Soil EC Sensor for Fertigation Salt Accumulation Control

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Solution Overview

Problem

Prior art fertigation systems face challenges such as over-fertilization leading to groundwater pollution and high costs associated with computer-controlled systems, particularly in determining salts accumulation in soils, which affects crop productivity in greenhouse cultivation.

Innovation Solution

A fertigation system with a salts accumulation determination method using a soil EC sensor and a fertigation control server that allows for easy introduction and high-level control, employing a simplified and accurate method to determine salts accumulation by measuring electrical conductivity changes with reference culture solutions and carbohydrate injections, and a cost-effective EC sensor design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a computer-controlled system is introduced for fertigation, then control precision and ability to respond to weather changes is improved, but system cost and complexity increases significantly

Engineering Contradiction:
Improvecontrol precisionVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces a simple EC sensor as an intermediary device that bridges the gap between traditional timer-based systems and complex computer-controlled systems. The sensor provides direct electrical conductivity measurements of soil solution, enabling precise fertigation control without requiring complex computing infrastructure. The sensor output can be integrated with simple controllers or timers, maintaining system simplicity while achieving high measurement precision.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If traditional EC measurement methods are used, then salts accumulation can be detected, but measurement accuracy is insufficient due to interference from soil particles and variable moisture content

Engineering Contradiction:
ImproveEC measurement accuracyVSAvoidmeasurement reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent extracts the measurement function from the complex soil environment by using a sensor design that measures electrical conductivity in the immediate vicinity of the probe tip. The measurement is taken in the soil solution layer directly surrounding the sensor, effectively separating the measurement from interfering factors such as soil particles, air gaps, and bulk moisture content variations. This extraction approach enables reliable EC measurement that directly reflects salts accumulation.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the measurement parameter from bulk soil electrical conductivity to localized soil solution electrical conductivity. By measuring EC in the immediate vicinity of the sensor tip rather than in the bulk soil, the system detects changes in ion concentration that directly indicate salts accumulation. This parameter change transforms the measurement from being influenced by multiple factors to being a direct indicator of fertilizer salt buildup.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If simplified timer-based fertigation systems are used, then system cost is reduced, but ability to respond to weather changes and prevent over-fertilization is lost

Engineering Contradiction:
Improvesystem simplicityVSAvoidfertigation efficiency
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The patent implements a feedback mechanism where EC sensor measurements are continuously monitored and used to adjust fertigation timing and dosage. The sensor provides real-time information about soil solution conductivity, which feeds back to the control system to determine when fertilization is needed and how much fertilizer to apply. This feedback loop enables simple timer-based systems to achieve high fertigation efficiency by responding to actual soil conditions rather than following fixed schedules.

Inventive Principle:
Principle #23Feedback

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables precise determination of salts accumulation, reducing the risk of over-fertilization, improving crop productivity, and lowering the economic burden on farming families by providing a cost-effective and user-friendly solution for monitoring soil conditions.

Implementation Method 1

employing a simplified and accurate method to determine salts accumulation by measuring electrical conductivity changes

Methodology Applied
Scientific EffectElectrical conductivity measurement: Conduction (electrical)

Data Source

PatentEP3278660B1Fertigation system, fertigation control server, salts accumulation determination method, and soil EC sensor
Publication Date: 2024.05.08 ROUTREK NETWORKS INC
  • EP3278660B1 patent drawingFigure 1A~1C
  • EP3278660B1 patent drawingFigure 2A~2B
  • EP3278660B1 patent drawingFigure 3A~3C

AI summary

A fertigation system comprises: a controller that transmits sensor data to a fertigation control server, and that controls a water supply valve, a culture stock solution supply valve, and a discharge valve on the basis of received data; and a fertigation control server that, on the basis of the sensor data received from the controller, calculates control amounts for the water supply valve, the culture stock solution supply valve, and the discharge valve, and returns the control amounts to the controller.