The World Agroforestry Centre together with the FoodAfrica programme launched a new plant environment facility to support screening of soils for crop micronutritional deficiencies. The initiative is a major innovation that could set a standard for conducting plant bioassays and linking plant responses to new spectral-based soil and plant tests.
The approach is to assess plant response to different nutrient treatments by growing plants in test tubes using small amounts of soil under controlled conditions of lighting, temperature and humidity. This approach will allow rapid screening of potential nutrient deficiencies in Africa soils using reproducible procedures. As only small soil quantities are required, existing archived soil samples from the Africa Soil Information Service AfSIS baseline can be deployed. AfSIS is an ICRAF-supported project, funded by the Bill & Melinda Gates Foundation, that is developing continent-wide digital soil maps for sub-Saharan Africa using new types of soil analysis and statistical methods.
The new laboratory facility was initiated by Dr. Keith Shepherd, Leader of ICRAF’s Science Domain on Land Health, assisted by Laboratory Manager Mercy Nyambura, who is also a PhD student in FoodAfrica and working at ICRAF, and other staff of ICRAF’s Soil-Plant Spectral Diagnostics Laboratory.
– The innovation will allow many combinations of nutrient treatments to be tested on a large number of soils in a short time and speed up the development of rapid soil and plant diagnostic tests based on spectral technology that use only light reflectance, Dr Shepherd explains.
The proposed procedure overcomes many of the limitations of conventional pot experiments, such as variation in growing conditions and watering regimes, the need for shipping large soil quantities, and limitations on the number of treatments that can be accommodated. The results will allow digital mapping of nutrient deficiencies using approaches developed by the AfSIS. This will help to target costly agronomic field trials to specific nutrient deficiencies and areas. Priority is being given to screening soils for micronutrient deficiencies because of their importance for human health and crop response to standard NPK fertilizers.
Capacity building through innovation
The FoodAfrica programme aims for capacity building, which means improving the skills and knowledge of local researchers, authorities and farmers.
– Our aim is to continue being innovative by providing and developing techniques that can rapidly improve soil and plant information. The protocols we develop can be passed on nationally and internationally and so the research institutions interested in conducting similar research can benefit from our work, Mercy Nyambura adds.
Plant growth and response to nutrient additions will be calibrated directly to the laboratory’s high-throughput, low cost infrared and x-ray spectroscopic techniques for soil and plant analysis, by-passing conventional soil and plant test methods. The new crop chamber can take up to 1000–1500 growth tubes. The researchers hope that the protocols they develop will set a standard for conducting similar plant bioassays in African laboratories.
The facility is funded by the FoodAfrica Research for Development Programme focusing on improving food security in West and East Africa through capacity building and information dissemination. The first soil samples being analyzed in the new lab aresamples collected for the AfSIS baseline survey, the first ever unbiased sample of Sub-Saharan Africa soils. MTT Agrifood Research Finland is conducting analysis of micronutrients on these samples using conventional methods under FoodAfrica Work Package 1. This will constitute the first comprehensive survey on micronutrient deficiencies in African soils. The goal is to build up a picture of the prevalence and distribution of micronutrient status in the region. The project started in 2012 and runs through 2015.