TY - JOUR
T1 - Soil aggregation and soil fraction associated carbon under different vegetation types in a complex landscape
AU - Li, Xiaoqing
AU - Vogeler, Iris
AU - Schwendenmann, Luitgard
PY - 2019
Y1 - 2019
N2 - Land cover change has been shown to affect soil characteristics and soil organic carbon (SOC) storage. However, little is known about the driving factors associated with soil carbon (C) stabilisation in complex landscapes. This study was conducted to investigate the effects of both inherent soil characteristics and recent vegetation cover change on soil aggregation and soil fraction associated C in a complex landscape. The specific objectives were: (1) determine bulk soil properties and SOC saturation deficit-(2) quantify soil aggregation, soil size-density fractions, and soil fraction associated C-and (3) identify the factors that influence soil fractions and soil fraction associated C in two adjacent catchments differing in vegetation cover, Central Otago, New Zealand. Catchment GH1 (n = 17 plots) was dominated by tussock grassland and native shrubs. Catchment GH2 (n = 21 plots) was converted from tussock grassland into a pine forest in 1981. The catchments differed in soil texture (e.g. sand content GH1: 62.9%, GH2: 50.7%, P = 0.007), soil SOC stocks (GH1: 5.0 kg C m
-2, GH2: 4.3 kg C m
-2, P = 0.04), mean weight diameter (MWD) (GH1: 782.3 m, GH2: 736.5 m, P = 0.002), and proportion of the macroaggregate heavy fraction (macro-HF) (GH1: 72%, GH2: 55%, P = 0.01). No significant differences were found in SOC saturation deficit (GH1: 14.8 mg g
-1, GH2: 13.1 mg g
-1, P = 0.13). Dominant vegetation cover explained 21% of the variation in MWD in GH1, whereas silt+clay C content explained 31.6% of the MWD variation in GH2. The macro-HF fraction was negatively correlated with the proportion of silt+clay. Our findings illustrate that physical and chemical soil characteristics are important drivers in such a complex landscape and may have masked the effect of recent vegetation change on soil aggregation, and soil fraction associated C.
AB - Land cover change has been shown to affect soil characteristics and soil organic carbon (SOC) storage. However, little is known about the driving factors associated with soil carbon (C) stabilisation in complex landscapes. This study was conducted to investigate the effects of both inherent soil characteristics and recent vegetation cover change on soil aggregation and soil fraction associated C in a complex landscape. The specific objectives were: (1) determine bulk soil properties and SOC saturation deficit-(2) quantify soil aggregation, soil size-density fractions, and soil fraction associated C-and (3) identify the factors that influence soil fractions and soil fraction associated C in two adjacent catchments differing in vegetation cover, Central Otago, New Zealand. Catchment GH1 (n = 17 plots) was dominated by tussock grassland and native shrubs. Catchment GH2 (n = 21 plots) was converted from tussock grassland into a pine forest in 1981. The catchments differed in soil texture (e.g. sand content GH1: 62.9%, GH2: 50.7%, P = 0.007), soil SOC stocks (GH1: 5.0 kg C m
-2, GH2: 4.3 kg C m
-2, P = 0.04), mean weight diameter (MWD) (GH1: 782.3 m, GH2: 736.5 m, P = 0.002), and proportion of the macroaggregate heavy fraction (macro-HF) (GH1: 72%, GH2: 55%, P = 0.01). No significant differences were found in SOC saturation deficit (GH1: 14.8 mg g
-1, GH2: 13.1 mg g
-1, P = 0.13). Dominant vegetation cover explained 21% of the variation in MWD in GH1, whereas silt+clay C content explained 31.6% of the MWD variation in GH2. The macro-HF fraction was negatively correlated with the proportion of silt+clay. Our findings illustrate that physical and chemical soil characteristics are important drivers in such a complex landscape and may have masked the effect of recent vegetation change on soil aggregation, and soil fraction associated C.
KW - land cover change
KW - New Zealand
KW - pine forest
KW - shrub encroachment
KW - size-density fractionation
KW - soil aggregation
KW - soil organic carbon saturation
KW - SIZE-DENSITY FRACTIONS
KW - LAND-USE CHANGE
KW - ORGANIC-CARBON
KW - SOUTH ISLAND
KW - NEW-ZEALAND
KW - GRASSLAND AFFORESTATION
KW - SHRUB ENCROACHMENT
KW - SATURATION DEFICIT
KW - TUSSOCK GRASSLAND
KW - PINE PLANTATIONS
UR - http://www.scopus.com/inward/record.url?scp=85062672046&partnerID=8YFLogxK
U2 - 10.1071/SR18193
DO - 10.1071/SR18193
M3 - Journal article
SN - 1838-675X
VL - 57
SP - 215
EP - 227
JO - Soil Research
JF - Soil Research
IS - 3
ER -