Skip to main content

Efficient and cost-effective in situ measurement of growth-related soil parameters


Abstract

To obtain best quality and quantity results for plant growth in soils and substrates, knowledge of the water and ion content of the soil and thus the dosage of irrigation and fertilizer is fundamental. This is particularly true when we want to support sustainability and the preservation of resources, but also wish to increase yield.
At the Institute of Agricultural Engineering of the University of Hohenheim a technology has been developed that measures soil water content, suction tension and salt content simultaneously and on-site. Signal transmission and the evaluation can be performed telemetrically or via cable, on-site or remote. The technology uses laser diodes, no spectroscopy is required.


Background

To obtain best quality and quantity results for plant growth in soils and substrates, knowledge of the water and ion content of the soil and thus the dosage of irrigation and fertilizer is fundamental. This is particularly true when we want to support sustainability and the preservation of resources, but also wish to increase yield.


Problem

Conventional measurement of single parameters, such as the water content or soil suction tension, is done by means of dielectric sensors or tensiometers. Those sensors generally require complex calibrations and do not allow you to determine the salts present in the soil.
So far, the nitrogen content in soils could only be determined by taking selective samples to the lab and applying methods such as UV spectroscopy. This method is time-consuming, expensive, and the fertilization recommendations obtained are not even sufficiently precise.
Accordingly, irrigation and fertilization are still largely based on intuition. In times of climate change, growing population, and a reduction in farmland, this is no longer an up-to-date solution.


Solution

At the Institute of Agricultural Engineering of the University of Hohenheim a technology has been developed that eliminates the above-mentioned disadvantages. Multiple probes are inserted into the soil to create a network of measurement support points. The probes contain a porous, hydrophilic matrix whose material and pore size can be adjusted to the growth-relevant parameters to be measured (e.g. soil suction tension, nitrates, phosphates, etc.). One or multiple laser diodes generate a laser light that radiates into the porous, hydrophilic matrix. The growth-relevant parameters cause a light scattering that is proportional to their concentration. The extent of the scattering is optically detected and converted into signals by image processing, which can then be evaluated and processed further. Signal transmission and the evaluation can be performed telemetrically or via cable, on-site or remote.


Advantages

  • Soil water content, suction tension and salt content can be measured simultaneously
  • Measurement takes place on site, not in the lab
  • Low calibration efforts
  • Number of measuring probes can be varied depending on the field size
  • Cost-effective measurement procedures via laser diodes
  • No spectroscopy, no wet chemistry required

Scope of application

The present technology allows to determine the water content, suction tension and salt content locally, ie on-site, with little calibration effort.


Service

Technologie-Lizenz-Büro GmbH is responsible for the exploitation of this technology and assists companies in obtaining licenses.


Technologie-Lizenz-Büro (TLB) der Baden-Württembergischen Hochschulen GmbH

Dr. Frank Schlotter
+ 49 721 790 040
fschlotter@tlb.de
www.tlb.de
Address
Ettlinger Straße 25
76137 Karlsruhe



Development status

Feasibility


Patent situation

  • DE pending

Keywords

Agriculture, fertilization, irrigation, water content, suction tension, salt content, nitrate, phosphate, measuring method, laser diode, laser back scattering, optical sensors, porous matrix material, solute measurement

Contact | Main Office

TransferAllianz e. V.
Christiane Bach-Kaienburg
(Managing Director)

c/o PROvendis GmbH
Schloßstr. 11-15
D-45468 Mülheim an der Ruhr