Protected organic matter in water-stable aggregates as affected by mineral fertilizer and manure applications

Abstract

N. 1999. Protected organic matter in water-stable aggregates as affected by mineral fertilizer and manure applications. Can. J. Soil Sci. 79: 419-425. Effects of long-term (18-yr) applications of cattle manure (20 Mg ha -1 yr -1 ) and NPK fertilizer on the labile organic matter (OM) and its protection in water-stable aggregates were investigated in a Le Bras silt loam (Humic Gleysol). Soil from the 0-to 10-cm depth was sampled from the untreated control, NPK, manure and NPK + manure treatments and fractionated into four size classes of slaking-resistant aggregates (>1000 µm, 250-1000 µm, 53-250 µm, <53 µm). Intact and crushed macroaggregates (250-1000 and >1000 µm) and intact microaggregates (<250 µm) were incubated for 21 d at 25°C, and mineralized C and N were determined. The amount of mineralized C in intact aggregates increased with increasing aggregate size irrespective of the agronomic treatments, but there was no consistent trend for total N. Manure application led to an increase in mineralized C in most aggregate fractions. Crushing the macroaggregates enhanced mineralization of C by 14 to 35% and N by 17 to 103%. Additional C and N rendered mineralizable by crushing represents a fraction of the macroaggregate-protected OM. Manure application increased the protected pools of C (up to threefold) and N (up to fourfold) located in the small macroaggregates (250-1000 µm). In contrast, NPK fertilization increased the pool of macroaggregate-protected N by 2.5-fold but had no effect on the protected C. We conclude that manure application contributed to the accumulation of macroaggregate-protected C and N, whereas mineral fertilizers increased the protected-N pool only. Macroaggregates can provide a mechanism for the protection of labile soil OM in an annually tilled cropping system and this mechanism is enhanced with long-term manure application.Key words: Aggregate-protected organic matter, manure application, mineralization, mineral fertilizer, water-stable aggregates Aoyama, M., Angers, D. A., N'Dayegamiye, A. et Bissonnette, N. 1999. Effets de l'application de fumier et de la fertilisation minérale sur la matière organique protégée dans les agrégats stables. Can. J. Soil Sci. 79: 419-425. Cette étude a évalué les effets à long-terme (18 années) de l'application de fumier de bovin (20 Mg ha -1 année -1 ) et de l'engrais minéral sur la fraction labile de la matière organique (MO) et sur la protection physique de celle-ci dans les agrégats d'un loam Le Bras (Gleysol humique). A partir des échantillons de sol provenant de la couche 0-10 cm des traitements témoin, avec fumier, avec engrais minéraux (NPK) et avec fumier+NPK, nous avons obtenu, par tamisage sous eau, quatre fractions d'agrégats stables (>1000 µm, 250-1000 µm, 53-250 µm, <53 µm). Les quantités de C et N minéralisées ont été mesurées dans une incubation (21 jours à 25°C) de macroagrégats brisés et intacts (250-1000 and >1000 µm) et de microagrégats (<250 µm) intacts. Les résultats indiquent que les quantités de C minéralisé augmentent avec la taill...

Effects of various organic materials on soil aggregate stability and soil microbiological properties on the Loess Plateau of China

“…Aggregate water stability and soil aggregation are known to play a major role in improving soil fertility and grain production. The application of manure increases the percentage of large sized water stable aggregates (> 5 mm) (Aoyama et al 1999). Similar results were found in this study.…”

Challenging Balance between Productivity and Environmental Quality: Tillage Impacts

“…Studies have shown that manure application increased SOC and nutrient status in the soil (Webster and Goulding, 1989;Collins et al, 1992;Rochett e and Gregorich, 1998) and labile carbon pools (Aoyama et al, 1999;Mikha and Rice, 2004). Total corn rootderived C (C in root biomass plus that in rhizodeposition) contributes from 1.5 times to more than 3 times more C to SOC than shoot-derived C (Balesdent and Balabane, 1996;Wanniarachchi et al, 1999;Wilts et al, 2004;Hooker et al, 2005).…”

Influence of Agricultural Wastes and Incubation Period on Aggregate Stability in Sandy Soil

“…Disaggregation occurred in all treatments after 20 days of incubation due to probably the more substrate demands of microorganisms in soil (Gulser, 2010). The application of manure and organic fertilizer increases the percentage of large sized water stable aggregates (> 5mm) (Aoyama et al, 1999 andWang et al, 2013). Usually, there was a significant positive correlation between mean weight diameter (MWD) and the amount of > 0.25mm aggregates (Guber et al, 2005).Most of organic fertilizer treatments had large MWD and high amount of > 0.25mm aggregates (Wang et al, 2013).…”