The APOLLO concept
APOLLO aims to open up the precision agriculture market by making affordable and easy-to-use agricultural advisory services available to farmers, farmer associations and agricultural consultants.
APOLLO developed and tested affordable and user-friendly agricultural advisory services based on freely available Earth Observation (EO) data, targeted primarily (although not exclusively) was based on the following foundations which make the services affordable, accessible and easy to use:
- The availability of free and open data from the European Union’s Copernicus programme (and other open sources, such as Landsat) presents an opportunity for the development of low-cost, tailored services, with a resolution appropriate for applications aimed at smallholder farmers;
- Automated processing methodologies support the development of affordable services;
- The pioneering use of Sentinel-1 data for estimating soil moisture allows avoiding the use of costly and cumbersome ground-based sensors and surveys for optimising irrigation and tillage operations.
- APOLLO services are developed to be available anywhere at any time through the online platform and a mobile application. The online platform provides full access to all APOLLO services and data, while the mobile application can also be used for basic reporting and alerting;
- APOLLO services are applicable to multiple crop types, and although tailored for smallholder farmers, are available to farms of other sizes;
- The APOLLO interfaces and supporting documentation are available in multiple languages – initially in the three languages of the pilot countries.
Easy to use
- The consortium included two farmers’ associations and an SME already active in the field of precision agriculture, which ensured that the development of the services was based on a firm understanding of the needs of the end users;
- APOLLO’s four flagship services place ease-of-use at the forefront, and are designed to minimise the burden on the end-user.
APOLLO services are aimed at (primarily) small farmers, farmers’ associations and agricultural consultants.
The majority of European farms are considered small, with an average of 12 hectares of land. 70% of EU farms are less than five hectares in size. Almost 97% of all farms in the EU are considered to be family farms. Small farmers in particular are unable to invest heavily in new technologies, and hence have not realised the many benefits of agricultural information services based on Earth Observation. APOLLO targeted (primarily) small farmers as direct customers.
Since agricultural cooperatives or associations federate the interests of a group of farms, they are an important actor to be addressed either as a direct customer in and of themselves, or as a multiplier through which individual farms could be targeted.
In addition to service small farms either directly or at the cooperative/association level, the APOLLO services can also be offered to agricultural consultants who provide advisory services to farmers, and who could be seen as a “tool-buying” community who would enlist APOLLO services as part of their own individual service offering.
APOLLO services development relied on the use of several technologies in the fields of Earth Observation and Agronomic Modelling.
Earth Observation (EO) refers the collection of information about our planet, using remote sensing technologies such as sensors mounted on satellites or drones. The European Union’s Copernicus programme provides EO data freely and openly for use by policy-makers, citizens and businesses alike. APOLLO makes full use of this invaluable resource, as well as drawing on other sources of globally available data.
Remote sensing data from sensors on Earth Observation satellites have demonstrated their potential to measure soil moisture quantitatively on bare surfaces and those covered by short vegetation. Thanks to their ability to operate in all weather conditions and to wide coverage, data from Synthetic Aperture Radar (SAR) offer the opportunity to monitor large areas with a high spatial resolution. The use of SAR images, such as those captured by the Copernicus programme’s Sentinel-1, can provide a precise estimation of the surface soil moisture.
The methodologies developed for the estimation of soil moisture from SAR sensors are based on the following principles: Microwave radiation emitted from the SAR instrument is reflected from the surface of the Earth. The returning signal (known as “backscatter”) is captured by the sensor. The signal is affected by numerous factors, including the characteristics of the land surface (roughness, topographic conditions) and of the measuring instrument. Crucially though, the signal is affected by the soil’s ability to resist an electric field, a property known as “permittivity”, which is normally expressed for a particular material relative to that of a vacuum, and referred to as the “dielectric constant”.
The soil’s dielectric constant is highly dependent on soil moisture. Therefore, assuming that the soil’s surface characteristics vary slowly in time, changes in the returning SAR signal can be correlated with changes in soil moisture content.
The soil moisture maps generated from Sentinel-1 data can be used by agencies that manage water distribution, or by individual farmers to schedule the irrigation of their fields in a more efficient way.
Temperature and rainfall
The APOLLO platform produces daily maps of climatic variables, namely temperature and precipitation at a ground resolution of 1km using data from meteorological stations and EO. Predictions in space and time were made for the mean, maximum, and minimum temperatures using spatio-temporal geostatistical model with a time series of Moderate Resolution Imaging Spectroradiometer (MODIS) 8 day images and topographic layers (digital elevation model and topographic wetness index). Sentinel data will be used once the appropriate mission is operational.
The daily precipitation records are obtained from NCDC’s Global Historical Climate Network Dataset (GHCND) data set. The methodology for precipitation assessment at high resolution space-time grids will be spatio-temporal regression kriging. The main additional parameters in the model are DEM and topographic layers. In addition, EO data on precipitation, such as CMORPH, are used to strengthen the model.
Crop growth monitoring service is a very common service in Earth Observation products for agriculture. However, these services usually provide results only based on the Normalised Difference Vegetation Index (NDVI) – a way of determining how much live green vegetation is present in an area. In addition to this, APOLLO utilised advanced vegetation indices derived from Sentinel-2 data for estimating biophysical parameters of crops (e.g. Leaf Area Index, Chlorophyll/Nitrogen content) providing a more accurate service for monitoring of crop health. Improved sensitivity of the absolute and relative indicators of crop development to produce timely information on potential problems.
Biomass is a crop parameter required as an input variable in crop yield forecasting models. For the application in APOLLO project, biomass estimation models had to be applicable across Europe in an operational way. The accuracy of the information should not significantly vary with crop type and agricultural practice. To achieve that, the APOLLO project has developed several models for estimation of biomass depending on major crop groups (crops with similar leaf structure and canopy architecture) from Sentinel-2 data (and Landsat 8 to improve temporal resolution).
Earth Observation data are used in agronomic models. The role of agronomic models is to translate these data to meaningful information for farmers. In this way, farmers receive information that helps them to be more efficient at their agricultural operations. For example, farmers can receive information from APOLLO related to irrigation such as the time and the amount of water that should they apply. Furthermore, they can acquire information on the development of their crops that can help them to detect problems such as pest infestation in good time.
Used as part of a farm management strategy and in combination with precision agriculture techniques, the APOLLO services can produce both environmental and economic benefits, as follows:
- Using less fuel for tilling thanks to optimal soil workability identified by the Tillage Scheduling service, saving money and reducing emissions, whilst simultaneously reducing soil degradation;
- Using (and possibly wasting) less water for irrigation thanks to the Irrigation Scheduling service;
- Rapidly identifying the existence of possible field problems such as pest infestations and nutrient deficiencies through the Crop Growth Monitoring service, leading to faster interventions and reduced losses;
- Making better-informed decisions on whether to sell or store their produce, thanks to the Crop Yield Estimation service;
- Increased profitability as a result of the above practices;
- Increased competitive advantage.