Effet du zaï amélioré sur la productivité du sorgho en zone sahélienne

La présente étude a pour objectif de montrer qu’en combinant la gestion de l’eau et de la matière organique avec la technique de zaï de restauration des sols, on peut assurer une meilleure production des cultures sur les sols dégradés. Dans ce cadre, un dispositif expérimental en blocs de Fischer randomisés a été utilisé pour tester la capacité de germination, la croissance et le rendement du sorgho sur les sols dégradés en fonction de la taille des poquets et des amendements organiques. En se basant sur les différents niveaux de ces deux facteurs, ce dispositif est constitué de 32 parcelles élémentaires représentant 8 traitements factoriels (2 x 4) et 4 réplications. Les résultats montrent un effet significatif de la taille des poquets et du type d’amendement sur la germination, la croissance et le rendement du sorgho. Le rendement en grains varie entre 383,10 ± 32,13 kg/ha dans les grands poquets de zaï + compost et 5,77 ± 1,90 kg/ha dans les petits poquets de zaï sans amendement. Les grands poquets augmentent les rendements en grains surtout au niveau des traitements zaï + compost dont ils améliorent significativement les rendements de 25 % par rapport aux petits poquets. La technique du zaï avec les grands poquets associée à l’amendement du compost peut donc permettre une production soutenue de la culture sur les terres dégradées en zone sahélienne.Impact of improved zaï on the yield of sorghum in sahelian zone. The present study aims to show that the effect of the organic matter and water management with zaï soil restoration technique, could improve agricultural productions on degraded soils. For this purpose, a random block experimental design of Fisher was used to test the germination capacity, the growth and the yield of sorghum on degraded land following zaï hole size and organic input. Base on different levels of these two factors, this design is formed by 32 plots accounting for 8 factorial treatments (2 x 4) and 4 replications. The results showed a significant effect of the size of the zai hole, the type of organic materiel input on the germination capacity, the growth and the yield of sorghum. The grain yield is ranged from 383, 10 ± 32, 13 kg/ha in zai big hole associated with compost input to 5, 77 ± 1, 90 kg/ha in small hole without organic input. The big holes increased grain yields especially in compost input treatment whose yields were 25 % higher than in small holes. The zai system with big hole associated with compost input could stand the agriculture productions on degraded land in sahelian zone

Effet du zaï amélioré sur la productivité du sorgho en zone sahélienne

Impact of improved zaï on the yield of sorghum in sahelian zone. The present study aims to show that the effect of the organic matter and water management with zaï soil restoration technique, could improve agricultural productions on degraded soils. For this purpose, a random block experimental design of Fisher was used to test the germination capacity, the growth and the yield of sorghum on degraded land following zaï hole size and organic input. Base on different levels of these two factors, this design is formed by 32 plots accounting for 8 factorial treatments (2 x 4) and 4 replications. The results showed a significant effect of the size of the zai hole, the type of organic materiel input on the germination capacity, the growth and the yield of sorghum. The grain yield is ranged from 383, 10 ± 32, 13 kg/ha in zai big hole associated with compost input to 5, 77 ± 1, 90 kg/ha in small hole without organic input. The big holes increased grain yields especially in compost input treatment whose yields were 25 % higher than in small holes. The zai system with big hole associated with compost input could stand the agriculture productions on degraded land in sahelian zone

Regeneration of five Combretaceae species along a latitudinal gradient in Sahelo-Sudanian zone of Burkina Faso

• Seedling density and the regeneration mechanisms of five tree species, Anogeissus leiocarpa, Combretum aculeatum, Combretum micranthum, Combretum nigricans, and Pteleopsis suberosa were investigated in relation to latitudinal gradient across the Sahelo-Sudanian zone of West Africa. • Data were collected on 461 quadrats (2m × 5m) laid out every 30 m on transect lines through Combretaceae communities at four latitudinal positions. Regeneration mechanisms were determined by excavating the below ground root system and assessing basal and aerial sprouts. • The results showed a significant species × latitudinal position effect on the total density of seedling populations, and the density of single- and multi-stemmed individuals (p < 0.001). C. aculeatum and C. micranthum were abundant in the North-Sahelian sector, C. nigricans and P. suberosa in the Sudanian sector and A. leiocarpa across a wide range from the South-Sahelian to South-Sudanian sectors. In general, 58% of the seedlings were regenerated asexually (as coppice, water sprout, layer, and root sucker) while 42% were sexual recruits (as true seedling and seedling sprouts). The proportion of vegetatively propagated seedlings increased with increasing latitude for all species except C. micranthum, for which a clear decreasing trend was observed. The relative importance of the different regeneration mechanisms varied among species: seedling sprouts were important for A. leiocarpa, C. aculeatum and C. nigricans, coppice for C. micranthum and sucker for P. suberosa • The significant interaction observed between species and latitudinal position highlights the importance of accurate species-site matching to ensure successful restoration of degraded areas in the Sahelo-Sudanian zone. Inter-species differences in regeneration mechanism could be related to their biology and ecological adaptation to the site-specific biotic and abiotic factors

Climate change threat magnitude levels ‘Very high’ and ‘High’ combined for all species.

<p>The criteria to define the threat levels are presented in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0184457#pone.0184457.t005" target="_blank">Table 5</a>.</p

<i>Boscia senegalensis</i>.

<p><b>Threat magnitude levels of (A) ‘Overexploitation’, (B) ‘Overgrazing’, (C) ‘Fire’, (D) ‘Climate change’, (E) ‘Cotton production’, (F) ‘Mining’ and (G) ‘Combined threat’.</b> The criteria to define the threat levels are presented in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0184457#pone.0184457.t005" target="_blank">Table 5</a>.</p

Species richness map of 16 important food tree species and eco-climatic zones.

<p>The three eco-climatic zones (Sahelian zone: < 600mm/a, Sudano-Sahelian zone: 600–900 mm/a and Sudanian zone: > 900 mm/a) are defined by the annual rainfall [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0184457#pone.0184457.ref004" target="_blank">4</a>] and are represented in this map by the bioclimatic variable 12 from the WorldClim 1.4 dataset [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0184457#pone.0184457.ref041" target="_blank">41</a>].</p

Threat magnitude rating.

<p>Threat magnitude rating.</p