Abdul Hamid, Sharifuddin

Abdul Rahman, Zaharah

Abu Bakar, Rosenani

Lim, K. C.

Universiti Putra Malaysia Institutional Repository

FOR Category F10900: AgricuHural SciencesDECOMPOSITION' AND NUTRIENT RELEASE OFOIL PALM EMPTY FRUIT BUNCH IN THEPRESENCE OF NAND K FERTILISERS:A.R. Zaharah, K.C: Lim,H.A.H. Sharifuddin and"A.B. RosenaniFaculty of AgricultureUniversiti Putra Malaysia, 43400 UPM; Serdang, Selangor, 'MalaysiaKeywords: empty oil palm fruitbunch, decomposition,mineralisation, nutrient release. 'non-linear regression. 'Introduction'Malaysian soils 'are;very 'deficient in organic 'matter and nu-trients, and recycling of empty oil palm fruit bunch (EFB)back to theland is a sound agricultural practice in line withthe overall concept of sustainable agriculture. Use of EFB isone method of sustaining the viability of the oil palm indus-try. It is widely recognised that integrated nutrient manage-ment system involving organic and inorganic fertilisers cancontribute to the maintenance of a sustainable system, inmaintaining high crop yield. Currently, field application ofEFB to oil palm is a widely accepted practice. Most ofplantations owners recognised the benefits of EFB applica-tion to oil palms as a mulch, but little information is availableon the process of decomposition and nutrient release fromthese EFB with and without inorganic fertiliser amendments.Materials and MethodsThree rates of EFB (0, 37.5 and 75 t/ha/y) were applied to,17- year old oil palms grown on Durian series soil. The EFBwere applied in a single layer of 2m width along the oil palminter-row for' the'37.5 t/ha/yr rate, while the 75 t/ha/year ratewere applied as double layer in a 2m band. Three,rates of N(0, 0.74 and 1.47 kg N/palmlyear) were applied 'as ammo-nium sulphate (21% N) and 3 rates of K (0, 1.75 and 3.50 kgKlpalmlyear) was applied as muriate of potash (50% K). Abasal fertiliser of 1 kg Phosphate rock (15.7% P) and 2.0 kgground magnesium limestone (10.2% Mg) were broadcast toall treatments. There were 3 replications for each treatment.Two whole EFB were randomly sampled from each treat-ment every 2 months until 10 months after application. Forthe double layer 2 EFB were taken both from top and bottomlayer. The samples were dried at 70°C, weighed and groundfor analysis. The analysis carried out was total N and K (dryashing). Data obtained were analysed using analysis ofvariance and non-linear regression using,exponential modelsweremade,Results and DiscussionThe general' pattern' of decomposition was an exponentialmodel with rapid initial losses in dry matter and decliningrates at later stages.. Total. physical disintegration of EFBtook 6 months after which little dry matter loss was ob-served. The single layer was fastest to decompose followedby-double layer top and double layer bottom EFB. The re-gression equation obtained for the decomposition of singlelayer EFB was:Dry matter = 1.9502. e -<l,4590 .months, with ~ = 0.777.The drymatter loss of double layer tp EFB was:Dry' matter= '1.6231.. e il.4363.montbs; 'with':~=o.7132; ,and' forthe double layer bottom" dry matter loss was:Dry matter = 1.7485 . e_O,2819,mootbs,with ~ = 0.8553. Theaddition of inorganic N significantly increased the decompo-sition rate of single layer EFB with 3.75 kg N/palm /yearbeing significantly affecting decomposition. Higher N ratedid not significantly accelerate decomposition. This is inagreement with previous work (Rosenani et al. 1996; VanVuuren and Van der Eerden, 1992) and thought to be due toenhanced microbial activity (parr and Papendick, 1978). In-organic K fertiliser. application did not significantly affectdecomposition rates. Potassium has been shown to reduce themineralisation of organic matter in soils (Viro, 1992), but itseffects were not detected in this experiment., This is likelydue to the inherent high content of EFB-K in the decompos-ing EFB that could have masked the effects' of added inor-ganic K. There was no release ofEFB-N at the end of the 10months of monitoring. The EFB-N contents remained rela-tively as high as the original N content in EFB placed in thethree layers. The mineralised N from the EFB could havebeen immobilised by the microorganisms involved in theprocess of decomposition. The 10monthsperiod used in thisexperiment apparently was inadequate to detect EFB-N re-leased. Application of N and K inorganic fertilisers did' notsignificantly affect the EFB-N release. The rates of EFB-Krelease were very rapid in the initial stages where 90% of thetotal K content was released during the first 6 months. At the10th month, 99% of the EFB-K was released. The doublelayer top EFB released K faster than the singe layer and dou-ble layer bottom. The exponential models obtained for theEFB-K release showed a very high ~ value. There was nosignificant difference detected in the regression coefficientsof EFB-K release with the addition of inorganic N and Kfertilisers.ConclusionThe general pattern of EFB' decomposition was an exponen-tial model with rapid initial losses in dry matter and EFB-Kand declining at the later months. There was no EFB-N re-lease detected during the ten months of field monitoring withand without the additionof inorganic fertilisers. EFB-K wasreleased very rapid and almost complete release of EFB-Kwas obtained at 10 months. The total amount of K releasedfrom 37.5 mt of EFB can supplement the K requirement ofoil palm for optimum yield with no extra addition of potas-sium fertiliser.References .:Parr J.F. and Papendick R.I.'I978.' Factors affectingdecompositionof crop residues by micoorganisms. In L. Power and J.Legg (eds.)Crop Residue Management Systems. Amer. Soc. Agron., Madi-son, WiSconsin, USA. p. 101-129. ' "Rosenani, A.B. Basran R.D., Zaharah A.R. and Zauyah, S. 1996.~Alysimetric study of the effect of N and P fertiliser application on,,', decomposition and nutrient release, of oil palm empty fruitbunches. PORlM Bull No. 32: 1~11Van Vuuren M.M.I. and Eerden L.J, 1992. Effects of three rates of, atmospheric deposition enriched with 15N on litter decomposi-., tion in a heathland. Soil BioI and Biochem, 24: 527-532.Viro, PJ. 1962. Factorial experiments on forest humus decomposi-tion. Soil Sci. 95:24-30. , 'Supported by IRPA Grant 01-02-04-004433

Decomposition and nutrient release of oil palm empty fruit bunch in the presence of N and K fertilisers

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Decomposition and nutrient release of oil palm empty fruit bunch in the presence of N and K fertilisers

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