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Fertilizer and Residue Quality Effects on Organic Matter Stabilization in Soil Aggregates
Author(s) -
Fonte Steven J.,
Yeboah Edward,
Ofori Patrick,
Quansah Gabriel W.,
Vanlauwe Bernard,
Six Johan
Publication year - 2009
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj2008.0204
Subject(s) - stover , fertilizer , agronomy , chemistry , organic matter , crotalaria juncea , manure , residue (chemistry) , soil water , silt , soil organic matter , leucaena , leucaena leucocephala , zoology , green manure , environmental science , field experiment , soil science , biology , paleontology , biochemistry , organic chemistry
This study examined the influence of organic residue quality and N fertilizer on aggregate‐associated soil organic matter (SOM) in maize ( Zea mays L.) cropping systems of southern Ghana. Six residue treatments of differing quality [ Crotalaria juncea L., Leucaena leucocephala (Lam.) de Wit, maize stover, sawdust, cattle manure, and a control with no residues added] were applied at 4 Mg C ha −1 yr −1 both with and without fertilizer N additions (120 kg N ha −1 season −1 ). Soils (0–15 cm) were sampled 3 yr after study implementation and wet sieved into four aggregate size classes (8000–2000, 2000–250, 250–53, and <53 μm). Small macroaggregates (2000–250 μm) were further separated into coarse particulate organic matter (>250 μm), microaggregates within macroaggregates (53–250 μm), and macroaggregate‐occluded silt and clay (<53 μm). Nitrogen fertilizer additions reduced aggregate stability, as was evident from a 40% increase in the weight of the silt and clay fraction ( P = 0.014) as well as a decrease in microaggregates across all residue types ( P = 0.019). Fertilizer similarly affected C and N storage within these aggregate fractions, while the effects of residue quality were largely insignificant. Our results suggest that fertilizer effects on soil aggregation may have important implications for long‐term SOM dynamics.