Modelling agroforestry systems of cacao (Theobroma cacao) with laurel (Cordia alliodora) and poro (Erythrina poeppigiana) in Costa Rica III. Cycles of organic matter and nutrients

Modelling agroforestry systems of cacao (Theobroma cacao) with laurel (Cordia alliodora) and cacao with poro (Erythrina poeppigiana) in Costa Rica

“…The study was carried out in the 'Central Experiment' of CATIE in Turrialba, Costa Rice [1,9,15] which was established in 1977.…”

“…The concentrations of nutrients in the precipitation and the corresponding annual inputs, presented in previous publications [9], had been determined for the upper part of the Turrialba valley, approximately 2 km North-west from the 'Central Experiment'. In order to obtain more representative values, precipitation samples were collected daily at the study site from February 1982 to January 1983. pH was determined from combined monthly samples, and nutrient concentrations (N, P, K, Ca and Mg) from combined bimonthly samples.…”

“…6). A previous study of soil water nutrient concentrations (20 lysimetric capsules; 50 and 100 cm from tree stems; 0-30 cm depth) [8,9] Apparently N is rapidly absorped by roots, whilst the differences in K, Ca and Mg are still apparent in the water percolating out of the root zone.…”

“…ha-1. a-1 ) of 120 N, 29.3 P205 and 33.0 K20 [1,9], or to total soil reserves on this site (kg. ha 1 for 0-45 cm) of 8,800 N; 3,600 P and 650 K.…”

“…One of the first difficulties is that the published evapotranspiration values for crops are presumably not additive. Nutrient cycling in agroforestry systems with cacao has been studied [1,3,9,13,28] and two publications give values for nutrient leaching [23,28].…”