European Journal of Sustainable Agroecosystems

Background: Sugarcane (Saccharum officinarum L) is a long-duration and high biomass C4 crop, which is the main sugar-producing crop in the world and an increasingly important feedstock for bioenergy purposes, but it is one of the most water-consuming crops because it requires between 20,000 and 30,000 m³ of water ha⁻¹ throughout each production cycle. With the water resources becoming scarcer due to, among other facts, climate change and population pressure, it is particularly important to improve the water use efficiency (WUE) of sugarcane. Deficit irrigation (DI), which means irrigation below the full water requirements of the crop, has been developed as one of the methods for saving water. Nevertheless, the effect of DI on water-use efficiency, cane yield, and juice quality varies depending on the type of irrigation, its timing, and method.
Aim: The review thoroughly summarizes studies conducted by experts on the impact deficit irrigation has on different parameters such as WUE, water productivity, yield, and product quality. The paper also aims to find out when one can save water and still maintain a reasonable level of yield.
Databases: Information was obtained from world-recognized databases such as Scopus, Web of Science, ScienceDirect, SpringerLink, MDPI, Frontiers, and Nature. The author used the following keywords to gather data: "sugarcane," "deficit irrigation," "water use efficiency," "water productivity," "partial root zone drying," "Saccharum officinarum."
The main conclusions state that the deficits in irrigation could enhance WUE and water productivity when compared to complete irrigation. Furthermore, in many instances, yield reduction with partially dry irrigation could be less than with complete irrigation. Water usage decreased by approximately 17.6%, while biomass was reduced by around 11.3%, leading to the increase in agronomic WUE from 2.9 to 4.1g L⁻¹. Computer simulations and trials have shown that if 50% of the total water available is used during non-critical periods, it could be enough to obtain good yields. Moreover, drip irrigation has increased WUE by 60-200% and decreased water use in comparison to traditional surface irrigation by 20-60%. It has been found out that certain genotypes had better water productivity than others, while growth stages are highly sensitive to drought and should not be subjected to deficit irrigation. It is worth mentioning that there are still numerous gaps in research related to deficit irrigation, such as long-term studies of ratoons, assessment of cost-effectiveness for small farmers, and implementation of combined approaches of deficit irrigation together with mulching, fertigation, and selection of drought-resistant plant types.