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Influence of rainfall amount and livestock grazing on soil respiration in a moist Kenyan savannah
Author(s) -
Ondier Joseph,
Okach Daniel O.,
John Onyango C.,
Otieno Dennis O.
Publication year - 2020
Publication title -
african journal of ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.499
H-Index - 54
eISSN - 1365-2028
pISSN - 0141-6707
DOI - 10.1111/aje.12670
Subject(s) - environmental science , grazing , soil water , agronomy , biomass (ecology) , canopy , soil respiration , water content , soil science , biology , ecology , geotechnical engineering , engineering
The influence of livestock grazing and changing rainfall patterns on soil respiration (Rs) in the tropical savannah in Lambwe is unclear. Measurements of Rs using chambers were conducted between June and November 2012 in a humid savannah in Western Kenya to determine how simulated rainfall amounts and cattle grazing affected soil respiration. The experimental layout was split plot comprising rainfall simulations which were laid on grazed and fenced blocks, respectively. The rainfall simulations split plots each measured 6 m × 3 m and were covered with rainout gutters above the canopy of the herbaceous layer to either increase or reduce ambient rainfall by 50%. Grazing increased soil bulk density and significantly ( p < 0.05) lowered soil respiration rates and soil water content irrespective of the rainfall treatment. The positive correlation between Rs and root biomass in both grazed and fenced plots revealed a significant contribution of root growth activities to Rs. Increased soil water content (SWC) by rainfall addition improved water penetration into deeper soil layers and therefore stimulated root and microbial activities which in turn built up soil respiration. Reduction in SWC by rainfall exclusion lowered microbial contact with the organic substrate and likely caused death and/ or inactivity of roots.