Carbon sequestration in dryland ecosystems of West Asia and North Africa

Abstract

The West Asia±North Africa (WANA) region has a land area of 1Á7 billion ha, and a population of 600 million. Deserti®cation and soil degradation are severe problems in the region. The problem of drought stress is exacerbated by low and erratic rainfall and soils of limited available water holding capacity and a soil organic carbon (SOC) content of less than 0Á5 per cent. The SOC pool of most soils has been depleted by soil degradation and widespread use of subsistence and exploitative farming systems. The historic loss of a SOC pool for the soils of the WANA region may be 6±12 Pg compared with the global loss of 66±90 Pg. Assuming that 60 per cent of the historic loss can be resequestered, the total soil-C sink capacity of the WANA region may be 3±7 Pg. This potential may be realized through adoption of measures to control deserti®cation, restore degraded soils and ecosystems, and improve soil and crop management techniques that can enhance the SOC pool and improve soil quality. The strategies of soil C sequestration include integrated nutrient management (INM) and recycling, controlled grazing, and growing improved fodder species on rangeland. Improved technologies for cropland include use of INM and biofertilizers, appropriate tillage methods and residue management techniques, crop rotations and cover crops, and water and nutrient recycling technologies. Through adoption of such measures, the potential of soil-C sequestration in the WANA region is 0Á2±0Á4 Pg C yr À1.

Implications of accounting for land use in simulations of ecosystem carbon cycling in Africa

“…10). Different cropland management options in S1 had a large effect on the carbon balance, as has previously been suggested, for example, by Lal (2002). When 100 % crop residue removal was assumed, the carbon sink was reduced by 1.4 PgC compared to no removal.…”

Effects of Residue Management and Cropping Systems on Wheat Yield Stability in a Semiarid Mediterranean Clay Soil

“…In semiarid Mediterranean region, soil quality evaluation under conservation and conventional tillage systems should be prioritized [52] and carbon and nitrogen dynamics modeled under these contrasting systems [53]. These models will be the research focus in near future and for estimating environmental consequences of shifting to No-tillage technologies and conservation cropping sequences in both dry [54] and irrigated systems [55].…”

Topsoil organic carbon storage of China and its loss by cultivation

“…Efforts have been made worldwide to enhance soil C sequestration to offset CO 2 emission from the industrial sector Schlesinger 1999Schlesinger , 2000Lal 2002a). Increasing attention had been paid to SOC dynamics and its potential for C sequestration in croplands for the last decade (Dadal and Mayer 1986;Rounsevell et al 1999;Smith et al 2000a, b;Jacinthe et al 2001;Uri 2001;Hao et al 2002;Schuman et al 2002).…”