Paper Number. Yield Gaps in Indonesian Smallholder Plantations: Causes and Solutions. Lotte Suzanne Woittiez 1, Maja Slingerland 1, Ken E.

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1 Paper Number Yield Gaps in Indonesian Smallholder Plantations: Causes and Solutions Lotte Suzanne Woittiez 1, Maja Slingerland 1, Ken E. Giller 1 ABSTRACT Indonesian oil palm smallholder farmers often achieve yields of only ton of fresh fruit bunches per hectare, roughly half the ton per hectare achieved by some large plantations, indicating the existence of a large yield gap. In order to close this gap and improve profitability, the underlying factors contributing to poor yields need to be identified and addressed. In an explorative study in two contrasting sites in Indonesia, 64 independent oil palm smallholders were interviewed about their agronomic practices, and a range of plantations was audited to cross-check the answers provided. Soil and leaf samples were collected from a subset of plantations to identify nutrient deficiencies. We present the preliminary results, as the research is still ongoing and additional samples remain to be collected and analyzed. The research was carried out in Sintang regency in West-Kalimantan and in desa Ramin, kecamatan Kumpeh, Muaro Jambi regency in Jambi, Sumatra. In Sintang regency, average current yields as estimated from interviews are 14.5 ± 6 ton per hectare in plantations of around 6 years after planting; in Ramin yields were 21 ± 7 ton per hectare on mineral soils, and 11 ± 5 ton per hectare on peat soils, in plantations of 12 years after planting. Fertilization practices were found to be suboptimal in both areas. Approximately 80% of the farmers relied on subsidized NPK fertilizer (Ponska, NPK ) with an addition of straight N (urea), straight P (SP-36), straight K (KCl), straight Mg (dolomite) and B (Borax). Analysis of pinnae samples show a K deficiency in 17 out of 24 plantations in Sintang and five out of six in Ramin. Soils were generally highly deficient in K, on average well below the critical concentration of 0.15 cmol/kg. We conclude that insufficient and/or imbalanced nutrition, and especially K deficiency, was a key constraint to yields in both research areas. Additional limiting factors were poor planting material (>50% of plantations in Sintang and Kumpeh contaminated with Dura trees), poor water management (waterlogging), incorrect harvesting practices, and rat damage. When attempting to improve productivity in smallholder plantations, these findings should be kept in mind and attention should focus on relieving the identified constraints. INTRODUCTION Oil palm is an important driver of economic development in rural Indonesia and provides smallholder farmers with a good opportunity to improve their livelihood (Sheil et al., 2009, Budidarsono et al., 2012, Lee, 2013). The profitability of a plantation depends on its productivity, and as land gets scarcer, improving yields becomes increasingly important as a strategy to increase income (Budidarsono et al., 2012). Current yields in smallholder plantations are well below what plantation companies achieve in similar soils and climate 1 Plant Production Systems Group, Wageningen University, The Netherlands

2 (Lee et al., 2013, Molenaar et al., 2013) indicating a large yield gap. In order to improve yields, it is important to identify the key causes of yield gaps in smallholder plantations, and to find solutions on how to close them. A number of studies on constraints in smallholder oil palm plantations in Indonesia have been carried out, leading to several interesting findings. Lee et al. (2013) did a survey of 313 households in 15 villages in Sumatra, and concluded that harvesting practices, particularly harvest interval, is a key constraint to productivity. Farmers harvesting only once per month were found to produce an average yield of 15 ton fresh fruit bunches per hectare, whereas farmers harvesting three times per month produced an average yield of 24 ton per hectare (Lee et al., 2013). In a previous survey by Molenaar et al. (2013) amongst 1069 households in six locations in Sumatra and Kalimantan, several key constraints were identified, such as insufficient fertilizer application, incorrect harvesting practices, presence of non-hybrid varieties in the plantations, poor (re)planting practices, and the overarching issue of lack of access to knowledge and finance. A study among 127 smallholder households in a NES project in Java (Hardjono et al., 2003) found that road upkeep, drainage upkeep, and fertilizer application techniques were least adopted and were therefore the most important constraints. Poor practices were mostly attributed to an overall lack of knowledge and experience. In all of the previous investigations, poor use of fertilizers appeared as a key constraint, but no data is available on actual nutrient deficiencies in smallholder plantations. In this paper, we report the preliminary findings of a study on agronomic practices and nutrient deficiencies among independent smallholders in Kalimantan and Sumatra. Independent smallholders generally perform less well than tied smallholders (Molenaar et al., 2013, Lee et al., 2013) and the need for improving yields is therefore even more pressing. Our research aims to answer the following research questions: 1. What are the current fertilization practices of smallholder oil palm farmers in terms of the five key nutrients required by oil palm (nitrogen (N), phosphorus (P), potassium (K), magnesium (Mg) and boron (B))? 2. Which nutrient deficiencies are prevalent in smallholder plantations? 3. Do particular nutrients significantly limit the yield in smallholder plantations? 4. What factors contribute to suboptimal fertilization in smallholder plantations? 5. What other key biophysical and management factors contribute to poor yields? Study area description MATERIALS & METHODS Sintang, West-Kalimantan. Sintang is located in West Kalimantan, about 250 km east of Pontianak along the river Kapuas (Figure 1). The topography is flat to gently rolling, with some steep granite mountains dotting the landscape to the east. The soils are clays or sandy clay loams, with some shallow peat pockets present in the Tebelian area. The climate is humid tropical, with an average annual temperature of 26.9 C, an average maximum temperature of 32.5 C and minimum temperature of 22.9 C. The yearly precipitation is around 3000 mm, with a rainy season from October to January and the driest month in August (~100 mm/month). Binjai cooperative consists of 2410 households divided over 7 villages. The total number of hectares (including scheme and independent plantations) was 4805, indicating an average plantation size of slightly less than 2 hectares per family. The

3 average yield was 17 to 18 ton per hectare per year, with a peak season in November and December and a low season from February to June. Bondo Sepolo (Tebelian) cooperative consists of 16 villages with a total oil palm area of 5579 ha. No data was available on the number of households in the village. The average yield was around 18 ton per hectare, with the peak season from October to January. Ramin, Jambi. Desa Ramin is located in sub-district Kumpeh of Muaro Jambi regency in Jambi province, about 40 km north-east of Jambi city (Figure 2). The climate is humid tropical, with an average annual temperature of 27 C, an average maximum temperature of 31 C and minimum temperature of 22.5 C. The yearly precipitation is around 2300 mm, with a rainy season from October to February and the driest months in June, July and August (~100 mm rainfall per month). The topography is flat low-lying coastal plain. Soils in the area are alluvial clays (34%) and deep peat soils (66%). Ramin village covers 3325 hectares of agricultural land, of which 2213 hectares (67%) are used for oil palm cultivation. The village consists of 397 households, of which 81% (321 households) are involved in farming (2014 data obtained from the monografi desa available in the kantor desa). Farmer selection In Sintang FASDA, a local NGO consisting of extension workers, volunteers and independent farmers and operating under the guidance of WWF Indonesia, provided a list of independent farmers in the area, including the number of hectares planted and the planting year. FASDA worked with two cooperatives, Tebelian and Binjai, in the south and north of Sintang respectively. The cooperative offices provided additional information about the number of farmers in the cooperative, the total size of the plantations and the production in the research areas in the year We randomly selected 24 farmers from the provided lists, of which 12 in Tebelian and 12 in Binjai. We limited our selection to those farmers who had an independent plantation that was planted before 2010 (so in the year 2009 or earlier). If a farmer was not at home or not available at the time of the visit, a next farmer was randomly drawn where possible. Alternatively, we locally asked for another farmer that fit our criteria, using the so-called snowball approach. In total, about two-thirds of the farmers visited were part of the random sample, and the remaining one-third were selected through the snowball method. In Jambi a sample of 34 households was randomly selected for interviewing using a list provided by the village head. In addition six farmers participating in a Demonstration Plot project were non-randomly selected. Plantation assessment and sample collection was only carried out in the fields of the farmers participating in the Demonstration Plot project. These farmers were selected based on motivation and on the position of their plantation (not on very waterlogged soils or peat soils) and therefore these six plantations are likely to be better than average in terms of management and productivity. Interviews In Sintang the selected farmers were visited once during the months November and December, Each plantation visit consisted of two parts: an interview and a field visit. During the interview, which lasted about half an hour on average, general farm characteristics and fertilizer use were discussed. Questions were asked about origin of the farmer (immigrant or local), size of the plantation, planting date, previous land use, source of planting material, estimated yields, and types and quantities of fertilizers used.

4 In Jambi the selected farmers were visited once in April and May, Semistructured interviews were carried out with questions concerning household and livelihood characteristics, land ownership, household income and expenses, and oil palm management practices. Plantation assessment and sample collection In Sintang one plantation was selected for assessment and sampling after each interview. If the respondent owned more than one independent plantation, the oldest one was selected for sampling. If the respondent owned several plantations of the same age, the one closest to the house was selected. Three trees in the plantation were selected randomly. If the selected tree was not representative or otherwise unavailable (e.g. smaller or more stunted than its neighbors, in the middle of a swamp, severely damaged by insects or diseases, etc.) then a new palm was selected. Each sample palm was first assessed on five different variables: presence of deficiency symptoms, presence of pest symptoms, presence of disease symptoms, weeding and pruning status, and flooding and/or erosion status. Soil samples were collected at 5 and 25 cm depth using an Eijkelkamp sampling core of Ø 53x50 mm and height 51 mm, volume 100 cc. Samples were collected in the palm circle (50 cm from the trunk) and in the interrow under the frond stack (3 m from the trunk, away from the harvesting path). For the leaf samples, the middle ~20 cm pieces of the eight largest leaflets of leaf 17 (four on the left and four on the right side of the rachis) were collected. In addition, a piece of rachis of approximately 20 cm in length was collected as rachis sample. Finally we counted the number of dura fruits out of a sample of 20 loose fruits. In Jambi only the plantations from the six non-randomly selected farmers participating in the Demonstration Plot project were assessed and sampled, according to the mentioned protocols. Dura bunches were counted during harvesting. Sample processing The soil samples were air dried in plastic trays for 2-4 days. After drying, the samples were pulverized using mortar and pestle. The samples were weighed and the color and texture of the sample was noted. A sub-sample of 10 gram was taken from each individual sample, and the sub-samples were combined to create two samples per plantation: a soil circle sample and an interrow sample, each containing six sub-samples (from three palms and two depths). The leaflet and rachis samples were air-dried under a fan. Before oven-drying, the rachis samples were shredded manually and the leaflets were cut into 5 mm strips. The samples were packed in paper envelopes and then oven-dried at ~50 C in a fan-fitted oven for 48 hours. After drying, the samples of each plantation were combined to create one leaflet and one rachis sample per plantation. The processed samples were packaged and sent to Bah Lias Research Station (Medan, Sumatera) for nutrient concentration analysis. Sample analysis Laboratory analyses were carried out according to standard laboratory procedures (Bah Lias Research Station, 2003). The following analyses were carried out on the soil samples: 1) water-extracted ph; 2) total organic matter using a spectrophotometer at 600 nm; 3) extractable P using the Bray II method; 4) Al + H through KCl extraction and titration; 4) soil organic N through two-step Kjeldahl; 5) soil extractable K using a flame photometer; 6)

5 soil extractable Mg and Ca using an atomic absorption spectrometer (AAS); 7) and soil texture by hydrometer method. For the tissue samples, the following analyses were carried out: 1) leaf nitrogen through sulphuric acid digestion and semi-micro Kjeldahl distillation; 2) leaf and rachis P through ashing followed by spectrophotometric analysis (vanadomolybdate method); 3) leaf and rachis K using a flame photometer after ashing; 4) leaf Ca and Mg (and Cu and Zn if required) by AAS after ashing; 5) leaf B using a colorimetric method after dryashing with CaO. Laboratory results were analyzed using Excel software. Current productivity RESULTS AND DISCUSSION Average yields in independent fields in Sintang based on the answers of the respondents were 14.5 ± 6 ton per hectare, from plantations with an average age of 6 years after planting (Figure 3). Yields from plasma fields in Sintang were better, with averages of 17 to 18 ton per hectare, indicating a gap between independent and plasma plantations (data from cooperative records). Average yields in desa Ramin, as estimated by the respondents, were 21 ± 7 ton of fresh fruit bunches per hectare on mineral soils. Yields from plantations on peat soils were significantly less (p<0.05) at 11 ± 5 ton per hectare. Fertilizer use All 24 interviewed farmers in the two cooperatives in Sintang used fertilizers in their oil palm plantation. The majority of the farmers used at least NPK Ponska, Urea or ZA, SP36, and nearly 70% of the farmers had also applied dolomite at any one time since planting (Table 1). Many farmers did not apply KCl, as they found it too expensive. Boron fertilizer was also considered expensive, and was usually applied in very small quantities (12 g/tree, one tablespoon), if any. Micronutrient fertilizers (especially copper and zinc) were not applied by any of the interviewed farmers. Organic fertilizers were applied by almost half of the farmers, in the form of empty fruit bunches (EFB) or manure, usually from chicken or cattle. In desa Ramin, farmers relied mostly on NPK fertilizers, especially NPK Phonska (79% of farmers; Table 1). Four farmers did not apply any fertilizers on their oil palm in the previous year. In general, few farmers used straight fertilizers, not even the subsidized ones. Based on the stated amount of fertilizers purchased and the fertilizer price, average yearly costs for fertilizer application were estimated be around 5.5 million IDR per year per hectare. However, when asked to estimate their yearly expenditure on fertilizers, farmers generally gave numbers well below 5.5 million IDR, which may mean that either the awareness of actual investments was limited, or the actual applications were less than what was stated in the interviews. The data from Sintang and Ramin show that the fertilization practices of the respondents were sub-optimal (Table 2). Fertilization was based on the application of NPK, mostly the subsidized NPK (Phonska). This blend is in fact not suitable for oil palm as the nutrient balance is not correct, and additional applications of straight N and especially straight K are required to provide optimum nutrition. However the application of straight K was uncommon, with only 15 to 30% of the farmers applying straight K. The application of Mg is necessary for oil palm but only 50 to 70% of the farmers applied Mg, usually in the

6 form of dolomite, which is poorly soluble and may not provide enough Mg to satisfy the palm demand. Boron application was below recommended rate in all plantations, and if applied it was usually done so by tablespoon, which is much less than the recommended gram per palm (Rankine and Fairhurst, 1999). Nutrient deficiencies The poor fertilization practices were reflected in the soil (Table 3) and leaf (Table 4) nutrient status in the plantations. Tissue nitrogen (N) deficiency (Table 2) was widely observed in the independent plantations (58%) in Sintang, as well as in three out of six plots in Ramin. Soil deficiencies in phosphorus (P) were observed in 40% of all the sampled plantations, and tissue deficiencies were observed in 10%. Potassium (K) deficiency was observed most frequently, with % of the independent plantations in Sintang, and five out of six plantations in Ramin showing both soil and leaf K deficiencies. Boron deficiency was not observed in the tissue samples from Sintang. Visual deficiency symptoms could be observed in the field for all five major oil palm nutrients (data not shown), but potassium (Figure 4) and boron (Figure 5) deficiencies were especially common. Other constraining factors Poor planting material. In Sintang, 12 out of 23 tested plantations were contaminated with Dura material (Figure 6). On average we found 25% Dura fruits in the contaminated plantations, but there was a large variation in the number of dura fruits, ranging from 5 to 75%. The number of Pisifera palms was not counted. The presence of Dura indicates planting material of inferior quality. In Ramin only four plantations were tested on Dura presence, and all were contaminated with Dura, ranging from 30 to 50% of the bunches. Flooding and waterlogging. In both Sintang and desa Ramin, waterlogging due to poor drainage was identified as a constraint. In Sintang, a separate interview among 25 plasma farmers showed that 17 out of 25 farmers owned a plantation that was (partly) located in a peat or freshwater swamp (data not shown). In Ramin, farmers reported several months of flooding annually in the years before 2013, and the trees showed clear signs of inundation (Figure 7). In the deep peat areas in Ramin, drought stress is likely to be an additional issue as no functional flood gates were present in the drainage system to prevent over-draining during the dry season. Other factors. A number of other constraints came forward during the interviews. Most of the respondents in Sintang and Ramin harvested once per two weeks, and none harvested at the recommended frequency of once per ten days, which shows that harvesting practices are suboptimal (Lee et al., 2013). Other issues that came up were lack of time or labor to do good management, rat damage to the bunches, occasional outbreaks of leaf-eating pest, and the general issue of lack of money to buy inputs and good-quality seeds for (re)planting. These issues are likely to contribute to the yield gap but their impacts have not yet been properly quantified. CONCLUSIONS Our research shows that fertilization practices in the research areas were sub-optimal. Farmers strongly relied on subsidized NPK fertilizers with a sub-optimal nutrient balance,

7 and did not apply sufficient straight fertilizers, especially K, to meet the palm demand. This was confirmed by the observation of wide-spread K deficiency in the tissue samples. In the case of oil palm, potassium is particularly important for bunch and oil production, and factorial fertilizer trials generally show a strong yield response to K fertilization (Corley and Mok, 1972, Kraip and Nake, 2006). It is therefore likely that the measured K deficiency has led to yield reductions and contributed to the yield gap in the research areas. Respondents named several reasons for not applying straight K fertilizers, of which the high costs were most important. Another reason was fear of buying adulterated fertilizers, which was recounted as a common issue on several occasions, and observed once in a fertilizer storage shed in Ramin. Apart from nutrient deficiencies, other yield-constraining factors that came forward in the interviews and field assessments were poor planting material (Dura contamination), water-logging, infrequent harvesting, lack of time and/or labor for maintenance, and rat attacks. If the yields in smallholder plantations are to be improved, particular attention needs to be given to providing correct knowledge about fertilizer balance, and providing access to good-quality fertilizers and to finance. ACKNOWLEDGEMENTS This research was co-funded by The Dutch Development Organization (SNV Netherlands) and K+S Kali GmbH (Germany). Laurie van Reemst contributed to the data collection in desa Ramin. We would like to thank all farmers, NGO staff, extension workers and other people involved for their enthusiastic contributions. REFERENCES BAH LIAS RESEARCH STATION Manual of Laboratory Methods. Medan: PT. PP. London Sumatra Indonesia Tbk. BUDIDARSONO, S., DEWI, S., SOFIYUDDIN, M. & RAHMANULLOH, A Socio- Economic Impact Assessment of Palm Oil Production. Technical Brief No. 27: Palm Oil Series. Bogor, Indonesia: World Agroforestry Centre - ICRAF, SEA Regional Office. CORLEY, R. H. V. & MOK, C. K Effects of nitrogen, phosphorus, potassium and magnesium on growth of the oil palm. Experimental Agriculture, 8, HARDJONO, W., RANAMUKHAARACHCHI, S. L. & SINGH, G Factors affecting adoption of management practicies in smallholder oil palm plantations of Banten Province, Indonesia. Asia-Pacific Journal of Rural Development, 13, KRAIP, J. & NAKE, S Response of oil palm (Elaeis guineensis Jacq.) to additions of nitrogen, phosphorus and potassium from planting to 7 years after planting: PNG OPRA Trial 501. LEE, C. H Oil Palm Expansion in Indonesia - Assessing Livelihood and Environmental Impacts from the Smallholder Sector. PhD, ETH Zurich. LEE, J. S. H., GHAZOUL, J., OBIDZINSKI, K. & KOH, L. P Oil palm smallholder yields and incomes constrained by harvesting practices and type of smallholder management in Indonesia. Agronomy for Sustainable Development, 1-13.

8 Yearly yield (tonne/ha) MOLENAAR, J. W., PERSCH-ORT, M., LORD, S., TAYLOR, C. & HARMS, J Oil palm smallholders. Developing a better understanding of their performance and potential. Jakarta: International Finance Corporation. RANKINE, I. R. & FAIRHURST, T. H Field Handbook: Oil Palm Series, Volume 3 Mature, Singapore, Potash & Phosphate Institute (PPI). SHEIL, D., CASSON, A., MEIJAARD, E., VAN NOORDWIJK, M., GASKELL, J., SUNDERLAND-GROVES, J., WERTZ, K. & KANNINEN, M The impacts of oil palm in Southeast Asia: What do we know and what do we need to know? Occasional paper no. 51. Bogor, Indonesia: CIFOR. Figures Figure 1: Location of Kabupaten Sintang, Kalimantan, Indonesia Figure 2: Location of Kabupaten Muaro Jambi, Sumatra, Indonesia Tree age (months) Figure 3: Yields from independent plantations in Sintang as estimated by respondents (n=19)

9 Figure 4: Visual leaf symptoms of potassium deficiency (confluent yellow spotting) Figure 5: Visual leaf symptoms of boron deficiency ( crinkled leaf ) Figure 6: Shell types in oil palm: pisifera, tenera, and dura

10 Figure 7: Signs of inundation in Ramin. Tables TABLE 1: FERTILISER USE PER SITE IN 2014 (% OF FARMERS) Sintang Ramin n=24 n=40 Subsidised NPK ( ) Non-subsidised NPK Straight N (usually urea) Straight P (usually SP-36) Straight K (usually KCl) Mg (usually dolomite) B (borax) Organic (EFB or manure) Copper/zinc 0 0 TABLE 2: RECOMMENDED FERTILISER APPLICATION RATES AND CRITICAL SOIL AND TISSUE NUTRIENT CONCENTRATIONS. Recommended Most common fertilizer application Critical levels (minimum concentrations) Nutrient fertilizer type (kg/palm)* Leaflets Rachis Soil N Urea %DM 0.15 % P SP %DM 0.10 %DM 15 mg/kg K KCl %DM 1.1 %DM 0.15 Cmol/kg Mg Dolomite %DM 0.2 Cmol/kg B Borax ppm *These are generic recommendations. For optimal fertilizer recommendations local conditions, especially soil type, need to be taken into account. TABLE 3: SOIL NUTRIENT CONTENTS IN SINTANG AND RAMIN (deficiencies are indicated in bold underlined). Sintang (n=24) Ramin (n=6) Average StDev Average StDev Circle

11 ph Organic matter % N Cmol/kg P mg/kg K Cmol/kg Mg Cmol/kg Ca Cmol/kg Interrow ph Organic matter % N Cmol/kg P mg/kg K Cmol/kg Mg Cmol/kg Ca Cmol/kg TABLE 4: TISSUE NUTRIENT CONTENTS IN SINTANG AND RAMIN (deficiencies are indicated in bold underlined). Sintang (n=24) Ramin (n=6) Average StDev Average StDev Leaflets N % dry matter P % dry matter K % dry matter Mg % dry matter Ca % dry matter B mg/kg dry matter nd nd Rachis P % dry matter K % dry matter Mg % dry matter Ca % dry matter B mg/kg dry matter nd nd