Avaliação da produtividade e estratégias de maneio na produção de arroz (Oryza sativa L.) usando o modelo APSIM: estudo de caso no regadio de Chokwé

Abstract

The Chókwè irrigation system is one of the largest in the country with around 35,000 ha and rice is the main crop during the hot season. The agroecological conditions prevailing in the region are excellent for rice production, but the yields verified are still well below their potential. The present study attempts to explore the potential of crop simulation models as useful tools to assess the performance of agricultural systems in different scenarios, when carefully calibrated and validated. The APSIM model simulates crop growth and the effects of environmental and management variables on production. The objective of this work was to calibrate and evaluate the APSIM model and apply it in the evaluation of the production potential and in the determination of better management strategies to improve the productivity of rice in Chókwè. Rice culture data were collected by monitoring variety tests, evaluating direct sowing and transplantation methods carried out in partnership with the JICA project. The monitoring was also carried out in farmers' fields in Chókwe during the 2013/2014 season. Additional information was obtained by compiling data on various trials conducted in the years 2007 to 2012 and provided by JICA, IIAM, ISPG and MIA. The results show that the APSIM model was satisfactorily calibrated and evaluated for the ITA312, Limpopo and IRGA409 varieties with agreement rates between 0.89 to 0.98. The calibrated APSIM model was used to assess the potential of rice production in Chókwè and to study the following management strategies: water level in the basin, cover fertilization levels, transplant days and sowing dates; the water level in the basin between 50 and 100 mm was identified as the most recommended for rice production; cover fertilization had a positive influence on yield and; transplanting seedlings for 20 to 30 days resulted in better yields. The present study also showed that the best sowing period is from September to November for the Limpopo and IRGA409 varieties and from October to November for the ITA312 variety. The Limpopo variety showed greater production stability with an average yield of 5 517 kg / ha.(TRADUÇÃO NOSSA)