Decomposition of grain-corn residues (Zea mays L.): A litterbag study under three tillage systems

Abstract

Burgess, M. S., Mehuys, G. R. and Madramootoo, C. A. 2002. Decomposition of grain-corn residues (Zea mays L.): A litterbag study under three tillage systems. Can. J. Soil Sci. 82: 127-138. This study was undertaken to obtain litterbag decomposition data for grain-corn residues in eastern Canadian conditions, to determine tillage and/or depth effects on residue mass loss, and to compare decomposition patterns for the different plant parts that constitute the residue (cobs, stems, leaves, husks). Mesh bags containing residues were buried or left on the soil surface in grain-corn plots under no-till, reduced tillage, and conventional tillage, and retrieved over a 2-yr period. Data were obtained separately for each plant part, then used to calculate pooled totals for all residues combined, for all residues except cobs, or for stems and leaves only, to facilitate comparison with studies based on different residue mixes. Buried residues lost mass faster than surface residues. Despite low overwinter temperatures, residue mass decreased substantially between placement in November and first sampling in mid-May. Surface litterbag residues lost 20% of initial mass during this period, residues buried at 5 cm lost 33%, and those at 20 cm lost 41%. Corresponding losses from mid-May to mid-October were 21, 42 and 32%, respectively. Mass loss was fastest for buried leaves, husks and stems (89-98% loss in 2 yr) and slowest for surface cobs (32% loss in 2 yr). On a voulu évaluer les effets du système de travail du sol et/ou de l'emplacement des résidus (en surface versus enfouis dans le sol) sur la décomposition des résidus, et comparer la décomposition des différentes parties de la plante qui constituent les residus. Des sacs-filet contenant des résidus furent soit enterrés ou laissés à la surface du sol dans des parcelles cultivées conventionnellement, avec travail du sol réduit ou en semis direct, et furent prélevés sur une période de 2 ans. La perte de masse fut évaluée séparément pour les rafles, tiges, feuilles et spathes. Les pertes de masse ont aussi été calculées pour tous types de résidus confondus, pour tous types sauf les rafles, et pour tiges et feuilles seulement afin de faciliter les comparaisons avec des études qui utilisaient différents mélanges de ces résidus. Les résidus enterrés ont perdu leur masse plus rapidement que ceux en surface. On a constaté une importante perte de masse entre le début de l'expérience en novembre et le premier échantillonnage à la mi-mai, malgré des températures faibles pendant cette période. Les résidus en sacs-filet placés en surface (0 cm) ont perdu 20% de leur masse initiale durant cette période; les résidus enterrés à 5 cm ont perdu 33%, et ceux à 20 cm ont perdu 41%. Les pertes entre la mi-mai et la mi-octobre étaient de 21%, 42% et 32% à 0, 5, et 20 cm de profondeur. La perte de masse était plus rapide pour les feuilles, spathes et tiges enfouies (de 89 à 98% de perte en 2 ans), et plus lente pour les rafles laissées en surface (32% de perte en 2 ans).

Decomposition of residues and loss of the δ-endotoxin from transgenic (Bt) corn (Zea mays L.) in soil

“…These data support our contention that the buried residues recovered were at a more advanced stage of decomposition than that of the surface residues. As decomposition also occurred during the winter (Burgess et al 2002), our contention that the surface residues were more decomposed than the post-harvest residues is also supported.…”

“…This is greater than the mass loss of 35% for corn residues within 1 yr reported by Gregorich and Ellert (1994) at the Winchester site. Similarly, Burgess et al (2002) reported 20% mass loss at the surface, 33% loss at 5 cm, and 41% loss at 20 cm at a site in south western Quebec, Canada, from fall to spring.…”

“…By comparison with the surface residues, the buried residues will have been subjected to more decomposition and loss of the most labile components (Webster et al 2000;Marstorp 1996) before the start of the incubation experiment because they will have been in intimate contact with the soil and decomposer organisms, protected from the extreme cold in the winter, and subjected to a moister environment in the fall. Burgess et al (2002) showed that 20% of the mass loss of corn residues was lost from litter bags at the soil surface during the winter, compared with 33% loss from bags buried at 5 cm and 41% loss from bags at 20 cm depth. These data support our contention that the buried residues recovered were at a more advanced stage of decomposition than that of the surface residues.…”

Annual carbon dioxide exchange in irrigated and rainfed maize-based agroecosystems

“…Total litter C input was estimated from the measured values of stover and root biomass taken at physiological maturity in each IMZ. Litter mass and C loss from the litter were measured at 6-month intervals, beginning after grain harvest, for a 3-year period using litterbags placed aboveground (Robertson andPaul, 2000 andBurgess et al, 2002) and a minicontainer system belowground (Paulus et al, 1999). A representative sample of plant biomass was collected a few days before the grain harvest, adjacent to each IMZ.…”

Biogeochemical Research Priorities for Sustainable Biofuel and Bioenergy Feedstock Production in the Americas

“…In a notillage (NT, one pass direct seeding without previous tillage) system, aboveground biomass will primarily build a duff layer, which reduces soil erosion; only limited amounts of C will be transported belowground by animal activity and dissolved C leaching into the soil. In contrast, moldboard plowing buries crop residue (Allmaras et al 1996;Staricka et al 1991) and changes the soil structure, which alters the decomposition dynamics (Burgess et al 2002) and tends to increase decomposition rates. Tillage depth and intensity varies between farms and between regions, depending on tillage implement.…”