Improving Food Security in West and East Africa through Capacity Building in Research and Information Dissemination (Food Africa)

University of Nairobi

Strengthening Capacity for Diagnosis and Management of Soil Micronutrient Deficiencies in

Sub-Saharan Africa for Improved Plant, Animal and Human Nutrition

Esala Martti, Keith D. Shepherd, Mercy Nyambura, Riikka Keskinen and Michael Gatari

Healthy soils Healthy crops Healthy livestock Healthy people

Soil micronutrients important for plant (green dots), animal (brown dots) and human nutrition (blue dots).

Micronutrient Problems

• Nutritional deficiencies” are responsible for over 50% of years lived with disability in children under five

• Nearly half of mortality in under-five’s in developing countries is due to under-nutrition,

• Underweight – Number-one contributor to the burden of disease in Africa south of the Sahara.

Poor soils, serious consequences

• In Sub-Saharan Africa, Multiple secondary and micronutrients (SMN) deficiencies are the norm - Se, I or Co.

• High risk of failure of simple fertilizer strategies – contributes to low adoption.

• Asia and Africa lose 11% of GNP every year owing to poor nutrition

• Africa soils less mineral rich than Asia green revolution soils – need to identify limiting factors.

Micronutrients In Africa

• Rapid and low cost analytical and diagnostic techniques that can speed large area survey and problem prevalence

• Improved and well-targeted guidelines for managing key micronutrient problems

• Scientific expertise in diagnosis and management of micronutrient problems, especially in new analytical techniques.

Capacity Development Needs

Building soil capacity to supply micronutrients to crops is a key resilience strategy for:

Human and laboratory capacity for diagnosing, surveying and managing soil nutrient deficiencies in Sub-Saharan is woefully inadequate for the task (Swift & Shepherd, 2007).

1. To develop new, rapid, low cost soil-plant analytical methods for diagnosing soil micronutrient deficiencies for crop, livestock and human health.

2. To establish a baseline on soil micronutrient status in sub-Saharan Africa soils.

3. To provide information for various stakeholders on management strategies and options for tackling key micronutrient deficiencies.

4. To strengthen African capacity on new science and technology for soil-plant micronutrient analysis, diagnosis and management.

Project Objectives

Sentinel site (100 km2): -16 Clusters (1 km2). -10 Randomly Selected Plots (1000 m2). -4 sub plots at 0-20 and 20-50 cm depth Geographical distribution of 60 sampling sites in sub-Saharan Africa. The dots represent the sampling locations.

www.africasoils.net Ajumako site

The Project Approach

Land degradation surveillance Framework (LDSF) sampling design.

A spatially stratified, hierarchical, randomized sampling framework • Minimized any local biases that may arise from convenience sampling. • Modeled under medical diagnostics approaches it is built around a hierarchical field

survey and sampling protocol. • Sentinel site (100 km2): -16 Clusters (1 km2). -10 Randomly Selected Plots (1000 m2). -4 sub plots at 0-20 and 20-50 cm depth • A total of 19000 top- and sub-soil samples

Soil Sampling

Total X-ray fluorescence spectroscopy X-ray diffraction spectroscopy Infrared spectroscopy

Spectral Fingerprinting Technologies

Portable Infrared and X-ray spectroscopy

Getting the best out of light

• Light-based technology moving rapidly towards portable and new spectral metrics emerging that will replace conventional soil guidelines.

• X-ray fluorescence (XRF) may be a

better measure of soils’ ability to supply nutrients.

• 19,000 soil samples from AfSIS baseline of 60 sentinel sites

• 3,790 soil samples collected from 30 countries around the world under a global micronutrient survey conducted in the 1970’s -Luke Soil Archives - Sillanpää Study

• A representative subset of 80 samples was re-analysed at Luke for soluble Cu, Fe, Mn, Zn and B by the same methods used in the 1970’s

• Increase in soluble B during the nearly 40-year long period of storage. Solubility of Cu, Mn and especially Fe decreased significantly. Zn not affected by storage

• 1,650 samples characterized with mid-infrared (MIR) analysis

Soil Legacy archives from an invaluable reserve for the needs of future research.

The Africa Soil Library

Mean conc. in 1970’s (mg l-1)

Mean change between

1970’s and 2013

(mg l-1)

Parameters for pairwise

t test

SE P

B 0.6 0.4 0.1 <.0001

Cu 16 -1.5 0.6 0.01

Fe 270 -56 6.5 <.0001

Mn 510 -17 7.6 0.03

Zn 12 -0.6 1.4 0.67

B Zn Mo

Micronutrient Africa Baseline

• No marked differences in the concentrations of the easily soluble elements between topsoil and subsoil.

• Median concentrations of soluble Cu (1.3 mg l-1), Zn (0.8 mg l-1), B (0.4 mg l-1) and Fe (64 mg l-1) in the topsoil-low relative to sufficiency guidelines for good crop growth.

• Using deficiency critical mid-points for Finnish soils as a guide, Africa topsoils have deficiency prevalence values of Mn (8%), Fe (42%), Cu (48%), Zn (56%), and B (79%).

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Theory and exploratory analysis of the Silanpaa data indicates pH, texture, and organic carbon are important predictors of micronutrient soil test values and plant micronutrient uptake. Spectral test can distinguish low, med and high value of plant Cu uptake ok. Standard tests only able to pick out high uptake values and did not have much discrimination at low uptake levels. Spectral methods could predict plant nutrient uptake potential and crop yield responses to applied nutrients as well or better than soil tests based on soil extracts, or at least complement existing soil tests.

Plant Micronutrient Uptake Modelling plant micronutrient uptake from the Silanpaa pot experiment data against soil test and MIR spectral data

Plant growth bioassays in test tubes for high throughput diagnosis of soil macro and micronutrient deficiencies.

Variability in response and risk are ignored when making recommendations

Calibrating relative yield response to soil tests

The huge missing link is testing and validation of plant nutrient uptake and crop response to fertilizers in relation to soil tests.

Plant tissue analysis can be used to identify nutrient-related problems, rule out nutrition as the source of a problem, monitor nutrient status as a basis for managing a crop fertility program and/or, evaluate the effectiveness of a fertility program. Plant growth potential and response to nutrients can quickly be measured this way and related to IR spectra of the soils as well as to convectional soil tests.

B Zn Mo

Soil property Map of Africa

Ethiopia: current spatial coverage of new ground

observations and measurements

Probability topsoil pH < 5.5 ... very acid soils

Africa Soil Information Service www.africasoils.net

Develop micronutrient distribution maps to assist African governments, development organizations and donors to focus on most promising strategies for alleviating the most urgent soil and crop micronutrient problems –e.g. EthioSIS, TanSIS

Decision-making in agricultural development occurs in an environment characterized by risk, uncertainty and imperfect information.

• Farmers, local- and national governments face big challenges in deciding on optimal soil fertility management strategies.

• Crop production depends on applied fertiliser, however, soil testing is used sparingly as a tool to underpin fertilizer decision in Africa.

Implications for Food Africa

Support to CGIAR, NGO and private sector projects with advice and protocols for soil and plant analysis to facilitate the process of establishing soil test values that will act as a guide to risk of deficiency and field trials to validate crop response trials. e.g. capacity development and spectral lab networks

• IAMM, Mozambique

•AfSIS, Sotuba, Mali

•AfSIS, Salien, Tanzania

•AfSIS, Chitedze, Malawi

•CNLS, Nairobi, Kenya

•SoilCares, Kenya

•IISS, Bhopal, India

•China

•ATA, Addis Ababa, Ethiopia (6)

•CNRA, Abidjan, Cote D’Ivoire

•KARI, Nairobi, Kenya

• ICRAF, Yaounde, Cameroon

• IAR&T, Obafemi Awolowo University, Ibadan, Nigeria

• IAR, Zaria, Nigeria

•FMARD, Nigeria

• IITA, Ibadan, Nigeria

• IITA, Yaounde, Cameroon

•SARI, Salien, Tanzania

Soil-Plant Spectroscopy Support Group

2 PhD and 5 MSc studentships and training/exchange between ICRAF, University of Nairobi, Luke and James Hutton Institute

Over 400 visitors to ICRAF Spectral Diagnostics Lab

Training for agricultural officers in 47 counties in Kenya through ChromAfrica LLC Support to other projects: -Optimizing Fertilizer Recommendations in Africa (OFRA)

-Transformation of agronomic research and delivery services for smallholder farmers in maize-based systems of Sub-Saharan Africa (TAMASA)

Africa Spectral Lab Network/Outreach

Implications for Food Africa Most smallholders farmers have access to only NPK fertilizers (the macro-nutrients)

Preference for site specific soil diagnosis and develop fertilizer recommendation blends for Africa’s farmers • NPK + secondary nutrients, and micronutrients for

efficiency and greater yields • Addressing deficiencies for improving smallholder crop

and livestock productivity and reducing risks of technology failure (e.g. NPK fertilizer use)-provide value for inputs.

• Targeted for regional production capabilities for fertiliser companies dealing with blending for more targeted supply of appropriate fertilizers for different regions

Exploring regional availability of ingredients for small holders options for addressing micronutrient deficiencies using organic resources (manures, composts, urban wastes) and lower likelihood of imbalances, toxic effects

S

When we supply NPK—what about other nutrients? Soil data analytics in agronomic trials for Advisory services to farmers and extension agents to address micronutrient deficiencies that affect crop growth and yield, and agronomic practices that will reduce micronutrient deficiencies..e.g. One acre fund, OFRA, Gates Crop Agronomy, Soil Cares and rural resource centre's.

Leibig’s law of the minimum: Growth is controlled by the scarcest resource

Implications for Food Africa

Thank you

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