The agricultural suitability of cashew nut substrate on the growth and yield of Sorghum Bicolor L. (Sorghum) and Arachis Hypogaea L. (Peanut) according to the sampling distance (Casamance / Sénégal)

Abstract

The issue of cashew tree allelopathy and in particular the association with annual crops often comes up in the agronomy debate. The aim of this study is to test the agricultural suitability of cashew nut substrate on sorghum and groundnut crops. For this purpose, three types of substrates were sampled at a distance from the crown of the cashew tree (R/2), at the edge of the crown (R) and at a distance equivalent to twice the crown radius (2R). These substrates are then placed in trays for the cultivation of these two species under semi-controlled conditions. The experiment was carried out in a site completely exposed to the sun and isolated from the trees in order to avoid shading and competition with soil nutrients. A total randomized experimental design consisting of three treatments (three types of substrate) in 5 replicates was used. Results showed that the total biomass production of sorghum on the R/2 substrate was twice as high as that obtained on R and 2R. It is estimated at 252g under R/2, 135g for R and 138g under 2R. As for sorghum, total groundnut biomass (leaves, roots, pods and stems) total biomass is higher on R (331g) and R/2 (294g) substrates compared to 2R (257g) with a significant difference (p = 0.0129). Most of the variables of the crops studied were more important on under cover than off cover. These results would indicate that if allelopathy is present, it would not be related to the substrate under the tree. A field experiment allowing the introduction of other parameters, such as the shading effect, would allow a better understanding of the conditions under which crops are associated with cashew nuts. This would be an alternative in improving crop yields and would also contribute to a better security for producers.