Direct seeding of six agroforestry tree species indigenous to the Sahel: the effect of fungicide and planting-hole depth on seed germination and seedling emergence capacity

Trees play a key role in drylands. Monitoring woody communities regeneration and understanding the drivers of its success is crucial to apprehend their long-term persistence. While re, grazing and water availability are key factors for regeneration in drylands, seeds arrival, germination and seedlings recruitment are still poorly studied in natural conditions in the West African Sahel. To promote regeneration, tree planting is a common tool used in West Africa. The cost is great, the success variable and their in uence on spontaneous regeneration is unknown. In this study, we conducted eld inventory to characterize the regeneration ability of woody communities in a Sahelian savanna. We investigated regeneration and adults stands in three land management types (plantations, communal grazing, old enclosures) to determine (i) the proportion of the regeneration modes and the in uence of mature trees; (ii) the in uence of management type and topography on regeneration; and (iii) their temporal dynamics. We rst showed that the regeneration diversity is poor, with half of the adult species not recorded in the regeneration phase. Most of the regeneration came from true seedlings compared to resprout. Second, mature trees have a strong in uence on regeneration density and composition. Third, topography in uences regeneration density whereas we observed little effect of the land management type. Finally, historical data highlighted a steep decline of regeneration density these last decades. These results question the persistence of woody vegetation in Sahelian savannas and highlight the need to protect large trees, in suitable micro-sites such as depressions to favor regeneration.

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Cost-effectiveness and ecological performance of direct seeding to compose arrangements in biodiverse agroforestry systems

Lobtchenko

Fernandes

Santos

et al. 2023

Preprint

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Deforestation of primary vegetation and degradation of pastures in Brazil has presented alarming numbers in recent years, which demonstrates the emerging need for environmental recovery strategies such as agroforestry systems (SAFs). Thus, the objective was to adopt a low cost technique such as direct sowing to compose spatial arrangements in SAFs in consortium with different agricultural crops and fertilizers, as well as to evaluate the cost-effectiveness. In the experiment, 23 native species from adjacent fragments were used. The treatments were formed by combining 2 sowing densities (5 and 10), 2 fertilizers (bovine manure and poultry litter), and 2 agricultural crops (watermelon and pumpkin). The seeds were arranged in a planting furrow measuring 2m in length, 10 cm in width and 5 cm in depth, spaced 2m apart and 2m between plots. Each treatment consisted of three repeat, and each repeat with 2 planting furrows. The use of direct seeding is a promising technique to increase species diversity in the composition of spatial arrangements of SAFs, especially if combined with organic fertilization and cultivation of agricultural crops, which has proven to be a profitable alternative to reduce restoration costs, can be completely amortized in a second cycle of cultivars, because until the establishment of the tree canopy of native species, the cultivation of agricultural crops can be a source of income to the farmer and ensure their food security.

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Direct seeding of six agroforestry tree species indigenous to the Sahel: the effect of fungicide and planting-hole depth on seed germination and seedling emergence capacity

Cited by 3 publications

References 30 publications

Managing tree cover to restore farm productivity and build landscape and livelihood resilience in West Africa

Managing tree cover to restore farm productivity and build landscape and livelihood resilience in West Africa

Sahelian woody communities are endangered by regeneration impoverishment in three land management types

Cost-effectiveness and ecological performance of direct seeding to compose arrangements in biodiverse agroforestry systems

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