YIELD INTENSIFICATION IN OIL PALM USING BMP AS A MANAGEMENT TOOL

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1 YIELD INTENSIFICATION IN OIL PALM USING BMP AS A MANAGEMENT TOOL C R Donough 1, C Witt 2 and T H Fairhurst 3 International Plant Nutrition Institute (IPNI) Southeast Asia Program P.O. Box 500 GPO, Penang, Malaysia 1 Consulting Agronomist crdonough@gmail.com; 2 Director IPNI Southeast Asia Program (now with the Gates Foundation) cwitt@ipni.net; 3 Project Advisor tfairhurst@tropcropconsult.com ABSTRACT: The gap between actual yield and maximum yield potential at a plantation may be partitioned into 3 components Yield Gap 1 due to inefficiencies during plantation development and the immature period, Yield Gap 2 due to inaccurate assessment of nutrient needs, and Yield Gap 3 due to inefficient management of the mature stand. Gaps 2 and 3 can be corrected in existing mature plantations using the best management practice (BMP) concept developed by IPNI. In the concept, a set of selected BMPs are implemented in several full-sized blocks representing a plantation and assessed for agronomic, economic and environmental performance, in comparison to a parallel set of reference (REF) blocks. More than just the practices in themselves, it is the process of BMP implementation and evaluation that is the management tool, providing practical, commercial-scale evidence to guide decisions on investments for yield intensification. Since July 2006, IPNI has established 30 commercial blocks with BMP in collaboration with its plantation partners at 6 sites in Indonesia. Results todate show the robustness of the BMP concept and its applicability across a wide range of environmental and operating conditions. Bunch yield with BMP averaged 3.4t ha -1 (+15%) higher due to more (+9%) and heavier (+6%) bunches. Crop recovery BMPs including a short harvest interval are important for high bunch yield in the short term, while other agronomic BMPs related to canopy and nutrient management are important for sustained or enhanced yield in the longer term. Cost per unit area is higher with BMP, but higher BMP yield improves profitability at the farm gate. In the final year of the project, oil and kernel yields are being estimated. The BMP concept is a model for continuous improvement a BMP that is successfully evaluated becomes current practice, and a new cycle of BMP evaluation starts. Keywords: BMP, yield intensification, oil palm 1. INTRODUCTION Oil palm produces the highest oil yield amongst the world s major oil crops. Yet the national average oil yields achieved in Indonesia and Malaysia (the world s two largest producers) continue to fall well below potential levels. Of even more concern is the apparent stagnation of achieved yields in both countries for the last two decades as total production increased in line with planted area. The most efficient plantations in both countries are estimated to be achieving oil yields well above 6t ha -1. How can the rest of the industry improve their performance? 2. YIELD POTENTIAL OF CURRENT OIL PALM PLANTING MATERIAL From measurements carried out in a fully mature commercial estate plot in Sabah, Malaysia, planted with standard dura (D) x pisifera (P) hybrid seed of a major Malaysian seed producer, annual yield of fresh fruit bunches (FFB) of the best individual palms exceeded 500kg, or the equivalent of 70t ha -1 [1]. Estimated annual oil yield of these palms, based on laboratory analysis of large numbers of bunches, came close to 20t ha -1. Oil content exceeded 35% in the best bunches. Seed producers do not (yet) use homozygous D or P seed parents, so the DxP planting materials available to growers are not homogenous for plant form, growth, or yield characteristics. This inherent variation makes it impossible for the best single palm yields to be reproduced on a large scale. The maximum oil yield potential at commercial-scale is estimated to be in the range of 10-11t ha -1 [2]. Exploitation of the variation in DxP populations by cloning is being actively attempted by almost all seed producers today. However, the supply of clonal planting material is still only sufficient for a small fraction of growers total planting requirements today.

2 3. REPORTED ACHIEVEMENTS In 2006, the IOI Group, one of the leading plantation groups in Malaysia, reported an average annual FFB yield of 38t ha -1, with an estimated oil yield of over 8t ha -1, for one estate [3]. At group level (ca. 150,000ha), average oil yield of 6t ha -1 and FFB yield exceeding 27t ha -1 have been reported. FFB yield higher than 40t ha -1 have been recorded for single blocks in many estates in Indonesia and Malaysia. The best palm oil mills in Indonesia and Malaysia have achieved oil extraction rates (OERs) in excess of 25%, indicating that very high palm oil yields up to and exceeding 10t ha -1 are already within reach in a good year in well managed estates using current planting material with the right growing conditions and the most appropriate BMPs. 4. YIELD GAP ANALYSIS The gap between actual achieved yield (Y) and the maximum yield potential (Y-max) (Figure 1) can be apportioned into 3 parts [4] Yield Gap 1 arises from inefficiencies during development of a plantation until the end of the immature period; this limits the attainable yield (Y-a) in the mature stand compared to Y-max for a particular site; Yield Gap 2 (G2) arises from inaccurate assessment of nutrient requirements, which further reduces the attainable yield to the nutrient-limited yield (Y-n); and Yield Gap 3 (G3) arises from inefficiencies in the management of the mature stand, bringing Y-n down to the actual yield (Y). There are limited opportunities for plantations to correct Yield Gap 1 the first during the initial establishment of the plantation, and thereafter at each occasion of replanting. However, Yield Gaps 2 and 3 can be corrected in existing mature stands. The yield gap analysis is useful for the identification, selection and prioritization of best management practices (BMPs) to be implemented for intensifying yield. Figure 1. Yield gap partitioning (adapted from Fairhurst et al, 2006) Relative Yield Gaps Yield 100% 80% 60% 40% 20% 0% Maximum yield potential of progeny for a given soil and climate GAP 1 Attainable yield Y-max Y-a Y-n Y 5. THE BMP CONCEPT GAP 2 Nutrientlimited yield GAP 3 Actual yield IPNI Southeast Asia (SEA) has developed a concept using Best Management Practice (BMP) as a management tool for yield gap correction and yield intensification in mature oil palm plantations [5] (Figure 2). Figure 2. Conceptual framework for evaluation of BMPs in mature oil palm plantations (after Witt & Donough, 2007) In the concept, a set of site-specific BMPs are identified and implemented in a number of fullsized management blocks representative of a plantation. The selected BMPs are assessed on their agronomic, economic and environmental performance. A parallel set of comparable blocks under standard practice are monitored as reference (REF) blocks for comparison.

3 In the process of BMP evaluation, the plantation identifies better ways to implement BMPs for increased yield, and decisions on larger investments in BMP are based on practical, commercial-scale evidence. Once the BMPs are successfully implemented at large scale, they become standard practice, and the cycle of evaluation and implementation starts over. The BMP concept is therefore consistent with principles 4 (BMP) and 8 (continuous improvement) of the Roundtable on Sustainable Palm Oil (RSPO). 6. VALIDATING THE BMP CONCEPT Since July 2006, IPNI SEA has established 30 commercial blocks (total area 1,080ha) with BMP in partnership with five collaborating plantation groups at six locations in North and South Sumatra, and West, Central and East Kalimantan [6]. These six sites span a wide range of environments where oil palms are currently grown in Indonesia (Table 1) so the results obtained may prove very valuable for guiding yield improvement efforts in the Indonesian oil palm plantation industry. Table 1. Location and site conditions in the IPNI SEA BMP project in Indonesia. Site Location BMP blocks 1 Palm Previous Condition age 2 Yield 3 at start 4 Key site factors impacting yield 1 North Sumatra 5 blocks (266ha) Good Level terrain, low rainfall 2 North Sumatra 5 blocks (156ha) Good Rolling terrain, variable stand 3 South Sumatra 5 blocks (256ha) Good Undulating terrain, water deficit 4 West Kalimantan 5 blocks (143ha) Poor Undulating terrain, spodosols 5 Central Kalimantan 5 blocks (124ha) Very Poor Water deficit, very sandy soil 6 East Kalimantan 5 blocks (135ha) Good Rolling terrain, high rainfall 1 number and total area of BMP blocks ; 2 range of palm age at start of each project, in years after planting; 3 Average yield of fresh fruit bunches (FFB) for 2-3 years prior to start of project (excludes plantings 5 years or younger); 4 Palm & field conditions at start of the project 7. BMPs IMPLEMENTED BMPs chosen for implementation are those that have been proven over time to benefit palm growth and productivity, and to conserve soil, water and nutrients. They can be grouped into 3 broad categories according to purpose (a) Crop recovery BMPs, (b) Canopy management BMPs, and (c) Nutrient management BMPs. Crop recovery BMPs included (1) Harvest interval (HI) of 7 days, (2) Minimum ripeness standard (MRS) = 1 loose fruit (LF) before harvest, (3) Same day transport of harvested crop to palm oil mill, (4) Harvest audits to monitor completeness of crop recovery and quality (i.e. ripeness) of the harvested crop, (5) Good in-field accessibility (clear paths, bridges wherever needed) (6) Clean weeded circles, (7) Palm platforms constructed and maintained wherever needed, and (8) Minimum under-pruning in tall palms to ensure crop visibility. Canopy management BMPs included (1) Maintenance of sufficient fronds to support high palm productivity, (2) Removing abnormal, unproductive palms, (3) In-filling unplanted areas, (4) Selective thinning in dense areas, and (5) Monitoring and management of pests (leaf eaters) and disease (Ganoderma), Nutrient management BMPs included (1) Spreading pruned fronds widely in inter-row area and between palms within rows, (2) Eradication of woody perennial weeds, (3) Mulching with empty fruit bunches (EFB), (4) Management of applied fertilizers (i.e. type, dosage, timing and placement), and

4 (5) Monitoring of plant nutrient status and growth. Specifics regarding these BMPs can be found in the IPNI Oil Palm Handbook (Mature) [7]. 8. BMP EVALUATION BMP evaluation is planned for 4 years at each site to allow for full effects of the chosen BMPs to manifest. All field activities are carried out and monitored by the local estate management team of IPNI SEA s project partners. Records are collected by the participating estates in the normal way for (a) crop production (i.e. bunch numbers counted in the field, and FFB weight derived from the mill weighbridge), (b) all field activities, and (c) labour and materials utilization, and cost. IPNI SEA provides support on specific activities (e.g. soil sampling, plant sampling and growth measurements, bunch analysis) and data processing and analysis. 9. RESULTS FROM THE FIELD The project started at different times at each site, so data available varies from months post-implementation. All results are annualized (i.e. converted to 1 year if actual data available is for a shorter period) unless specified. 9.1 Yield of FFB FFB yield with BMP was higher at every site (Table 2). BMP yield averaged 3.4t ha -1 (+15%) higher than REF yield of 22.4t ha -1. In the period before project implementation (i.e. pre-bmp), yield of the blocks assigned as REF was higher, so the superiority of the blocks with BMP is even greater if this is taken into account. At sites 2 and 3, REF yield was lower in the post-implementation period (i.e. post-bmp) partly due to the carry-over effect of water deficit in 2006 on FFB yield in The effect was most severe at site 3 (South Sumatra). Another reason for the lower REF yield at these 2 sites was high crop loss. Table 2. FFB yield (t ha -1 ) with BMP. Diff 5 Diff Site BMP 3 REF 4 BMP REF Pre-BMP 1 Post-BMP Avg period before BMP implementation (12-24 months data depending on the site); 2 period from start of BMP implementation (34-44 months data depending on the site); 3 mean values for 5 BMP blocks; 4 mean values for 5 REF blocks; 5 difference between BMP and REF; 6 pre-bmp data unavailable (assumed the same as the same block was split into 2 for BMP implementation in one half, and the other half as REF); 7 average of all 6 sites. Assuming a FFB price of IDR1,000 kg -1, the average additional BMP yield is worth IDR3.4 million (ca. USD380 at USD1=IDR9,000) ha -1 each year. Most of the cost of implementing BMP is incurred in the first year, averaging IDR3million ha -1. In subsequent years, the cost of maintaining BMP standards is only slightly higher. There are variations across sites, as well as between blocks at the same site, due to sitespecific factors, but overall the cost of BMP implementation is recouped very quickly. Table 3. Bunch numbers and average bunch weight with BMP. Diff 5 Diff Site BMP 3 REF 4 BMP REF Bunches (ha -1 ) 1 Av B Wt (kg) 2 1 1,681 1, ,326 1, , ,725 1, ,268 1, ,227 2, Avg 6 1,558 1, annual number of bunches harvested; 2 average single bunch weight; 3 mean values for 5 BMP blocks; 4 mean values for 5 REF blocks; 5 difference between BMP and REF; 6 average of all 6 sites. The additional BMP yield came from more bunches (+127 bunches ha -1, or +9%) except at site 1 where 20 bunches ha -1 more was recovered from the REF blocks each year (Table 3). At all sites, slightly heavier bunches (+0.9kg bunch -1, or +6%) were produced with BMP.

5 This means that the cost of BMP harvesting will be slightly higher, the quantum of increase depending on the basis of harvesting payment i.e. bunch numbers or bunch weight. The results imply better profitability for the plantation if payment to harvesters is based on bunch weight. 9.2 Maximum FFB yields attained todate Todate the highest recorded FFB yield for a single block with BMP was 37.9t ha -1 (Table 4), achieved at site 1. The highest FFB yield (36.8t ha -1 ) for a single REF block was also from site 1. Table 4. Maximum FFB yields attained todate with BMP compared to REF. Highest recorded FFB yield (t ha -1 ) 1 Site With BMP With REF highest recorded FFB yield of a single block in any one year during the period of BMP implementation. The FFB yield maxima with BMP as shown in Table 4 are indicative of the level that can be attained at each site, based on results todate. The indicative attainable yield at the best site in Kalimantan (site 6) is almost comparable to the best Sumatra site (site 1). FFB yield is still improving at sites 4 and 5 in Kalimantan, in spite of the poorer soils at these locations (spodosols with hardpan within 1m of soil profile at site 4; soil with >80% sand fraction at site 5). Achievement todate at site 3 is also still well below the actual attainable level in a good year (i.e. unaffected by water deficit) due to persisting problems with crop recovery (even with implementation of BMP harvesting) due to inadequate labour. Ultimately, it could be that similar FFB yield maxima are achievable across a wide range of conditions with the proper implementation of site-specific BMPs. 9.3 Harvest interval (HI) The additional BMP yield in the first year can be attributed to improved crop recovery with implementation and maintenance of a short 7- day harvest interval (HI) (Table 5). Most if not all studies of oil palm harvesting in the past have demonstrated higher recovered yield with more frequent harvesting. Table 5. Harvest interval (HI) in the first year of BMP implementation. Avg HI 1 Max HI 2 FFB yield Site BMP 3 REF 4 BMP REF diff (+1%) (+17%) (+23%) (+15%) (+18%) (+6%) Avg (+12%) 1 average interval (days) between successive occasions of harvesting; 2 maximum recorded interval (days) between successive occasions of harvesting; 3 mean values for 5 BMP blocks; 4 mean values for 5 REF blocks; 5 difference in FFB yield (t ha-1) between BMP and REF; 6 average of all 6 sites. Where the HI was well controlled in the REF blocks (e.g. site 1), the difference between BMP and REF was small. The additional cost of implementing BMP harvesting averaged about IDR million ha -1 (USD12-13 ha -1, data not shown), so even at site 1 this cost is can be recovered within the first year (if the cost of implementing other BMPs are not considered since their effects take more time to show). 9.4 Harvester productivity and required numbers with BMP harvesting With BMP harvesting (i.e. short HI), harvesters daily output in terms of bunch numbers as well as total bunch weight is lower (Table 6). The exception is at site 5 where daily output per harvester increased with BMP. This is related to the low yield still prevailing at this site, but there could be other factors. From these results, the indications are that at site 5 it should be cheaper to pay harvesters based on

6 bunch numbers. Elsewhere, payment based on bunch weight should be more beneficial to the plantation. Table 6. Harvesters daily output of bunches and total bunch weight with BMP. Total bunches (no manday -1 ) 1 % Total FFB Wt (kg manday -1 ) 2 % Site BMP 3 REF 4 Diff 5 BMP REF Diff % 1,661 1,725-4% % 1,597 1,730-8% % 1,344 1,459-8% % 1,172 1,253-6% % 2,012 1, % % 1,340 1,476-9% Avg % 1,521 1,562-3% 1 total number of bunches harvested daily; 2 total weight of bunches harvested daily; 3 mean values for 5 BMP blocks; 4 mean values for 5 REF blocks; 5 % difference between BMP and REF; 6 average of all 6 sites. Harvesters cover on average 33% more ground daily with BMP harvesting (Table 7) as fewer bunches that fulfill the MRS are available for harvest each time due to the short HI. Table 7. Daily area per harvester and number of harvesters needed. Area covered No. of harvesters (ha manday -1 ) 1 % per 1,000ha 2 % BMP 3 REF 4 Diff 5 BMP REF Diff Site % % % % % % % % % % % % Avg % % 1 total area walked in 1 day by 1 harvester; 2 total number of harvesters needed to work 1,000ha to the defined standard i.e. BMP or REF; 3 mean values for 5 BMP blocks; 4 mean values for 5 REF blocks; 5 % difference between BMP and REF; 6 average of all 6 sites. Based on the available data todate, 30% more harvesters will be needed to carry out BMP harvesting per 1,000ha, compared to the observed REF harvesting achievement (average HI todate = 12 days). At site 1 where average HI in the REF blocks was consistently 10 days, the additional harvester requirement is only 18%. In the project final year, HI is being fixed at 10-days in all REF blocks at all sites so that a better comparison is obtained against the BMP HI of 7-days. The final cost-benefit analysis of BMP harvesting needs to take into account indirect costs for additional harvesters including capital expense for extra housing. 9.5 Oil and kernel yield estimates To estimate and compare product (i.e. oil and kernels) yields from each project block (BMP and REF), bunch analysis (BA) is being carried out in the final year of the project at every site except site 2 (where IPNI SEA s project partner chose not to invest in the facilities needed). Preliminary data is available only from site 1 (Table 8) as BA only started in April 2010 at site 3, and will commence at the 3 Kalimantan sites from late June Table 8. Oil and kernel contents, and estimated oil and kernel yields, with BMP at site 1 Estimated values 1 for Yield 6 (t ha -1 ) of OB 2 KB 3 OER 4 KER 5 Oil PK 7 Site 1 BMP REF estimated from bunch analysis; 2 - % oil content in bunches; 3 - % kernel content in bunches; 4 oil extraction rate at the mill, derived from OB corrected by a factor (0.855) for milling losses; 5 kernel extraction rate at the mill, corrected by a factor (0.9) for milling losses; 6 estimated yield of oil and palm kernels, calculated using OER or KER and corresponding average FFB yield in the post-bmp period; 7 palm kernels; 8 mean values for BMP blocks; 9 mean values for REF blocks. Oil content is slightly lower with BMP because the harvested bunches had less LF due to the shorter HI (LF data not shown). The difference in kernel content was marginal. After correction for milling process losses, the estimated yields of oil and kernels with BMP were 7.1t ha -1 and 1.6t ha -1 respectively, both marginally better than corresponding REF yields. Firm conclusions have to wait until the project is completed, but with the availability of BA data it should be possible to estimate the product yield potential of FFB, hence potential mill extraction rates for oil and kernel, before milling.

7 This is a frequent bone of contention between palm oil mills and plantations supplying crop to them for processing, often leading to unproductive (even counter-productive) actions all due to lack of information. If the BA data is combined with harvest audit data from the field, and FFB grading and process losses data from the mill, it could be possible to derive more realistic benchmarks for performance based on yield of oil and kernels, for both the plantation and the mill in the future. 9.6 Effects of other BMPs Other BMPs related to canopy and nutrient management took longer to fully implement, and their effects should start to be seen from the 3 rd year of project implementation. The observed FFB yield differentials between BMP and REF in the first 1-2 years post-bmp (Table 9) were due to better crop recovery as BMP HI was well maintained at 7-days while REF HI reflected problems with harvesting at most sites at that time (Table 10). Table 9. Progression of FFB yield differential between BMP and REF over time. Site Year Year 3+ 2 Avg 3 FFB yield (t ha -1 ) BMP expressed as % of REF 1 100% 111% 104% 2 125% 126% 125% 3 126% 134% 129% 4 114% 106% 111% 5 121% 127% 124% 6 109% 108% 109% Avg 4 114% 117% 115% 1 first 2 years from start of project implementation at each site; 2 3 rd year and therafter from start of project implementation at each site; 3 average over total period of implementation; 4 average for all sites each year. Control of HI in REF blocks has improved from the 3 rd year onwards, but problems persist at some sites with extended HI especially during peak cropping months. In 2009, the problem was exceptional as the long Lebaran holiday period coincided with the peak crop month. At sites where REF HI has been maintained at the target level of 10 days from the 3 rd year post- BMP, the BMP-REF FFB yield differential in this period of the project should be indicative of non-crop recovery BMPs, as the FFB yield difference between 7-day and 10-day HI is very small, if at all, based on the results from site 1. However, where REF HI remained problematic after the 3 rd year post-bmp, it may not be possible to obtain a good indication of the value of non-crop recovery BMPs within the remaining period of the project. Further analysis of data (not reported here) on plant nutrient status and growth, and soil analysis, should add some clarity to the picture. Table 10. Progression of harvest intervals between BMP and REF over time. Site Year Year 3+ 2 BMP harvest interval (HI) (days) (Maximum HI in brackets) 1 7 (8) 7 (8) 2 7 (9) 7 (9) 3 8 (10) 7 (9) 4 7 (9) 7 (12) 5 7 (8) 7 (9) 6 7 (8) 7 (8) Avg REF harvest interval (HI) (days) (Maximum HI in brackets) 1 10 (13) 10 (13) 2 14 (30) 10 (14) 3 11 (19) 12 (26) 4 15 (38) 13 (21) 5 12 (29) 13 (25) 6 12 (21) 10 (13) Avg first 2 years from start of project implementation at each site; 2 3 rd year and thereafter from start of project implementation at each site; 3 average for all sites. 10. CURRENT CONCLUSIONS The BMP concept is clearly applicable across a wide range of conditions. It can be implemented by estate management teams relatively easily. Results from paired blocks are easy to analyze statistically without the need for sophisticated statistical methods or software. The high FFB yield maxima achieved todate across sites with such wide-ranging conditions shows the immense potential for increased yields in existing plantations in Indonesia.

8 At this point, it is clear that for improvement of FFB yield in mature plantations in the short term, a short HI combined with other croprecovery BMPs is essential. However, there are indications from site 1 that the most economic FFB yield may be obtained with a 10-day HI instead of the currently implemented BMP HI of 7-days. This will be evaluated further in the project final year at all other sites. For sites where the current REF HI exceeds 10- days, BMP harvesting is clearly more profitable despite a higher cost, as the additional quantum of crop recovered is so large, with still room for even further improvement at some sites. Thus for best results, plantation managers should not rely merely on cost cutting, but instead focus equally if not more on management parameters that reflect actual performance and productivity on the ground. Implementation of a HI as short as 7-days will be problematic at locations where there is a large difference in crop levels between peak and trough periods of the year. Thorough analysis of the project data at each site should be useful to guide strategies for wider scale-up of BMP harvesting. Benefits from non-crop recovery BMPs will take longer to manifest. Quantification of these benefits may require a longer period than is currently planned for the ongoing project. Nonetheless, some indications of the benefits should be seen by the time the project ends in mid Early indications of oil and kernel yields suggest that the higher FFB yields with BMP may be tempered with lower oil content due to average lower ripeness (i.e. numbers of LF) of the crop harvested from BMP blocks. In the final analysis, there will be a need to balance oil content (i.e. lower oil content with BMP leading to higher cost of production) and potential crop losses in the field (i.e. lower LF losses with BMP increasing recoverable oil yield and thus revenue). 11. ACKNOWLEDGEMENTS All data presented in this paper were generated from the ongoing BMP project in Indonesia by our project partners (in alphabetical order) Permata Hijau Group, PT Bakrie Sumatera Plantations Tbk, PT REA Kaltim Plantations, PT Sampoerna Agro Tbk, and Wilmar International Ltd. The project would not be possible without commitment and support from top management of these companies. The results achieved at each site reflect that, as well as the dedication and effectiveness of the estate team(s) undertaking project implementation on the ground. Funding for the project was contributed by IPNI, Canpotex International Pte Ltd, and K+S Kali GmbH. 12. REFERENCES [1] IJM Plantations Berhad, Sandakan, Sabah, Malaysia. Unpublished data. [2] Breure, C J (2003) The search for yield in oil palm: Basic principles. In: Oil palm Management for large and sustainable yields (Fairhurst & Härdter, eds), PPI/PPIC-IPI, Singapore, [3] IOI Corporation Berhad (2006) Annual Report [4] Fairhurst T H, Griffiths W and Gfroerer- Kerstan A (2006) Concept and implementation of best management practice for maximum economic yield in an oil palm plantation in Sumatra. Paper presented at International Oil Palm Conference 2006, Bali, Indonesia. [5] Witt C and Donough CR (2007) Oil palm management: Ecological yield intensification through BMP. Poster presented at 5 th Roundtable (RT5) on Sustainable Palm Oil, November 2005, Kuala Lumpur, Malaysia. [6] Donough C R, Witt C and Fairhurst T H (2009) Yield intensification in oil palm plantations through best management practice. Better Crops 93(1): [7] Rankine, I. and Fairhurst, T. (1999) Field Handbook: Oil Palm Series Volume 3 Mature. PPI/PPIC and 4T Consultants, Singapore, 135pp.