IMPLICATIONS OF CROP RESIDUE MANAGEMENT AND CONSERVATION TILLAGE ON SOIL ORGANIC-MATTER

Citation
Jf. Dormaar et Jm. Carefoot, IMPLICATIONS OF CROP RESIDUE MANAGEMENT AND CONSERVATION TILLAGE ON SOIL ORGANIC-MATTER, Canadian Journal of Plant Science, 76(4), 1996, pp. 627-634
Citations number
61
Categorie Soggetti
Plant Sciences",Agriculture
ISSN journal
00084220
Volume
76
Issue
4
Year of publication
1996
Pages
627 - 634
Database
ISI
SICI code
0008-4220(1996)76:4<627:IOCRMA>2.0.ZU;2-E
Abstract
Under natural grassland or native prairie, aboveground residue or surf ace litter modifies the microenvironment. It promotes water infiltrati on and, by insulating the soil surface, moderates soil temperatures an d limits evaporation. Root mass decomposes and transforms within the c onditions created by surface litter. Together with root exudates, this below-ground residue or subsurface litter reacts with soil minerals t o form aggregates, lower bulk density and increase water-holding capac ity. Bringing such soils under cultivation leads to lower soil organic matter content, thereby increasing bulk density. The role of surface litter becomes even more important, as it affects wind and water erosi on, reduces the impact of raindrops, prevents crusting, protects the s oil from drying by sublimation, and captures snow. Management of crop residues depends on the role of the residue. A distinction must be mad e between above- and below-ground residues: their roles are distinctly different. Aboveground crop residue protects the soil and creates the conditions for below-ground residue to decompose and transform. These decomposition products, in turn, create favourable soil structure for plant growth. Research is needed on the effect of repeated harvesting of ''excess'' aboveground residues.