Relationships between Soil–Landscape and Dryland Cotton Lint Yield

Abstract

in OM, N, and P on both terraced and steep cultivated hillslopes. Selective removal of finer particles by water Topographical land features shape the spatial variability of soils erosion caused a linear decrease in clay content of 0.02% and crop yields, especially in dryland cotton (Gossypium hirsutum L.). The objectives of this study were to (i) quantify the relationships m Ϫ1 , and a corresponding increase in silt content of between cotton lint yields vs. derived topographical attributes in com-0.04% m Ϫ1 downslope on the steep cultivated hillslope. bination with measured soil physical properties, and (ii) quantify the Kravchenko et al. (2000) reported higher crop yield relationships between measured soil physical properties and derived at lower slope locations, and a wide range of yield values topographical attributes. The dominant soil of the study area was on moderate and higher slopes during moderate to dry classified as Vaiden soil series (very-fine, smectitic, thermic Aquic weather conditions; however, low yield values were Dystruderts). More than 4500 elevation point data were recorded in measured on lower slope locations during the wet seaa 42-ha field using a real-time kinematic-global positioning system son. Kravchenko et al. (2000) also examined the effects (RTK-GPS) used in a geographic information system (GIS) to derive of derived topographic and hydrologic derived indices topographic (slope, curvature and aspect) and hydrologic attributes on variability in soil properties and crop yield. They (wetness index, flow direction, flow length, flow accumulation, and sediment transport index). Surface (0-17 cm) sand, clay, saturated reported crop yield had a significant negative correlahydraulic conductivity (K s), bulk density (b), water content at seven tion with elevation, slope and curvature. Sinai et al. equilibrium pressure levels ranging from Ϫ0.01 to Ϫ1.5 MPa, and (1981) calculated a soil surface curvature factor from 2-yr cotton lint yield data were measured from sites selected based on the elevation of neighboring points in a grid-sampled classified normalized difference vegetation index (NDVI). Stepwise field. The factor was positive in concave positions in linear regression indicated that cotton lint yield variability was exthe landscape, negative in convex positions, and highly plained by soil properties (65% in 2001 and 58% in 2002), and topocorrelated with soil water content. The redistribution of graphic and hydrologic attributes (40 and 21%), as well as their comsoil water downslope, both at the surface and subsurface bined effects (82 and 72%). Elevation, flow direction, sediment (throughflow), gave soil properties downslope indicatransport index, percentage sand content, and volumetric water contive of soil water conditions and moved solute laterally. tent (v) at Ϫ0.001 MPa pressure explained most of the lint yield variation. Overall, statistical analysis indicated that higher elevation This process could be beneficial in terms of higher yield areas generally yielded lower (r ϭ Ϫ0.50, P...

Spatial Relation of Apparent Soil Electrical Conductivity with Crop Yields and Soil Properties at Different Topographic Positions in a Small Agricultural Watershed

“…Dry years showed no differences at various topographic positions. Many studies have shown yearly differences in crop yields due to topography [18,19,[43][44][45][46]. In agreement with our results, Muñoz et al [44] also reported that topography had major influence on corn yields during the year with higher precipitation.…”

Planejamento agrícola e implantação de sistema de cultivo de cana-de-açúcar com auxílio de técnicas geoestatísticas

“…Estatística descritiva para as variáveis argila, silte, areia, pH, matéria orgânica, acidez potencial, soma de bases, capacidade de troca catiônica e saturação por bases das amostras coletadas nos pontos da malha Iqbal et al (2005).…”

Atributos topográficos na diferenciação de Argissolos

“…Vários estudos têm apresentado a influência do aspecto sobre a distribuição dos solos na paisagem (Lotspeich & Smith, 1953;Finney et al, 1962;Daniels et al, 1987;Birkeland, 1999;Thomas et al, 1999;Rech et al, 2001;Iqbal et al, 2005). De acordo com van Boxel (2002), essa influência é marcante sobre a pedogênese, em razão do controle que exerce sobre as condições microclimáticas locais e, consequentemente, no desenvolvimento da vegetação.…”