On Yield Gaps and Better Management Practices in Indonesian Smallholder Oil Palm Plantations

On yield gaps and better management practices in Indonesian smallholder oil palm plantations Lotte S. Woittiez Thesis committee Promotor Prof. Dr Ken E. Giller Professor of Plant Production Systems Wageningen University & Research Co-promotors Dr Maja A. Slingerland Associate professor, Plant Production Systems Group Wageningen University & Research Prof. Dr Meine van Noordwijk Special professor Agroforestry Wageningen University & Research Other members Prof. Dr Niels P. R. Anten, Wageningen University & Research Prof. Dr Klaus Dittert, Georg-August-University Göttingen, Germany Dr Gede Wibawa, Riset Perkebunan Nusantara, Indonesia Dr Carina van der Laan, Sustainable agriculture in tropical forest landscapes This research was conducted under the auspices of the C. T. de Wit Graduate school of Production Ecology and Resource Conservation On yield gaps and better management practices in Indonesian smallholder oil palm plantations Lotte S. Woittiez Thesis submitted in fulfilment of the requirements for the degree of doctor at Wageningen University by the authority of the Rector Magnificus, Prof. Dr A. P. J. Mol, in the presence of the Thesis Committee appointed by the Academic Board to be defended in public on Wednesday 10 April 2019 at 1.30 p.m. in the Aula. Lotte S. Woittiez On yield gaps and better management practices in Indonesian smallholder oil palm plantations, xii + 289 pages. PhD thesis, Wageningen University, Wageningen, the Netherlands (2019) With references, with summaries in English, Dutch, and Bahasa Indonesia. ISBN: 978-94-6343-591-8 DOI: https://doi.org/10.18174/470340 Abstract Palm oil is currently the most important vegetable oil in the world, and Indonesia is the world’s largest producer. Oil palm plantations are an important source of revenue, but rapid expansion has led to deforestation and loss of biodiversity. Forty per cent of the plantation area in Indonesia is owned by smallholders, whose yields are relatively poor. The objective of this thesis was to investigate the yield gaps and agronomic practices in Indonesian smallholder oil palm plantations, with a focus on fertiliser application, and to propose and test better management practices that can contribute to sustainable intensification. The research consisted of an in-depth literature review, several surveys, the collection of samples in smallholder plantations, and a three-year experiment with 14 smallholder farmers. In yield gap analysis, three yield levels are recognised: potential, limited, and actual yield. The potential yield in a plantation is determined by radiation, CO2 concentration, temperature, planting material, culling, planting density, pruning, pollination, and crop recovery (harvesting). The yield-limiting factors are rainfall, irrigation, soil, waterlogging, topography, slope, and nutrition. The yield-reducing factors are weeds, pests, and diseases. In smallholder plantations, the yield gap is mostly explained by poor planting material, poor drainage, sub-optimal planting density, poor culling (leading to large variability and the presence of unproductive palms), infrequent harvesting, soil erosion, poor nutrient management, and rat damage, but the effects of these factors on yield vary depending on local conditions. The survey data showed clear evidence of insufficient and unbalanced fertiliser applications, and visual nutrient deficiency symptoms were observed in many plantations. Leaf sample results showed that 57, 61 and 80% of the plantations in Jambi and Sintang were deficient in N, P and K, respectively. In Riau, 95, 67 and 75% of the plantations were deficient in N, P and K. The implementation of better management practices (including harvesting, weeding, pruning, and nutrient application) in 14 smallholder fields for three years resulted in palms with significantly larger leaves and heavier bunches compared with palms under farmer management, but improvements in yield were small and not statistically significant, and financial returns on better practices were negative. Possible causes of the small yield response were good starting yields, increased inter-palm competition for sunlight, and environmental constraints (particularly the 2015 El Niño event and waterlogging in Jambi). i On the basis of our findings on yield gaps, nutrient limitations and better practices, we discuss how Indonesian smallholders may be supported to achieve sustainable intensification at a larger scale, and we reflect on the broader implications of our findings for a future supply of truly sustainable palm oil. ii Table of contents Abstract i Table of ccontents iii List of figures v List of tables vii List of abbreviations viii CHAPTER 1 General introduction 1 1.1 A brief history 2 1.2 Palm oil production and sustainability 5 1.3 Smallholder oil palm plantations in Indonesia 7 1.4 Better Management Practices 9 1.5 Research questions & thesis outline 12 CHAPTER 2 Yield gaps in oil palm: A quantitative review of contributing factors 17 2.1 Introduction 20 2.2 Plantation life cycle and vegetative growth 22 2.3 Fruit development 25 2.4 Magnitude, causes, and management of yield gaps 32 2.5 Current causes of yield gaps and future outlook 55 CHAPTER 3 Fertiliser application practices and nutrient deficiencies in smallholder oil palm plantations in Indonesia 65 3.1 Introduction 66 3.2 Materials and methods 68 3.3 Results 73 3.4 Discussion 81 3.5 Conclusions 85 CHAPTER 4 Nutritional imbalance in smallholder oil palm plantations in Indonesia 89 4.1 Introduction 91 4.2 Background 94 4.3 Methodology 98 4.4 Results 105 4.5 Discussion 113 4.6 Conclusions 118 Supplementary materials 120 iii CHAPTER 5 Do wealthy farmers implement better agricultural practices? 137 5.1 Introduction 138 5.2 Methods 141 5.3 Results 146 5.4 Discussion 152 5.5 Conclusions 157 CHAPTER 6 People, palms and productivity: Testing better management practices in Indonesian smallholder oil palm plantations 161 6.1 Introduction 163 6.2 Materials and methods 166 6.3 Results 176 6.4 Discussion 186 6.5 Conclusions 192 Supplementary materials 195 CHAPTER 7 General discussion 201 7.1 Introduction 202 7.2 Summary of the key findings 203 7.3 Limitations of the research 204 7.4 Causes of yield gaps in oil palm 208 7.5 Nutrient deficiencies and yield effects 210 7.6 Other causes of yield gaps in smallholder fields 213 7.7 Options for sustainable intensification 218 7.8 Underlying constraints to intensification 223 7.9 Personal reflections and concluding thoughts 228 Bibliography 233 Summary 261 Ringkasan 267 Samenvatting 273 Acknowledgements 279 Curriculum Vitae 281 PE&RC Training and Education Statement 285 Propositions 287 Financial support 289 iv List of figures Chapter 1 Figure 1.1 A mature oil palm plantation near Medan, Sumatra. 3 Figure 1.2 Historical oil palm area in Indonesia. 4 Figure 1.3 Global annual vegetable oil production in 2017/18. 4 Figure 1.4 Ripening fresh fruit bunch, and tenera fruit. 5 Figure 1.5 Oil palm plantations and forests in West Kalimantan. 7 Figure 1.6 Independent oil palm plantation with intercrop. 9 Figure 1.7 Better management practices implemented in Ghana. 11 Figure 1.8 Scheme of research questions and chapters. 13 Chapter 2 Figure 2.1 Development of oil palm yield over time. 23 Figure 2.2 Inflorescence and bunch development. 28 Figure 2.3 Oil palm production levels and contributing factors. 33 Chapter 3 Figure 3.1 Soil nutrient concentrations in Sintang and Jambi. 76 Figure 3.2 Leaflet N and P concentrations. 77 Figure 3.3 Rachis and leaflet concentrations of P, K and Mg. 78 Figure 3.4 Leaflet K, Mg and Ca as percentage of total leaf cations. 79 Figure 3.5 Leaf area in relation to years after planting. 81 Chapter 4 Figure 4.1 Research area, plantations and mills in Rokan Hulu. 95 Figure 4.2 Satellite image of smallholder plantations. 101 Figure 4.3 Age and yield differences among farmer types. 104 Figure 4.4 Nutrient application rates per farmer type. 106 Figure 4.5 Nutrient balances per farmer type. 107 Figure 4.6 Share of farmers per type that implement GAP. 110 Figure 4.7 Plantation conditions per farmer type. 112 Chapter 5 Figure 5.1 Application rates of N, P and K from survey. 147 Figure 5.2 Application rates of N, P and K from literature. 148 Figure 5.3 Costs of fertilisers applied by smallholders. 149 Figure 5.4 Nutrient application in relation to training. 150 v Figure 5.5 Nutrient application as a function of plantation size. 151 Figure 5.6 Knowledge sharing in the research areas. 152 Chapter 6 Figure 6.1 Rainfall and temperature in Jambi and Sintang. 169 Figure 6.2 Nutrient application practices in the control plots. 178 Figure 6.3 Mean leaflet nutrient concentrations. 179 Figure 6.4 Mean rachis nutrient concentrations. 180 Figure 6.5 Vegetative growth parameters. 181 Figure 6.6 Mean monthly yields and bunch weights. 182 Figure 6.7 Yearly yields. 185 Figure S6.1 Tissue nutrient concentrations in fields S4 and S6. 195 Figure S6.2 Frond length and PCS in fields S4 and S6. 198 Figure S6.3 Monthly bunch yield in fields S4 and S6. 199 Chapter 7 Figure 7.1 Results of duplicate sample analyses. 207 Figure 7.2 Nutrient applications in all research areas. 211 Figure 7.3 Tissue nutrient concentrations in all research areas. 212 Figure 7.4 The main factors contributing to smallholder yields. 214 Figure 7.5 Cow in a smallholder plantation in Jambi. 223 vi List of tables Chapter 2 Table 2.1 Yield-determining factors: potential yield (Yp). 36 Table 2.2 Yield-limiting factors: water-limited yield (Yw). 44 Table 2.3 Water-limited yield on different soils. 46 Table 2.4 Yield-limiting factors: nutrient-limited yield (Yn). 47 Table 2.5 Role of key nutrients in oil palm physiology. 48 Table 2.6 Effects of N, P, K and Mg on yield.

Load more