Reducing sugarcane irrigation demand through planting date adjustment in Alagoas State, Brazil

Abstract

Sugarcane is both an important crop for the Brazilian Northeast economy, which faces severe water scarcity, and a water-intensive crop. Thus, it is important to develop irrigation strategies to reduce irrigation water demand in the region. This study aims to determine the sugarcane planting date that results in the maximum rainwater availability to the crop in the growing cycle. The crop effective precipitation was estimated from a soil water balance performed during three planting cycles of sugarcane, cultivar ‘RB 92579’. The crop was planted under subsurface drip irrigation in five months: October, November, December, January, and February, corresponding to the dry season period of the region. The experiment was conducted at the Açúcar e Álcool Coruripe Mill, located in the Coruripe municipality, State of Alagoas, Brazil, during the years 2012 to 2016. For all planting dates and growing cycles studied, the average effective rainy precipitation was equal to 30% of the total rainfall under irrigated conditions and 54.5% without considering the irrigation component in the soil water balance. November was the planting date that resulted in the minimum irrigation depth for the sugarcane growing cycle, with the potential irrigation water saving ranging from 5 to 129 mm.

Agricultura irrigada no Brasil: inovação, empreendedorismo e sistemas de produção

“…Com isso, a quantidade de terra necessária para atender a demanda de cana-de-açúcar poderia ser substancialmente reduzida, sobrando terra para ser destinada a outros usos, inclusive para preservação de vegetação nativa. Ademais, a verticalização através do ganho de eficiência, que gera um efeito "poupa-terra", tem sido uma marca da agricultura brasileira VIEIRA FILHO, 2016;RESENDE et al, 2021). E quando adotada sob os conceitos modernos de irrigação deficitária (ou irrigação por deficit controlado) e utilizando exclusivamente a disponibilidade hídrica outorgável, a produção irrigada é mundialmente reconhecida com uma das melhores alternativas para o aumento da sustentabilidade ambiental e do uso racional da água, sobretudo no contexto das mudanças climáticas (FERERRES; SORIANO, 2006;GEETS;RAES, 2009;PATLE et al, 2019;KIJNE et al, 2020;MALHI et al, 2021;GIORDANO et al, 2021).…”