Litter production rates and soil moisture influences interannual variability in litter respiration in the semi-arid Loess Plateau, China

A better understanding of the factors affecting interannual variability in litter respiration is critical to precisely understand local carbon cycling, especially under the changing climate. In this study, litter respiration was obtained by subtracting in situ soil respiration in a control (LCK) treatment by that in a litter removal (LR) treatment for the period 2009-2013 in a 30-year-old black locust plantation (Robinia pseudoacacia L.) on a ridge slope in a small watershed of Loess Plateau, China. Annual cumulative litter respiration ranged from 48 +/- 15 to 165 +/- 36 g C m(-2) y(-1), with mean value of 113 +/- 45 g C m(-2) y(-1) and coefficient of variation (CV) of 40%; annual contribution rate of litter respiration to total soil respiration (hereafter refer to as litter contribution rate) also exhibited a similar interannual variability (ranged from 8 +/- 3% to 20 +/- 7%; mean = 15 +/- 5%; CV = 31%). Additionally, annual mean soil moisture was highest in 2010 (53.2 +/- 8.4% WFPS) and lowest in 2013 (31.4 +/- 9.5% WFPS), with mean value of 41.6 +/- 7.9% WFPS and CV of 19%; annual litter production rates also exhibited a similar interannual variability (ranged from 379 +/- 34 to 565 +/- 69 g m(-2) y(-1); mean = 477 +/- 71 g m(-2) y(-1); CV = 15%). Annual mean soil moisture was mainly affected by the frequency and distribution of precipitation, and annual litter production rates varied with summer precipitation. Annual cumulative litter respiration and litter contribution rate increased linearly with both annual litter production rates and mean soil moisture content. The contribution of soil water to litter respiration was larger than that of litter production rates. Therefore, litter production rates and soil moisture resulted from precipitation needs to be taken into account for precisely predicting litter respiration in the dryland ecosystems, especially under the changing climate. (C) 2015 Elsevier Ltd. All rights reserved.