IMPACT OF MINERAL NUTRITION MANAGEMENT ON GANODERMA INCIDENCE IN OIL PALM PLANTED ON PEAT SOIL

摘要

The basal stem rot (BSR) disease of oil palm due to Ganoderma fungus is seriously threatening oil palm plantation in Malaysia and Indonesia, as well as part of Africa. Its increases with time and replanting cycles and therefore impact the profitability of the commodity. Ganoderma infection is widespread in mineral, peat, acid sulphate soils, etc. Mineral nutrition management on peat soil is undoubtedly an important factor to optimizing the nutrition balance of palms to producing high yield. However, it has been reported on many crops that mineral or organic fertilizers could affect the incidence of the diseases. Generally while some nutrients are favorable for the development of diseases, others seem to provide some protection to the plants. It is known that the equilibrium chemical composition in plants affect their resistance to pest and disease. Reports also mentioned that the change in soil mineral nutrition levels and balance due to fertilizer applications could also affect the soil microbial development, including pathogenic microbe. Here we report the results of a long-term field trial using NPK (3x3x3) fertilizer with 3 replicates was conducted during the period of 1999-2012 in a Ganoderma endemic area on peat soil in Riau-Indonesia. The objective of this study was to assess the impact of mineral fertilizer application on Ganoderma incidence on mature oil palm as well as on their productivity. The incidence of Ganoderma infection was observed regularly in the field by counting the number of dead palms in the treatment plots. The results indicated that the application of Phosphorus (P) and Nitrogen (N) fertilizers increased significantly the percentage of Ganoderma incidence; while the application of Potassium (K) fertilizer did not give a significant effect. Based on cumulative 14 years (1999 - 2012) observation the control (without P), the application of 0.45 kg P2O5/palm/year and 0.90 kg P2O5/palm/year increased the percentage of Ganoderma incidence 190 % and 240 % respectively. For N fertilizer treatments, the application of 0.69 kg N/palm/year and 1.38 kg N/palm/year increased the percentage of Ganoderma incidence by 16 % and 18 % respectively compare to control (without N). The estimated yield loss due to Ganoderma incidence recorded during observation (cumulative 1999-2012) on P treatments varied from 6 to 15 ton/ha (0.5 to 1.1 ton/ha/year) and for N treatments varied from 9 to 12 ton/ha (0.7 to 0.9 ton/ha/year) respectively.