Projected Changes in Soil Organic Carbon Stocks Upon Adoption of Recommended Soil and Water Conservation Practices in the Upper Tana River Catchment, Kenya

Abstract

Large areas in the Upper Tana river catchment, Kenya, have been over‐exploited, resulting in soil erosion, nutrient depletion and loss of soil organic matter (SOM). This study focuses on sections of the catchment earmarked as being most promising for implementing Green Water Credits, an incentive mechanism to help farmers invest in land and soil management activities that affect all fresh water resources at source. Such management practices can also help restore SOM levels towards their natural level. Opportunities to increase soil organic carbon (SOC) stocks, for two broadly defined land use types (croplands and plantation crops, with moderate input levels), are calculated using a simple empirical model, using three scenarios for the proportion of suitable land that may be treated with these practices (low = 40 per cent, medium = 60 per cent, high = 80 per cent). For the medium scenario, corresponding to implementation on ~348 000 ha in the basin, the eco‐technologically possible SOC gains are estimated at 4·8 to 9·3 × 106 tonnes (Mg) CO2 over the next 20 years. Assuming a conservative price of US$10 per tonne CO2‐equivalent on the carbon offset market, this would correspond to ~US$48–93 million over a 20‐year period of sustained green water management. This would imply a projected (potential) payment of some US$7–13 ha−1 to farmers annually; this sum would be in addition to incentives that are being put in place for implementing green water management practices and also in addition to the benefits that farmers would realize from the impact on production of these practices themselves. Copyright © 2012 John Wiley & Sons, Ltd.

Combined deep sampling and mass-based approaches to assess soil carbon and nitrogen losses due to land-use changes in karst area of southwestern China

“…2). Historically, any land-use changes that disrupt the prior long-standing balance of input and decay processes will induce a shift in SOC stocks (Batjes, 2014;Janzen, 2015). Almost invariably, for example, converting forest to grassland or arable cropland resulted in loss of soil C and N (Don et al, 2011;Foley et al, 2005;Guo and Gifford, 2002;Wei et al, 2014), not only because disturbance stimulates SOM decay (Post and Kwon, 2000;Six et al, 2002), but also because inputs from aboveground and belowground are reduced (Guo and Gifford, 2002).…”

Effects of permanent grass versus tillage on aggregation and organic matter dynamics in a poorly developed vineyard soil

“…2 They also control the hydrological and biogeochemical cycles, acting as a filter for groundwater 3 (Keesstra et al 2012), storing organic matter and nutrients (e.g. Batjes et al 2014;Jaiarree et al 4 2014; Köchy et al 2015 a b), protecting land from hydrogeological hazards such as water 5 erosion.Soil organic matter (SOM) protection and soil structure are key factors for soil conservation 6 and sustainable land management (e.g. Cerdà et al 1996, Wick et al 2014, and for carbon 7 sequestration and fertility (Gosling et al 2013 and references within).…”

“…Munoz-18 Rojas et al 2012;De Moraes Sá et al 2013;Gelaw et al 2013;Parras-Alcántara et al 2013, 201419 Srinivasarao et al 2014;Yu and Jia 2014;Behera et al 2015;Peng 2015). Agriculture can strongly 20 limit SOM accumulation, influencing soil aggregate formation and turnover (Jastrow 1996;Cerdà, 21 2000;Jacobs et al 2010;Gosling et al 2013).…”

Soil organic carbon along an altitudinal gradient in the Despeñaperros Natural Park, southern Spain

“…In temperate climates, recent studies show differences in C sequestration rates in soils depending on use and management (Muñoz-Rojas et al, 2012a, b), climate and mineralogical composition , texture, slope and elevation (Hontoria et al, 2004), and tillage intensity and no-till duration (Umakant et al, 2010). Soil conservation strategies are being seen as a strategy to increase soil OM content (Barbera et al, 2012;Batjes et al, 2014;Jaiarree et al, 2014;Srinivasarao et al, 2014;Fialho and Zinn, 2014).…”