Influence of land use on the dynamics of soil organic carbon in northern Kazakhstan

Abstract

The practice of monoculture land use without regard for local environmental conditions can accelerate organic matter decomposition. In the agriculturally and environmentally important soils of northern Kazakhstan, which primarily support cereal cultivation, economic rewards might encourage such monoculture practices. The purpose of this study was to clarify the influence of land use on the dynamics of soil organic carbon in situ for the three different soil classes, Dark Chestnut (DC), Southern Chernozem (SC) and Ordinary Chernozem (OC), in this region. Fluctuations in CO 2 emission from the soils showed a similar pattern to temperature fluctuations. Land use markedly influenced the seasonal variation of CO 2 emission, in particular fluctuations in CO 2 sensitivity to soil temperature. To estimate daily CO 2 emission, a prediction equation of CO 2 emission using stepwise multiple regression of the Arrehenius model was derived from environmental soil factors by soil type and land use type. Using soil environmental factors, 40-80% of the variation in CO 2 emission could be estimated. For cereal fields, the mean annual CO 2 emission was estimated to range from 0.75 (DC) to 1.14 (SC) Mg C ha −1 , and carbon input as plant residues ranged from 0.75 (DC) to 1.82 (SC) Mg C ha −1 . The annual carbon budget ranged from 0.10 to 0.35 Mg C ha −1 . In contrast, the carbon budget of summer fallow fields was approximately −0.8 Mg C ha −1 . Thus, the carbon budget of the typical 4-year crop rotation system was estimated to range from −0.42 (DC) to 0.25 (OC) Mg C ha −1 . It should be noted that carbon budgets were negative at DC and SC sites. Although the carbon budget of meadow fields ranged from 0.81 to 1.26 Mg C ha −1 , meadow management at all sites contributed to carbon sequestration. Therefore, to prevent depletion of soil organic carbon in northern Kazakhstan, we recommend that meadow management be introduced as part of the crop rotation system, especially at SC and DC sites.

Regional evaluation of the spatio-temporal variation in soil organic carbon dynamics for rainfed cereal farming in northern Kazakhstan

“…4b. The measured daily soil temperature at a depth of 5 cm was recorded by Takata et al . (2007a) using a maximum–minimum thermometer (CT‐410WR, CUSTOM, Tokyo, Japan) at the time of CO 2 measurement in the SC region.…”

“…which was determined in our previous study (Takata et al . 2007a; the parameters are shown in Table 3).…”

“…2005). Takata et al . (2007a) showed that CO 2 emission from a field varies depending on soil temperature, precipitation and the content of potentially mineralizable carbon (PMC) in the surface soil and provided nine predicted equations of CO 2 emission using these factors in the chernozem zones of northern Kazakhstan.…”

Analysis of Spatial and Temporal Variation of Soil Organic Carbon Budget in Northern Kazakhstan

“…2. Daily CO 2 emission, soil water content, precipitation, daily mean air temperature, and daily precipitation at OC site Upper figure shows daily CO 2 emission, middle figure shows soil water content and lower figure shows mean air temperature (solid line) and precipitation (rods) (Source: Takata et al 14,15 ). × : Cereal, ▲ : Fallow, □ : Meadow.…”

“…Takata et al 14 studied the influence of land use (cereal field, summer fallow field and meadow fields) on the dynamics of soil organic carbon in situ for the 3 different soil classes (DC, SC and OC) in the area. An alkaline absorption method was used to determine CO 2 emission.…”