Grassland carbon sequestration and emissions following cultivation in a mixed crop rotation

Abstract

a b s t r a c tGrasslands are potential carbon sinks to reduce unprecedented increase in atmospheric CO 2 . Effect of age (1-4-year-old) and management (slurry, grazing multispecies mixture) of a grass phase mixed crop rotation on carbon sequestration and emissions upon cultivation was compared with 17-year-old grassland and a pea field as reference. Aboveground and root biomass were determined and soils were incubated to study CO 2 emissions after soil disturbance. Aboveground biomass was highest in 1-year-old grassland with slurry application and lowest in 4-year-old grassland without slurry application. Root biomass was highest in 4-year-old grassland, but all 1-4-year-old grasslands were in between the pea field (0.81 ± 0.094 g kg −1 soil) and the 17-year-old grassland (3.17 ± 0.22 g kg −1 soil). Grazed grasslands had significantly higher root biomass than cut grasslands. There was no significant difference in the CO 2 emissions within 1-4-year-old grasslands. Only the 17-year-old grassland showed markedly higher CO 2 emissions (4.9 ± 1.1 g CO 2 kg −1 soil). Differences in aboveground and root biomass did not affect CO 2 emissions, and slurry application did not either. The substantial increase in root biomass with age but indifference in CO 2 emissions across the age and management in temporary grasslands, thus, indicates potential for long-term sequestration of soil C.

Carbon stock, chemical and physical properties of soils under management systems with different deployment times in western region of Paraná, Brazil

“…For pasture, negative change of TOC stock was observed in the first two layers (Figure 4e), however smaller than the other areas evaluated, mainly due to the contribution of pasture root system to accumulate C, as reported by Acharya, Rasmussen and Eriksen (2012), once the study area is occupied with permanent pasture for 39 years. The stratification index (SI) proposed by Franzluebbers (2002) was calculated in relation to TOC levels of 0-0.05 layer and the 0.10-0.20 m layer (arable layer).…”

Comparison of ingrowth core and sequential soil core methods for estimating belowground net primary production in grass–clover swards

“…Lack of seasonal fluctuation in BGB could be a result of simultaneous root birth and decomposition, while errors in the larger BGB pool masked the relatively small changes caused by root net growth, leading to underestimation and high errors (Figure ). The underestimation of soil core approaches should not be ascribed to the BGB sampling procedure, because the BGB result was comparable to similar sites (Hebeisen et al ., ; Niklaus et al ., ; Acharya et al ., ) and the variation of BGB sampling was well controlled in our work (Figure ), given that the CV range of BGB sampling is about 30–55% in the 0–30 cm grassland soil layer (Bengough et al ., ). Missing the seasonal maximum and minimum BGB could be another cause for underestimation (Neill, ), but this was unlikely in managed sites with the BGB sampling frequency that was used in the present work.…”

Soil Compressibility under Irrigated Perennial and Annual Crops in a Semi-Arid Environment

“…The average values for σ p for P were 7 % lower than for NVP at a layer of 0.00-0.10 m, and 29 % lower at a layer of 0.20-0.30 m. The reduction in σ p seen in P is associated with the type of soil tillage at the time the crop was planted and with root activity. Grasses have a high capacity for repairing soil structure (Silva and Mielniczuk, 1997;Kodešová et al, 2011) because they are constantly renewing their root system (Acharya et al, 2012), favouring the formation of biopores and the accumulation of C and promoting better physical quality of the soil than annual crops (Blainski et al, 2008).…”