Effects of Salinity on Fresh Fruit Bunch (FFB) Production and Oil-To-Bunch Ratio of Oil Palm (Elaeis Guineensis) Planted in Reclaimed Mangrove Swamp Areas in Sabah
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Oil Palm Bulletin 65 (November 2012) p. 12-20. Effects of Salinity on Fresh Fruit Bunch (FFB) Production and Oil-to-bunch Ratio of Oil Palm (Elaeis guineensis) Planted in Reclaimed Mangrove Swamp Areas in Sabah Winner Henry* and Hoong Hak Wan* ABSTRACT alam sekitar dan kelestarian diambil kira dalam pembangunan tanah. Artikel ini bertujuan untuk The planting of oil palm was quite extensively mengkaji pendekatan ke atas penebusgunaan carried out in the ex-mangrove swamp areas in dan kelemahannya di dua ladang di pantai timur Sabah before environmental and sustainability Sabah: satu terletak di daerah Kunak manakala issues were taken into consideration in land satu lagi terletak di daerah Semporna. Kebanjiran development. This article examines the approach on air laut akibat banjir pasang surut dan penyusupan reclamation and its weaknesses in two plantations: melalui pintu air pasang surut dan permatang one in the Kunak district and the other in the telah menjejaskan prestasi pengeluaran buah Semporna district in the east coast of Sabah. The tandan segar (BTS) dan kadar perahan minyak subsequent influx of sea water caused by tidal dengan ketara. Taburan kawasan yang terjejas flooding and seepages through tide-gates and bunds, akibat paras kemasinan melebihi 5 m2 cm-1 telah had significantly affected the performance of palms ditentukan melalui kaji selidik tanah dan pemetaan both in fresh fruit bunch (FFB) production and oil dengan menggunakan ArcGIS. Berdasarkan extraction rate. The distribution of areas affected by taburan kawasan, hasil BTS untuk tempoh lima salinity above 5 m2 cm-1 was determined through tahun terakhir di kawasan terjejas adalah pada soil surveys and mapping using ArcGIS. Based on purata 16.5 t ha-1 thn-1 berbanding 23.5 t ha-1 the distribution, FFB yields for the last five years thn-1 di kawasan normal. Dalam tempoh lima bulan, from the affected fields was found to be around tandan yang dituai diambil secara rawak untuk 16.5 t ha-1 per annum and the normal areas was menjalankan analisis komponen buah dan tandan. 23.5 t ha-1 per annum. The harvested bunches were Kesan paras kemasinan telah menjejaskan nisbah randomly collected for fruit set and bunch analysis minyak:tandan tetapi tiada perbezaan terhadap was carried out over a five-month period. The oil- nisbah komponen buah. Di kawasan terjejas dengan to-bunch was found to be significantly affected by air masin, nisbah minyak:tandan direkodkan pada the salinity even in a situation where no difference kadar 16.5%-18.7% berbanding 22.2%-22.4% di in fruit set was observed. Oil-to-bunch ranging kawasan normal. Selain daripada impak negatif from 16.5%-18.7% was obtained from the saline terhadap alam sekitar dan ekologi, penebusgunaan areas when compared to the range of 22.2%-22.4% kawasan hutan paya bakau memberikan pulangan from the non-saline areas of the ex-mangrove areas. ekonomi yang lebih rendah kerana usaha Besides the negative impact on the environment and menghalang penyusupan air laut ke dalam ladang ecology from the reclamation of mangrove swamps, adalah sukar dan melibatkan kos yang tinggi. a lower economic return was attained, due to the difficulties in ensuring that the intrusion of sea Keywords: oil palm, fresh fruit bunch (FFB), water would not occur. salinity, reclaimed mangrove swamp, oil-to-bunch ratio. ABSTRAK INTRODUCTION Penanaman sawit di kawasan bekas paya bakau di Sabah telah dilaksanakan agak meluas sebelum isu Oil palm has been an important crop in Sabah since 1980s. The majority of the oil palm planting during * Sawit Kinabalu Sdn Bhd, the early days was on relatively flat to undulating Jalan Tuaran, land, with good mineral soil characteristics. 88300 Kota Kinabalu, Sabah, Malaysia. 12 Effects of Salinity on Fresh Fruit Bunch (FFB) Production and Oil-to-bunch Ratio of Oil Palm In 1986, Sawit Kinabalu Sdn Bhd (formerly The impact on yield, fruit set and oil-to-bunch ratio Sabah Land Development Board before were examined. corporatisation) decided to open up the mangrove swamp areas in Madai Estate, Kunak, this was one LOCATIONS of the early attempts in Sabah on this sort of land development. The second large scale reclamation Madai Estate, one of the two areas involved in of a mangrove swamp area by the group was in the large scale mangrove reclamation for oil palm 1990 at Pegagau Estate, Semporna. As is typical of planting, is situated between latitudes 4o41’N and mangrove swamp areas, they are both in low lying 4o50’N and longitudes 118o06’E and 118014’E. It is areas and are subjected to regular inundation by approximately 80 km from Tawau, Sabah (Figure 1). the sea or brackish water during high tides. The vegetation before reclamation was dominantly The boundary on the western side of the Madai Rhizophora sp., Avicennia sp. and Nypa fructicans Estate is marked by Tingkayu River. The north- (nipah). The salinity levels of the soils were eastern side of the estate is the ex-mangrove swamp generally above 20.0 m2 cm-1 before reclamation. area which is adjacent to Darvel Bay. Although oil palm is tolerant to the situation of The Pegagau Estate, on the other hand, is situ- a relatively high water table, it is intolerant to sa- ated between latitudes 4o20’N and 4o27’N and lon- line and excessively acidic soil conditions (Toh et gitudes 118o24’E and 118o30’E in Semporna Pen- al., 1987). Apparently, after nearly two decades of insular, Sabah (Figure 1). The eastern boundary is planting, the salinity of some of the fields is still a surrounded by Pegagau River and the ex-man- major concern because of poor management lead- grove area in the south is bordered by Celebes Sea. ing to deteriorated bunds and improper tidal-gates. Both of the estates are fully planted with oil palms covering about 2884 ha in Madai and 3257 ha in Although, the results quoted here are not new Pegagau. The reclaimed areas are 906 ha and 1224 as there were succesful cases reported earlier in ha in Madai (Figure 2) and Pegagau Estates (Figure Peninsular Malaysia, this article briefly describes 3) respectively. the approach taken during reclamation and its weaknesses in handling mangrove swamp area. Figure 1. The location of Madai and Pegagau Estates in Sabah. 13 Oil Palm Bulletin 65 Figure 2. Location of reclaimed areas in Madai Estate. Figure 3. Location of reclaimed areas in Pegagau Estate. SOILS Where Yr is the relative crop yield (%), 100 is the maximum yield, ECe (dS/m) is the average salinity Four soil series has been identified in the ex- of soil saturation extract, t (dS/m) is the threshold mangrove areas of Madai Estate, with Carey soil soil salinity value where the yield begins to decline, series as the dominant soil that covers about 52% and s is the rate of yield decline per unit increase of the area. Carey soil series is sandy textured acid in ECe. Beyond the threshold level, yield decreases sulphate soil and with pH ranged from 3.1 to 3.3. linearly with increasing salinity. The salinity values The other soils found are Tongkang, Tebuan and at zero yields provide an estimate of maximum Permatang series. salinity that plants can tolerate, and is used to calculate the leaching requirements. Salt tolerance Soil surveys carried out in the mangrove areas is characterised by the values of both the threshold of Pegagau Estate identified Sabrang series which and slope. covers about 42% of the area to be the dominant one. Sabrang soil series is of moderately deep soil, Salt accumulation in root zone causes the de- characterised by massive bluish marine clay at velopment of an osmotic stress (osmotic effect) and depths of 50 to 100 cm from the soil surface. The disrupts cell ion homeostasis by inducing inhibi- other soil series are Sedu, Serkat and Linau. These tion in the uptake of essential nutrients like K, Ca are the potential acid sulphate soils. and NO3 (possibly leading to nutrient deficiency) and accumulation of Na and Cl to potentially toxic A selection of land with suitable soil physical levels within cells (specific ion effect)(Marschner, and chemical characteristics is essential in oil palm 1995; Zhu, 2001). These primary stresses induce the investment (Hoong, 2005). Soils with high salin- generation of reactive oxygen species (ROS) (Mel- ity levels are likely to give a lower yield unless the loni et al., 2003), cause hormonal changes (Munns, salinity levels can be reduced through the flushing 2002), alter carbohydrates metabolism (Gao et out of the excessive salts from the area, during the al., 1998), reduce the activity of certain enzymes regular raining periods. (Munns, 1993) and impair photosynthesis (Loreto et al., 2003). SALINITY AND CROP TOLERANCE Table 1 gives the approximate salinity classes According to Chartzoulakis (2004), crops and and the likely effects on plant performance report- different cultivatrs of the same crop vary considerably ed by Watling (2007). in their tolerance to salinity. Mass and Hoffman (1977) concluded that crop yield is not reduced until USDA (1954) classified ECe ranged from class the threshold of salinity is exceeded according to the 0 which is free of salt and the maximum of class 3 following equation: (> 15 m2 cm-1) which is strongly affected by salinity. 2 -1 ECe between 4-8 m cm is put under class 1 which Yr = 100 - (ECe – t) s is slightly affected by salinity. Toh et al. (1987) sug- 14 Effects of Salinity on Fresh Fruit Bunch (FFB) Production and Oil-to-bunch Ratio of Oil Palm TABLE 1. APPROXIMATE SOIL SALINITY CLASSES Salinity rating ECe Remarks Slightly saline 1.5-2.0 Salinity effects usually minimal Moderately saline 2.0-5.0 Yield of salt sensitive plants restricted Highly saline More than 5.0 -15.0 Only salt tolerant plants yield satisfactorily Extremely saline >15.0 Few salt tolerant plants yield satisfactory Source: Watling (2007).