Reviewing Mini-lysimeter Controlled Irrigation in Container Crop Systems

Abstract

This study reviews how mini-lysimeters have been used effectively to optimize irrigation control in container horticulture production. Lysimeters are devices that measure evapotranspiration (ET) from the water balance of a fixed soil volume. The primary components of lysimeter-controlled irrigation are load cell sensors, a multiplexer, a data logger, a controller, and solenoid valves. The two common mini-lysimeter systems are platform lysimeters and suspension lysimeters. In these systems, a bending-beam single-point load cell is fastened between two plates, and a container is placed directly on the top platform. Platform lysimeters are commonly used for smaller pot sizes, and suspension lysimeters have been used for large shade trees up to 2.8 m tall and weighing 225 kg. Mini-lysimeters have been used for decades to calibrate ET models and create on-demand irrigation control programs that replenish plant daily water use or maintain deficit conditions. Research has demonstrated that lysimeter-based irrigation can respond more effectively to seasonal and diurnal variations in water demand, increasing irrigation cycles when evaporative demand is high, and decreasing irrigation cycles when demand is low. A strength of these systems is that for containerized plants, such as nursery production systems, mini-lysimeters capture whole-plant water use, which presents a more holistic measure compared with soil moisture sensors or leaf moisture sensors.

A gravimetric method to monitor transpiration under water stress conditions in wheat

“…Due to the difficulty of maintaining soil water content in a field setting, experiments of this kind are most often conducted in a controlled environment using potted plants. Although there are multiple methodologies for measuring transpiration and soil water content in isolation, no approach combines the two as effectively as the gravimetric method (Liyanage et al., 2022; McCauley et al., 2021; Pieters et al., 2022). Gravimetric instruments, such as a weighing lysimeter, measure soil water content by mass.…”

“…Gravimetric instruments, such as a weighing lysimeter, measure soil water content by mass. When coupled with a data logger, automated watering of potted plants allows soil moisture to be maintained within a narrow range (McCauley et al., 2021). Provided evaporation is sufficiently controlled, transpiration may then be estimated as the change in weight of the potted plants over a specified period of time.…”

Root Exploration, Initial Moisture Conditions, and Irrigation Scheduling Influence Hydration of Stratified and Non-Stratified Substrates

“…Lysimeters have been used to measure substrate moisture status and control irrigation of containerized systems [23][24][25]. Typically, there are two types of lysimeters utilized in container production research, hanging single containers with an S-type load cell [23] or placing a container on a cantilever base with a beam load cell with a platform attached on top [26].…”