Growth and yield responses of commercial sugarcane cultivars to residue mulching in different environments

Abstract

Mulching in sugarcane agriculture involves retaining leaf residue on the ground after harvesting. Many sugarcane industries across the world support this agronomic practice because of its benefits as opposed to burning sugarcane at harvest. In the South African industry, however, there have been isolated reports of negative responses of certain cultivars to mulching. The objective of this study was to evaluate the cane yield and quality responses, population dynamics, and mulch yields of popular sugarcane cultivars to mulching in three major agronomic regions of South Africa. A field trial was established in each of the three major South African sugarcane production regions (Coastal rainfed, Northern irrigated, Midlands) in 2008. Each trial comprised eight of the most popular cultivars for the respective regions. Trials were planted as 2 x 8 factorial strip-plots with four replicates. Burning and mulching were the main plots (strips) and cultivar was sub-plot. In the coastal rainfed and the irrigated region cultivar responses to mulching were evaluated over a period of three summer crops (1st, 2nd, and 3rd ratoon) and one winter crop (5th ratoon), while the Midlands trial was harvested for one summer crop (1st ratoon). The impact on stalk population, heights and soil water was evaluated during each growing season. Cane yields (TCANE), estimated recoverable crystal percentage (ERC) and ERC yields (TERC), as well as mulch yields were determined at each harvest.