Soil loss and declining sugarcane yields on sloping land in Fiji

Ram, A.N. and Gawander, J.S. and Jokhan, Anjeela D. and Garan, K. (2007) Soil loss and declining sugarcane yields on sloping land in Fiji. [Conference Proceedings]

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Abstract

GROWING sugarcane on sloping land receiving high intensity rainfalls causes extensive soil erosion in Fiji. This soil loss and accompanying declining cane yields on undulating terrain is of major concern to the Fijian sugar industry. In recent years, growers have not
only abandoned best management practices to conserve the soil, but they have also uprooted the borders of vetiver grass. This, to a large extent, has accelerated the loss of top soil and thus soil degradation causing, with the burning of trash, the yield to decline even more rapidly. As quantitative data on erosion from field plots are scanty in Fiji, an experiment was initiated on a sloping cane farm (8° slope) to determine soil loss under
different management practices and impact on the cane yield of the plant cane and of ratoon crops. The different management practices studied were sugarcane planted across slope, sugarcane planted uphill and downhill, cane planted across the slope with vetiver
grass grown as hedgerow, and trash cover with cane planted across slope. There was significant (P<0.05) difference in cane yield in the plant-cane crop. In ratoons, there were no significant differences among treatments. However, the plots in which trash was conserved and cane planted across the slope maintained yields better than the other three treatments. Soil loss was largely affected by the different planting strategies
associated with the conservation practices. Trash acted as a protective layer under high rainfall, and 153 and 221 kg soil/ha/y were eroded in the first- and second-ratoon crops, respectively. Where the sugarcane was planted uphill and downhill soil losses were 16 376, 259 and 2274 kg/ha/y, in plant cane and the two ratoon crops, respectively. The very low soil loss in the first-ratoon crop is attributed to the drought conditions of that
year. Planting sugarcane across the slope, conserving trash mulch, and keeping a vetiver hedgerow therefore reduces soil erosion and, with increasing period of cultivation, will sustain cane production to provide stable economic returns to Fijian farmers.

Item Type:	Conference Proceedings
Subjects:	S Agriculture > S Agriculture (General)
Divisions:	Faculty of Science, Technology and Environment (FSTE)
Depositing User:	USP RSC Assistant
Date Deposited:	21 Dec 2017 23:00
Last Modified:	21 Dec 2017 23:00
URI:	https://repository.usp.ac.fj/id/eprint/10389

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