Indonesia’s peat land cover a surface of some 14.9 million hectares, mainly in Sumatra, Kalimantan and Papua. Peat soil, with its low PH and low micro and macro nutrient content, are poor soil for growing plants, especially commodity crops in general.
Only palm oil, rubber and acacia trees, tenacious trees that can grow in poor soil, can thrive on peat land. Peat land have long been used to grow palm oil by both companies and smallholders because oil palm has shown to be able to grow well in such a poor type of soil as long as the practice is well managed.
The management of peat land must at least consider a number of practices that differ from those for planting crops in mineral-high soil. They include a physical rehabilitation of the soil, a good water management, fertilizing and a good pick of the planted variety.
The physical rehabilitation of the land must be done according to the thickness of the peat layer. Oil palm is best grown in peat land with thin layers of peat, below 50 cm. In such a peat land, no physical treatment needs to be conducted. If the thickness of the peat layer is superior at 50 cm, then the peat needs to be compacted, using soil compactors, so that it can support the weight of the oil palm tree and thus prevent the tree from slanting. Another way to prevent the trees from slapping is by adding minerals in the soil where the tree is being planted. Mineral soil is mixed with peat soil to fill the hole where the seedlings are planted.
Water management is crucial when planting in peat land. It is important to prevent the crop from being under water or lack water. This management is important as peat land are usually found in flood-prone low land during the rainy season and are prone to drought during the dry season, Peat has high water capillary properties and thus dries up quickly and soil water cannot rise up to the surface.
To key to maintain the moistness of at the landlady in managing the water level. This can be achieved by digging drainage canals that will enable maintaining the water table at the desired depth. It is important to maintain the water table as around 60 cm in the drainage canals all year round, so that the oil palm planted in the peat land can continue to get enough water. Putting water gates at the ends of the drainage canals become also important to be able to maintain the level of the water in the canals. During the rainy seasons, these water gates are left open while in dry seasons, they should remain closely shut.
Fertilizing is also really needed as peat soil are poor in nutrient. There must be adequate macro and micro fertilizing. Calum, phosphor, nitrogen, magnesium and boron fertilizers are the important additives. The composition of the fertilizer will depend on the age of the crop. For crops that are not yet producing fruits, nitrogen fertilizer needs to be given in a higher dose.
Micro fertilizers such as boron also need to be given considering that peat soil are especially poor in micro nutrient. During the seedling period and when the plant is still very young, the addition of humid materials that is sprayed on the ground around the plant becomes important to accelerate growth. Humid material contain growth hormones.
The technique of choosing the right variety of crop, with a shorter trunk to enable the peat soil to support the tree and not result in a stanting growth. At present, many nursery companies are offering new variety of oil palm seedlings. High productivity and short trunk are criteria that are important in determining the choice of the variety. Remember that a short trunk will reduce the possibility of a slanting growth.
The productivity of oil palms managed by smallholders in peat land are in general still low, at around 10 to 15 tons per hectares per year. In comparison, oil palm planted in peat land by large companies already have productivity levels of between 20 to 30 tons per hectares per year.
The low productivity of palm oil smallholders planting in peat soil are mostly caused by a lack of knowledge and also capital, so that they are not aware or capable to conduct the necessary special treatment for planting oil palm in peat land. If the smallholders want to apply a good management for the cultivation of oil palm on peat soil, then working jointly with companies becomes one of the likely alternatives.
By becoming a plasma farmer, they can follow the same company management that allows a good productivity level for oil palm planted in peat soil. They will be able to gain more profit because of higher yields.
Indonesia is fortunate to have the right environment to develop palm oil. This crop can grow well in almost all types of land as long as there is adequate rainfall, of more than 2,500 mm per year. With an average production of 20 -25 tons per hectare per year, Indonesia would be able to churn out four tons of Crude Palm Oil (CPO) per hectare per year. This amount is much higher that the production of other vegetable oil-producing crops such as soybeans or rapeseed which respectively can only produce less than 0.5 ton per hectare per year.
The high yields of palm oil has led to countries producing other types of vegetable oils to feel threatened by palm oil from Indonesia and they have consequently often launched negative campaign against palm oil. An indirect way to conduct these negative campaign is by building a negative public opinion regarding the use of peat soil for palm oil cultivation.
Dr Ir Suwardi, M.Agr, is a lecturer at the Department of Soil Sciences and Land Resources at the Faculty of Agriculture, Bogor Institute of Agriculture (IPB),