Abstract

The growing concern about alternative energy sources enhances the interest for optimizing soil physical conditions to improve biomass production for biofuel. Studies involving linear correlation or geostatistics have been conducted to explain the dependence among soil physical properties and crops yield, however, limited studies have been carried out on oil crops. A field study was carried out on an Oxisol in Brazil to investigate the influence of soil physical properties on crambe (Crambe abyssinica Hochst) yield and linear and spatial behavior of crambe yield as correlated to soil physical properties. Undisturbed soil samples were collected from soil depths, 0 to 0.1, 0.1 to 0.2 and 0.2 to 0.3 m using core samplers to determine bulk density and gravimetric moisture content. Soil resistance to penetration was verified in a depth of 0 to 0.3 m and crambe yield was determined in plots of 4 m². The linear relation among the variables in 30 random spots was analyzed and then sampling was carried in 30 geo-referenced spots, in a regular grid in order to verify spatial correlation among the variables using the cross-semivariogram. The variables showed low linear correlation. Crambe yield was spatially correlated with soil resistance to penetration in the 0.1 to 0.2 m depth. Correlation between soil physical properties and crambe yield was verified by spatial and linear analyses.

Key words: Geostatistics, soil physical properties, crambe yield, cross-semivariogram.