Resumen

CASTRO-TANZI, Sebastián. Calcium is a limiting nutrient in coffee groves under intensive fertilizer management on Ultisols. Agron. Costarricense [online]. 2017, vol.41, n.1, pp.105-119. ISSN 0377-9424.  http://dx.doi.org/10.15517/rac.v41i1.29756.

Intensively managed coffee (Coffea arabica) agroecosystems demand considerable amounts of potassium (K) and nitrogen (N). In groves fertilized with high rates of N, K and P, however, it is reasonable to foresee that calcium (Ca) or magnesium (Mg) availability can limit crop production and development. This study explored whether a link exists between coffee plant leaf tissue Ca, Mg and K contents and the fertility of these exchangeable bases in Ultisols. The study also analyzed whether the availability of one of these nutrients in leaves limits crop productivity. In the span of 2 years, soil and leaf tissue samples were collected in 26 coffee farms in Tarrazú, Costa Rica. Using linear regression analysis models, soil and leaf Ca, Mg and K concentrations were compared; the models indicated strong associations between the status of those nutrients in leaf tissue and their availability in the soil exchangeable solution. To assess whether C, Mg or K acted as nutrients limiting yields, crop productivity indicators were recorded and leaf tissue samples collected in 2 plots in each of 39 coffee farms (12 plants per plot; 78 plots total). Within each farm, the crop productivity indicator was used to classify each plot as of higher or lower productivity in relation to its pair. By this post-hoc classification, a quasi-experiment with a random block design was generated. This design was used to analyze the variation of N, K, Ca and Mg concentration of the leaf tissue collected in the plots. Ca leaf content tended to be higher in leaf samples from plots with higher productivity; Ca/K and Ca/N ratios tended to be significantly higher as well (p-value<0.05). These results highlight the importance of soil Ca for coffee productivity in Ultisols of moderate to low fertility.

Palabras clave : Coffee (Coffea arabica); soil fertility; calcium; magnesium; potassium; coffee nutrient management; Ultisols; soil exchangeable bases.

        · resumen en Español     · texto en Español     · Español ( pdf )