Agrometeorology of rainfed castor beans (Ricinus communis)

Abstract

The aim of the present paper was to define the agroclimatological aptitude of the Argentinean semiarid and arid zones to produce industrial oil and biofuel from castor. Castor bean oil (Ricinus communis L.), which currently has more than 700 applications, has an “unlimited” market because its uses are multiple andthere is a growing internationaldemand.InArgentina itsproduction was always relegatedtomarginal soils, but since it ceased to be grown in 1989 castor oil is imported. Due to the international prices of castor bean oil, its multiple applications and in Argentina its diverse climate, this work on potential cultivation areas considering the species bioclimatic needs was carried out. To define the agroclimatic aptitude ofthis crop in Argentina,the climatic data ofthe meteorological stations corresponding to the period 1981–2010 was analyzed. Using available databases and geographical limits for the different variables, aptitude types were defined and mapped: optimal (>750 mm; temperature 24.0–27.0 ◦C; >−8 ◦C; >180 frost-free days); very suitable (>750 mm; temperature 21.0–23.9 ◦C; >−8 ◦C; >180 frost-free days); suitable with humid regime (>750 mm; temperature 16.0–20.9 ◦C; >−8 ◦C; >180 frost-free days), suitable 1 with sub-humid regime (450–750 mm; temperature 24.0–27.0 ◦C; >−8 ◦C; >180 frost-free days); suitable 2 with subhumid regime (450–750 mm; temperature 21.0–23.9 ◦C; >−8 ◦C; >180 frost-free days); suitable 3 with sub-humid regime (450–750 mm; temperature 16.0–20.9 ◦C; >−8 ◦C; >180 frost-free days); marginal due to humidity (200–450 mm); marginal due to temperature (<16.0 ◦C); marginal due to frosts (<180 frostfree days or <−8 ◦C) and not suitable areas (combination of 2 or more ofthe following variables: <200 mm; <16.0 ◦C; <−8.0 ◦C; <180 frost free days). Areas classified as optimal and very suitable in the eastern sector of Argentina overlay with the areas for the production of traditional oilseed crops. So, its cultivation is not recommended. The areas that can be destined to its cultivation are the ones zoned as suitable, defined under conditions of sub-humid regime (450–750 mm), with different thermal regimes: suitable 1 (24.0–27.0 ◦C), suitable 2 (21.0–23.9 ◦C) and suitable 3 (16.0–20.9 ◦C). Therefore, land might be used in parts of the provinces of Salta, Jujuy, Tucumán, Chaco, Formosa, Santiago del Estero, Córdoba, San Luis, La Pampa, western Buenos Aires, La Rioja and Catamarca. This agro-climatic zoning model to determine potential production areas for castor bean can be applied to any part of the world, using the bioclimatic limits of the species presented in this work.