Effect of peanut shells amendment on soil properties and growth of seedlings of Senegalia senegal (L.) Britton, Vachellia seyal (Delile) P. Hurter, and Prosopis juliflora (Swartz) DC in salt-affected soils

Abstract

Key message: The soil amendment with peanut shells (4, 6 or 8 t ha−1) improves soil properties and growth ofSenegalia senegal(L.) Britton, Vachellia seyal (Delile) P.Hurter andProsopis juliflora(Swartz) DC seedlings on salty soils (86, 171, 257 mM NaCl). Context: Salinization causes the degradation of biological, chemical, and physical properties of soils. Salty soils reclamation can be achieved with organic amendments and afforestation with salt tolerant species. Aims: The aim of the study was to assess in greenhouse conditions the effect of peanut shells on soil chemical characteristics and growth of multipurpose leguminous trees Senegalia senegal, Vachellia seyal, and Prosopis juliflora under salt-affected soils. Methods: Seedlings were individually cultivated in plastic bags containing a mixture of non-saline and non-sterile soil and crushed peanut shells. Four doses of peanut shells (0, 4, 6, and 8 t ha−1) of 73-33 variety were tested. Salt stress was gradually applied after 1 month of cultivation at a rate of 43 mM NaCl per day until concentrations of 0, 86, 171, and 257 mM were reached. Seedlings growth, physiological responses, and soil characteristics were evaluated after 3 months of stress. Results: Peanut shells application improved soil chemical properties (carbon, nitrogen, phosphorus contents, pH, total microbial activity, and cation-exchange capacity) and reduced soil salinity. They also increased height, collar diameter, shoots and root biomass, chlorophyll, and proline contents of seedlings. Conclusion: The organic amendment with peanut shells improves soil fertility and tree growth under saline conditions.