Restoration of grazing land to increase biomass production and improve soil properties in the Blue Nile basin: effects of infiltration trenches and Chloris Gayana reseeding

T Erkossa,D Geleti,A Haileslassie,F Laekemariam,T O Williams

doi:10.1017/s1742170519000425

Abstract

AbstractDegradation of crop and grazing lands is a pervasive problem that negatively impacts agricultural productivity and livelihoods of crop-livestock farmers in the Blue Nile basin of Ethiopia. Area enclosure together with a cut and carry livestock feeding system is often advocated as an approach for the regeneration of degraded grazing lands. This paper reports the results of a two-year farmer participatory study conducted to assess the effects of infiltration trenches (ITs) and Chloris gayana Kunth (Rhodes grass; cultivar Masaba; tetraploid; C4 grass species) reseeding on restoration of degraded grazing lands. A split plot design was used with IT as the main plot and C. gayana reseeding as a sub-plot on 28 private grazing plots under enclosure. The results showed that IT alone increased soil moisture content and prolonged the growing period. IT and C. gayana reseeding together significantly (P ≤ 0.05) increased herbage dry matter yield and improved soil chemical properties. The highest mean herbage dry matter yield (21 Mg ha−1 per cut) was recorded for plots treated with IT and reseeded with C. gayana. The higher herbage dry matter yield was attributed to increased soil moisture and the resultant prolonged growing period induced by the trenches coupled with the ability of C. gayana to effectively utilize the retained water. The results suggest that an integrated land management approach involving enclosure, in-situ water conservation and C. gayana reseeding can rapidly increase biomass productivity on degraded grazing lands while also enhancing soil quality with concomitant livelihood benefits for farmers.

Highlights

Land degradation (LD) poses a conspicuous impediment to agricultural production and livelihoods in the semi-arid and humid lowlands of western Ethiopia (Erkossa et al, 2009; IFDC, 2012)
This study revealed that the use of infiltration trenches (ITs) consistently increased water availability during the growing period, confirming the findings of the previous studies, and contributed to increased herbage dry matter yield per cut
Reinforcing this physical intervention with agronomic practices such as reseeding the land with an improved grass species (e.g. C. gayana) that can effectively utilize the retained water to produce above ground fodder and below ground biomass led to significantly higher herbage dry matter yield, with economic and ecological advantages

Summary

Introduction

Land degradation (LD) poses a conspicuous impediment to agricultural production and livelihoods in the semi-arid and humid lowlands of western Ethiopia (Erkossa et al, 2009; IFDC, 2012). Open grazing constitutes the main livestock feeding system for the majority (72%) of farmers. Both the crop and grazing lands are degrading at an increasing rate, due to natural and anthropogenic factors (Tireza et al, 2013; Assemu and Shigdaf, 2014). The resettlement involved merely moving subsistent farmers from severely degraded highlands to the fragile lowlands with no guidance on appropriate use and management of the ‘new’ land. The settlers continued the same type of farming practices that led to the LD that necessitated their departure from their place of origin (Feleke, 2003)

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