In Thailand for the sugarcane milling year of 1993/94, 37.6 million tonnes of cane was crushed, of which 9.5 million tons (25%) was burnt cane, compared with only 1.8 million tons (5.1%) in 1992/93. The lower amount in 1992/93 was due to a labour shortage. As a result of burning, the average sugar recovery in 1993 was 101.5 kg/ton of cane compared with 104.1 kg/ton of cane in 1992/93. Molasses production increased in 1993 with an average of 50.6 kg/ton of cane compared to an average of 46.1 kg/ton of cane in the previous year.

This experiment conducted in Suphan Buri province showed the effect of pre-harvest burning on 3 sugarcane varieties (U-Thong 1, U-Thong 2 and F 140), each being harvested at 3 different times (November 1993, January and March 1994). After cutting, green canes and burnt canes were distinguished and left in the field. Change in stalk weight of green and burnt canes were examined over set periods for 2 weeks. Also, changes in CCS and purity were used as quality indicatiors in burnt cane left standing, burnt cut cane and green cut cane over the 2 weeks period.

It was found that burnt cut cane lost more weight (19.7%) (Fig.1-3) and cane quality than green cut canes (14.2%) during the 2 weeks period. In burnt cut cane, U-Thong 2 and F 140 lost more stalk weight than U-Thong 1 variety. The poorest sugar quality was found in burnt cane left standing in the field (Fig.4). There was no reduction in CCS of green cut cane during 14 days (except for green cut cane harvested in November) though purity was reduced after 5 days. In burnt cut cane, the high sugar content varieties U-Thong 2 and F 140 showed greater reduction in CCS. There was no significant difference in fiber percentage between burnt cut and green cut cane. Burnt cut cane which was left in the field had a low recovery of sugar and had a longer sugar processing time.

In Thailand, the average temperature in March is greater than in November and January. Hence, Sugarcane harvested in March had more weight loss than in November and January especially in burnt cane. It is recommended that burnt cane harvested in November should be transported to the mill within 72 hours. For burnt cane harvested in January and March transportation to the mill should occur within 24 hours after burning as this practice will reduce the loss of stalk weight and cane quality.

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