (control, drought stress at seedling and flowering stages), three zai levels (control (tillage); 15 and 25 cm zai depth) and the variety at four levels (Gorom local, Moussa local, KVx396-4-5-2D, Tiligre). The experimental design was a split-split-plot replicated three times. Grain yield and economic data were recorded and cost and returns analysis performed. 25 cm zai depth recorded the highest total variable cost and the control the least. In control conditions, the highest grain yield and net revenue were recorded in 25 cm zai depth for 50% of the varieties and in 15 cm zai depth for the others. In seedling and flowering stages drought stress conditions, the highest net revenue was recorded in 25 cm zai depth, while the lowest was recorded in the control (tillage). The highest benefit-cost ratio was consistently registered in the control (tillage) for drought-tolerant varieties. For drought-sensitive varieties, higher benefit-cost ratio was registered in zai pits in seedling-stage drought stress conditions. The use of manual zai substantial increases cowpea grain yield, but does not consistently guarantee a high economic profit. The mechanical construction of zai could reduce the cost of pits implementation and increase the financial profitability.

The diagnosis of fertility is a prerequisite for the formulation of balanced and site-specific fertilizer recommendations. To do this, omission trials were set up on 60 plots in the Sourou Valley. The trials were divided into Hydromorphic tropical eutrophic ferruginous brown soils and Vertic tropical eutrophic ferruginous brown soils. Each trial included 06 treatments: 0N-0P-0K, 0N-30P-40K, 120N-0P-40K, 120N-30P-0K, 120N-30P-40K and 120N-30P-40K + 2.5 t.ha-1 of organic matter. Grain and straw yields, soil chemical characteristics and plant nitrogen, phosphorus and potassium exports were determined. The results showed that Vertic tropical eutrophic ferruginous brown soils are slightly richer in carbon, nitrogen and phosphorus than into Hydromorphic tropical eutrophic ferruginous brown soils. Indeed, the initial nitrogen, phosphorus and potassium contents calculated from the exports were respectively 71.20 kg.ha-1, 30.02 kg.ha-1 and 187.19 kg.ha-1 for the Vertic tropical eutrophic ferruginous brown soils, against 52.47 kg.ha-1, 19.10 kg.ha-1 and 159.62 kg.ha-1 for the into Hydromorphic tropical eutrophic ferruginous brown soils. Furthermore, the results showed that nitrogen and phosphorus are the two limiting nutrients for rice production on these two soil types. The internal N use efficiency was 80.59 kg grain.kg-1 N on into Hydromorphic tropical eutrophic ferruginous brown soils and 60.09 kg grain.kg-1 N for Vertic tropical eutrophic ferruginous brown soils. The results of this diagnostic will be used as a basis for the formulation of balanced and site-specific fertilizer recommendations.

The deficiency in available phosphorus for crops is a major constraint on cereal production in Mali. The objective of this study was to assess the combined effects of phosphorus sources at different rate and tillage practice on maize agronomic performance and soil chemical properties. The treatments used consisted of the combination of three sources of phosphorus at three doses each and two types of tillage, arranged in a split-plot device with three repetitions. Contour plowing increased corn grain yield by 22 and 16% compared to conventional plowing in 2013 and 2014, respectively, and improved the availability of PNT's phosphorus due to its ability to increase soil moisture. Maize growth and phosphorus uptake were better with contour plowing compared to conventional plowing with an increase of 44% and 65% respectively in 2013 and 2014. Relative agronomic efficiency was higher with contour plowing. level compared to conventional plowing. The powdered form of PNT significantly (P <0.05) increased phosphorus adsorption indices compared to the granule form. These results show that there is a great opportunity to improve maize production in Mali through the use of natural phosphorus combined with an adequate tillage practice.

Burkina Faso's agricultural systems are space-intensive and are characterized by their low productivity. In the past, a shifting cultivation system with fallow was practiced by farmers. With demographic pressure and the migratory phenomenon, this traditional system of regeneration and management of soil fertility has almost disappeared. The search for manure formulas adapted to the main crops of the East was the object of our study. To this end, a participatory evaluation using the matrix scoring method made it possible to establish the value of these combinations of manures. The study covered thirty (30) fields in leached tropical ferruginous soils with a sandy clay texture (Kotchari, Pentinga). The participatory evaluation by producers made it possible to assess the probability of acceptance of several manure formulas by them. This probability of accepting the manure options generally reflects the performance of a combination of manures and the producers' preference for this manure. For the producer, yield, economic reproducibility, accessibility to inputs and valuation of labor constitute criteria for the adoption or rejection of a manure formula. The cultural weight of speculation is also a criterion for adopting a fertilizer formula. It emerges from this participatory evaluation: the relevance of the organo-phosphate manure formulas (5t / ha fo + 50Kg / ha Urea 5t / ha; fo + 200Kg / ha BP + 50Kg / ha Urea and 5t / ha fo + 200Kg / ha BP + 50Kg / ha Urea + 150Kg / ha NPK on sorghum; 200Kg / ha + 100Kg / ha NPK BP 200Kg / ha BP + 50Kg / ha Urea). It is therefore advisable to produce enriched composts with a view to intensification. Organo-mineral manure is essential for the peasants in a perspective of sustainable intensification and in their agro-socio-economic criteria. The agronomic effectiveness of rock phosphate associated with mineral fertilizers (Urea, NPK especially) on cowpeas is perceived and seems a less expensive alternative.Judicious management of local resources (natural phosphates, organic matter) combined with good cultivation techniques (crop associations and rotations) can be an alternative to the use of imported fertilizers and an approach for the development of sustainable agriculture.