Eco-restoration of degraded lands through trees and grasses improves soil carbon sequestration and biological activity in tropical climates

Abstract

Despite several studies, role of eco-restoration strategies involving trees and grasses on soil organic carbon pools and fractions, response of soil enzymes in degraded land of tropical climate has remain largely overlooked. Four native fast growing fodder trees, namely, Ficus infectoria, Morus alba, Acacia nilotica and Leucaena leucocephala with combination of grasses viz., Cenchrus ciliaris, Chrysopogon fulvus and Panicum maximum were used as eco-restoration tool in Bundelkhand region. Total organic carbon (TOC), microbial biomass C (MBC), and activities of important soil enzymes were measured. After 9 years, land under Ficus, Morus, Acacia and Leucaena had ~63, 105, 87 and 81% greater TOC than fallow land in surface layer and Cenchrus, Panicum, and Chrysopogon increased TOC by 84, 91 and 77% at surface layers, respectively, over fallow land. MBC increased by 2–2.5 folds in both soil layers. All C fractions responded positively to eco-restoration. Ficus, Morus, Acacia and Leucaena boosted up carbon management index (CMI) by 51, 84, 71 and 65% at surface layers, respectively over fallow land. Similarly, grasses also improved CMI by >60%. Soil organic carbon accumulation under Ficus, Morus, Acacia and Leucaena were ~ 55, 91, 77 and 71% higher than fallow land at surface layers, and 71, 85, 95 and 69% higher than fallow land at subsurface soil layers. We developed an index for comparing ecorestoration efficiency (ERE). We found Morus + Panicum, Acaia + Panicum to be effective restoration strategies for eco-restoration under degraded lands of tropical climates. Our study indicated that implementation of these ecological restoration strategies could be a quantitatively important component of national climate change mitigation strategies in India and thus should be continually paid a great attention.