Drying‐Off Periods for Irrigated Sugarcane to Maximize Sucrose Yields Under Brazilian Conditions

Abstract

The natural ripening process in sugarcane plants is influenced by several factors, including water stress. In irrigated sugarcane areas, water application is often withheld prior to harvest, a process called drying-off, which is done to increase the sucrose content and yield, and to provide suitable conditions of soil moisture for mechanical harvesting. Based on this, the objective of this study was to determine the drying-off periods for irrigated sugarcane in different Brazilian regions to maximize sucrose yields. The APSIM-Sugarcane model was used to simulate 12-month plant cane in 12 Brazilian sites for a long-term period. Three soil types with different water-holding capacities (low, medium and high) were adopted. The drying-off periods were determined based on the relationship between relative stalk dry mass yield (dried-off and fully irrigated) and days in which water was withheld prior to harvest, considering yield reduction up to 4% as a target. As expected, the drying-off periods varied considerably according to locations, soil types and harvest dates, with the median ranging from 15 to 115 days. In general, more drying-off days are required at the beginning and end of the harvesting season, when higher interannual variability is also observed. The results obtained are useful for planning and decision-making in irrigated sugarcane areas, since they allow evaluation of the best strategy to maximize sucrose yield. RÉSUMÉLe processus naturel de maturation de la canne à sucre est influencé par plusieurs facteurs, dont le stress hydrique. Dans les zones de production de canne à sucre irriguée, l'application de l'eau est normalement suspendue avant la récolte, un processus nommée séchage, lequel est réalisé pour augmenter le contenu et rendement de saccharose, et pour assurer des conditions adéquates d'humidité du sol pour la récolte mécanique. Basée sur cela, l'objectif de cette étude a été de déterminer les périodes de séchage pour des cannes à sucre irriguées dans différentes régions du Brésil pour maximiser le rendement de saccharose. Le model APSIM-Sugarcane a été utilisé pour simuler, à long terme, la canne de 12 mois dans 12 sites brésiliens. Trois types de sol avec différentes capacités de rétention (faible, moyenne et forte) ont été adoptés. Les périodes de séchage ont été déterminées par la relation entre la productivité relative (sèche et irriguée) et le nombre de jours pendant lesquels l'eau a été suspendue avant la récolte, compte tenu de l'objectif de réduction de 4% de la productivité. Comme prévu, les périodes de séchage ont varié considérablement selon les localités, types de sol et dates de récolte, dont la médiane a varié de 15 à 115 jours. En général, plus de jours de séchages sont nécessaires au commencement et à la fin de saison de récolte, quand une haute variabilité interannuelle est observée. Les résultats obtenus sont utiles pour les processus de planification et de prise de décision dans les zones de canne à sucre irriguée, puisque cela permet d'évaluer la meilleure stratégie pour m...

New APSIM-Sugar features and parameters required to account for high sugarcane yields in tropical environments

“…Better modelling of RGP will probably reduce the uncertainties in sugarcane simulations. For example, the drying-off days to increase sucrose yield in irrigated sugarcane estimated in Brazil (Dias and Sentelhas, 2018a), South Africa (Donaldson and Bezuidenhout, 2000) and Australia (Robertson et al, 1999) with APSIM-Sugar and CA-NEGRO models would be improved, since they used relative stalk dry mass as a trigger to withhold water before harvest. Several sugarcane yield gap analyses performed with crop models in Brazil (Dias and Sentelhas, 2018b;Marin et al, 2016;Monteiro and Sentelhas, 2017) and other countries (Cheeroo-Nayamuth et al, 2000;Van den Berg and Singels, 2013;Zu et al, 2018) did not take into account the RGP in the simulations.…”

“…The use of APSIM-Sugar has increased in Brazil recently. This model has been applied to evaluate the impact of a green cane trash blanket on yield (Costa et al, 2014;Marin et al, 2014;Oliveira et al, 2016), for irrigation planning (Dias and Sentelhas, 2018a), for yield gap analysis (Dias and Sentelhas, 2018b) and for uncertainties under climate change scenarios (Marin et al, 2015).…”

Sugarcane response to different soil water replenishment‐based deficit irrigation treatments during different growth stages in an Indian semi‐arid region*

“…Being a year‐long crop, sugarcane requires continuous supply of IW throughout its growth cycle, and thus IW management is a very important aspect (Inman‐Bamber & McGlinchey, 2003; Singandhupe et al, 2008; Carr & Knox, 2011; Cardozo, de Oliveira, & La Scala, 2018; Dias & Sentelhas, 2018). Under such circumstances, deficit irrigation is inevitable (Garg & Dadhich, 2014; Bahmani & Eghbalian, 2018; Lucas et al, 2019).…”

Sugarcane variety trait modelling: evaluating and improving the APSIM-Sugar model for simulating crop performance under current and future climates across Brazil

“…For example, the drying-off days to increase sucrose yield in irrigated sugarcane estimated in Brazil (Dias and Sentelhas, 2018a), South Africa (Donaldson and Bezuidenhout, 2000) and Australia (Robertson et al, 1999) with APSIM-Sugar and CANEGRO models would be improved, since they used relative stalk dry mass as a trigger to withhold water before harvest. Several sugarcane yield gap analyses performed with crop models in Brazil (Dias and Sentelhas, 2018b;Marin et al, 2016;Monteiro and Sentelhas, 2017) and other countries Jones and Singels, 2015;van den Berg and Singels, 2013;Zu et al, 2018) did not take into account the RGP in the simulations.…”

“…The use of APSIM-Sugar has increased in Brazil recently. This model has been applied to evaluate the impact of a green cane trash blanket on yield , for irrigation planning (Dias and Sentelhas, 2018a), for yield gap analysis (Dias and Sentelhas, 2018b) and for uncertainties under climate change scenarios .…”