Biomass accumulation in sugarcane : final report 79/9028

Abstract

Growth analysis experiments were conducted at Ayr and Bundaberg from 1979 to 1982 to study biomass accumulation in plant and ratoon crops of sugarcane. Crops were planted and ratooned in March, June, September and December, and harvested at 6, 9, 12 and 15 months of age. Data were acquired for yields of total fresh and dry matter, in addition to yields of the following vegetative components: dry leaf, green leaf, tops and stalks. Fibre analyses were determined on all components, while glucose, fructose and sucrose % were also determined in the latter three components. It was shown that yield of total dry matter increased with age at harvest for all months of crop initiation. Potential for dry matter accumulation was closely associated with intercepted solar radiation. Growth for three months was ranked December-March > March-June > September-December > June-September. These rankings represented the interaction of crop growth stage with solar radition. The proportion of total dry matter allocated to soluble and structural carbohydrate was shown to be dependent on variety as well as an interaction between age at harvest and month of harvest. Canes older than nine months of age, harvested between June and December, had established a plateau type equilibrium between the proportion of total dry matter in soluble and structural carbohydrate. Good prospects existed for forward extension of the crushing season to March for ethanol production based on 15 month old cane. Models were developed to describe the growth of yield components of the biomass in relation to intercepted solar radition, month of crop initiation, age at harvest and crop class.