Water Demand of Sugarcane Varieties Obtained by Lysimetry

The aim of this study is to determine the water demand of the varieties RB867515, IAC91-1099, and IAC87-3396 of sugarcane using weighing lysimetry in the environmental conditions of the Cerrado of Goias, Brazil. The experiment was conducted in Goiânia, GO, Brazil, from March 2016 to March 2018 during the cycles of plant-cane and ratoon cane, lasting 12 months each. For this purpose, 120 pots of 200 L were installed in the experimental area. Eight lines with 15 pots were spaced 1.5 m apart. Three pots were installed on electronic weighing platform scales. The soil water content was monitored by ECH2O EC-5 sensors installed in the sugarcane root zones. Irrigation was performed every two days by replenishing water in the soil up to field capacity. The water demand for the varieties IAC91-1099, RB867515, and IAC87-3396 was on average 9.2, 8.2, and 7.6 L.day−1, respectively, for the first cycle (plant-cane), and 8.4, 7.9, and 6.6 L.day−1, respectively, for the second cycle (ratoon cane). There was a decrease in water consumption of all varieties from the first to the second growing cycle. The variety RB867515 had the smallest decrease (3.7%) between cycles, followed by IAC91-1099 (8.7%), and IAC 87–3396 (13.2%). The differences in average water demand between varieties reached 17.4 and 21.4% in the first and second cycles, respectively, compared to the varieties with a greater (IAC91-1099) and lower (IAC87-3396) water demand. This is due to differences in morphological characteristics (stem diameter, stem height, number of green leaves, and leaf area), which also decreased from the first to the second cycle. There is a need to consider the variety cultivated and the cycle.