Penyusunan Model Simulasi Tanaman Jarak (Ricinus Communis L.)

Abstract

This research aimed to construct a crop simulation model of castor oil (Ricinus communis L.) comprising crop development, crop growth, and water balance submodels. The research was conducted for two-year period (2002 and 2003) at three locations having distinct environmental conditions, i.e. Malang (575 msl), Sukamandi (50 m) and Situbondo (5 m). The field experiment was done to collect data to support the construction and validation of the crop model being developed. The experiment in Malang during 2002 had four nitrogen treatments and two cultivars (ASB 81 and ASB 60), soil type was inceptisols with sufficient soil water by adding irrigation water. As a comparison, in the same year, field experiment at Sukamandi (soil type of entisols) with higher temperature and low rainfall was conducted using three level irrigation treatments. In year 2003, the experiment was conducted at Situbondo (soil type of entisols) at a relatively large area of land (1 ha) using treatments of sowing date without irrigation while nitrogen was sufficient. The cultivar used was ASB 81. The field experiments conducted at three locations produced required data for model construction. The research showed that nitrogen and water affected growth of the crop significantly by increasing biomass of individual organs and yield castor. Crop development, on the other hand, was determined by temperature and parameters of base temperature and thermal unit of various crop stages derived from this experimental data. The model being developed simulates processes related to crop growth in response to its inputs (weather variables, soil and agronomic inputs). The model can be employed as a decision support tool in the management of castor oil plantation