Challenges and opportunities for improving N use efficiency for rice production in sub-Saharan Africa

ABSTRACT In sub-Saharan Africa (SSA), rice production from smallholder farms is challenged because of a lack of fertilizer inputs and nutrient-poor soils. Therefore, improving nutrient efficiency is particularly important for increasing both fertilizer use and rice yield. This review discusses how to improve the return from fertilizer input in terms of agronomic N use efficiency (AEN), that is, the increase in grain yield per kg of applied N, for rice production in SSA. The AEN values we summarized here revealed large spatial variations even within small areas and a certain gap between researcher-led trials and smallholder-managed farms. Experimental results suggest AEN can be improved by addressing spatial variations in soil-related factors such as P, S, Zn, and Si deficiencies and Fe toxicity in both irrigated and rainfed production systems. In rainfed production systems, differences in small-scale topography are also important which affects AEN through dynamic changes in hydrology and variations in the contents of soil organic carbon and clay. Although empirical evidence is further needed regarding the relationship between soil properties and responses to fertilizer inputs, recent agricultural advances have generated opportunities for integrating these micro-topographical and soil-related variables into field-specific fertilizer management. These opportunities include UAV (unmanned aerial vehicle) technology to capture microtopography at low cost, database on soil nutrient characteristics at high resolution and more numbers of fertilizer blending facilities across SSA, and interactive decision support tools by use of smartphones on site. Small-dose nursery fertilization can be also alternative approach for improving AEN in adverse field conditions in SSA. ABBREVIATIONS: AEN: agronomic nitrogen use efficiency; FISP: farm input subsidy program; VCR: value cost ratio; SOC: soil organic carbon; SSA: sub-Saharan Africa; UAV: unmanned aerial vehicle Graphical Abstract

[1]  M. Wopereis,et al.  Yield-limiting macronutrients for rice in sub-Saharan Africa , 2019, Geoderma.

[2]  Hidetoshi Asai,et al.  Laboratory Visible and Near-Infrared Spectroscopy with Genetic Algorithm-Based Partial Least Squares Regression for Assessing the Soil Phosphorus Content of Upland and Lowland Rice Fields in Madagascar , 2019, Remote. Sens..

[3]  T. Razafimbelo,et al.  Phosphorus uptake of rice plants is affected by phosphorus forms and physicochemical properties of tropical weathered soils , 2018, Plant and Soil.

[4]  W. Dogbe,et al.  Spatial Variation in Surface Soil Total Carbon and Its Relationship with Soil Color in a River Floodplain Ecosystem of Northern Ghana , 2018, Japan Agricultural Research Quarterly: JARQ.

[5]  Kazuki Saito,et al.  Phosphorus micro-dosing as an entry point to sustainable intensification of rice systems in sub-Saharan Africa , 2018, Field Crops Research.

[6]  T. Toojinda,et al.  Functional roles of root plasticity and its contribution to water uptake and dry matter production of CSSLs with the genetic background of KDML105 under soil moisture fluctuation , 2018 .

[7]  P. V. van Oort,et al.  Mapping abiotic stresses for rice in Africa: Drought, cold, iron toxicity, salinity and sodicity , 2018, Field crops research.

[8]  Koffi Djaman,et al.  Managing Fertilizer Recommendations in Rice-Based Cropping Systems Challenges and Strategic Approaches , 2018 .

[9]  D. Makihara,et al.  Root plasticity under fluctuating soil moisture stress exhibited by backcross inbred line of a rice variety, Nipponbare carrying introgressed segments from KDML105 and detection of the associated QTLs , 2018 .

[10]  F. Ewert,et al.  Yield variation of rainfed rice as affected by field water availability and N fertilizer use in central Benin , 2018, Nutrient Cycling in Agroecosystems.

[11]  J. Gweyi-Onyango,et al.  Grain yield responses of lowland rice varieties to increased amount of nitrogen fertilizer under tropical highland conditions in central Kenya , 2018 .

[12]  W. Burke,et al.  Review: Taking stock of Africa’s second-generation agricultural input subsidy programs , 2018 .

[13]  S. Zwart,et al.  Impacts of climate change on rice production in Africa and causes of simulated yield changes , 2017, Global change biology.

[14]  L. Verchot,et al.  Global Sequestration Potential of Increased Organic Carbon in Cropland Soils , 2017, Scientific Reports.

[15]  Hidetoshi Asai,et al.  Vis-NIR Spectroscopy and PLS Regression with Waveband Selection for Estimating the Total C and N of Paddy Soils in Madagascar , 2017, Remote. Sens..

[16]  Y. Fujihara,et al.  The effect of sulfur fertilization on rice yields and nitrogen use efficiency in a floodplain ecosystem of northern Ghana , 2017 .

[17]  E. Fegraus,et al.  Soil nutrient maps of Sub-Saharan Africa: assessment of soil nutrient content at 250 m spatial resolution using machine learning , 2017, Nutrient Cycling in Agroecosystems.

[18]  Kazuki Saito,et al.  Variability and determinants of yields in rice production systems of West Africa , 2017 .

[19]  L. Herrera-Estrella,et al.  Improving phosphorus use efficiency: a complex trait with emerging opportunities. , 2017, The Plant journal : for cell and molecular biology.

[20]  Jica,et al.  Yield gap analysis towards meeting future rice demand , 2017 .

[21]  Kazuki Saito,et al.  On-farm rice yield and its association with biophysical factors in sub-Saharan Africa , 2017 .

[22]  Ken E. Giller,et al.  Agronomic biofortification of crops to fight hidden hunger in sub-Saharan Africa , 2017 .

[23]  Y. Uga,et al.  Association between root growth angle and root length density of a near-isogenic line of IR64 rice with DEEPER ROOTING 1 under different levels of soil compaction , 2017 .

[24]  Michael Thiel,et al.  High Resolution Mapping of Soil Properties Using Remote Sensing Variables in South-Western Burkina Faso: A Comparison of Machine Learning and Multiple Linear Regression Models , 2017, PloS one.

[25]  Céline Nauges,et al.  Returns to fertilizer use: does it pay enough? Some new evidence from Sub-Saharan Africa , 2016 .

[26]  M. Wissuwa,et al.  From promise to application: root traits for enhanced nutrient capture in rice breeding. , 2016, Journal of experimental botany.

[27]  Kazuki Saito,et al.  Strategic phosphorus (P) application to the nursery bed increases seedling growth and yield of transplanted rice at low P supply , 2016 .

[28]  E. Davidson,et al.  Managing nitrogen for sustainable development , 2015, Nature.

[29]  R. Bell,et al.  Nursery Fertilizer Application Increases Rice Growth and Yield in Rainfed Lowlands with or without Post-Transplanting Crop Stress , 2015 .

[30]  Keith D. Shepherd,et al.  Mid‐Infrared and Total X‐Ray Fluorescence Spectroscopy Complementarity for Assessment of Soil Properties , 2015 .

[31]  Kazuki Saito,et al.  On-farm testing of a nutrient management decision-support tool for rice in the Senegal River valley , 2015, Comput. Electron. Agric..

[32]  M. Wopereis,et al.  Rice yield growth analysis for 24 African countries over 1960–2012 , 2015 .

[33]  K. Cassman,et al.  Assessment of rice self-sufficiency in 2025 in eight African countries , 2015 .

[34]  Kazuki Saito,et al.  Causes of yield stagnation in irrigated lowland rice systems in the Senegal River Valley: Application of dichotomous decision tree analysis , 2015 .

[35]  M. Rose,et al.  Unmasking Novel Loci for Internal Phosphorus Utilization Efficiency in Rice Germplasm through Genome-Wide Association Analysis , 2015, PloS one.

[36]  S. K. Sarangi,et al.  Improved nursery management further enhances the productivity of stress-tolerant rice varieties in coastal rainfed lowlands , 2015 .

[37]  Alexander J. Stein,et al.  Zinc-enriched fertilisers as a potential public health intervention in Africa , 2015, Plant and Soil.

[38]  Pedro A Sanchez,et al.  En route to plentiful food production in Africa , 2015, Nature Plants.

[39]  R. Hijmans,et al.  Soil quality and constraints in global rice production , 2014 .

[40]  J. Rodenburg,et al.  Narrowing the rice yield gap in East and Southern Africa: Using and adapting existing technologies , 2014 .

[41]  J. Yanai,et al.  Soil color analysis for statistically estimating total carbon, total nitrogen and active iron contents in Japanese agricultural soils , 2014 .

[42]  Sudhanshu Singh,et al.  Improved Management Options for Submergence-Tolerant (Sub1) Rice Genotype in Flood-Prone Rainfed Lowlands of West Bengal , 2014 .

[43]  T. Jayne,et al.  How do fertilizer subsidy programs affect total fertilizer use in sub‐Saharan Africa? Crowding out, diversion, and benefit/cost assessments , 2013 .

[44]  T. Hatta,et al.  Topographic distribution of the soil total carbon content and sulfur deficiency for rice cultivation in a floodplain ecosystem of the Northern region of Ghana , 2013 .

[45]  M. Yano,et al.  Control of root system architecture by DEEPER ROOTING 1 increases rice yield under drought conditions , 2013, Nature Genetics.

[46]  T. Gaiser,et al.  Spatial and temporal variation in yield of rainfed lowland rice in inland valley as affected by fertilizer application and bunding in North-West Benin , 2013 .

[47]  K. Habtegebrial,et al.  Nitrogen and sulphur fertilizers effects on yield, nitrogen uptake and nitrogen use efficiency of upland rice variety on irrigated Fulvisols of the Afar region, Ethiopia , 2013 .

[48]  David R. Lee,et al.  Explaining the African food riots of 2007–2008: An empirical analysis , 2013 .

[49]  K. Giller,et al.  When yield gaps are poverty traps: The paradigm of ecological intensification in African smallholder agriculture , 2013 .

[50]  P. Pesaresi,et al.  The protein kinase Pstol1 from traditional rice confers tolerance of phosphorus deficiency , 2012, Nature.

[51]  T. Jayne,et al.  Do Fertilizer Subsidies Boost Staple Crop Production and Reduce Poverty Across the Distribution of Smallholders in Africa? Quantile Regression Results from Malawi. , 2012 .

[52]  M. Yano,et al.  Identification of qSOR1, a major rice QTL involved in soil-surface rooting in paddy fields , 2011, Theoretical and Applied Genetics.

[53]  N. Uphoff,et al.  Rice yield and its relation to root growth and nutrient-use efficiency under SRI and conventional cultivation: an evaluation in Madagascar , 2011, Paddy and Water Environment.

[54]  A. Dorward,et al.  The Malawi agricultural input subsidy programme: 2005/06 to 2008/09 , 2011 .

[55]  A. Diagne,et al.  The Possibility of a Rice Green Revolution in Large-Scale Irrigation Schemes in Sub-Saharan Africa , 2011 .

[56]  J. Six,et al.  Agronomic use efficiency of N fertilizer in maize-based systems in sub-Saharan Africa within the context of integrated soil fertility management , 2011, Plant and Soil.

[57]  M. Yano,et al.  Fine-mapping of qRL6.1, a major QTL for root length of rice seedlings grown under a wide range of NH4+ concentrations in hydroponic conditions , 2010, Theoretical and Applied Genetics.

[58]  K. Homma,et al.  The effects of soil drying and rewetting on rice growth in lowland aquatic Ferralsols in the southeastern forest region of Madagascar , 2010, Plant and Soil.

[59]  D. Kossou,et al.  Response of lowland rice to agronomic management under different hydrological regimes in an inland valley of Ivory Coast , 2009 .

[60]  C. Barrett,et al.  Soil quality and fertilizer use rates among smallholder farmers in western Kenya , 2009 .

[61]  J. Black,et al.  Factors Influencing the Profitability of Fertilizer Use on Maize in Zambia , 2009 .

[62]  K. Homma,et al.  Soil management: The key factors for higher productivity in the fields utilizing the system of rice intensification (SRI) in the central highland of Madagascar , 2009 .

[63]  A. Audebert,et al.  Rice Yield Gap due to Iron Toxicity in West Africa , 2009 .

[64]  A. Gulati,et al.  Investment, subsidies, and pro‐poor growth in rural India , 2008 .

[65]  K. Giller,et al.  Soil type, management history and current resource allocation: Three dimensions regulating variability in crop productivity on African smallholder farms , 2007 .

[66]  Kazuki Saito,et al.  Farmers' knowledge of soils in relation to cropping practices: A case study of farmers in upland rice based slash-and-burn systems of northern Laos , 2006 .

[67]  A. Ismail,et al.  Seedling Nutrient Status before Submergence Affects Survival after Submergence in Rice , 2006 .

[68]  C. Barrett,et al.  Productivity in Malagasy rice systems: Wealth-differentiated constraints and priorities , 2006 .

[69]  Keijiro Otsuka,et al.  RICE GREEN REVOLUTION IN ASIA AND ITS TRANSFERABILITY TO AFRICA: AN INTRODUCTION , 2006 .

[70]  M. Wopereis,et al.  Mineral fertilizer management of maize on farmer fields differing in organic inputs in the West African savanna , 2006 .

[71]  A. Mochizuki,et al.  Increased productivity of rainfed lowland rice by incorporation of pond sediments in Northeast Thailand , 2006 .

[72]  M. C. S. Wopereis,et al.  Combining Field and Simulation Studies to Improve Fertilizer Recommendations for Irrigated Rice in Burkina Faso , 2005 .

[73]  M. C. S. Wopereis,et al.  Spatial variability of indigenous supplies for N, P and K and its impact on fertilizer strategies for irrigated rice in West Africa , 2005, Plant and Soil.

[74]  R. Weil,et al.  Significance of Soil Organic Matter to Soil Quality and Health , 2004 .

[75]  Stephan M. Haefele,et al.  A framework to improve fertilizer recommendations for irrigated rice in West Africa , 2003 .

[76]  M. Wopereis,et al.  Rice yield gaps in irrigated systems along an agro‐ecological gradient in West Africa , 2003 .

[77]  M. Jackson,et al.  Physiological and molecular basis of susceptibility and tolerance of rice plants to complete submergence. , 2003, Annals of botany.

[78]  H. J. Enserink,et al.  EVALUATION OF ON-FARM SOIL FERTILITY RESEARCH IN THE RAINFED LOWLAND RICE FIELDS OF SUKUMALAND, TANZANIA , 2003, Experimental Agriculture.

[79]  Stephan M. Haefele,et al.  Improving the productivity and profitability of irrigated rice production in Mauritania , 2001 .

[80]  D. Johnson,et al.  Improved water control and crop management effects on lowland rice productivity in West Africa , 2001, Nutrient Cycling in Agroecosystems.

[81]  M. C. S. Wopereis,et al.  Soil fertility management in irrigated rice systems in the Sahel and Savanna regions of West Africa: Part I. Agronomic analysis , 1999 .

[82]  M. D. Reddy,et al.  Yield performance of rainfed lowland rice as affected by nursery fertilization under conditions of intermediate deepwater (15–50 cm) and flash floods , 1991, Plant and Soil.

[83]  A. Bationo,et al.  Improving the Profitability, Sustainability and Efficiency of Nutrients Through Site Specific Fertilizer Recommendations in West Africa Agro-Ecosystems , 2018, Springer International Publishing.

[84]  K. Kajisa.  On the Determinants of Low Productivity of Rice Farming in Mozambique: Pathways to Intensification , 2016 .

[85]  H. Asai,et al.  Limited Si-nutrient status of rice plants in relation to plant-available Si of soils, nitrogen fertilizer application, and rice-growing environments across Sub-Saharan Africa , 2014 .

[86]  Jeanne Y. Coulibaly,et al.  Africa's rice economy before and after the 2008 rice crisis , 2013 .

[87]  Kazuki Saito,et al.  Towards a better understanding of biophysical determinants of yield gaps and the potential for expansion of the rice area in Africa , 2013 .

[88]  Kazuki Saito,et al.  Increasing rice productivity through improved nutrient use in Africa , 2013 .

[89]  K. Otsuka,et al.  Lessons from the Asian Green Revolution in Rice , 2013 .

[90]  M. Wopereis,et al.  Estimation of cultivated area, number of farming households and yield for major rice-growing environments in Africa. , 2013 .

[91]  A. Tanaka,et al.  Factors affecting variation in farm yields of irrigated lowland rice in southern-central Benin , 2013 .

[92]  D. Larson,et al.  An African Green Revolution: Finding Ways to Boost Productivity on Small Farms , 2013 .

[93]  Kazuki Saito,et al.  Grain Yield Performance of Selected Lowland NERICA and Modern Asian Rice Genotypes in West Africa , 2010 .

[94]  Keijiro Otsuka,et al.  Increasing Rice Production in Sub-Saharan Africa: Challenges and Opportunities , 2007 .

[95]  M. C. S. Wopereis,et al.  Combining field and simulation studies to improve fertilizer recommendations for irrigated rice in the Senegal River Valley. , 2004 .

[96]  T. Masunaga,et al.  Sulfur and zinc levels as limiting factors to rice production in West Africa lowlands , 2000 .

[97]  A. Dobermann,et al.  Rice: Nutrient Disorders & Nutrient Management , 2000 .

[98]  T. Reardon,et al.  Incentives for Fertilizer Use in Sub-Saharan Africa: A Review of Empirical Evidence on Fertilizer Response and Profitability , 1998 .

[99]  S. Datta,et al.  Phosphorus requirements and management for lowland rice. , 1990 .