Soil fauna significantly influences soil properties. Organic and inorganic fertilization in agriculture, including the amendment with phosphate rock, may affect its presence in soils. This study evaluated the effect of calcined phosphate rock associated with organic matter on the abundance and diversity of soil macrofauna in semi-arid areas of Burkina Faso. Nine treatments were replicated four times each and applied in a complete randomized block design in sorghum and cowpea fields. These treatments were: absolute control (Control) without fertilizer, control with organic matter only (OM), Burkina Phosphate Rock (BPR) with 23 P ha-1, calcined phosphate rock (CPR with 23 P kg ha-1), Triple super phosphate (TSP), complex fertilizer (NPK), CPR ½ +TSP ½, CPR ¾ +TSP ¼, CPR ¼ +TSP ¾ Urea provided N, and KCl supplied K in the BPR and TSP treatments. P was supplied by Triple Super Phosphate (TSP) in the TSP treatment. K and P were supplied by the complex fertilizer NPK in NPK treatment. Results showed that BPR and CPR did not significantly (P˃0.05) improve soil fauna abundance and diversity after two years. Four orders, Coleoptera, Haplotaxida, Hymenoptera, and Isoptera, were largely dominant (more than 50 %) in all treatments, crops, and years. The population diversity of soil macrofauna rises from 0.98 (2021) to 1.49 (2022) in the sorghum field and from 1.16 (2021) to 1.63 (2022) in the cowpea field. Soil macrofauna numbers rise from 24.64 ind/m2 (2021) to 39.59 Ind/m2 (2022) in the cowpea field. Our findings suggest that cultivated soil fauna can be managed more appropriately with fertilizers from phosphate rock by combining organic matter application and cereal-legume associations.

Due to its multiple functions, soil macrofauna plays a major role in the functioning of agroecosystems. However, its abundance and diversity can be influenced by various human activities such as agricultural practices. This study, initiated on ferric lixisols in the Sudano-Sahelian zone of Burkina Faso, aims to evaluate the effects of four agroecological practices on soil macrofauna. So, forty farmers' plots were sampled, based on a typology of cropping practices, associating water and soil conservation techniques (stone barriers) with generalized or localized (zaï) application of organic matter. Generalized input of organic matter is combined with mineral fertilization by microdose or not and localized input is combined with crop rotation or not. Macrofauna was collected, sixty days after sowing, using the monolith method. Three (3) monoliths were collected per plot. Manually sorted macrofauna was identified in the laboratory. The results allowed that thirty-six (36) families were identified whom the best abundant are: Termitidae (35 %), Formicidae (18 %) and Iulidae (7.7 %). Functionally, saprophages constitute 61.4 % of the population against 16.6 % of phytophagous, 13.9% of predators and 7.6 % of geophagous. Agroecological practices with uniform application of organic manure yielded the highest number of invertebrates (62.2 %) compared to localized application (37.8 %). The use of organic manure as an agroecological practice allows for better colonization of the soil by living organisms, provided that it is evenly distributed throughout the plot.

Sorghum is the staple crops in the Saharan areas of West Africa. Like other crops, its production is highly dependent on the improved crop seed varieties and on water use efficiency (WUE) and nitrogen use efficiency (NUE). The objective of this study was to assess the effect of sorghum root growth and water and nitrogen use efficiency on grain yield and harvest index under rainfed and drip irrigation conditions. The study was conducted in the Central region of Burkina Faso in 2014. The improved seed variety Sariaso 14 was sown. 60 kg ha-1 of nitrogen was applied. A randomized split-split-plot design with four replications was used. The results showed that the two watering systems had significant effects on sorghum WUE, NUE, root growth, grain yield and harvest index. Root growth was found to be twice higher in the rainfed condition than in the irrigation one. On the other hand, WUE and NUE were higher by 92 and 26% respectively in the irrigated plot. Irrigation was found to improve grain yield and harvest index by 44% and 56% respectively. Irrigation is considered more beneficial for farmers given the erratic distribution of rainfall.