IMPACT4SOIL OpenAire LAReferencia - Red Federada de Repositorios Institucionales de Publicaciones Científicas Latinoamericanas UnpayWall Scientific Electronic Library Online - Brazil Crossref Microsoft Academic Graph Revista Brasileira de Ciência do Solo Open Access 2008-07-04 <p>Maize root growth is negatively affected by compacted layers in the surface (e.g. agricultural traffic) and subsoil layers (e.g. claypans). Both kinds of soil mechanical impedances often coexist in maize fields, but the combined effects on root growth have seldom been studied. Soil physical properties and maize root abundance were determined in three different soils of the Rolling Pampa of Argentina, in conventionally-tilled (CT) and zero-tilled (ZT) fields cultivated with maize. In the soil with a light Bt horizon (loamy Typic Argiudoll, Chivilcoy site), induced plough pans were detected in CT plots at a depth of 0-0.12 m through significant increases in bulk density (1.15 to 1.27 Mg m-3) and cone (tip angle of 60 ￂﾺ) penetrometer resistance (7.18 to 9.37 MPa in summer from ZT to CT, respectively). This caused a reduction in maize root abundance of 40-80 % in CT compared to ZT plots below the induced pans. Two of the studied soils had hard-structured Bt horizons (clay pans), but in only one of them (silty clay loam Abruptic Argiudoll, Villa Lￃﾭa site) the expected penetrometer resistance increases (up to 9 MPa) were observed with depth. In the other clay pan soil (silty clay loam Vertic Argiudoll, Pￃﾩrez Millￃﾡn site), penetrometer resistance did not increase with depth but reached 14.5 MPa at 0.075 and 0.2 m depth in CT and ZT plots, respectively. However, maize root abundance was stratified in the first 0.2 m at the Villa Lￃﾭa and Pￃﾩrez Millￃﾡn sites. There, the hard Bt horizons did not represent an absolute but a relative mechanical impedance to maize roots, by the observed root clumping through desiccation cracks.</p> soil compaction plantio direto plantio convencional root growth raízes conventional tillage 0401 agriculture, forestry, and fisheries 04 agricultural and veterinary sciences zero tillage camadas compactadas Taboada, Miguel Angel, Alvarez, Carina Rosa, 2008-04-01 journalpaper <p>Maize root growth is negatively affected by compacted layers in the surface (e.g. agricultural traffic) and subsoil layers (e.g. claypans). Both kinds of soil mechanical impedances often coexist in maize fields, but the combined effects on root growth have seldom been studied. Soil physical properties and maize root abundance were determined in three different soils of the Rolling Pampa of Argentina, in conventionally-tilled (CT) and zero-tilled (ZT) fields cultivated with maize. In the soil with a light Bt horizon (loamy Typic Argiudoll, Chivilcoy site), induced plough pans were detected in CT plots at a depth of 0-0.12 m through significant increases in bulk density (1.15 to 1.27 Mg m-3) and cone (tip angle of 60 ￂﾺ) penetrometer resistance (7.18 to 9.37 MPa in summer from ZT to CT, respectively). This caused a reduction in maize root abundance of 40-80 % in CT compared to ZT plots below the induced pans. Two of the studied soils had hard-structured Bt horizons (clay pans), but in only one of them (silty clay loam Abruptic Argiudoll, Villa Lￃﾭa site) the expected penetrometer resistance increases (up to 9 MPa) were observed with depth. In the other clay pan soil (silty clay loam Vertic Argiudoll, Pￃﾩrez Millￃﾡn site), penetrometer resistance did not increase with depth but reached 14.5 MPa at 0.075 and 0.2 m depth in CT and ZT plots, respectively. However, maize root abundance was stratified in the first 0.2 m at the Villa Lￃﾭa and Pￃﾩrez Millￃﾡn sites. There, the hard Bt horizons did not represent an absolute but a relative mechanical impedance to maize roots, by the observed root clumping through desiccation cracks.</p> Root Abundance Of Maize In Conventionally-Tilled And Zero-Tilled Soils Of Argentina 10.1590/s0100-06832008000200031 https://doi.org/10.1590/s0100-06832008000200031