Moroccan researchers publish high-resolution soil nutrient maps

MOROCCO – A team of Moroccan scientists has produced the most detailed maps yet of phosphorus and potassium levels in the country’s agricultural soils, aiming to help farmers make better fertilizer decisions and improve crop yields.

Published on August 8, 2025, in Scientific Data, the work was led by researchers from the National Institute for Agricultural Research (INRA) and uses a machine learning approach known as Random Forest to predict the availability of exchangeable phosphorus and potassium.

Lead researcher Dr. Ahmed El Mahi explained, “Phosphorus and potassium are vital for plant growth, but until now, information on their distribution in Morocco was often scattered or limited to small areas. Our maps make it possible to plan interventions where they are most needed.”

The study analyzed 5,276 soil samples for phosphorus and 6,978 for potassium, collected between 2010 and 2022 from across Morocco.

Half of the samples came from the OCP group’s Fertimap project and the rest from government and regional agricultural bodies. The data was divided into training and testing sets, with 70 percent used to train the model and 30 percent to verify its accuracy.

Researchers selected 15 factors for phosphorus prediction and 50 for potassium, ranging from climate variables to soil properties. Statistical measures, including root mean square error and coefficient of determination, confirmed the model’s strong performance.

Two maps, two findings

The phosphorus map shows that most Moroccan soils are well supplied, though deficiencies exist near Fez, Settat and north of Marrakech. In contrast, the potassium map reveals shortages in several areas rich in phosphorus, such as El Jadida and near Tetouan.

Dr. El Mahi noted, “These findings underline the importance of balanced fertilization. Farmers can lose yield potential if one nutrient is abundant but another is lacking.”

While the soil study signals progress for crop management, Morocco’s avocado sector is contending with weather-related setbacks. Successive heat waves this year have reduced expected harvests by about one third.

“We were aiming for 150,000 tonnes, but we now expect between 90,000 and 110,000,” said Abdellah Elyamlahi, president of the Moroccan Association of Avocado Producers (MAVA) in a interview with Freshplaza. “The age of the plantations will help offset some losses, but we still face a shortfall of about 50,000 tonnes.”

Export buyers are already anticipating higher prices. Elyamlahi confirmed, “Naturally, the drop in volumes will lead to an increase in prices, but not excessively. The prices of Moroccan avocados will certainly be higher at the beginning of the season, but it is important to keep in mind that the starting prices are not decisive for the rest of the campaign.”

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