EFFECT OF IRRIGATION SYSTEM TYPE ON PROFITABILITY OF EUCALYPTUS (Eucalyptus globulus) PLANTATIONS
Herrera, Miguel A.
Irrigation is used increasingly in establishment of forest plantations in order to increase growth and productivity. The effect on profitability of a eucalyptus (Eucalyptus globulus) plantation in the Central Valley of the Bio Bio Region, Chile, of three irrigation systems was studied: microsprinklers (T1), drip irrigation (T) and surface irrigation (T3). The variable projected to harvest age was the volumetric increase of the trees. To calculate costs of T1 and T2, a database was used of 200 agricultural operations of varying size where these systems were installed and implemented. For T3, current costs of construction and maintenance of the structures required were used for financial evaluation. Profitability was determined using net present value (NPV), potential land value (PLV) and modified internal return rate (MIRR). Profitability with T1 and T2 had negative values; that is, these irrigation techniques did not generate economic benefits. Surface irrigation (T3) was profitable for the volume projected to eight and ten years harvest age. The greatest returns were obtained with the three indicators using a discount rate of 8 % and a price of pulp wood of US$ 32 m(-3) ssc. NPV was US$ 989 ha(-1) and US$ 1106 ha(-1); PLV was US$ 2152 and 2406 ha(-1), and MIRR was 10.4 % and 10.1 % These results justify the use of surface irrigation (T3) as an efficient technique in the integrated management of a high-producing eucalyptus plantation.