Modeling oil palm crop for Brazilian climate conditions

Abstract

CONTEXTThe increasing world demand for palm oil led to the expansion of oil palm plantations, especially in the new lands in Southeast Asia, the main producing region in the world. The expansion of oil palm plantations has also occurred in Latin American countries, such as Brazil. Roughly 400 million hectares in Brazil are suitable for the planting of oil palm, but most of this area is currently covered by forest, mainly by the Amazon Rainforest. Climate change has reduced the extent of land suitable for oil palm cultivation in Brazil since under unfavorable climatic conditions, crop yields are reduced. To reconcile the increase in oil palm production in Brazil with the preservation of forests, modeling has been used as a tool to define the best suitable areas for planting expansion, as well as for the assessment of management techniques that aim to increase the yield. OBJECTIVEThus, the object of this study was to implement the oil palm crop sub-model in the ECOSMOS integrated simulator and to evaluate its performance to simulate oil palm energy and carbon balance and the crop yield. METHODSThe carbon allocation scheme for oil palm is quite different from the other crops of ECOSMOS. So, we use the sub-PFT (plant functional type) approach, where each phytomer in the plant evolves simultaneously, but individually. RESULTS AND ConclusionsThe results showed that the model was able to simulate net radiation (Rn), latent heat flux (LE), and net ecosystem CO2 exchange (NEE) with good accuracy. In contrast, the sensible heat flux (H) was not well simulated due to the lack of information on the soil's physical-hydric properties. The model simulated accurately the annual yield for plants aged between 12 and 25 years, whereas the yield was overestimated for plants aged outside this range. Also, the model better simulated the yield of genetic varieties with seasonal yield, compared to varieties with more uniform yield over the months. SIGNIFICANCEThe robust and consistent results presented for most of the evaluated processes, especially for energy and carbon fluxes, make the oil palm sub-model described here suitable for improve the oil palm production in Brazil. For future studies, efforts should be directed to consider key factors for oil palm, such as the ratio between male and female inflorescences and the abortion rate of inflorescences, which affect crop yield, for a better understanding of the oil palm growth and production.