Radiation interception and biomass accumulation in a sugarcane crop grown under irrigated tropical conditions
1994
Muchow, R.C. (Commonwealth Scientific and Industrial Research Organisation, St Lucia (Australia). Div. of Tropical Crops and Pastures) | Spillman, M.F. (Commonwealth Scientific and Industrial Research Organisation, Aitkenvale (Australia). Div. of Tropical Crops and Pastures) | Wood, A.W. (CSR Technical Field Dept., Ingham (Australia). Macknade Mill) | Thomas, M.R. (Commonwealth Scientific and Industrial Research Organisation, St Lucia (Australia). IPPP Biometrics Unit)
For an autumn-planted sugarcane crop grown under irrigated conditions at Ayr, Queensland, crop samplings were conducted from 167 to 445 days after planting. Less than 60 percent of the seasonal incident solar radiation was intercepted by the crop. A radiation extinction coefficient of 0.38 was estimated from the relationship between green leaf area index and the fraction of the radiation intercepted (fi). The maximum crop growth rate over a 140 day period was 41.1 g per sq m per d. The maximum radiation use efficiency value of 1.75 M per J found is independent of fi and incident radiation, and can be used as a baseline value to assess the extent of yield limitation and the scope for yield improvement at different locations. The maximum biomass production was 72 t per ha and the maximum fresh cane yield was 201 t per ha. However, these maximum yields were attained up to 4 months before the final sampling. Future research should examine the wider applicability of this early yield plateau, and focus on the factors responsible for the early cessation in yield accumulation.
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