Soil fertility and nutritional status of coffee grown in CO₂-enriched atmosphere

Abstract:

The objective of this work was to evaluate the effects of atmospheric CO₂ levels on soil chemical attributes, in rows (coffee crop) and between rows (Urochloa decumbens), and on macronutrient contents in coffee leaves. A randomized complete block design was used, in a split-plot, with six replicates. The treatments consisted of two CO₂ levels in the atmosphere, 390 and 550 μmol mol^-1. Soil samples were collected in and between coffee rows in 2013 and 2014, at the soil layers of 0-5.0, 5.0-10, 10-20 and 20-40 cm, and of 0-10, 10-20 and 20-40 cm, respectively. Soil pH, Ca²⁺, Mg²⁺, available K, P, and S contents, base saturation, and soil organic matter were evaluated. In 2013 and 2014, a reduction in available P contents was observed in coffee rows as the CO₂ levels in the air were increased. In 2014, soil available K contents were reduced and K contents in coffee leaf were increased under 550 μmol mol^-1 CO₂. In coffee grown in atmosphere enriched with CO₂, soil available P content is more reduced, which indicates the need of an adequate replacement of this nutrient.

Index terms:
Coffea arabica; soil carbon; leaf analysis; FACE; greenhouse gases; nutrients