Litterfall production and associated carbon and nitrogen flux along exclosure chronosequence at Kewet district, central lowland of Ethiopia

Fikrey Tesfay,Kiros Meles Hadgu,Kibebew Kibret,Aster Gebrekirstos

doi:10.1186/s40068-020-00172-7

Fikrey Tesfay, Kiros Meles Hadgu + Show 2 more

Open Access

https://doi.org/10.1186/s40068-020-00172-7

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Abstract

BackgroundLitterfall input and associated nutrient flux are critically important in the restoration of soil in degraded landscapes through exclosures. This study was conducted to evaluate the effects of exclosure on seasonal litterfall production and nutrient content, and estimate annual C and N inputs to the soil in an age sequence at Kewet district, central lowland of Ethiopia. Leaf litterfall production was recorded by a 0.25 m2 litter trap from a systematically laid line transects from 5, 15, and 20 years old exclosures and adjacent grazing land.ResultsLeaf litterfall input in the exclosures ranged from 37 g m−2 in January (at the old exclosure) to 7.33 g m−2 (at the young exclosure), and 3 g m−2 in March at the grazing land. Litterfall input showed seasonal variation and peaked in the dry months. Mean monthly leaf litterfall production was significantly (p <0.05) higher (22 g m−2) in the old exclosure than the adjacent grazing land (9 g m−2). Total annual leaf litterfall ranged from 1073 kg ha−1 (grazing land) to 2662 kg ha−1 (old exclosure). There were no significant differences in leaf litterfall nutrients i.e., N, P, K, Ca, and Mg concentrations, except for C. The annual leaf litterfall associated C and N input ranged from 412 (grazing land) to 1025 (old exclosure) and 27 (middle age exclosure) to 68 kg ha−1 (old exclosure), respectively. The positive change recorded in leaf litterfall production and associated C and N return is associated with restoration of vegetation.ConclusionsThrough well-managed area exclosure, leaf litterfall production in the degraded landscapes can reach the level of tropical dry lowland forest in about a decade. Further research on the contribution of dominant tree species in litter production along the age of exclosure is recommended to improve the effectiveness of rehabilitation of degraded lands.

Highlights

Litterfall input and associated nutrient flux are critically important in the restoration of soil in degraded landscapes through exclosures
The pattern of annual C and N input through leaf litterfall mirrored that of annual leaf litterfall production
Nitrogen inputs to the forest floor derive largely from litterfall (Parker 1983). These results suggest that litter is a major process responsible for soil organic matter and nutrient enrichment beneath isolated trees in semi-arid savannas (Mlambo and Nyathi 2008)

Summary

Introduction

Litterfall input and associated nutrient flux are critically important in the restoration of soil in degraded landscapes through exclosures. Litterfall is a principal biological pathway of organic matter return from plant components to the soil through litter decomposition and subsequent release of nutrients (Rogers 2002; Dawoe et al 2010; Kim et al 2010; Demessie et al 2012). It plays an important role in energy and Tesfay et al Environ Syst Res (2020) 9:11. The build-up of SOC and release of nutrients in soils is a dynamic balance between both above (net primary production i.e., in terms of quality and quantity of litterfall) and belowground litter inputs and organic matter outputs (loss through decomposition) in the form of C O2 efflux (Tian et al 2010; Mehta et al 2013). Soils may sequester more carbon when the decay rates is slow (Mehta et al 2013) or inputs of organic matter from plants such as leaf litterfall increase (Chenu et al 2019)

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