Scaling of pores in 3D images of Latosols (Oxisols) with contrasting mineralogy under a conservation management system

Abstract

The aim of this study was to evaluate the spatial and morphological configuration of the pore space in 3D images of Latosols with different mineralogy under a conservation tillage system in a coffee crop area. The visualisation and quantification of pore size distribution by data mining and spatial variability by semi-variogams were investigated in 3D images with 60-µm spatial resolution generated by X-ray CT scan (EVS/GE MS8x-130) in soil core samples collected at different depths of a kaolinitic Red-Yellow Latosol (RYL) and a gibbsitic Red Latosol (RL) from Brazil. Greater spatial variability occurred in the horizontal direction of the 3D image, a novel finding in this area of research. The pores detected were different between the Latosols studied, mainly at 0.20–0.34 m depth. The largest number (>4000) and volume (±30 mm3) of pores was found in the RL. The soil classes differed in 3D pore characteristics, and this aspect may be important in the characterisation of causes of pore variability. Sphericity was similar for both soils, with greater emphasis on pore classes with a diameter <0.4 mm, mainly at the 0.20–0.34 m depth. A higher percentage of spheroid pores occurred in RL (±25%), whereas the platy pores were more abundant in RYL (>15%).

Aggregates morphometry of a Inceptisol under conservationist system

“…The positive results in terms of aggregation in the crop line have probably conditioned improvements in soil-air-water relationship, favoring root growth at deeper depths, and therefore greater soil exploration for water and nutrients (CARDUCCI et al, 2014a(CARDUCCI et al, , 2014bSERAFIM et al, 2011;SILVA et al, 2013SILVA et al, , 2014.…”

“…2+ from inputs (gypsum and limestone), applied during the crop establishment, has favored the development of coffee plant roots throughout the soil profile (CARDUCCI et al, 2014a(CARDUCCI et al, , 2014b. Plant root distribution within the soil has great influence on aggregate formation and stabilization, the mechanical force produced by root growth gathers the mineral particles (FOLONI et al, 2006), as well as releases exudates and organic polysaccharides (COSTA JÚNIOR et al, 2012).…”

“…Based on the above, a soil management system with conservation practices combined with fertilization and concomitant agricultural gypsum application (CARDUCCI et al, 2014a(CARDUCCI et al, , 2014bSERAFIM et al, 2011SERAFIM et al, , 2013aSERAFIM et al, , 2013b can beneficially contribute in morphometric attributes of soil aggregates (size and structural arrangement). Thus, this research aimed at evaluating morphometric attributes of aggregates from a Inceptisol, after one year and a half of coffee farming (Coffea arabica L.) within the region of Alto São Francisco (MG), Brazil, under conservationist system of soil management.…”

Root spatial distribution in coffee plants of different ages under conservation management system

“…This fact is relevant when considering the suggestions of Carducci et al (2014b) on porosity studies carried out with X-ray CT scan on the 6-years stand age, in which the soil fine macropores (Ø = 1 mm), as well as the large mesopores (Ø = 0.2 mm ), favored the development of fine roots (Ø ≤ 1 mm).…”

“…Based on this premise, some coffee growers in Minas Gerais have adopted a soil management system which consists of periodically mowed grass cultivation (Brachiaria decumbens) between planting rows as a permanent source of organic matter, associated with the building of fertility in deep soil layers, which is possible due to the adoption of a deep, fertilized planting furrow and to the gypsum application on soil surface. This management improves physical and chemical soil conditions, as well as increases root system depth (van Raij, 2008;Serafim et al, 2013a, b, c;Silva, 2012;Carducci et al, 2014b;Silva et al, 2014).…”