Design and testing of an automatic irrigation controller for fruit tree orchards, based on sap flow measurements

2008 ◽  
Vol 59 (7) ◽  
pp. 589 ◽  
Author(s):  
J. E. Fernández ◽  
R. Romero ◽  
J. C. Montaño ◽  
A. Diaz-Espejo ◽  
J. L. Muriel ◽  
...  
Keyword(s):  
Remote Control ◽  
Soil Water ◽  
Sap Flow ◽  
Field Capacity ◽  
Threshold Value ◽  
Pulse Velocity ◽  
Fruit Tree ◽  
Stem Water Potential ◽  
Crop Water ◽  
Flow Measurements

We designed and tested an automatic irrigation control system for fruit tree orchards, designated CRP. At the end of each day, the device calculates the irrigation dose (ID) from sap flow readings in the trunk of trees irrigated to replenish the crop water needs, relative to similar measurements made in over-irrigated trees. It then acts on the pump and electrovalve to supply an ID sufficient to keep the soil close to its field capacity during the irrigation period. Remote control of the system is possible from any computer or Smartphone connected to the Internet. We tested the CRP in an olive orchard in southern Spain. The device was robust and able to filter and amplify the output voltages of the heat-pulse velocity probes and to calculate reliable sap flow data. It calculated and supplied daily irrigation amounts to the orchard according to the specified irrigation protocol. The remote control facility proved to be useful for getting real-time information both on the CRP behaviour and the applied IDs, and for changing parameters of the irrigation protocol. For our conditions, olive trees with big root systems growing in a soil with a remarkable water-holding capacity, the approach mentioned above for calculating ID had not enough resolution to replace the daily crop water consumption. The device, however, was able to react when the soil water content fell below the threshold for soil water deficit. The threshold value was identified with simultaneous measurements of stem water potential in the instrumented trees. Our results suggest a change in the irrigation protocol that will allow the CRP to apply a recovery irrigation whenever that threshold is reached, making the device suitable for applying a deficit irrigation strategy in the orchard.

Comparison of three crop water stress index models with sap flow measurements in maize

2018 ◽  
Vol 203 ◽  
pp. 366-375 ◽  
Author(s):  
Ming Han ◽  
Huihui Zhang ◽  
Kendall C. DeJonge ◽  
Louise H. Comas ◽  
Sean Gleason
Keyword(s):  
Water Stress ◽  
Sap Flow ◽  
Stress Index ◽  
Crop Water ◽  
Crop Water Stress Index ◽  
Flow Measurements ◽  
Water Stress Index ◽  
Sap Flow Measurements ◽  
Crop Water Stress

Modeling of plant water uptake in two distinct forest stands using whole-plant capacitance approach

2021 ◽  
Author(s):  
Veronika Skalova ◽  
Michal Dohnal ◽  
Jana Votrubova ◽  
Tomas Vogel ◽  
Miroslav Tesar
Keyword(s):  
Soil Water ◽  
Water Uptake ◽  
Sap Flow ◽  
Meteorological Data ◽  
Water Pressure ◽  
Thermal Dissipation ◽  
Richards Equation ◽  
Soil Drought ◽  
Flow Measurements ◽  
Whole Plant

<p>Soil-plant-atmosphere interactions are studied to improve the estimation of actual transpiration – the key part of the catchment water balance. The one-dimensional soil water flow model S1D, involving vertically distributed macroscopic root water uptake and whole-plant hydraulic capacitance, was used. The model is based on the numerical solution of Richards' equation coupled with a transient transpiration stream algorithm.</p><p>The study focuses on the catchment Liz located in the Bohemian Forest, Czech Republic. The catchment is covered with Norway spruce (Picea abies) and European beech (Fagus sylvatica). In 2020, sap flow measurements by thermal dissipation probes were conducted at both forest environments. Soil water pressure head, soil water content, and soil temperature data, as well as complete meteorological data from the nearby meteorological station, were also available for the whole period of interest.</p><p>The registered sap flow and simulated transpiration fluxes are compared with a particular attention to the different behavior of isohydric (spruce) and anisohydric (beech) trees. The model reasonably well reproduces the plant responses caused by both the high midday potential transpiration demand and the occasional soil drought.</p><p>The research is supported by the Czech Science Foundation Project No. 20-00788S.</p>

Examination and parameterization of the root water uptake model from stem water potential and sap flow measurements

2012 ◽  
pp. n/a-n/a ◽  
Author(s):  
Yuting Yang ◽  
Huade Guan ◽  
John L. Hutson ◽  
Hailong Wang ◽  
Caecilia Ewenz ◽  
...  
Keyword(s):  
Water Potential ◽  
Water Uptake ◽  
Sap Flow ◽  
Root Water Uptake ◽  
Stem Water Potential ◽  
Flow Measurements ◽  
Stem Water ◽  
Sap Flow Measurements

scholarly journals The Dual Method Approach (DMA) Resolves Measurement Range Limitations of Heat Pulse Velocity Sap Flow Sensors

Forests ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 46 ◽  
Author(s):  
Michael Forster
Keyword(s):  
Sap Flow ◽  
Entire Range ◽  
Full Range ◽  
Heat Pulse ◽  
Pulse Velocity ◽  
Dual Method ◽  
Ratio Method ◽  
Sap Flux Density ◽  
Flow Measurements ◽  
Method Approach

Sap flow, the movement of fluid in the xylem of plants, is commonly measured with the heat pulse velocity (Vh) family of methods. The observable range of Vh in plants is ~−10 to ~+270 cm/h. However, most Vh methods only measure a limited portion of this range, which restricts their utility. Previous research attempted to extend the range of Vh methods, yet these approaches were analytically intensive or impractical to implement. The Dual Method Approach (DMA), which is derived from the optimal measurement ranges of two Vh methods, the Tmax and the heat ratio method (HRM), also known as the “slow rates of flow” method (SRFM), is proposed to measure the full range of sap flow observable in plants. The DMA adopts an algorithm to dynamically choose the optimal Vh measurement via the Tmax or HRM/SRFM. The DMA was tested by measuring sap flux density (Js) on Tecoma capensis (Thunb.) Lindl., stems and comparing the results against Js measured gravimetrically. The DMA successfully measured the entire range of Vh observed in the experiment from 0.020 to 168.578 cm/h, whereas the HRM/SRFM range was between 0.020 and 45.063 cm/h, and the Tmax range was between 2.049 cm/h and 168.578 cm/h. A linear regression of DMA Js against gravimetric Js found an R2 of 0.918 and error of 1.2%, whereas the HRM had an R2 of 0.458 and an error of 49.1%, and the Tmax had an R2 of 0.826 and an error of 0.5%. Different methods to calculate sapwood thermal diffusivity (k) were also compared with the kVand method showing better accuracy. This study demonstrates that the DMA can measure the entire range of Vh in plants and improve the accuracy of sap flow measurements.

scholarly journals Root growth, water uptake, and sap flow of winter wheat in response to different soil water conditions

2018 ◽  
Vol 22 (4) ◽  
pp. 2449-2470 ◽  
Author(s):  
Gaochao Cai ◽  
Jan Vanderborght ◽  
Matthias Langensiepen ◽  
Andrea Schnepf ◽  
Hubert Hüging ◽  
...  
Keyword(s):  
Soil Water ◽  
Sap Flow ◽  
Root Density ◽  
Soil Types ◽  
Flow Measurements ◽  
Water Conditions ◽  
Physically Based ◽  
Soil Water Conditions ◽  
Sap Flow Measurements ◽  
Water Treatments

Abstract. How much water can be taken up by roots and how this depends on the root and water distributions in the root zone are important questions that need to be answered to describe water fluxes in the soil–plant–atmosphere system. Physically based root water uptake (RWU) models that relate RWU to transpiration, root density, and water potential distributions have been developed but used or tested far less. This study aims at evaluating the simulated RWU of winter wheat using the empirical Feddes–Jarvis (FJ) model and the physically based Couvreur (C) model for different soil water conditions and soil textures compared to sap flow measurements. Soil water content (SWC), water potential, and root development were monitored noninvasively at six soil depths in two rhizotron facilities that were constructed in two soil textures: stony vs. silty, with each of three water treatments: sheltered, rainfed, and irrigated. Soil and root parameters of the two models were derived from inverse modeling and simulated RWU was compared with sap flow measurements for validation. The different soil types and water treatments resulted in different crop biomass, root densities, and root distributions with depth. The two models simulated the lowest RWU in the sheltered plot of the stony soil where RWU was also lower than the potential RWU. In the silty soil, simulated RWU was equal to the potential uptake for all treatments. The variation of simulated RWU among the different plots agreed well with measured sap flow but the C model predicted the ratios of the transpiration fluxes in the two soil types slightly better than the FJ model. The root hydraulic parameters of the C model could be constrained by the field data but not the water stress parameters of the FJ model. This was attributed to differences in root densities between the different soils and treatments which are accounted for by the C model, whereas the FJ model only considers normalized root densities. The impact of differences in root density on RWU could be accounted for directly by the physically based RWU model but not by empirical models that use normalized root density functions.

scholarly journals Root growth, water uptake, and sap flow of winter wheat in response to different soil water availability

2017 ◽  
Author(s):  
Gaochao Cai ◽  
Jan Vanderborght ◽  
Matthias Langensiepen ◽  
Andrea Schnepf ◽  
Hubert Hüging ◽  
...  
Keyword(s):  
Winter Wheat ◽  
Water Potential ◽  
Soil Water ◽  
Sap Flow ◽  
Root Density ◽  
Soil Types ◽  
Flow Measurements ◽  
Physically Based ◽  
Sap Flow Measurements ◽  
Water Treatments

Abstract. How much and where water is taken up by roots from the soil profile are important questions that need to be answered to close the soil water balance equation and to describe water fluxes in the soil–plant–atmosphere system. Physically-based root water uptake (RWU) models that relate RWU to transpiration, root density, and water potential distributions have been developed but far less used or tested. This study aims at evaluating the simulated RWU of winter wheat by the empirical Feddes–Jarvis (FJ) model and the physically-based Couvreur (C) model for different soil water conditions and soil textures against sap flow measurements. Soil water content (SWC), water potential, and root development were monitored non-invasively at six soil depths in two rhizotron facilities that were constructed in two soil textures: stony vs. silty with each three water treatments: sheltered, rainfed, and irrigated. Soil and root parameters of the two models were derived from inverse modeling and simulated RWU was compared with sap flow measurements for validation. The different soil types and water treatments resulted in different crop biomass, root densities and root distributions with depth. The two models simulated the lowest RWU in the sheltered plot of the stony soil where RWU was also lower than the potential RWU. In the silty soil, simulated RWU was equal to the potential uptake for all treatments. The variation of simulated RWU among the different plots agreed well with measured sap flow but the C model predicted the ratios of the transpiration fluxes in the two soil types slightly better than the FJ model. The root hydraulic parameters of the C model could be constrained by the field data but not the water stress parameters of the FJ model. This was attributed to differences in root densities between the different soils and treatments which are accounted for by the C model whereas the FJ model only considers normalized root densities. The impact of differences in root density on RWU could be accounted for directly by the physically-based RWU model but not by empirical models that use normalized root density functions.

scholarly journals Water use pattern of Pinus tabulaeformis in the semiarid region of Loess Plateau, China

2016 ◽  
Vol 25 (3) ◽  
pp. e077 ◽  
Author(s):  
Shengqi Jian ◽  
Xueli Zhang ◽  
Zening Wu ◽  
Caihong Hu
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Water Use ◽  
Loess Plateau ◽  
Sap Flow ◽  
Pinus Tabulaeformis ◽  
Flow Measurements ◽  
Stand Transpiration ◽  
The Mean

Aim of the study: We analyzed the water-use strategy of P. tabulaeformis and determine the relationships between environmental factors and transpiration rates in the P. tabulaeformis woodlands.Area of study: Loess Plateau region of Northwest China.Material and Methods: Sap flow density of the P. tabulaeformis trees was measured with Granier-type sensors. Stand transpiration was extrapolated from the sap flow measurements of individual trees using the following Granier equation.Main results: The mean sap flow rates of individual P. tabulaeformis trees ranged from 9 L day−1 to 54 L day−1. Photosynthetically active radiation and vapor pressure deficit were the dominant driving factors of transpiration when soil water content was sufficient (soil water content>16%), considering that soil water content is the primary factor of influencing transpiration at the driest month of the year. During the entire growing season, the maximum and minimum daily stand transpiration rates were 2.93 and 0.78 mm day−1, respectively. The mean stand transpiration rate was 1.9 mm day−1, and the total stand transpiration from May to September was 294.1 mm.Research highlights: This study can serve as a basis for detailed analyses of the water physiology and growth of P. tabulaeformis plantation trees for the later application of a climate-driven process model.Keywords: Sap flow; stand transpiration; environmental factor; Pinus tabulaeformis; Loess Plateau.

scholarly journals On the Use of Sap Flow Measurements to Assess the Water Requirements of Three Australian Native Tree Species

Agronomy ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 52
Author(s):  
Xi Sun ◽  
Jie Li ◽  
Donald Cameron ◽  
Gregory Moore
Keyword(s):  
Soil Moisture ◽  
Tree Species ◽  
Sap Flow ◽  
Potential Evapotranspiration ◽  
Vapour Pressure Deficit ◽  
Weather Conditions ◽  
Pulse Velocity ◽  
Ratio Method ◽  
Flow Volume ◽  
Flow Measurements

The measurement of sap movement in xylem sapwood tissue using heat pulse velocity sap flow instruments has been commonly used to estimate plant transpiration. In this study, sap flow sensors (SFM1) based on the heat ratio method (HRM) were used to assess the sap flow performance of three different tree species located in the eastern suburbs of Melbourne, Australia over a 12-month period. A soil moisture budget profile featuring potential evapotranspiration and precipitation was developed to indicate soil moisture balance while the soil-plant-atmosphere continuum was established at the study site using data obtained from different monitoring instruments. The comparison of sap flow volume for the three species clearly showed that the water demand of Corymbia maculata was the highest when compared to Melaleuca styphelioides and Lophostemon confertus and the daily sap flow volume on the north side of the tree on average was 63% greater than that of the south side. By analysing the optimal temperature and vapour pressure deficit (VPD) for transpiration for all sampled trees, it was concluded that the Melaleuca styphelioides could better cope with hotter and drier weather conditions.

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