Articles
Plant-based sensing for irrigation management in the field
Article number
1335_30
Pages
247 – 262
Language
English
Abstract
Optimizing irrigation is a challenge for sustainable agriculture.
The water status of most annual crops is strongly related to soil water status due to shallow, dense root systems and low hydraulic resistance (Rplant). Such crops can be managed with soil moisture measurements and models of ET. However, trees and vines have characteristics that complicate meteorological and soil-based methods: tall, discontinuous rough canopies and deep, low density and erratic root systems with relatively high hydraulic resistance.
The high Rplant leads to a greater dependence of water potential on evaporative demand, and leads to dynamic daily water potentials.
Sap flux gauges and meteorological modeling can be used to estimate crop water use though discontinuous canopies and crop level effects on stomatal conductance complicate such models.
With uncertainty of root distributions and strong weather response, direct measurement of plant water status is desirable in woody crops like winegrapes that require regulated stress for best grape quality.
Methods have been developed to estimate or measure plant stress though few are well-suited to commercial use.
Remote sensing of spectral characteristics may relate to water status, but is indirect and has many interferences.
Some measure a tissue response to water potential variations, such as visual symptoms of stress or dendrometers (shrink/swell sensors) and turgor gauges on trunk, leaf or fruit.
These also are indirect and correlations to tissue properties often change.
Other methods measure plant water potential directly: the pressure chamber, stem psychrometer or embedded microtensiometer or microosmometer.
The much higher temporal resolution with continuous monitoring of stem potential will raise questions about diurnal patterns of plant growth and function, and if irrigation management at much shorter intervals will be valuable.
No single measure or model will provide optimal irrigation management, and the integration of direct and remote sensing with modeling is needed.
User-friendly software interfaces are needed to facilitate end-user data interpretation and the final decision-making.
The water status of most annual crops is strongly related to soil water status due to shallow, dense root systems and low hydraulic resistance (Rplant). Such crops can be managed with soil moisture measurements and models of ET. However, trees and vines have characteristics that complicate meteorological and soil-based methods: tall, discontinuous rough canopies and deep, low density and erratic root systems with relatively high hydraulic resistance.
The high Rplant leads to a greater dependence of water potential on evaporative demand, and leads to dynamic daily water potentials.
Sap flux gauges and meteorological modeling can be used to estimate crop water use though discontinuous canopies and crop level effects on stomatal conductance complicate such models.
With uncertainty of root distributions and strong weather response, direct measurement of plant water status is desirable in woody crops like winegrapes that require regulated stress for best grape quality.
Methods have been developed to estimate or measure plant stress though few are well-suited to commercial use.
Remote sensing of spectral characteristics may relate to water status, but is indirect and has many interferences.
Some measure a tissue response to water potential variations, such as visual symptoms of stress or dendrometers (shrink/swell sensors) and turgor gauges on trunk, leaf or fruit.
These also are indirect and correlations to tissue properties often change.
Other methods measure plant water potential directly: the pressure chamber, stem psychrometer or embedded microtensiometer or microosmometer.
The much higher temporal resolution with continuous monitoring of stem potential will raise questions about diurnal patterns of plant growth and function, and if irrigation management at much shorter intervals will be valuable.
No single measure or model will provide optimal irrigation management, and the integration of direct and remote sensing with modeling is needed.
User-friendly software interfaces are needed to facilitate end-user data interpretation and the final decision-making.
Authors
A.N. Lakso, D.S. Intrigliolo
Keywords
water potential, sensors, fruit crops, nut crops, irrigation, drought stress, water use model, sap flow, root distribution, hydraulic resistance, remote sensing, dendrometer
Online Articles (92)