Izham Ahmad, Yahya Awang and Zamani Omar

Growth of wild durian seedlings (Durio lowianus) planted on six different media [100% coconut coir dust (CCD); 2 CCD: 1 sand; 1 CCD: 1 sand; 100% peat, 1 CCD: 1 peat; and 3 soil: 2 sand: 2 organic matter: 1 POME] was evaluated for six months. Differences in leaf number were marked at the four month after planting with plants grown on soil-based medium produced more leaves than the other media. At the sixth month, plants grown on soil-based medium had 41 leaves while leaf number for other media were between 17 and 27. similar trend of results were detected for plant height and stem diameter but marked differences in the two parameters were only noticed at five months after planting. Stem diameter of plants grown on soil-based medium was 26% larger than those grown on other media. Plants grown on soil-based media also had the largest number of branches (6.4/plant). This was followed by those grown on 100% peat (4.4/plant). The number of branches for other treatments were generally fewer, ranging from 2.0 to 2.9 per plant.

Mineralogy and Sand Surface Morphology of Selected Andisols from West Sumatra

D. Fiantis, J. Shamsuddin, E. Van Ranst, S. Zauyah and I. Fauziah

Andisols from Mt. Marapi and Mt. Pasaman in west Sumatra, Indonesia were studied to characterize their mineralogy and the surface morphology of the sand grains. The minerals in the sand grains included quartz, plagioclase, hornblende, augite, hypersthene, olivine and volcanic glass having different surface morphology. The morphology surface features present are bubbles, pitted, curve platy and sponge-like. Some of the sand grains are coated with amorphous materials. Halloysite is confirmed by the presence of strong peaks of Si and Al and a weak peak of Fe on the SEM-EDX spectra. The clay fraction is composed mainly of allophane, cristobalite, feldspars and halloysite. Soils from the Mt. Pasaman have some gibbsite, while those of the Mt. Marapi have opaline silica in the surface horizons. The abundance of opaline silica tends to decrease with the age of the volcanic ash soils.

Land Use System in an Acid Sulfate Soil of Central Kalimantan, Indonesia

S. Muhrizal and J. Shamsuddin

Large reclamation projects in south and central Kalimantan, Indonesia during the 1980s by constructing irrigation and drainage canals have made large tracks of acid sulfate and peat soils available for agricultural use. However, the reclamation has resulted in environmental degradation f\due to the release of toxic substances such as iron, aluminum and sulfate because of pyrite oxidation. We assessed the pollution from different types of land use constructed in acid sulfate soils. This monitoring study during the rainy season of 1996/97 (December 1996-march 1997) was carried out at unit Tatas Experimental Station in central Kalimantan, Indonesia. Leachates were collected and analyzed for pH, Fe, Al and SO42 in the drain water from different kinds of land use systems namely: raised bed system, shallow drainage system, flooded rice system with intermittent drainage, rain-fed rice system and secondary forest system. The soils is a sulfic hydaquents, extremely acid with dark humic topsoil (0-15 cm) and a uniformly brown layer (25 - 95 cm) without jarosite. The sulphidic material (pyrite) is below 95 - cm depth. The lowest pH value of drained water from several land uses was 2.6 occurring during the height rainfall (January). The value increased to 3.2 in March when the rainfall decreased. This suggests that oxidation occurring dry season (between June- September/October) when the water table dropped down to the pyrite layer produced a high amount of acidity and this was leached out during the first month of dry spell thus lowering the pH. The concentration of Al and Fe were in the opposite direction. The trend was more noticeable under upland rice condition and secondary forest compared to the other land use types. For all the land use types, sulfate was released in great amounts to the environment, and this was followed by Al and Fe. Pollution from acid sulfate soils was probably the greatest during the onset of high rainfall.

Potential use of Rhizobacteria for Sustainable Oil Palm Seedling Production

H.G. Amir, Z.H. Shamsuddin, M.S. Halimi, M.F. Ramlan and M. Marziah

Associative nitrogen fixing rhizobacteria (e.g. Azospirillum and Bacillus spp.) have been reported to enhance growth and fix N2 with several non-leguminous crops. These rhizobacteria have the potential to reduce application of nitrogenous fertilizer and consequently reduce costs for the Malaysian palm oil industry. Thus, the objectives of the experiments were; 1) to quantify N2 fixing capacity of Azospirillum spp. And locally isolated rhizobacteria on growth of the host plants. Two experiments were conducted in UPM glasshouse (undrained pots) and at FELDA Bukit Mandi Nursery Field Station (drained pots) with Selangor series soil at 8 kg/pot. For the undrained pot study, the soil was maintained at field capacity. The soils was labeled with 15N by adding 100 ml/pot of (15NH4)2SO4, 10 % i.e but not for the drained pot study in the field. Newly germinated oil palm seeds were planted at one seed/pot with seven treatments and five replicates, arranged in a randomized complete block design and harvested at two different intervals. 130 and 260 days after planting (D130 and D260). Each pot was inoculated with the respective inoculum treatment (killed inoculum (controls), Azospirillum bransilense (sp 7), A. lipoferum (CCM 1863), locally isolated rhizobacteria Bacillus sphaericus (UPMN 10) and B. subtilis (UPMN 13) at planting and at two monthly intervals. The n2 fixation rate was analyzed by emission spectrometer at Malaysian Institute for Nuclear Technology Research (MINT). Results showed that the inoculation of Azospirillum and the bacillus spp. In the glasshouse experiment could successfully fix N2 (30-40% Ndfa) in association with the host plants. The inoculation process also stimulated plant growth (tops and roots) comparable to the control with fertilizer-N,. the experiments indicated that Azospirillum and Bacillus spp. Can be regarded as a potential biofertilizer and bioenhancer for sustainable oil palm seedling production. However, mo07-Mar-2004 higher inoculum population in the soil especially for field applications.

Oil palm Empty Fruit Bunch as a Source of Nutrients and Soil Ameliorant in Oil Palm Plantation

A.R. Zaharah and K.C. Lim

A lysimeter study on the decomposition and nutrient release from oil palm empty fruit bunch (EFB) component parts (spikelet, stalk and mixture of stalk and spikelet) was carried out with and without mineral N fertilizers under field conditions over a period of nine months. A field experiment was also conducted where 17 year-old oil palms were treated with different N and K inorganic fertilizer rates, with and without EFB mulching. Two years of yield data were collected and at the end of this period, the soils were collected and analyzed for pH, exchangeable Ca, Mg and K and organic C content. It was observed that the EFB component parts decomposed at a significantly different rates in the order of stalk > mixture > spikelet. The decomposition pattern for all the parts conforms to the double exponential model by which most organic materials decompose. Lignin, polyphenol, carbon and nitrogen content in the EFB showed good correlation with soil N dynamics. The model identified was: soil min N = 20.45 - 25.02RN + 0.388PP + 0.47 LIG - 0.40 LIG/N (R2 = 0.80). Application of EFB parts lead to complete soil N immobilization for the entire 36 weeks of experimental period accompanied by 80 - 88% loss of K, Mg and Ca. In mature oil palm, application of inorganic N, EFB and N + EFB significantly increase EFB yield. The soil chemical characteristics like pH, organic C and exchangeable K were significantly improved with EFB application, making EFB a suitable ameliorant in improving soil quality for sustainable oil palm production.

Effect of Arbuscular Mycorrhiza fungi Colonization on Growth and Physiological Responses of Grafted Cocoa under Field Conditions

M.V. Rini, T. Jamal, Z.A. Idris and H. Azizah

The effect of mixed specis of arbuscular mycorrhizal fungi (AMF) inoculum. Glomus mosseae Scutellospora calospora on growth and physiology of cocoa was evaluated in the field. A split-plot design was used with AM treatment as the main plot and cocoa clones as the subplot. Five selected cocoa clones (viz. KKM 3, KKM 4, KKM 5, PBC 178) were grafted onto nine year-old cocoa (hybrid UIT1 x Na32) trees. Data were collected at 3, 5, and 7 months after AMF inoculation. Inoculated clones showed better and significant plants growth with longer scion lengths and larger leaf area index compared to uninoculated ones. The crop physiology was also significantly affected by AMF clones. The most interesting observation as a result of AMF inoculation was, inoculated PBC clones flowered at 8.5 months after grafting while the KKM clones flowered only at 12 months after grafting.