Soil monitoring system visualises the condition of agricultural land

Murata Manufacturing is promoting measures to address salinity impact to agricultural land by conducting field trials utilising a soil monitoring system that makes it possible to visualise the condition of agricultural land in the Mekong Delta in collaboration with Can Tho University, a national university of Vietnam. The initiative is part of “Studies on Sustainable Soil Uses”, based on an agreement between the governments of Japan and Vietnam to provide ODA (Official Development Assistance) in support of measures to address the problem of salinity impact to agricultural land.

Background of the Project
Vietnam’s Mekong Delta region is subject to salinity impact from the infiltration of seawater during the dry season as a result of a decline in the volumetric flow rate of the Mekong River and the action of the tides under the impact of climate change driven by global warming. In addition to salt damage, the environment for agriculture has become harsher than in the past due the increasing severity of droughts and floods. The Mekong Delta region contains 30 per cent of Vietnam’s farmland and accounts for the majority of its domestic food production, and the damage, which is estimated to run into billions to tens of billions of yen, has become a serious problem.

Murata has been conducting the Project since 2017 in collaboration with Can Tho University, which possesses deep knowledge of agricultural and environmental research in the Mekong Delta. The company is using compact sensor units that draw on its know-how and expertise in the fields of electronic components, circuit design and software design to measure the condition of agricultural land and channel water with high precision. Combining these observations with independently developed monitoring tools, we can visualise and analyse the environmental conditions with a view. It contributes to the implementation of IT in agriculture in the Mekong Delta region by preventing salt damage to rice paddies and orchards, ameliorating salt and sulfur contamination of agricultural land and water channels, and creating a mechanism to comprehensively manage fertilizers, crops and irrigation systems.

Features of the Soil Monitoring System
The wireless transmitter-receiver system consists of a gateway, a router and several sensor nodes. Each sensor node is made up of a transmitter and three sensor units to measure the soil, field and channel water quality, and the sensing data is accumulated in the cloud.

The main features are as follows.

  • A compact approximately 13cm sensor unit equipped with three sensors for measuring two types of electrical conductivity, temperature and moisture content
  • High-precision analysis of conditions utilising a sensor incorporating a uniquely shaped sensor element and a proprietary algorithm
  • Over a year of continuous operation on three size AA batteries
  • IP68 dust and water resistance and reliable rustproofing enabling prolonged use in harsh environments

Future Outlook
The Project began with a three-year plan from 2017 utilising know-how developed in the restoration of agricultural land based on monitoring of the salt content condition of farmland damaged by the tsunami triggered by the Great East Japan Earthquake of 2011. In addition to Soc Trang and Ca Mau Province, where the monitoring system was initially introduced, in October 2018 we deployed the system in other four locations in Ben Tre and Kien Giang province. Through joint researches with many research institutions, Murata will continue to make efforts to realize global SDGs by utilising its unique sensing and wireless technologies.

Installation in the Mekong Delta

  • The delta region of the lower reaches of the Mekong River including southeastern Cambodia
  • An initiative for improving the fertility and quality of soil for crop production on alluvial soils, acid sulfate soils and saline-affected soils in the Mekong Delta of Vietnam. It is also aimed at improving profitability and realizing sustainable agriculture capable of adapting to climate change.
  • A device used to generate and transmit electromagnetic waves carrying messages or signals
  • Indicates the ability of a material to conduct electricity
  • The highest level of dustproof and waterproof performance among the protection grades for the exterior surfaces of electronic devices
  • Sustainable Development Goals: International goals from 2016 to 2030 adopted at the United Nations Summit of September 2015

New sensors helping with our food supply

Industrialisation has left much of the urban environment contaminated with a variety of heavy metals, chemicals and pesticide residue. Now, research by a team from Macquarie University has produced a series of maps that plot the concentrations of metal pollutants across cities like Sydney and Darwin, and towns such as Mount Isa and Port Pirie.

The Director of the Macquarie team is Professor Mark Taylor, an academic and former Commissioner of the NSW Land and Environment Court. Senior researcher, Marek Rouillon, and the rest of the group, investigate environmental pollution and risks to human health from aerosols, dusts, sediments, soil and water. The team works in a range of locations across Australia, including Broken Hill, Mount Isa, Newcastle, Port Pirie, Sydney and Townsville.

Results of the survey indicate the spread of contamination in many ways reflected the growth of major cities, with the highest concentrations in older suburbs. The contaminant of most concern across Sydney backyards is lead. According to Professor Taylor, it would be expected that there would be contamination in a major city. “We live in an industrial environment,” he said, adding that, “We have used lead-based petrol and paint for most of the 20th Century.”

One technique that is key to the work being conducted by the Macquarie team is X-ray fluorescence spectrometry (XRF) analysis for measuring levels of contaminant metals. Simple screening for toxic metals is performed by placing an analyser, such as the Delta Premium from Olympus directly onto soil or dust. The analyser provides detection of metals for site characterisation, contamination tracking, remediation, monitoring, and property evaluations.

Andrew Saliba, Regional Sales Specialist with Olympus, said the latest portable X-ray fluorescence (pXRF) analysers, such as the Delta Premium, have been developed specifically for complete environmental investigations of metal contaminants in a wide range of industrial and domestic materials. The high-power, high-performance, incredibly rugged Delta allows in-situ analysis in a wide range of harsh environments from remote mining and exploration sites to backyards in major urban centres.

According to Saliba, the traditional use of pXRF has been for alloy identification, grading ore, mineral exploration, metallurgy and mine site remediation. “The technology has been refined and is now often used by environmental consultancies specialising in contaminated land remediation and recycling companies needing to determine what materials are in waste products,” he said.

Macquarie researcher Marek Rouillon has been working to evaluate the reliability and repeatability of XRF analysis on environmental samples. Professor Taylor and Rouillon regularly present their findings at seminars, outlining the spread of heavy metal contamination in suburban gardens in addition to explaining the application and relevance of the pXRF instrument for this project.

Typical 'natural' or 'background' concentrations of lead for the Sydney region are in the range 20 – 30 mg/kg or parts per million (ppm). However, due to the intense use of lead containing products, much of Greater Sydney has been contaminated with the metal. Their results indicate Sydney residences have a mean soil lead concentration of 220 mg/kg, which is approximately 10 times the typical natural background for Sydney's soils and rocks.

In conjunction with the contamination mapping, Macquarie researchers also run the community orientated VegeSafe program. This is the largest study of its kind in the country and has provided information about metal contamination levels to more than 500 households across Sydney, and over 1000 households across Australia.

VegeSafe seeks to inform people about metals and metalloids in their garden soils and provides a free sampling program for domestic and community garden soils. Participants submit soil samples from private or community gardens and receive a formal report and links to information and advice about "what to do next" if the soils contain elevated concentrations of metals and metalloids. “The VegeSafe motto is 'Carry on Gardening'," Professor Taylor said, “because this is exactly what we want people to do knowing that their soils are metal free as is the produce from their gardens.”

According to Rouillon, the simplest mitigation technique for householders would be to cover the contaminated soil with either grass or mulch, to effectively reduce the potential generation of dust if the soil is dry and gets picked up by wind.

In contaminated suburbs where vegetables will be grown, the Macquarie team recommends growing produce in above ground Vegetable plots, using fresh clean topsoil. “Typically, undisturbed soil in urban areas accumulates contaminants over long periods of time and should be avoided when growing home produce” Rouillon stated.

“Our recommendations are determined by different scenarios and contaminant concentrations,” Rouillon said. “VegeSafe provides specific recommendations and advice to a gardener for their particular situation.”