Sustainable land management at Ramu sugar – Assessment and requirements

TitleSustainable land management at Ramu sugar – Assessment and requirements
Publication TypeBook Chapter
Year of Publication2001
AuthorsHartemink, AE, Bourke RM, Allen MG, and Salisbury JG
Book TitleFood Security in Papua New Guinea
Series VolumeProceedings no. 99
Pagination344 - 364
PublisherAustralian Centre for International Agricultural Research
Abstract  Ramu Sugar Plantation was established in 1979. This paper presents an overview of changes in soil chemical and physical properties that have resulted from continuous sugarcane cultivation since that time. Between 1979 and 1996, the soil pH decreased from about 6.5 to 5.8 and this acidification was accompanied by a decrease in cation exchange capacity and exchangeable cations. Organic carbon levels declined from about 56 grams per kilogram in 1979 to 32 grams per kilogram in 1996. The inter-row of the sugarcane was compacted and had significantly higher bulk densities and a very slow water intake. Semiquantitative nutrient budgets showed a shortfall in nitrogen, phosphorus and potassium, and levels of these nutrients in the sugarcane leaves significantly decreased between the mid-1980s and 1990s. Yields at the plantation are largely determined by insect pests, diseases and weeds. It is concluded that significant soil changes occurred that may affect the sustainability of sugarcane growing in the long term if such trends continue