IPNI SEAP Staff Publication List

2017

Hoffmann, M.P., C.R. Donough, S.E. Cook, M.J. Fisher, C.H. Lim, Y.L. Lim, J. Cock, S.N. Mohanaraj, K. Indrasuara, P. Tittinutchanon and T. Oberthür. 2017.
Yield gap analysis in oil palm: Framework development and application in commercial operations in Southeast Asia.
Agricultural Systems, 151:12-19.
Abstract: Narrowing the gap between actual and attainable yields in existing oil palm plantations is perceived as a key to fulfill the growing global demand for vegetable oil. To assess the scope for intensification we need robust estimates of attainable yields, which has been so far rarely done for perennial crops. For this purpose, we evaluated the complexities associated with estimating yield gaps (YGs) in oil palm (i.e. carry-over effect and aging), and adapted the existing framework for YG studies in annual crops. Based on this framework, we analyzed YGs for four sites within oil palm plantations located in Sabah (Malaysia), Central Kalimantan and North Sumatra (Indonesia) using a unique commercial yield data set covering an area of 38,300 ha.
We assessed for each site at plantation scale water-limited potential yield using the PALMSIM simulation model, attainable yield determined by best performing blocks within the plantation as defined by 90th percentile of observed yields and actual yields (blocks representing the median yields). The water-limited potential yield did not differ very much; 35-39 t fresh fruit bunch (FFB) during the plateau phase, the most productive phase in the life time of a palm. This reflected the favorable environmental conditions found in many parts of Sumatra and Borneo for oil palm. Attainable yields were in the range of 26-31 t FFB/ha. The exploitable YG between attainable and actual yield ranged for the four sites from 5 to 7 t FFB/ha/year. For one site (Central Kalimantan), we assessed yield variability due to varying soil conditions at the block scale according to its dominant soil type. This suggested that they were indeed exploitable by management. If the plantation could close the gap between attainable and actual yield this could give about 21,000 t/yr higher FFB.
This indicated the large scope for intensification oil palm offers in many parts of insular Southeast Asia.

IPNI. 2017.
Planters' Diary 2017.
International Plant Nutrition Institute (IPNI), Penang, Malaysia.


2016

Aye, T.M. 2016.
Field handbook - 4R Nutrient Management of Table Grape in Myanmar. (In Burmese)
International Plant Nutrition Institute, Penang, Malaysia.

Cock J., S.P. Kam, S. Cook, C. Donough, Y.L. Lim, A. Jines-Leon, C.H. Lim, S. Primananda, B.T. Yen, S.N. Mohanaraj, Y.M.S. Samosir and T. Oberthür. 2016.
Learning from commercial crop performance: Oil palm yield response to management under well-defined growing conditions.
Agricultural Systems, 149:99-111.
Abstract: Farmers learn from their own experiences. However, they are rarely sure if an exceptionally good or bad outcome is due to chance effects or whether it is due to a given combination of management practices and environmental conditions. We surmised that, if each harvest event is adequately characterized and a large number of these events are analyzed together, it should be possible to associate crop response to management within a particular set of growth conditions. We tested this hypothesis using the perennial crop, oil palm.

Donough C.R., A. Cahyo, R. Wandri, M. Fisher and T. Oberthür. 2016.
Plant nutrients in palm oil.
Better Crops With Plant Food, 100:19-22.
Abstract: An apparent knowledge gap concerning the amount of plant nutrients in palm oil motivated a study to determine plant nutrient content in palm oil and assess the impact of fertilizer management on such content. Export of plant nutrients was low in palm oil extracted by industrial mills; part of the nutrients likely remain in post-milling residues. Selected nutrients in palm oil were affected by fertilizer application rate, but not timing or frequency.

IPNI. 2016.
Planters' Diary 2016.
International Plant Nutrition Institute (IPNI), Penang, Malaysia.

Ocampo, A., M. Pampolino, L. Luar, R. Pedro, M. How, V.L. Cosico, E.D. Santos, S. Hilado, A. Valdez, P.J. Santos, T. Oberthür and A. Shcherbakov. 2016.
Nutrient management for cassava in the Philippines.
Poster presentation at the 46th Crop Science Society of the Philippines Conference, Phela Grande Hotel, General Santos City, Philippines, 13-18 June 2016.
Abstract: Cassava is an important crop in the Philippines used as food, feed, and raw material for industrial products. The current yield of cassava is only about 12 t/ha, while yields >75 t/ha (fresh weight) are possible under controlled conditions (FAO, 2013). Whilst it is known that cassava responds to fertilization, there is a lack of quantitative knowledge on the response of cassava to fertilizer under specific biophysical conditions, which are important in the development of an improved nutrient management strategy for cassava (FAO, 2013).

Pampolino, M. 2016.
Optimizing fertilizer formulation for smallholders in Asia and Africa.
Fertilizer Focus, July/August 2016:42-45.
Abstract: The demand for increased cereal production to feed an increasing world population would be better met by intensifying production of wheat, rice and maize to increase attainable yields, rather than by expanding cultivated areas.

Pauli, N., C. Donough, T. Oberthür, J. Cock, R. Verdooren, Rahmadsyah, G. Abdurrohim, K. Indrasura, A. Lubis, T. Dolong, J.M. Pasuquin and M. Fisher. 2016.
Changes in soil quality indicators under oil palm plantations receiving Best Management Practices.
Re-produced in The Planter, Vol 92, page 29-37.
Abstract: The effect of best management practices (BMPs) to intensify oil palm production and improve yield were evaluated in Indonesia and Malaysia. While no clear, consistent differences were found in the soil properties between BMP and reference (REF) treatments over four years, improvements in soil pH and % soil organic carbon (SOC) were recorded for both treatments. The study found no significant deterioration in the measured soil properties over the four years, suggesting that appropriate management practices for oil palm can improve several aspects of soil quality.

Oberthür, T. 2016.
Plant Intelligence® & Estate Scale Experimentation (PI & ESE): Management processes for plantation operators. Pages 103-105.
Intelligencia de plantaciones para la correcta toma de decisiones en campo: Gestion de procesos para operadores de plantaciones. Pages 13-16.
Proceedings of the 2nd C//PAL Palm Congress, Santo Domingo del Cerro, La Antigua Guatemala, 22-24 August 2016.
Abstract: Plantation Intelligence & Estate Scale Experimentation (PI & ESE) are management processes that have their origin in concepts from manufacturing. These concepts describe how managers use information and control technologies to improve efficiency and profitability of manufacturing. Some time ago, it occurred to us that there was scope for better systems of management in agriculture; not just oil palm, but all forms of agricultural management. The principle of better management we pursued was improved control of production processes, enabled by information. The change we sought was systemic. The processes hinge on conceptual models that link available data about actual yield variation (i.e. production) and site characteristics in a managed system.

Rhebergen T., T. Fairhurst, S. Zingore, M. Fisher, T. Oberthür and A. Whitbread. 2016.
Adapting oil palm best management practices to Ghana: Opportunities for production intensification.
Better Crops With Plant Food, 100:12-15.
Abstract: An increasing global demand for palm oil, and limited availability of agricultural land in Southeast Asia, has driven a rapid expansion of new oil palm plantings in West Africa.
Sub-optimal climate conditions and generally low yields in West Africa, combined with highly fragmented land holdings limit the potential for expansion of large-scale plantings.
Research conducted in Ghana indicates that production increases can alternatively be sought by applying best management practices to land already planted with oil palm.

Sugianto, H., C. Donough, Rahmadsyah, C.H. Lim and T. Oberthür. 2016.
Nutrient use efficiency in oil palm nurseries.
Better Crops With Plant Food, 100:16-18.
Abstract: Soil tests are useful in selecting suitable topsoil for use as growth medium in oil palm nurseries to avoid differences in plant growth between sites. Nutrient use efficiency (NUE) in oil palm nurseries can be improved with appropriate application rates and timing. Further improvements in NUE in oil palm nurseries could come with more efficient irrigation and use of slow-release nutrient sources.

Xu X., P. He, J. Zhang, M.F. Pampolino, A.M. Johnston and W. Zhou. 2016.
Spatial variation of attainable yield and fertilizer requirements for maize at the regional scale in China.
Field Crop Research, 203:8-15.
Abstract: Understanding attainable yield, soil nutrient supply capacity and fertilizer requirements in current intensive maize (Zea mays L.) production at regional and national scales in China is essential in making informed decisions on policy, research and investment. In this study, results of a large number of on-farm experiments (n = 5893) were collected for the period 2001-2015 from the main maize production areas in China to study the spatial variability of attainable yield, relative yield (RY) and fertilizer requirements by coupling geographical information system with the Nutrient Expert for Hybrid Maize system. We found strong spatial variation in attainable yield across all sites, with a coefficient of variation (CV) of 25.5%.Mapping the spatial variability of RY indicated that 85.3%, 79.3% and 72.5% of RY for nitrogen (N), phosphorus (P) and potassium (K) of the study areas ranged from 0.68 to 0.87, from 0.83 to 0.95 and from 0.84 to 0.94, respectively. The RY was higher in North Central China than other regions. The RY can reveal the spatial heterogeneity of soil nutrient supply capacity, and has been integrated into crop management strategies for calculating fertilizer requirements using the Nutrient Expert® for Hybrid Maize decision sup-port system. Overall, there were large variations in N, P and K fertilizer requirements across all sites with CVs of 19.5%, 31.6% and 35.0%, respectively, and the ranges of 150-210 kg N ha-1, 50-90 kg P2O5ha-1 and 50-110 kg K2O ha-1 accounted for 72.0%, 81.7% and 81.5% of the study areas, respectively. The results of 605 field experiments in 10 provinces during 2010-2014 showed that the Nutrient Expert® for Hybrid Maize system not only reduced N and P fertilizer application rates by 31.6% and 15.5%, respectively, but also increased maize yield by 3.3% compared with farmers' current practices. The combination of the fertilizer recommendation system and geographical information system with a large database of field trials provides a useful tool to identify spatial variation in fertilizer requirements in fields and regions, and contributes towards more efficient and effective fertilizer management.

Xu, X., P. He, M.F. Pampolino, Y. Li, S. Liu, J. Xie, Y. Hou and W. Zhou. 2016.
Narrowing yield gaps and increasing nutrient use efficiencies using the Nutrient Expert® system for maize in Northeast China.
Field Crops Research 194:75-82.
Abstract: A science-based, reliable, and feasible fertilizer recommendation method is required to respond to the low nutrient use efficiency caused by inappropriate fertilization practices. Soil test-based fertilizer recommendations are difficult to use for smallholder farms because of constraints such as access, cost and timeliness in multiple cropping systems. In this study, we combined on-farm experiments from 2012 to 2014 in 20 farmers’ fields on spring maize in Northeast China with a simulation model (Hybrid Maize model), to test the continual performance in agronomic, economic and environmental aspects of the Nutrient Expert® for Hybrid Maize decision support system. Six treatments were set as follows: Nutrient Expert® (NE), farmers’ practice (FP), soil testing (OPTS) and nitrogen (N), phosphorus (P), and potassium (K) omission treatments based on NE. We estimated yield gaps as the difference between simulated yields with the Hybrid Maize model and measured yields; calculated economic benefit and nutrient use efficiency; and estimated greenhouse gas emissions using published equations approximating nitrous oxide emissions as a function of N fertilizer rate. On average, the NE, FP, and OPTS treatments attained yields of 80%, 74%, and 77% of the potential yield, respectively. The exploitable yield gap between the NE and FP treatments was 0.9 t/ha, and between the NE and OPTS treatments was 0.5 t/ha. On average, the NE treatment increased the gross return above fertilizer cost (GRF) by US$303 and US$167 compared with the FP and OPTS treatments across all sites, respectively, in which about 91% and 98% of increase GRF was attributed increase in grain yield rather than reduction in fertilizer cost. There were slightly higher nutrient use efficiencies under the NE treatment than under the OPTS treatment. Relative to the FP treatment, however, on average, the NE treatment increased recovery efficiency of N, P, and K by percentage point of 12, 15, and 10, respectively. Agronomic efficiency of N, P, and K were increased by 6, 35, and 10 kg/kg, respectively. Finally, partial factor productivity increased by 14 kg/kg for N and 45 kg/kg for P while decreased by 29 kg/kg for K. Furthermore, the calculated soil inorganic N at harvest of maize crop, total greenhouse gas (GHG, kg CO₂ eq/ha) emissions, and GHG emission intensity (kg CO₂ eq/t grain) were 42%, 17%, and 23% lower in the NE treatment than the FP treatment, respectively. We conclude that the Nutrient Expert® for Hybrid Maize system has the potential to close existing yield gaps in the spring maize production systems of Northeast China by improving yield, nutrient use efficiency, and profitability with low environmental pollution.