Fallow Effects on Soil

Authors: Nielsen, David; Calderon, Francisco

Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 4/6/2010
Publication Date: 5/20/2011
Citation: Nielsen, D.C., Calderon, F.J. 2011. Fallow Effects on Soil. p. 287-300 In J.L. Hatfield and T.J. Sauer (ed) Soil Management:building a stable base for agriculture. ASA and SSSA, Madison, WI.

Interpretive Summary: Fallow production systems continue to be used throughout various regions of the world, but particularly in semi-arid regions where precipitation is highly variable in timing and amount. Systems which reduce or limit fallow frequency and tillage intensity generally result in greater amounts of surface crop residues remaining during fallow periods. Those residue increases generally produce positive effects on soil quality for crop production including increases in soil OM, nutrients, physical structure, water content, and micro-organisms, as well as reductions in soil loss by wind and water erosion. This chapter reviews literature dealing with fallow effects under varying tillage and cropping frequency on soil organic matter, soil physical structure, soil water, nutrient availability, microbial activity and diversity, and erosion.

Technical Abstract: Fallow production systems continue to be used throughout various regions of the world, but particularly in semi-arid regions where precipitation is highly variable in timing and amount. Systems which reduce or limit fallow frequency and tillage intensity generally result in greater amounts of surface crop residues remaining during fallow periods. Those residue increases generally produce positive effects on soil quality for crop production including increases in soil OM, nutrients, physical structure, water content, and micro-organisms, as well as reductions in soil loss by wind and water erosion. This chapter reviews literature dealing with fallow effects under varying tillage and cropping frequency on soil organic matter, soil physical structure bulk density, water filled pore space, compaction, soil aggregation, water holding capacity, soil hydraulic conductivity), soil water (runoff, evaporation, infiltration, precipitation storage efficiency), nutrient availability (particularly N and P), microbial activity and diversity, and wind and water erosion.