Simulating sugarcane yield response to ETc replacements and green cane trash blanket maintenance in Brazil¹

Simulando a resposta da produtividade da cana-de-açúcar a reposições da ETc e quantidade da palhada no Brasil

HIGHLIGHTS:

The APSIM-Sugar agreed very well for soil moisture, biometric, and physiological variables.

ETc replacements affects stalk yield more than GCTB, above 50% ETc replacement, yield response was irrelevant.

The recommended amount of GCTB is at least 5.50 Mg ha^-1, considering soil health and the need for biofuel generation.

ABSTRACT

Determining the proper crop water requirement associated with the optimum amount of green cane trash blanket (GCTB) on the soil is one of the most discussed issues for sugarcane growers. In this context, this research aimed to evaluate the effects of different amounts of GCTB and ETc replacement scenarios on sugarcane yields across key producing regions in Brazil using the agricultural production systems simulator (APSIM). The sugarcane APSIM (APSIM-Sugar) was parameterized and validated for sugarcane in Brazil, compared to both 100% GCTB cover and bare soil, both fully irrigated. After validation through field data, the APSIM-Sugar model was used to simulate 25 different scenarios with varying GCTB amounts and irrigation demands in 12 regions of Brazil for a 30-year period to estimate stalk yield. Overall, modeled and field data agreed very well regarding soil moisture and biometric and physiological variables, achieving strong modeling efficiency. For most producing regions of Brazil, interaction between the factors did not increase stalk yield significantly, and up to 50% of ETc replacement resulted in the highest increases in stalk yield, with the greatest improvement between 0-25%, producing an average increase of 30 Mg ha^-1 per year. The recommended amount of GCTB is at least 5.50 Mg ha^-1, taking into account soil health and the need for biofuel generation.

Key words:
APSIM-Sugar; green cane trash blanket; modeling