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

Abstract

Root system growth and soil structure are interdependent and the threshold of separation between both of them is complex. However, by the evaluation of soil pore space, it is possible to characterize the root system growth environment. The aim of this study was to evaluate the effect of conservation management system over time on pore distribution and on root system development of coffee plantation in Cerrado Oxisol, located in the state of Minas Gerais, Brazil. Two coffee plantation areas were sampled (3 or 6 years old). Trenches were dug lengthwise along the planting row to expose the root system and the vertical profiles were divided into 0.05 × 0.05 m grid cells (0.70 × 1.50 m grid), totaling 420 sample sites. Digital images were taken and using the computer software Safira, it was measured layers along the soil profile, which was spaced 0.10 m apart. Disturbed and undisturbed soil cores the length, the surface area and the volume of the root system were sampled at 0.20 to 0.34, 0.80 to 0.94, and 1.50 to 1.64 m depths layers, in order to determine particle size, total porosity, and pore size distribution. The 3-years coffee stand had the greatest volume of macropores and the largest number of absorbent roots, besides a noticeable root system growth below 1 m depth. The 6-years old coffee stand presented pores reconfiguration due to increase in the intermediate-sized pores and to the uniform root distribution in both horizontal and vertical directions up to 0.9 m depth.