The APHLIS website offers post harvest losses estimates (PHLs) - cumulative % weight losses from production - for the cereal crops of Sub-Saharan Africa, for individual countries and for their provinces. The PHL calculator that makes these estimates can also be downloaded by users as an Excel spreadsheet and default values changed to a user's preferences. A Users' Guide to the system can also be downloaded. The data on which this system is based was submitted by local experts who together form the APHLIS Network. The left hand menu bar provides access to this database by country.
APHLIS is still under development and now in its third phase. For more details see the ongoing project activities (APHLIS phase III).
Estimates of postharvest losses are important data for policy makers, for food security staff making cereal supply estimates and for agricultural practitioners proposing, or actually managing, interventions to reduce postharvest losses. Before the introduction of APHLIS, the origin and justification of PHLS figures were not well founded. APHLIS was established to generate figures for the PHLs of cereal crops in a fully transparent manner and in a way that can enable the updating of PHL estimates as new data become available.
What are the PHLs
Post harvest losses occur during harvesting and handling due to grain shattering, due to spillage during transport and also result from biodeterioration at all steps in the post harvest chain including storage. The principle agents of biodeterioration are moulds, insects, rodents and birds. A variety of insects pests, like the larger grain borer shown here on maize grain, are one cause of post harvest losses. They start their attack in the mature crop and carry over into storage.
What PHL estimates include
The estimated PHLs are the reduction in weight of ready to consume grain incurred during harvesting operations, farm storage, transport and market storage in East and Southern Africa and specifically -
- Reflect losses of quantity (weight loss); quality change is only relevant if food is no longer fit for human consumption. For a consideration of quality losses access the ‘Postharvest quality losses (review)’ in menu on the left hand column of this page.
- Include grain spilt during handling and consumed by farmers’ animals as such grain is no longer available for human consumption, even if the animals are a component of the farmers’ livelihoods.
- Are from this year’s production, cereals from the previous season(s) are carryover stocks and dealt with separately.
- Are reported for national and sub-national units (provinces) which follow political rather than agro-climatic boundaries, thus loss estimates for any particular area may hide wide internal variations.
- Do not take into account any cereal processing losses.
Structure of the system
There are five basic components of the system.
- A database that hold keys agricultural data by country and by province for most of the countries of Sub-Saharan Africa. The database displays its data as a series of tables accessible from the buttons on the left hand column.
- A network of local experts – the APHLIS Network – that supplies agricultural data and verifies PHL estimates – see using ‘APHLIS Network’ button in the left hand column.
- A PHL calculator that determines a cumulative % weight loss (PHL) using the information in the database and a PHL profile (the typical PHLs incurred at each step in the post harvest chain) for the specific conditions in question. The estimated losses are displayed by crop type in tables for the region, country and province. These are accessed from the ‘Losses’ button on the left hand column.
- A mapping tool that displays the losses for cereal type by province as well as other data such as the climate types (by Köppen code) for the provinces in the study area and the incidence of larger grain borer. Use ‘PHL Map’ button in the left hand column.
- A downloadable version of the PHL calculator in which the user can define most of the default values. Use the ‘Downloads’ button in the left hand column.
Scope of the system
The PHL calculator responds to queries about the PHLs for countries, provinces, crops, climatic areas, seasons and farming system and displays these in a series of loss tables accessible from the ‘Losses tables’ button in the left hand column of this page. The estimated PHLs take account of extreme or unusual climatic events such as rain at harvest or particular pest problems such as situations where the larger grain borer is a serious pest. The first loss table gives a regional weighted average PHL by crop. By clicking on the various country links it is possible to see the PHL by crop for country and then for province. By clicking on a provincial loss figures it is possible to display the key data used in the calculation.
It is possible to trace the figures used for estimating the PHL for crop in each climate type. A quality assessment is given of these figures as to whether they are specific to the cereal type, farm type and climate and the bibliographical source of the data can also be traced in a full reference list.
Go to the PHL maps to see the geographical distribution of losses as well
as other features of interest in loss estimation.
Customising the PHL for user preferences
The PHL calculator can be downloaded as a spreadsheet from this website. Users can then change most default values to obtain customised PHLs for an area of any size of interest – country, province or part of a province in Sub-Saharan Africa. The following defaults can be changed -
- Language – English, French or Portuguese
- Cereal type
- Prevailing climate
- Production figures and the proportion split between subsistence and commercial farmers
- The number of annual harvests
- The proportion of grain marketed at about the time of harvest
- Whether or not there was rain at time of harvest
- Duration of farm storage
- Whether or not larger grain borer is a serious pest
- The individual loss values for each link in the postharvest chain
Tracing the loss figures
The downloadable PHL calculator displays the figures used for estimating the PHL for crop in each climate type and offers an assessment of the quality of these figures as to whether they are specific to the cereal type, farm type and climate. The bibliographical source of the data can also be traced in a full reference list.
As the PHL profiles used by the PHL calculator are intended to be specific to the crops and region for which they were developed, the downloadable calculator should not be used for the estimation of losses for other crops, farming systems or regions.
Warnings about the PHL estimates
When users of APHLIS request estimates for the PHL of a particular crop, in a particular province, then a pre-determined set of appropriate PHL values for each step in the PH chain is inserted into the PHL calculator. This set of figures is called a ‘PHL profile’. One problem faced in seeking to provide PH profiles is that for many provinces there are no specific PHL data. It is therefore inevitable that many different provinces will have to share the same data. This was achieved by clustering together the provinces of many countries that are basically similar with respect to the factors that influence PHLs; the most convenient method of doing this is based on climate classification. Climates have been classified into one of three types, tropical savannah/forest, arid/desert or warm temperate. For each crop there is a PHL profile for each climate, so with seven crops there is a total of 21 profiles. In assembling PH profiles it is necessary to create a generalised loss figures for each step in the PH chain. These generalised figures were obtained from all estimates available by 1) removing outliers, 2) avoiding the use of ‘of questionnaire/guesstimate data where there is sufficient measured loss estimates, and 3) averaging what data remained. However, in many cases the PHL profiles are very generalised, i.e. are not composed of loss figures from the same cereal or from the same climatic area in question. This is indicated in the downloadable PHL calculator which records each individual figure in a PHL profile as being ‘same’ or ‘other’ and estimates as being ‘measured’ or ‘questionnaire/guesstimates’. Generally speaking, loss estimates from the model can be regarded as more reliable when they are from the ‘same’ situations and are ‘measured’.
As the PHL profiles used by the PHL calculator are intended to be specific to the crops and region for which they were developed, the calculator should not be used for the estimation of losses for other crops, farming systems or regions.
PHL estimates are based on the best data available, but this is not necessarily very accurate. If more up-to-date data are to hand then these could be used by downloading the spreadsheet version of the PHL calculator and altering the default values.
Feedback on PHL estimates and contribution of new PHL data
Contact us to give feedback on using the system. We are keen to receive well documented loss figures to add to the database, to learn about successes or failures in using the system and suggestions for improvements.
The European Commission and its agents accept no responsibility for the accuracy or otherwise of data or estimates obtained from APHLIS and these are provided entirely at the users’ risk.