Residue removal and tillage interaction effects on soil properties under rain-fed corn production in Central Mexico

Determining the effects of residue removal and tillage systems on surface c rop residue accumulation, organic carbon sequestration and nutrient cycling is essential for sustainable land management. This study evaluated the eff ects of 6 years of conventional and conservation tillage with different amo unts of crop residues left on the soil surface on selected soil properties of a Vertisol and an Andisol used for rain-fed corn (Zea mays L.) productio n in Central Mexico (Apatzingan and Casas Blancas, Mich.). The results show ed that conservation tillage. i.e. no tillage (NT) with 100, 66 and 33% of crop residues left on the field, and minimum tillage (MT), significantly in creased surface crop residue accumulation on the soil surface. In the 0-50 mm surface layer. organic C, microbial biomass C and N, inorganic and total N. and extractable P were approximately twice higher with NT/100%, NT/66%, NT/33%. and MT than with conventional tillage (CT) and NT/0% treatments. H igher levels of soil organic C, microbial biomass C and N, inorganic and to tal N, and extractable P were directly related to surface accumulation of c rop residues promoted by conservation tillage management. Removal of surfac e crop residues can seriously reduce production sustainability in climates where stressful conditions occur. In general, the mid-term (6 years) sustai nability of Vertisol and Andisol for rain-fed corn production seemed to be enhanced by conservation tillage management. To obtain the benefits of cons ervation tillage in the sub-humid tropical region of Apatzingan (Vertisols) , where organic matter is rapidly oxidized, it is necessary to leave at lea st 60% of the crop residue on the soil surface, while in the sub-humid temp erate region of Casas Blancas (Andisol), where organic matter is oxidized s lower, leaving 30% of crop residue is sufficient. (C) 2001 Elsevier Science B.V. All rights reserved.