Environmental sustainability of oil palm cultivation in Papua New Guinea

Papua New Guinea's oil palm industry is the country's largest agricultural export earner. Oil palm is grown on about 130,000 hectares by more than 18,000 smallholder growers supporting an estimated 200,000 people, and by two companies. Environmental sustainability of the industry is\ud increasingly coming under scrutiny by growers, palm oil purchasers and various interest groups in Papua New Guinea and worldwide. The oil palm industry and the high population associated with it both have an impact on the land used for oil palm, as well as on surrounding ecosystems.\ud \ud This report focuses on the effects of oil palm cultivation on soil, water and the atmosphere. For nutrient balances to be sustainable, inputs and losses should be balanced and minimised. Nutrient cycling factors that are difficult to estimate include loss of nitrogen by leaching (the main factor of concern), gaseous losses of nitrogen and biological nitrogen fixation. The carbon balance is generally favourable, except for large losses of carbon dioxide during initial plantation establishment (where oil palm replaces forest) and probably also during replanting. Net soil erosion from fields appears to be generally small, except for bare connected areas on moderate slopes and some in-field roads. Health of soil is influenced by net acid addition rate (largely related to fertiliser use), return of organic residues and traffic. Health of aquatic ecosystems may be affected by nitrogen inputs leached from fields and poor riparian vegetation. There is limited availability of data that are specifically relevant to these environmental sustainability issues in Papua New Guinea.\ud \ud The Papua New Guinean oil palm industry has committed itself to certification of environmental stewardship, particularly through the Roundtable on Sustainable Palm Oil. There is thus a need for practical and meaningful indicators of environmental sustainability that are based on a clear understanding of the oil palm agroecosystem, to underpin certification and to guide improvements in management