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Performance of DSSAT CSM-CANEGRO Under Operational Conditions and its Use in Determining the ‘Saving Irrigation’ Impact on Sugarcane Crop

dos Santos Vianna, Murilo, Sentelhas, Paulo Cesar
Sugar tech 2016 v.18 no.1 pp. 75-86
climatic factors, crop models, crop yield, data collection, dry season, irrigation management, planting date, sandy soils, semiarid zones, sugarcane, Brazil
Sugarcane is a crop of major importance for Brazil. Many of the sugarcane fields are located in the center-south of the country, where sugarcane is grown as a rainfed crop. However, it has recently also expanded into marginal areas where irrigation is required. As water is less available during the dry season in these areas, a study was conducted to evaluate the performance of the DSSAT CSM-CANEGRO model under operational conditions in Brazil, and to determine the benefits of different complementary irrigation strategies for increasing yield in different regions in the country. Two different datasets were used to evaluate the performance of DSSAT CSM-CANEGRO in the most traditional sugarcane areas in Brazil, where the model was used to simulate plant cane crop yield. Further, the crop model was used to simulate sugarcane yield under different climatic conditions, in order to assess its sensitivity under real conditions. Additionally, five different complementary irrigation scenarios were simulated, with a fixed irrigation depth of 30 mm, and with the number of irrigations ranging from zero (rainfed crop) to five (150 mm per cycle), during the dry season at each location. The CSM-CANEGRO presented a satisfactory performance to estimate the operational sugarcane yield in different environments, with an acceptable root mean square error of about 15 t ha⁻¹. Based on the simulations with the different complementary irrigation strategies, it was possible to understand that the 12-month plant cane’s response to water depends on amounts of water, soil type and planting date. The highest yield increments were observed in the sandy soils, where the water deficit is more intense. However, for the majority of the locations evaluated, the average yield increment for the irrigation depth applied, between 30 and 150 mm, was no greater than 30 %, with the exception of Petrolina, PE, which has a semi-arid climate.