Soil Properties Under Manured<i>Tamarindus indica</i>in the Littoral Plain of South-Western Madagascar

Abstract

Abstract The current study investigated how the presence of tamarinds and manure affect (1) soil chemical properties; (2) C and N mineralization; (3) microbial biomass indices (C, N, and fungal ergosterol); (4) microbial residues, that is, amino sugars; and (5) the germination of sorghum seeds in soils of the littoral zone in southwestern Madagascar. Soil pH was lower under than outside the tamarind canopy, whereas SOC, total N content, and the cation exchange capacity were roughly three times higher than in the uncovered situation. Under the tamarind canopy, basal respiration was increased nearly threefold, whereas net N mineralization remained unaffected. However, net N mineralization was increased by 74% in the manure treatment, especially under the tamarind canopy. Tamarind did not inhibit the germination of sorghum seeds. Contents of microbial biomass C and N, and especially fungal ergosterol, were also higher under the tamarind canopy. Muramic acid, galactosamine, and glucosamine were increased threefold under the tamarind canopy. The mean fungal C to bacterial C ratio was 0.67 and remained unaffected by any treatment. The presence of manure increased the contribution of microbial residue C to SOC from 28% to 41% and of microbial biomass N to total N from 3.5% to 5.6%, especially under the tamarind canopy. Keywords: basal respirationergosterolmicrobial biomassmicrobial residuesN mineralizationSOC Acknowledgements We greatly appreciate the technical assistance and advice of Gabriele Dormann. Furthermore, we would like to thank Rakotomalala Yedidya Ratovonamana, Dr. Katja Brinkmann, Sabine Ahlers, Ann-Katrin Becker, Luisa Bierwirth, Mick Locke, Tahiry Ranaivoson, Jemisa Rarojoson, Dr. Eike Rommelfanger, Anja Sawallisch, Claudia Thieme-Fricke, and Eva Wiegard for their indispensable help and advice.