Three dimensions to measure the impact of soil nutrients on the nutritional values of crops

When farmers need to know the nutritional value of a crop, the usual way to find out is by taking hundreds of samples of the grains into a laboratory and analyzing them. This process is not only very expensive but inefficient; the analysis is carried out at the final crop growth stage, when it is already too late for correcting nutrient concentration. If nutrient deficiencies were detected earlier in the growth process, farmers would be able to intervene in the crops using fertilizers, ensuring the presence of proper nutrient concentrations in the crops and in the food products that come from them. 

That is why scientists at the ITC Faculty are researching the use of remote sensing technology to better understand the nutrient uptake from the soil to plants and to grains. Using remote sensing technology, researchers would be able to detect and predict nutrient deficiencies in the growth process. Farmers would then be able to correct the deficiencies, and the detection process could be done remotely across large areas and across time, with less cost than traditional sampling. 

Genotypes, management and soil 

To develop this method, ITC researchers had to dissect the three main factors that have an impact on the nutritional quality of crops. The first factor is the variety of crops that are being cultivated. Every crop variety has genetically different nutrient concentrations, and within a single farm, there can be more than 10 different varieties of wheat. 

The second factor is management, which refers to the utilization of fertilizers, and other agricultural practices that farmers use to increase their yield and nutrient content.  

The third factor is the environment. This includes climatic conditions, such as precipitation, temperature, humidity and soil properties. Soil properties do not refer to only the nutrient concentrations in the soil, but also additional properties like organic matter content and other properties that influence the uptake of the nutrients to the plants.  

The environmental factor is especially important in the context of climate change. An increasing number of studies show that elevated CO2 levels diminish the nutritional value of crops. By having elevated CO2 for certain crops, they will generate higher yields, but those grains will not be as nutritious.

The three dimensions of a nutritious plant 

ITC scientists are especially interested in investigating the environmental factors because farmers already provide researchers with information about the crop variety and the management of the soil. Therefore, the main focus of the scientists is to investigate how soil properties, such as soil nutrient concentrations, affect the nutritional values of crops. That is the starting point for the three dimensions in which the nutritional values of crops can be measured: 

1. Soil: Soil conditions and soil properties will impact the nutrient uptake of the plant. As an example, if the soil doesn’t have enough nitrogen, the root system of the plant will not develop for a proper, strong, nutrient uptake. This means that soil conditions and properties define how the nutrients will be absorbed by the plant. 
   Soil nutrients are measured by using satellite images at the beginning of the crop growth when the farmers are preparing the land. That is also the moment when fertilizers are added to the soil.  
2. Canopy: The canopy is the upper part of a plant, composed of the leaves and stems that create its cover. The nutrients that plants absorb from the soil, such as zinc, move through the vessels to reach all the parts of the plant, including the grains. The nutrient uptake from the soil to the crop canopy and grains varies across the key crop growth stages. Nutrient life cycle from the soil to the plant and further to the grains graphic example.
3. Grains: The grains are the small seeds produced by the cereal crop, which farmers collect to turn into a food source. The quantity of nutrients in the final crop production varies across crop varieties being highly influenced by environmental conditions and agriculture management practices. 
   By measuring and comparing nutrients - from the moment when farmers plant, to when the plants start growing, and finally to the flowering and the ripening phase, scientists will be able to discover what is the most important crop growth stage to predict nutrients. The earlier they can predict nutrients, the better, as the farmers would be able to intervene ahead of time and prevent nutrient deficiencies. With this methodology, remote sensing technology is becoming a competitive, effective alternative to traditional sampling. 

What do we do at ITC?

The EO4Nutri project aims to estimate and predict crop nutrients project with remote sensing. EO4Nutri is funded by the European Space Agency, and developed by the ITC Faculty in partnership with the National Research Council of Italy – Institute for Electromagnetic Sensing of Environment (CNR-IREA), University of Milano-Bicocca, Rothamsted Research and Ludwig Maximilian University of Munich.