Fertilizer and Residue Quality Effects on Organic Matter Stabilization in Soil Aggregates

Abstract

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.

Earthworms and litter management contributions to ecosystem services in a tropical agroforestry system

“…Thus, agricultural management which affects macroaggregate dynamics could have far reaching implications for SOM stabilization and agroecosystem sustainability (Six et al, 2000;Denef et al, 2007). Although tillage produces perhaps the most obvious impacts of management on soil aggregates (Beare et al, 1994;Six et al, 1999), other management factors such as fertilization, burning and residue application can have important influences on soil structure and associated C storage as well (Mulumba and Lal, 2008;Fonte et al, 2009b). While the potential for SB agriculture to degrade soils is well understood, relatively few studies have specifically addressed effects on soil structure and the implications of this for SOM dynamics.…”

Organic Amendments to Avocado Crops Induce Suppressiveness and Influence the Composition and Activity of Soil Microbial Communities

“…oil organic matter is fundamental to the long-term sustainability of agroecosystems, and it plays a critical role in global biochemical cycles (1). In the agriculture of the past century, the use of manure and other organic waste material was progressively supplanted by synthetic agrochemicals.…”

Effets d’application sur le long terme de fertilisants organiques et minéraux sur l’agrégation et les activités microbiennes d’un sol tropical sableux au Burkina Faso

“…Cette dégradation des sols a été décrite comme étant l'une des contraintes majeures à l'autonomie et à la sécurité alimentaire (Bationo et al, 2007 ;Fonte et al, 2010). Pour ces sols déstructurés, le labour, l'intensification des systèmes culturaux, la minéralogie des argiles (kalonite à faible CEC) et des pH défavorables accentuent leur vulnérabilité.…”

“…Elle garantit aussi un environnement favorable pour les racines des plantes et pour la circulation de l'oxygène (Brondik & Lal, 2005 ;Ouattara et al, 2006). Dans les sols sableux tropicaux, la MO en décomposition est un facteur important de l'agrégation (Fonte et al, 2010). Durant sa décomposition, la MO peut induire une modification des communautés microbiennes, le développement d'hyphes mycéliens et la sécrétion de molécules (exosaccharides) capables d'agréger les particules solides à l'échelle des agrégats (Tisdall & Oades, 1982 ;Six et al, 2000).…”