Development and implementation of harvest management planning tools for the maximisation of CCS in the Tully district

Abstract

The Tully Sugar Limited milling district is characterised by large geographical, varietal, and seasonal differences in sugar yield. Growers are increasingly looking for ways to increase profitability by capitalising on these differences. This is a multifaceted task as there are several variables such as variety, crop class, crop age, CCS, cane yield, and soil type to consider simultaneously when planning the harvest. Adding to the complexity of the harvest planning task in the Tully district is influence of large harvesting groups, high mill crushing rates, and a wet tropical environment. A study of Tully Sugar Industry productivity data by Lawes et al..2004 indicated that, weather effects excluded, the time of harvest and crop age at harvest had the biggest effect on CCS and biomass accumulation. The harvest planning decision making process identified by the growers in the SRDC funded “Working Together For Our Future” Action Group working on Low CCS indicated the key drivers considered by growers when planning a harvest schedule are: • time of harvest in the previous season, • agronomic factors, • block topography, • group rotation, • the growers view of the climate forecast. Using these factors growers formulate a harvest schedule for their cane blocks - “Harvest Plan”. Typically growers then vary this plan to taking account of the weather and transport logistics at the time of harvest. This complex decision making process can be simplified if growers had the ability to produce a number of management scenarios using decision support tools. A review of harvest planning decision support tools revealed that there were no “off the shelf “ decision support tools available for users. However the CSIRO SugarMax models could be adapted for use in harvest planning. The SugarMax tool was developed through previous SRDC projects CSE003 (SRDC, 2005) and CSE005 (SRDC, 2006) to provide increased capacity for growers to learn from and adopt improved time-of-harvest schedules.