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Effect of farm management on topsoil organic carbon and aggregate stability in water: A case study from Southwest England, UK
Author(s) -
Collier Sarah M.,
Green Sophie M.,
Inman Alex,
Hopkins David W.,
Kendall Hazel,
Jahn Molly M.,
Dungait Jennifer A. J.
Publication year - 2021
Publication title -
soil use and management
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.709
H-Index - 81
eISSN - 1475-2743
pISSN - 0266-0032
DOI - 10.1111/sum.12658
Subject(s) - topsoil , arable land , soil carbon , soil water , environmental science , pasture , tillage , soil organic matter , soil health , soil science , woodland , agronomy , hydrology (agriculture) , soil management , forestry , geography , ecology , agriculture , geology , biology , geotechnical engineering
There are few reliable data sets to inspire confidence in policymakers that soil organic carbon (SOC) can be measured on farms. We worked with farmers in the Tamar Valley region of southwest England to select sampling sites under similar conditions (soil type, aspect and slope) and management types. Topsoils (2–15 cm) were sampled in autumn 2015, and percentage soil organic matter (%SOM) was determined by loss on ignition and used to calculate %SOC. We also used the stability of macroaggregates in cold water (WSA) (‘soil slaking’) as a measure of ‘soil health’ and investigated its relationship with SOC in the clay‐rich soils. %SOM was significantly different between management types in the order woodland (11.1%) = permanent pasture (9.5%) > ley‐arable rotation (7.7%) = arable (7.3%). This related directly to SOC stocks that were larger in fields under permanent pasture and woodland compared with those under arable or ley‐arable rotation whether corrected for clay content ( F = 8.500, p < .0001) or not ( F = 8.516, p < .0001). WSA scores were strongly correlated with SOC content whether corrected for clay content (SOC adj R 2 = .571, p < .0001) or not (SOC unadj R 2 = 0.490, p = .002). Time since tillage controlled SOC stocks and WSA scores, accounting for 75.5% and 51.3% of the total variation, respectively. We conclude that (1) SOC can be reliably measured in farmed soils using accepted protocols and related to land management and (2) WSA scores can be rapidly measured in clay soils and related to SOC stocks and soil management.