The monitoring of soil moisture content and plant water status is of particular importance since these conditions are essential for proper management of nutrition and irrigation.

Proper monitoring would allow for efficient irrigation management that saves water, energy, fertiliser use and time, improving the quantity and quality of production. Sustainable soil preservation is relevant for monitoring watered soils and safeguarding food production, as well as for the preservation of their associated ecosystem services that are increasingly threatened by pollution.

Nowadays, the problem of environmental pollution is growing, especially in soil. Soil absorbs a wide variety of harmful substances, from heavy metals to organic pollutants and microplastics.  Some unsustainable agricultural practices continue to contaminate the soil, mostly due to the use of copper- and cadmium-based fertilisers or pesticides. In addition, agricultural practices are not the only sources of soil pollution: poorly managed waste and industrial activities are also responsible for soil contamination.

Another source of concern for soil contamination is oil leakage that flows out of broken oil pipelines. Oil leakages may spread over large areas, causing irreparable damage without being detected. As a result, the presence of these soil pollutants causes a chain reaction, altering soils’ biodiversity, nutrients, groundwater, and reducing soil organic matter.

However, the wide variety of contaminants, soils, and climatic conditions results in high costs for monitoring and comprehensive assessment of soil quality and land pollution.

Soil absorbs a wide variety of harmful substances

For all these reasons, there is a great need to monitor soils for different purposes, from pollution prevention to watercontent control, simultaneously ensuring high reliability and low-cost methods. This theme was partially addressed in the project WetSoil, led by the Electromagnetics Research Group (EMRG) at the University of Malta (UM).

WetSoil, a project funded by the Energy and Water Agency, saw through the development of a soil-moisture-content-monitoring system which consisted of five antennas, each having a different length, connected to a central system.

A signal is sent from the central system down to each antenna and, depending on the response received back at the central system, the amount of water in the soil at different depths could be quantified.

This system is currently part of a pilot project and additional experiments are being conducted to quantify contaminants in Maltese soils. This will help farmers automate their irrigation schedule based on scientific knowledge and plan their fertilisation schemes for optimal use.

Lourdes Farrugia is a senior lecturer and researcher.

Sound Bites

•        Today, flood irrigation remains the most popular crop irrigation method worldwide. Using this method, water is pumped or brought to the fields and is allowed to flow along the ground among the crops. This method is simple and cheap, and thus it is widely used by societies in less developed parts of the world.

•        Most of the farmers in Malta base their crops’ irrigation timing and water volume requirements on experience acquired through the years, as well as upon individual assessment. This is achieved by looking at the soils’ appearance, texture and the plants’ condition, colour and leaf appearance. Farmer’s survey report, WetSoil.

For more soundbites, listen to Radio Mocha Malta https://www.fb.com/RadioMochaMalta/.

DID YOU KNOW?

•        While only 20% of the world’s farmland is irrigated, it produces 40% of our food supply.

•        Globally, agriculture water withdrawals account for more than double the combined withdrawals for municipal and industrial use.

•        Agriculture wastes 60% of the 2,500 trillion litres of water it uses each year.

•        There are many vegetables that can grow without requiring a lot of water. Some examples include asparagus, rhubarb, corn, and beans.

•        On the other hand, there are crops that are highly water-intensive. These include rice, soybeans, wheat and sugarcane.

For more trivia, see: www.um.edu.mt/think.