IPNI SEAP Staff Publication List

2014

Aye, T.M. 2014.
Field Handbook - 4R Nutrient Management of Oil Palm in Myanmar. (In Burmese)
International Plant Nutrition Institute, Penang, Malaysia.

Aye, T.M. 2014.
Field Handbook - 4R Nutrient Management of Rice in Myanmar. (In Burmese)
International Plant Nutrition Institute, Penang, Malaysia.

Aye, T.M. 2014.
Field Handbook - 4R Nutrient Management of Sugarcane in Myanmar. (In Burmese)
International Plant Nutrition Institute, Penang, Malaysia.

Aye, T.M. 2014.
Field Handbook - 4R Nutrient Management of Cassava in Myanmar. (In Burmese)
International Plant Nutrition Institute, Penang, Malaysia.

Aye, T.M. 2014.
Field Handbook - 4R Nutrient Management of Rubber in Myanmar. (In Burmese)
International Plant Nutrition Institute, Penang, Malaysia.

Cock, J., C.R. Donough, T. Oberthür, K. Indrasuara, Rahmadsyah, A.R. Gatot and T. Dolong. 2014.
Increasing palm oil yields by measuring oil recovery efficiency from the fields to the mills.
Oral presentation at the International oil palm conference (IOPC) 2014 Green Palm oil for food security and renewable energy, Bali, Indonesia, 17-19 June 2014.
Abstract: Oil palm has been commercially cultivated in South East Asia for more than a century to produce crude palm oil (CPO, or oil) and palm kernels (PK, or kernel). The primary products are the fresh fruit bunches (FFB) that are perishable and once harvested must be processed rapidly to extract the oil and the kernel.
In other perishable crops like cassava and sugarcane, which must be processed rapidly after harvesting, the primary products are delivered to the processing plant or mill, weighed and analyzed to determine the amount of extractable final product i.e. starch or sugar. The producers are paid according to estimated final product content of their crop and therefore have a strong incentive to improve it. Furthermore, producers receive information on the product content of individual lots arriving at the mills. Consequently they are able to equate management practices and block characteristics with quality; hence they can improve the quality of the primary product. Similarly, the efficiency of mills in terms of their ability to extract starch or sugar can be evaluated if the quality of the product entering the mills is known.
In oil palm, the FFB received at palm oil mills is graded for ripeness and other criteria that may affect the milling process and oil extraction rate (OER). However, there is no estimate of the oil content of the FFB received. The palm oil mills process FFB of unknown oil content from many sources, and then estimate the OER based on the amount of oil they produce. Thus, in the current system, while FFB yield can be attributed to specific blocks by growers, the OER is not determined for individual blocks or even estates: it is assigned indiscriminately using the average OER of the mill which receives FFB from many sources and blocks. On the basis of "what you cannot measure you cannot manage", oil palm growers can, and do, manage their plantings to maximize FFB yield, but not OER. The International Plant Nutrition Institute's Southeast Asia Program (IPNI SEAP) has shown that when best management practices (BMPs) are implemented in the field to maximize FFB yield, OER may not necessarily be maximized at the same time (Oberthür et. al., 2012). Furthermore, there is no total oil balance at the mill based on total oil arriving in the FFB and oil eventually extracted from the FFB. Hence, milling efficiency is not normally evaluated on an overall balance of oil entering the mill and oil produced, but through estimates of losses in different stages of the process.
IPNI SEA recently showed that by combining bunch analysis (BA) data with harvest audit data, growers can compute their Field Oil Recovery Efficiency (FORE) and the Estimated Oil Content (EOC) of the harvested FFB delivered to the mill. The FORE is of the efficiency with which the oil produced in the field is recovered at harvest. The efficiency would be 100% if all bunches were harvested, the bunches were harvested ripe or mature and there were no losses of loose fruits (Donough et. al., 2013). Thus estimates of FORE provide information on the efficiency of the harvesting operations in recovering oil. The pre-milling EOC of the FFB received for processing will allow mills to measure their Mill Oil Recovery Efficiency (MORE), which is a better indicator of mill performance than OER per se. Use of recovery efficiency measures in the field and at the mill will allow a more holistic and inclusive analysis of the overall oil recovery, clearly describing the efficiency of operations managed in the field and at the mill.
Knowledge of EOC will also allow mills to pay growers for the oil content of their crop, which in turn will stimulate growers to improve FORE. A virtuous cycle of estimating potential product contents of individual FFB deliveries and using the information to improve crop recovery in the plantation may thus start.
In this paper, we present the conceptual definitions and framework for assessing oil recovery efficiency (ORE) starting from the field until the mill.

Cook, S., C.H. Lim, S.N. Mohanaraj, Y.M.S. Samosir, C. Donough, T. Oberthür, Y.L. Lim, J. Cock and S.P. Kam. 2014.
Palm oil at the crossroads: the role of Plantation Intelligence to support change, profit and sustainability.
The Planter, Vol 90, page 563-575.
Abstract: This paper describes a process of Plantation Intelligence^® – the generation and use of analysis of commercial data held by oil palm companies. Plantation Intelligence^® consists of a series of insights, developed with partners, which describe the status and trends of key performance indicators. Analysis also describes the productivity of key inputs such as fertilizer and labor. Such insights can be used to guide decisions and to avoid some of the common biases that managers make, especially when under pressure. It is anticipated that Plantation Intelligence^® will provide greatest value to companies who recognize the need for change and who are able to embed the process in 'normal' management.

Donough, C.R., A. Cahyo, T. Oberthür, R. Wandri, J. Gerendas and G. Abdul Rahim. 2014.
Improving nutrient management of oil palms on sandy soils in Kalimantan using the 4R concept of IPNI.
Poster presentation at the International Oil Palm Conference (IOPC): Green Palm Oil for Food Security and Renewable Energy, Bali, Indonesia, 17-19 June 2014.
Abstract: As oil palm cultivation expands into increasingly marginal areas in Kalimantan, with very sandy soils, some coupled with unevenly distributed rainfall, proper nutrient management becomes even more important for oil palm productivity and economic viability of the plantations. On such sandy soils, leaching loss of nutrients is expected to be higher especially during high rainfall periods. Based on the 4R concept of nutrient management (IPNI, 2012), efficiency of applied fertilizers on such soils can be improved by higher application frequency. To test this hypothesis, a project was started in October 2011 at PT Sungai Rangit by IPNI SEAP, PT Sampoerna Agro and K+S Kali GmbH. In the project, blending of individual fertilizers prior to field application allows four rounds each of N, P, K, and Mg per year in the improved practice treatment (referred to as nutrition best management practice, NBMP), compared to the control treatment where the fertilizers are applied individually according to standard estate practice (SEP). Two rates of application viz. full and reduced (approx. 20% lower) are tested as well, giving a total of four treatment combinations. In each treatment block, two plots are embedded, one receiving the same fertilizers as the rest of the block, the other left unfertilized.
Gerendas et. al. (2013), reporting on the application frequency effect after the first year, showed that the fertilizer recovery efficiency (FRE) with the NBMP was 10% and 18% higher for N and K, respectively. However in the second year of the project, overall yield was reduced in all treatments in line with a general regional yield decline and only N showed a better FRE with NBMP. With respect to the application rate effect todate, there has not been an apparent yield 'penalty' with the reduced rate either with NBMP or SEP, and FRE has generally been higher, as expected, with the reduced rate. Given the yield decline in the second year that was unrelated to the current treatments, and with two more years to run in the project, it would be premature to make conclusions now on either application frequency or application rate.
Initial results for nutrient content in FFB from oil palms grown in this environment showed much lower values compared to earlier reports from North Sumatra, suggesting that nutrient removal values may be influenced by local conditions. This information is important for the profitability of plantations and for sustainable intensification of oil palm production in similar conditions elsewhere.

Donough, C.R., S.N. Mohanaraj, Rahmadsyah and T. Oberthür. 2014.
Growth of oil palm seedlings influenced by nursery practices in Malaysia and Indonesia.
Poster presented at the International Oil Palm Conference (IOPC): Green Palm Oil for Food Security and Renewable Energy, Bali, Indonesia, 17-19 June 2014.
Abstract: In 2011, the International Plant Nutrition Institute's Southeast Asia Program (IPNI SEAP) initiated a project called 'BMP All Stages' with plantation partners in Sabah, Malaysia, and South Sumatra, Indonesia, to assess the impact on future oil palm yield of best management practices (BMPs) during the nursery, immature, and mature stages of the oil palm production cycle. At each stage, BMPs are compared to the current standard estate practices (SEPs ) of IPNI SEAP's project partners. At each location, planting materials are produced in oil palm nurseries to plant five sets of commercial-scale blocks (20 ha per block minimum area) of oil palm. Each block will be monitored, initially for growth and subsequently for yield, until the completion of at least four years of crop production. At both locations, several rounds of the nursery stage have now been completed. Initial results from the nursery stage are presented here, as part of the ongoing evaluation.
In Sabah, the following SEPs differed from the BMPs prescribed by IPNI SEAP:
-- Plastic pot trays, instead of conventional polybags, were used in the pre-nursery;
-- Organic material and mycorrhizal fungi inoculum were added to the pre- and main nursery potting medium;
-- Organic-based fertilizers were included in the pre- and main nursery fertilization programs; and
-- Drip irrigation was used in the main nursery.
In South Sumatra, the SEPs were very similar to IPNI SEAP's prescribed BMPs except for fertilization, where:
-- The SEP provided ca. 60% more nutrients from a higher number of applications in the pre-nursery; while
-- In the main nursery, the difference was not as large, and varied for individual nutrients, with a key difference being the P fertilizer source, with ca. 60% water-soluble form supplied to the BMP seedlings.
Results todate show that at the end of the nursery stage, i.e. when seedlings were ready for field planting, growth was better with BMP in South Sumatra but the opposite was true in Sabah. If this is confirmed when all the remaining nursery rounds are completed, revisions may be justifiable to current industry standard nursery practices.

Dutta, S., K. Majumdar, V. Shahi, A. Kumar, V. Kumar, N. Gupta, T. Satyanarayana, M.L. Jat, M.F. Pampolino, A.M. Johnston. 2014.
Nutrient Expert® - Wheat: A tool for increasing crop yields and farm profit.
Better Crops – South Asia 8:11-13.
Abstract: The Nutrient Expert®–Wheat fertiliser decision support tool-based fertiliser recommendation was compared with existing fertiliser management practices in 109 on-farm sites in Punjab, Haryana and Bihar. The tool addressed the spatial and temporal variability in soil nutrient supply as well as the difference in tillage. The tool-based recommendation also improved yield and profitability over farmers’ fertilisation practices and State recommended fertiliser rates for wheat.

Fairhurst, T. and W. Griffiths. 2014.
Oil palm: Best management practices for yield intensification.
International Plant Nutrition Institute, Penang, Malaysia.

Hoffmann, M. 2014.
Understanding potential yield in the context of the climate and resource constraint to sustainably intensify cropping systems in tropical and temperate regions.
PhD dissertation for University of Göttingen.

Hoffmann, M.P., A. Castaneda Vera, M.T. van Wijk, K.E. Giller, T. Oberthür, C. Donough and A.M. Whitbread. 2014.
Simulating potential growth and yield of oil palm (Elaeis guineensis) with PALMSIM: Model description, evaluation and application.
Agricultural Systems, Vol 131, page 1-10.
Abstract: Reducing the gap between water-limited potential yield and actual yield in oil palm production systems through intensification is seen as an important option for sustainably increasing palm oil production. Simulation models can play an important role in quantifying water-limited potential yield, and therefore the scope for intensification, but no oil palm model exists that is both simple enough and at the same time incorporates sufficient plant physiological knowledge to be generally applicable across sites with different growing conditions. The objectives of this study therefore were to develop a model (PALMSIM) that simulates, on a monthly time step, the potential growth of oil palm as determined by solar radiation and to evaluate model performance against measured oil palm yields under optimal water and nutrient management for a range of sites across Indonesia and Malaysia. The maximum observed yield in the field matches the corresponding simulated yield for dry bunch weight with a RMSE of 1.7 Mg/ha/year against an observed yield of 18.8 Mg/ha. Sensitivity analysis showed that PALMSIM is robust: simulated changes in yield caused by modifying the parameters by 10% are comparable to other tree crop model evaluations. While we acknowledge that, depending on the soils and climatic environment, yields may be often water limited, we suggest a relatively simple physiological approach to simulate potential yield, which can be usefully applied to high rainfall environments and is considered as a first step in developing an oil palm model that also simulates water-limited potential yield. To illustrate the application possibilities of the model, PALMSIM was used to create a potential yield map for Indonesia and Malaysia by simulating the growth and yield at a resolution of 0.1. This map of potential yield is considered as a first step towards a decision support tool that can identify potentially productive, but at the moment degraded sites in Indonesia and Malaysia.

Hoffmann, M.P., A. Castaneda Vera, M.T. van Wijk, K.E. Giller, T. Oberthür, C. Donough, A.M. Whitbread and J.M. Fisher. 2014.
Simulating potential growth and yield of oil palm with PALMSIM.
Better Crops with Plant Food 98(4):25-26.
Abstract: The growing demand for palm oil can be met by reducing the gap between potential yield and actual yield. Simulation models can quantify potential yield, and therefore indicate the scope for intensification. A relatively simple physiological approach was used to develop PALMSIM, which is a model that simulates, on a monthly time step, the potential growth of oil palm as determined by solar radiation in high rainfall environments. The model was used to map potential yield for Indonesia and Malaysia. This map could be used to identify degraded areas that have high yield potential for oil palm.

IPNI. 2014.
Planters' Diary 2014.
International Plant Nutrition Institute, Penang, Malaysia.

IPNI. 2014.
Project Specifics Booklet – An introduction on IPNI cocoa care project for sustainable intensification.
International Plant Nutrition Institute, Penang, Malaysia

IPNI. 2014.
Project Specifics Booklet – An introduction of IPNI Plantation Intelligence incorporating Estate-Scale-Experimentation.
International Plant Nutrition Institute, Penang, Malaysia

Majumdar, K., T. Satyanarayana, S. Dutta, M.F. Pampolino, M.L. Jat, V. Sahi, W. Iftikar, V. Govil, V.K. Singh. 2014.
On-farm performance of Nutrient Expert® for Maize: fertilizer recommendation, yield, and nutrient use efficiency.
Better Crops – South Asia 8: 24-26.
Abstract: On-farm trials over 500 sites across six maize growing states in India compared the Nutrient Expert® decision support tool-based fertiliser recommendation system against farmers’ fertilisation practices and state recommended practices. Results showed significant yield improvement with higher nutrient use efficiency and savings of fertiliser through the tool-based recommendation.

Pampolino, M.F., C. Witt, J.M. Pasuquin, A.M. Johnston, M.J. Fisher. 2014.
Development and evaluation of Nutrient Expert® decision support tool for cereal crops.
Better Crops – South Asia 8: 4-6.
Abstract: Nutrient Expert® (NE) is a computer-based decision support tool that uses the principles of site-specific nutrient management for developing fertiliser recommendations tailored to a specific field or growing environment. Results of field evaluation have shown that NE is effective in providing recommendations that can increase yields and profits compared with farmers’ current practices. NE accounts for the important factors affecting site-specific recommendations, which makes it an excellent tool for providing tactical information to crop advisors and farmers as well as strategic information to highlevel decision makers. NE is also a suitable starting point for developing nutrient management tools to reach more users.

Pasuquin, J.M., M.F. Pampolino, C. Witt, A. Dobermann, T. Oberthür, M.J. Fisher and K. Inubushi. 2014.
Closing yield gaps in maize production in Southeast Asia through site-specific nutrient management.
Field Crops Research, Vol 156, page 219-230.
Abstract: Rising incomes and changing dietary requirements are swiftly transforming maize (Zea mays L.) in South- east Asia from a food staple into an important industrial commodity. Increased maize production is required to meet rising demands, but additional production should come from the sustainable intensification of existing farmlands to minimize the undesirable effects of agriculture on the environment. We hypothesize that maize yields, profit, and N use efficiencies can be significantly increased through site- specific nutrient management (SSNM), thereby reducing yield gaps in the region. Through a combined approach of simulation modeling and on-farm research in at least 65 sites in 13 major maize-producing domains across Indonesia, Vietnam and the Philippines from 2004 to 2008, we were able to (a) quantify maize yield gaps and yield responses to fertilizer application, (b) evaluate the agronomic and economic performance of SSNM, and (c) evaluate the incremental profitability of SSNM in various production and grain and fertilizer price scenarios. The average exploitable yield gap between the attainable yield and current farmers' yield in Southeast Asia was about 0.9 t/ha. Yield responses to fertilizer application across the region followed the order N > P > K. Yield response to N was higher in irrigated sites than in rainfed sites (6 t/ha versus 2 t/ha), while P and K fertilizer responses were similar across production systems (<2 t/ha). Yield with SSNM was 1.0 t/ha (+13%) higher than the current farmers' fertilizer practice (FFP) measured in the same cropping seasons. Yield increases were associated with a 10% decrease in the average N rate, but with increased application of K at sites where the previous K rates were low. Average N use efficiency increased by 42%, mainly by adjusting the rates and timing of N application to the stages of crop development. Across all sites and seasons, profitability increased by US$167/ha per crop, which was equivalent to 15% of the total average net return. Opportunities for achieving higher income over the FFP (US$100/ha season) were greatest in highly favorable rainfed environments; less favorable rainfed areas were vulnerable to unfavorable market prices. We conclude that SSNM has the potential to close existing yield gaps in the maize.

Pasuquin, J.M., J. Cock, C.R. Donough, T. Oberthür, Rahmadsyah, A. Lubis, G. Abdurrohim, K. Indrasuara, T. Dolong and S. Cook. 2014.
Leaf nutrient analysis as a management tool in yield intensification of oil palm.
Better Crops with Plant Food, Vol 98, Issue 1, page 19-21.
Abstract: In the BMP trials established in six commercial plantations in Indonesia, the improved nutritional regimes had no consistent effect on leaf nutrient concentrations, and there were no obvious relationships between leaf nutrient status and yield. The authors suggest that Plantation Intelligence^®, based on the observation and analysis of farm operations (operational research) and on-farm experimentation principles with data from commercial operations, can be used to adjust critical nutrient levels to fit the particular conditions of commercial blocks.

Pauli, N., C. Donough, T. Oberthür, J. Cock, R. Verdooren, Rahmadsyah, G. Abdurrohim, K. Indrasuara, A. Lubis, T. Dolong and J.M. Pasuquin. 2014.
Changes in soil quality indicators under oil palm plantations following application of 'best management practices' in a four-year field trial.
Agriculture, Ecosystems & Environment, Vol 195, page 98-111.
Abstract: Increasing the yield of existing oil palm plantations is one means of accommodating some of the growing demand for palm oil. The International Plant Nutrition Institute (IPNI) has developed and tested a process to deploy a series of 'best management practices' (BMPs) that cover a range of agronomic practices intended to intensify oil palm production and improve yield at a given site using cost-effective, practical methods. Many of these BMPs include techniques that should also improve soil quality, such as the addition of organic matter to the soil surface, and improved timing and tailored application of mineral and organic fertilizers. Six plantations in Kalimantan and Sumatra applied BMPs prescribed by IPNI (BMP treatment), and standard management practices (REF treatment) in paired blocks of oil palm over four years; 30 pairs of blocks were included in the research. Soils were sampled in both treatments before and after the field trial, from beneath weeded circles surrounding individual palms and beneath frond piles in between rows of palms, at 0-20 cm depth and 20-40 cm depth. Soils were tested for a range of properties, including soil pH, % soil organic carbon (% SOC), total N, available P, and exchangeable cations. No clear, consistent differences were found in the degree of change in soil properties between BMP and REF treatments over four years. However, improvements in some soil properties were noted for both treatments, particularly for soil pH and % SOC. There was no significant deterioration in the measured soil properties over the four years. The results suggest that appropriate management practices for oil palm can improve several aspects of soil quality. Further research on the mechanisms by which BMPs can improve soil quality, and monitoring over longer periods of time is recommended to give plantation managers a clearer picture of the potential 'co-benefits' that can be obtained with adoption of BMPs designed to increase oil palm yield.

Rhebergen, T., M. Hoffmann, S. Zingore, T. Oberthür, K. Acheampong, G. Dwumfour, V. Zutah, C. Adu-Frimpong, F. Ohipeni and T. Fairhurst. 2014.
The effects of climate, soil and oil palm management practices on yield in Ghana.
Oral presentation at the International Oil Palm Conference (IOPC): Green Palm Oil for Food Security and Renewable Energy, Bali, Indonesia, 17-19 June 2014.
Abstract: The demand for palm oil and derived products in Ghana is presently outstripping supply, and fruit bunch yields are decreasing. Yield gaps in oil palm smallholdings and plantations in Ghana are explained by sub-optimal climate conditions, soil fertility constraints, and field management. In 2012, the International Plant Nutrition Institute and Solidaridad West Africa initiated an seven year project, to implement 'Best Management Practices (BMP)' to improve productivity in three oil palm plantations and 20 smallholder farms. In order to assess entry points for increasing productivity in existing oil palm plantings, a simple model is used to partition yield gaps between different causes. Differences in yield between fields under BMP and standard plantation and smallholder practices provide an indication of the scope for yield improvement. Estimates of yield potential (Yp) and water-limited yield (Yw) were obtained using PalmSim, an oil palm growth and yield model and also used to estimate yield gaps. With the PalmSim model, simulated Yp and Yw in BMP sites ranged from 38-45 and 21-32 t FFB/ha respectively. The average difference between the simulated Yp and Yw across all sites was 15.0 t/ha , indicating a large yield gap explained solely by water stress. The average yield in plantations after 12 months of BMP implementation was 12.8 t/ha compared with 11.6 t/ha for control plots (REF) (+1.2 t/ha, +10%), and for smallholder farmers, average BMP yields were 10.9 t/ha, compared with 8.4 t/ha in REF fields (+2.5 t/ha, +30%). The short-term yield response with BMP can be explained by shorter harvest intervals and complete crop recovery after the installation of proper access in BMP fields. Yield gaps were larger in smallholder farms at 12.6 t/ha, compared with 6.4 t/ha in plantations. There is a large potential to increase yields in smallholder farms simply by improving crop recovery with the installation of proper infield access and tight control of harvest intervals. Field trials will continue until 2018, by which time we expect all fields under BMP will have reached maximum attainable yield. To meet the projected oil demand in Ghana and to avoid palm oil imports, yield intensification is required in existing plantings because there is limited land available for further expansion that meets the requirements for sustainable palm oil production.

Sapkota, T.B., K. Majumdar, M.L. Jat, A. Kumar, D.K. Bishnoi, A.J. McDonald and M. Pampolino. 2014.
Precision nutrient management in conversion agriculture based wheat production of Northwest India: Profitability, nutrient use efficiency and environmental footprint.
Field Crops Research, Vol 155, page 233-244.
Abstract: In the high-yielding wheat production systems in Northwest (NW) Indo-Gangetic Plains of India, intensive tillage operations and blanket fertilizer recommendations have led to high production costs, decreased nutrient use efficiency, lower profits and significant environmental externalities. No-tillage (NT) has been increasingly adopted in this region to reduce costs and increase input use efficiency. But, optimal nutrient management practices for NT based wheat production are still poorly understood. Opportunities exist to further enhance the yield, profitability, and resource use efficiency of NT wheat through site-specific nutrient management (SSNM).
On-farm trials were conducted in seven districts of Haryana, India for two consecutive years (2010-11 and 2011-12) to evaluate three different approaches to SSNM based on recommendations from the Nutrient Expert^® (NE) decision support system in NT and conventional tillage (CT) based wheat production systems. Performance of NE based recommendations was evaluated against current state recommen- dations and farmers' practices for nutrient management. Three SSNM treatments based on NE based recommendation were (1) 'NE80:20' with 80% N applied at planting and 20% at second irrigation (2) 'NE33:33:33' with N split as 33% basal, 33% at Crown Root Initiation (CRI) and 33% at second irrigation; and (3) 'NE80:GS' with N split as 80% basal and further application of N based on optical sensor (Green Seeker^TM )-guided recommendations. Yield, nutrient use efficiency and economic profitability were deter- mined following standard agronomic and economic measurements and calculations. Cool Farm Tool (CFT), an empirical model to estimate greenhouse gases (GHGs) from agriculture production, was used to estimate GHG emissions under different treatments.
Wheat grain and biomass yield were higher under NT in 2010-11 but no difference was observed in 2011-12. The three NE-based nutrient management strategies increased yield, nutrient use efficiency as well as net return as compared to state recommendation and farmers' fertilization practice. Global warming potential (GWP) of wheat production was also lower with NT system as compared to CT system and NE-based nutrient managements as compared to farmers' fertilization practice. State recommended nutrient management had similar GWP as NE-based nutrient managements except NE80:GS in which GWP was the lowest. Results suggest that no-tillage system along with site-specific approaches for nutrient management can increase yield, nutrient use efficiency and profitability while decreasing GHG from wheat production in NW India.

Satyanarayana, T., K. Majumdar, S. Dutta, M.L. Jat, S.K. Pattanayak, D.P. Biradar, Y.R. Aladakatti, M.F. Pampolino, A.M. Johnston. 2014.
Nutrient Expert® - Maize: A tool for increasing crop yields and farm profit.
Better Crops – South Asia 8: 7-10.
Abstract: Nutrient Expert®-based fertiliser recommendations were validated and demonstrated across 191 major maize growing locations in southern India and Odisha showed an overall increase in yield by 1.1 t/ha over the current farmer fertiliser practice. It also helped in improving the profitability of maize farmers in the region. Nutrient Expert®, which follows the principles of the 4R Nutrient Stewardship approach, proved to be a boon to smallholder farmers in the region.

Xu, X., P. He, M.F. Pampolino, A.M. Johnston, S. Qiu, S. Zhao, L. Chuan, W. Zhou. 2014.
Fertilizer recommendation for maize in China based on yield response and agronomic efficiency.
Field Crops Research 157:27-34.
Abstract: A generic but flexible and location-specific fertilizer recommendation method is necessary due to inappropriate fertilization in China. A new fertilizer recommendation method, Nutrient Expert® (NE) for Hybrid Maize, was developed using maize datasets from 2000 to 2010 in main maize production areas. The results showed that the average of indigenous nutrient supply were 130, 41 and 124 kg/ha, the mean of yield response were 2.1, 1.2, and 1.2 t/ha, and the average agronomic efficiency were 11.4, 15.7, and 11.8 kg/kg for N, P, and K, respectively. There was a significantly negative exponential relationship between yield response and indigenous nutrient supply, and a significant negative linear relationship between yield response and relative yield. Analysis also indicated that the quadratic curve relation was obvious between yield response and agronomic efficiency. NE system was established based on yield response and agronomic efficiency (AE) through above analysis, and on-farm field experiments were conducted in 408 farmers’ fields to validate this system at seven provinces in China. The results showed that fertilizer recommendation based on NE method could maintain grain yield and profitability and improve nutrient use efficiency through 4R nutrient stewardship and it is proved to be a promising approach for fertilizer recommendation when soil testing is not timely or not available.

Xu, X.P., P. He, S.J. Qiu, M.F. Pampolino, A.M. Johnston, S.C. Zhao, L.M. Chuan, W. Zhou. 2014.
Estimating a new approach of fertilizer recommendation across small-holder farms in China.
Field Crops Research, 2014, 163:10-17.
Abstract: Over and imbalanced fertilization has caused a series of environmental problems and threaten the food security in China. On-farm experiments were conducted from 2010 to 2012 at 408 sites in seven provinces to evaluate a new fertilizer recommendation approach, Nutrient Expert® (NE) for Hybrid Maize (Zea mays L.), to meet the requirements of nutrient management for small-holder farms in China. Compared with the current farmers’ fertilizer practices (FP), NE maintained grain yield and profitability, but decreased 30.4% of nitrogen (N) fertilizer (68 kg N ha⁻¹) and 11.3% of phosphorus (P) fertilizer (7 kg P₂O₅ ha⁻¹), while potassium (K) fertilizer rate increased by 38.8% (19 kg K₂O ha⁻¹). NE increased agronomic efficiency of applied N (AE_N) by 47.0%, N recovery efficiency (RE_N) by 51.0%, and partial factor productivity of applied N (PFP_N) by 35.5%. More importantly, NE decreased by 21.5 and 49.7 kg ha⁻¹ of apparent N loss for summer maize and spring maize as compared with FP, respectively. The differences in agronomic and environmental parameters between NE and FP confirmed that the Nutrient Expert for Hybrid Maize is a promising nutrient decision support tool which not only increasing grain yield, nutrient use efficiency and profit, but also reducing nutrient loss and environmental pollution.