Sugar cane is indigenous to Papua New Guinea (PNG). It is widely cultivated in village gardens all over PNG, throughout the year, and is chewed to extract the sweet juice. Modern sugarcane varieties cultivated for refined sugar are complex hybrids (Saccharum spp.). Commercial cultivation and production of sugar is confined to the Ramu Agri-Industries Ltd nucleus estate at Gusap–Dumpu in the Ramu Valley of Madang Province. This article focuses on commercial sugar production. The nucleus estate is located at an altitude of 400 m in an environment where mean annual rainfall is about 2000 mm. The cultivation of sugar at the plantation is seasonal; cane is planted from late February to May to reduce problems associated with insect pests and weeds, and to take advantage of optimum growing conditions. Cane is harvested from April to October using mechanical harvesters.
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Adoption and history
Proposals to establish a sugarcane industry in PNG were first made in the 1930s, with the identification of a possible site for a commercial plantation and processing operation in Oro Province. The establishment of a sugarcane industry was given further consideration in 1951 and again in 1964. The 1964 study concluded that an industry would not be economically viable until domestic sugar consumption reached about 30 000 tonnes which, it was thought at the time, would be achieved by 1975, but was not reached until the early 1980s. An intensive agronomic research program was commenced in 1965, focusing on the Markham Valley. Other studies followed in the 1970s and a 20 hectare pilot project was initiated by the Department of Agriculture, Stock and Fisheries in the Kemp Welch area of Central Province.
After Independence in 1975, the PNG Government moved ahead with plans to establish a national sugar industry for the purposes of import replacement and export diversification. Several potential sites for a sugarcane plantation were identified, and the Gusap–Dumpu site was eventually selected on the basis that it did not require irrigation or flood protection works. In 1979 a detailed soil survey was undertaken, about 7000 ha of suitable land was identified, and the first sugar cane was planted.
The total area planted to sugar cane on the estate increased rapidly from three hectares in 1979, to 1350 ha in 1982 and 6000 ha in 1989. The area planted to sugar cane on the estate remained at 5000–6000 ha from 1990 to 2006, but expanded in 2007. The 1990s saw a marked expansion in the area planted to cane by the company on land owned by local villagers (‘outgrowers’), from 800 ha in 1995 to 2200 ha in 1999. The area had decreased to 1200 ha by 2007 because of competing claims for payment for use of land by various landowners. The company responded by increasing the area under cane on its estate. In total, about 10 000 ha of company and outgrower land is involved, including that under cane, under short or long fallow, or abandoned.
Levels of production
The aggregate production of sugar from the nucleus estate (including outgrower production) has fluctuated over the past 20 years, particularly between 1982 and 1991, but has nevertheless increased from 11 000 tonnes in 1982 to 49 000 tonnes in 2002. The contribution of outgrowers to sugarcane production increased during the 1990s. By 2001–2003, about 150 outgrowers provided land which produced around 30% of total sugar cane. However, this proportion had declined to less than 15% by 2007 because of ongoing problems with land ownership.
Because of detailed company records, there are better data on crop yield for commercial sugarcane production than for any other agricultural crop in PNG. Cane yields averaged 58 t/ha between 1982 and 2007, with a range of 28–88 t/ha. This resulted in a mean sugar yield of 5.3 t/ha, with a range of 2.0–8.2 t/ha. The fluctuations in crop yield (and hence in annual production) have been caused by insect pests and diseases and, to a lesser extent, by weeds and climatic variability. For example, the marked decline in production in 1986 was due to the Ramu stunt disease epidemic of 1984–1985, which required that the entire estate be replanted. Other important pests have been moth stem borer, cicadas and white grub.
Efforts to control these problems have been reasonably successful and have resulted in an increase in sugar production since 1992. Crop yields (and total production) were poor in 2006 and 2007 because of an increase in ratoon stunting disease, caused by a bacterial infection. The problem was made worse by inadequate weed control. These problems have been addressed, including heat-treating planting material to kill the bacteria.
Processing, exporters and markets
Most of the sugar produced at the nucleus estate is sold domestically. The domestic sugar industry is protected from imports by a 70% tarif and Ramu Agri-Industries Ltd enjoys a near monopoly in the PNG market. The import tariff has resulted in high domestic retail prices for sugar in comparison with world prices. The tariff will decrease to 40% in early 2011.
Since 1993, domestic sales of sugar have ranged between 30 000 and 37 000 tonnes per year. Consumption levels of sugar in PNG have declined from about 8 kg/person/year in the early 1980s to less than 6 kg/person/year by 2006.
About 7000–10 000 tonnes per year of sugar is exported, but only in years when production is surplus to domestic requirements. Consequently, no sugar was exported in 1985, 1993 and 1996.
Molasses is a by-product of the sugar refining process and about 15 000 tonnes are produced each year. About 2000–3000 tonnes of molasses is sold for livestock feed. It is also used to produce about two million litres of ethanol (alcohol), most of which is exported and is worth K2–2.5 million per year.
Ramu Agri-Industries anticipates that sugar yields per hectare will increase because of the use of more productive cane varieties that have been selected in the company’s breeding program. The company is aiming to achieve yields of 6.5–8.0 t/ha of sugar, compared with 4–7 t/ha in recent years. It plans to increase production to 50 000 tonnes/year by 2010. However, there are potential threats to increased output. Sugarcane smut, a fungal disease that is not in PNG but is present in Indonesia and Australia, is a risk to future production on the estate, as well as to village production of chewing cane.
The company anticipates that sugar consumption in PNG will increase at about 4% per year, which will mean a domestic demand of 45 000 tonnes by 2014. However, given the current rate of population growth, consumption will still be about 6 kg/person/year. Ramu Agri-Industries is seeking to have the maximum allowable quantity exported to the United States increased from 7500 tonnes/year to 11 000 tonnes/year, as the US pays about twice the world price for sugar as an indirect form of aid.
Because import protection on sugar will be reduced and domestic demand is limited, Ramu Agri-Industries has embarked on an ambitious program of diversification, commencing with oil palm and cashew. More than 8000 ha of oil palm will be planted by early 2009, and about 15 000 ha will be planted by 2015. An area of 100 ha will be planted to cashew in 2008, which will be increased to 500 ha by 2010 if this venture is successful. A number of other agricultural products are being examined in detail, including timber for fuelwood and hardwood for export; noni, from which the juice would be extracted for export; edible bamboo for the Asian market; and jatropha oil for use as a biodiesel fuel.