DOCSLIB.ORG

And Soil Matric Potential- Based Irrigation Trigger Values

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
And Soil Matric Potential- Based Irrigation Trigger Values EC3045 December 2019 Perspectives and Considerations for Soil Moisture Sensing Technologies and Soil Water Content- and Soil Matric Potential- Based Irrigation Trigger Values Suat Irmak, Professor, Soil and Water Resources and Irrigation Engineering Soil- water status (soil moisture) plays a critical role in soil oxygen deficiency can cause stomata closure as well even determining yield potential of crops. Soil- water in the plant when plants do not experience water deficit stress. As a re- root- zone must be maintained in a balance so that plants sult, stomata closure reduces the transpiration rate and yield, can optimize their transpiration (biomass/yield production because transpiration and yield are strongly and linearly process) as well as water, nutrient, and micronutrient uptake. correlated (Irmak, 2016). Accurate determination of soil- water status (either matric Given its vital importance on numerous processes, plant potential or water content) is not only very important for physiological functions, and soil- water- atmosphere relation- irrigation and water resources management, it is also a fun- ships, soil moisture determinations and irrigation manage- damental element of soil- water movement, chemical (fate) ment decisions must be made based on technology rather transport, crop water stress, evapotranspiration, hydrologic than non- technological approaches (i.e., hand- feel method, and crop modeling, climate change, and other important calendar day approach, based on neighbors’ schedule, visual disciplines. Irrigation management requires the knowledge observations of soil and/or crop status) to optimize crop of “when” and “how much” water to apply to optimize crop production efficiency. Furthermore, unlike some of the production and increase and maintain a high level of water weather variables, soil moisture is not a transferrable vari- use efficiency. Insufficient irrigation applications can impose able between the locations or fields and it is a field- specific water stress on crops, which and can also cause irreversible variable and hence must be measured for each field. Side by damage to plants and this may lead to reductions in crop side fields and even different locations within a field can have yield and yield quality. Overirrigation cause anaerobic soil substantially different soil- water status due to various factors conditions, promote undesirable chemical and biological and the interactions of these factors. Assuming that the same reactions in the soil, which can cause yield reductions and be well- calibrated technology is used to monitor soil moisture, wasteful of water and energy resources. For example, from a the factors that contribute to differences in soil- water status multi- year research at the UNL South Central Agricultural between the two side by side fields include, but not limited to, Laboratory near Clay Center, Irmak (2014) reported that differences in the following variables between the fields: even only 25% more water than needed in the maize root- zone reduced grain yields as much as 15 bu/ac, which is a • Soil physical and textural properties substantial portion of attainable maize yield in south central • Organic matter content Nebraska. Reduced oxygen concentrations in soil due to wet soil or flooding conditions can cause stomatal closure • Field slope of plants, which causes plant stress, because plants cannot • Crop type transpire water vapor at an optimal/potential rate although water is available. Some researchers have reported that the • Planting date © The Board of Regents of the University of Nebraska. All rights reserved. 1 • Crop emergence water molecules from soil particles. As the soil gets drier, the plants must exert increasingly more energy to extract water • Plant growth and development rates and maturity date molecules because water molecules are extracted from the • Irrigation management (method, timing, amount) large soil pores first and water is held more tightly in the smaller pores and the bond between water molecules and soil • Fertilizer management (method, timing, amount) pores becomes even stronger as soil gets drier. Plants extract • Variability in precipitation (timing, amount) most readily available water molecules first and gradually extract more strongly held water molecules and that is the • Soil and crop management practices between the fields reason for SMP gradually increasing as soil gets drier (the (especially tillage) maximum value of SMP is zero, which indicates very wet • Crop water use (evapotranspiration) rates soil conditions). As soil gets drier, SMP increases negatively (more negative tension), but in practical applications, the • Residue cover type, percentage, and amount negative sign in SMP is usually ignored. SMP is usually ex- • Pesticides application method, amount, and timing pressed in units of energy such as erg/gr (1 bar = 1 x 106 erg/ gr), or in joule/kg (1 bar = 100 joule/kg). Commonly used • Field wetting history subunits are megapascal (MPa), kilopascal (kPa), centibars • Crop exposure to water, heat, and wind stress (timing, (cb) or millibars (mb) (1 bar = 0.1 MPa = 100 kPa = 100 cb duration, and magnitude) = 1000 mb). SMP can also be presented in units of pressure such as atmosphere (1 bar = 1 atm = 14.7 psi), or in units • Crop exposure to fertilizer stress (timing duration, and of water head of an equivalent water column in centimeters magnitude) (1 bar = 1022 cm H2O at sea level) or equivalent mercury • Disease pressure (Hg) column [1 bar = 76 cm (29.92 inch) Hg at sea level]. Additional information about SMP is provided in Irmak and • Other variables/factors Haman (2001) and Irmak et al. (2016). All these differences will result in substantial differences Numerous methods have been used to determine soil- in soil moisture and different irrigation management require- water status directly or indirectly. However, none of these ments between the fields. The potential of using soil mois- methods is perfect. Decision- making on “which technique ture data/information from another field/location to make should be used” to monitor soil moisture highly depends on effective irrigation management decisions is almost impos- the purpose of the application, soil conditions, crop type, sible. Thus, accurate soil moisture measurement for a given management practices, desired accuracy, durability, complex- production field is necessary for various applications and is ity, financial conditions, and other factors. While in practice much more important than it is usually thought or perceived. SWC- based technologies are more widely used, scientifically SMP is a more powerful and robust method to determine soil- water deficit or soil- water availability for plant uptake. Soil Water Content vs. Soil Matric Potential to However, the application of SMP in practice is a little more Express Soil- Water Status complicated (i.e., development of soil- water release curves). Soil- water status in the soil profile can be expressed in Thus, SWC- based applications are used probably more widely two very different ways: than SMP- based technologies. However, if the soil- water release curves are developed and SMP values are converted 1. Soil water content (θ) and to SWC or if irrigation management is practiced directly 2. Matric potential (Ψ). based on certain threshold or SMP trigger points, this would be a more robust and representative irrigation management Soil water content (SWC) indicates the quantity of water strategy as it has been researched, taught, demonstrated, and in the soil, but does not directly indicate the availability of practiced in the Nebraska Agricultural Water Management this water to plants. Soil matric potential (SMP) represents Network (NAWMN; https:// water .unl .edu /category /nawmn) the relative availability of the amount of water held in the soil functions. In sensitive research and many other scientific ap- profile for plant uptake/use and the quantity of soil- water plications, the use of SMP rather than SWC is preferred. Two from SMP is determined through soil- water characteristics of the most fundamental parameters in the entire soil water curves developed for specific soil types. In more practical status, agriculture, hydrology, crop production and crop terms, SMP is a direct indication of how much energy must physiology, and other related disciplines are the field capacity be exerted (application of pressure) by plants to extract the and permanent wilting point and these two fundamental soil 2 © The Board of Regents of the University of Nebraska. All rights reserved. properties that drive almost all soil- water- atmosphere rela- in ranking. Before establishment of NAWMN, the presence tionships were developed based on SMP rather than SWC. of soil moisture sensor companies in Nebraska was extremely In practice, quantification of SMP is a more difficult limited or did not exist. Due to extensive demonstrations, ed- process than quantifying SWC. Also, measurement of soil- ucational programs, and documented large scale impacts of water retention curve for individual soil types to quantify soil NAWMN, in the last several years, a number of soil moisture water availability from SMP measurements is a sensitive and sensor companies started to be present/visible and market difficult task. Any instrument that is able to detect the change various soil moisture sensors in Nebraska, which is a good in some of the soil properties as a function of SWC can be and positive step towards further promoting the technology used to
Load more

Recommended publications
  • UC Irvine UC Irvine Electronic Theses and Dissertations
    UC Irvine UC Irvine Electronic Theses and Dissertations Title Investigating short-term response of soil moisture-temperature-CO2 interactions to weather anomalies Permalink https://escholarship.org/uc/item/9qv54265 Author Anjileli, Hassan Publication Date 2016 Peer reviewed|Thesis/dissertation eScholarship.org Powered by the California Digital Library University of California UNIVERSITY OF CALIFORNIA, IRVINE “Investigating short-term response of soil moisture-temperature-CO2 interactions to weather anomalies” THESIS submitted in partial satisfaction of the requirements for the degree of MASTER OF SCIENCE in Civil Engineering by Hassan Anjileli Thesis Committee: Professor Amir AghaKouchak, Chair Professor Kuolin Hsu Dr. Peter A. Bowler 2016 © 2016 Hassan Anjileli i Table of contents List of figures ................................................................................................................................. iii List of tables ................................................................................................................................... iv Acknowledgements ......................................................................................................................... v Abstract of the thesis ...................................................................................................................... vi 1 Introduction ............................................................................................................................. 1 2 Materials and Methods ...........................................................................................................
    [Show full text]
  • Integrated Vineyard Precision Control System Pilot
    INTEGRATED VINEYARD PRECISION CONTROL SYSTEM PILOT FINAL REPORT TO WINE AUSTRALIA Project Number: UA 1802 Principal Investigator: PROFESSOR SETH WESTRA Research Organisation: UNIVERSITY OF ADELAIDE Date: 12 AUGUST 2019 Project Title: Integrated Vineyard Precision Control System Pilot Project Number: UA 1802 Date: 12 August 2019 Acknowledgments: The project has been supported by funding from the South Australian Wine Industry Development Scheme (SAWIDS), the Riverland Wine and Wine Australia. The contributions of Chris Byrne, The ‘Thinking 10’ Riverland Growers, Paul Dalby, Liz Waters and Paul Smith are gratefully acknowledged. Disclaimer: The information contained in this publication is based on knowledge and understanding at the time of writing (June 2019). The authors advise that the information contained in this publication comprises general statements based on scientific research. The reader is advised and needs to be aware that such information may be incomplete or unable to be used in any specific situation. No reliance or actions must therefore be made on that information without seeking prior expert professional, scientific and technical advice. To the extent permitted by law, the University of Adelaide (including its employees and consultants) excludes all liability to any person for any consequences, including but not limited to all losses, damages, costs, expenses and any other compensation, arising directly or indirectly from using this publication (in part or in whole) and any information or material contained in it. Signatures Issue No. Date of Issue Description Authors Approved 01 09/07/2019 Draft Final BB, KC, BO, VP, MQ, RRS, TR, JS, KT, WU, SW, SAW, HZ, ZS. SW Report 02 12/08/2019 Final Report BB, KC, BO, VP, MQ, RRS, TR, JS, KT, WU, SW, SAW, HZ, ZS.
    [Show full text]
  • Winter Soil Respiration in a Humid Temperate Forest: the Roles of Moisture, Temperature, and Snowpack
    University of New Hampshire University of New Hampshire Scholars' Repository Institute for the Study of Earth, Oceans, and Earth Systems Research Center Space (EOS) 12-23-2016 Winter soil respiration in a humid temperate forest: The roles of moisture, temperature, and snowpack Alexandra R. Contosta University of New Hampshire, Durham, [email protected] Elizabeth A. Burakowski University of New Hampshire, Durham, [email protected] Ruth K. Varner University of New Hampshire, Durham, [email protected] Serita D. Frey University of New Hampshire, Durham, [email protected] Follow this and additional works at: https://scholars.unh.edu/ersc Recommended Citation Contosta, A. R., E. A. Burakowski, R. K. Varner, and S. D. Frey (2016), Winter soil respiration in a humid temperate forest: The roles of moisture, temperature, and snowpack, J. Geophys. Res. Biogeosci., 121, 3072–3088, https://dx.doi.org/10.1002/2016JG003450 This Article is brought to you for free and open access by the Institute for the Study of Earth, Oceans, and Space (EOS) at University of New Hampshire Scholars' Repository. It has been accepted for inclusion in Earth Systems Research Center by an authorized administrator of University of New Hampshire Scholars' Repository. For more information, please contact [email protected]. PUBLICATIONS Journal of Geophysical Research: Biogeosciences RESEARCH ARTICLE Winter soil respiration in a humid temperate forest: 10.1002/2016JG003450 The roles of moisture, temperature, and snowpack Key Points: Alexandra R.
    [Show full text]
  • Capacitive Soil Moisture Sensor Theory, Calibration, and Testing
    Capacitive Soil Moisture Sensor Theory, Calibration, and Testing Joshua Hrisko Maker Portal LLC New York, NY July 5, 2020 1 Introduction Soil moisture can be measured using a variety of different techniques: gravimetric, nuclear, electromagnetic, tensiometric, hygrometric, among others [1]. The technique explored here uses a gravimetric technique to calibrate a capacitive-type electromagnetic soil moisture sensor. Capacitive soil moisture sensors exploit the dielectric contrast between water and soil, where dry soils have a relative permittivity between 2-6 and water has a value of roughly 80 [2]. Accurate measurement of soil water content is essential for applications in agronomy and botany - where the under- and over-watering of soil can result in ineffective or wasted resources [3]. With water occupying up to 60% of certain soils by volume, depending on the specific porosity of the soil, calibration must be carried out in every environment to ensure accurate prediction of water content [4]. Fortunately, the accuracy of measurement devices has been increasing while the cost of the sensors has been decreasing. In this experiment, the Arduino platform is used to program a microcontroller to read the analog signal from the capacitive sensor, which in turn outputs a voltage. The inverse of this voltage can be linearly fit to approximate volumetric soil moisture content via gravimetric methods. This is done by measuring the volume and weighing dry and wet soil across a range of moistures. This is the process carried out in this paper. 2 Capacitance as a Proxy for Soil Moisture Capacitance is defined as the amount of charge a material can store under a given applied electrical potential [5].
    [Show full text]
  • Soil Moisture Sensors for Urban Landscape Irrigation: Effectiveness and Reliability
    SOIL MOISTURE SENSORS FOR URBAN LANDSCAPE IRRIGATION: EFFECTIVENESS AND RELIABILITY RUSSElL J. QUAUS, JOSHUA M. SCOTI, AND WD..LlAM B. DEOREO Made in U"ilLd Stales 0/America Reprinted from JOUllNAL OF THE AMEJUCAN WATER RESOURCES ASSOCIATION Vol. 37, No.3, June 2001 Copyright 0 2001 by the American Water Rcsourecs Association JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION VOL :37, NO.3 AMERICAN WATER RESOURCES ASSOCIATION J lfN I'; 2001 SOIL MOISTURE SENSORS FOR URBAN LANDSCAPE IRRIGATION: EFFECTIVENESS AND RELIABILITY1 Russell J. Qualls, Joshua M. Scott, and Willia.m B. DeOreo2 ABSTRACT: Granular matrix soil moisture sensors wen' :Jsed to 1982; Nieswiadomy and Molina, 1989; Nie..:wiadomy, control urban landscape irrigation in Boulder, Colorado, during 1992;). However, price is unable to explain all of the 1997. The purpose of the study was to evaluate the effectiveness and reliability of the technology for water conservation. The 23 test variability in water use, particularly within the annu­ sites included a traffic median, a small city park, and 21 residential al cycle. Hence, other variables have been included to sites. The results were very good. The system limited actual appli­ explain additional variation, including air tempera-­ cations to an average of 73 percent of the theoretical requirement. tur , precipitation, lot size, property value, and num­ This f1>sulted in an average saving of $331 per installed sensor, The ber of residents per household (Danielson, 1979; sensors were highly reliable. All 23 sensors were placed in service at least three years prior to the 1997 study during earlier studies. Foster and Beattie, 1979; Maidment and Miaou, 1986; Of these, only two had failed by the beginning of the 1997 study, Miaou, 1990; Lym n, 1992; Bamezai, 1994, 1997).
    [Show full text]
  • Soil Moisture Measurement Delta-T Devices Company Profile
    Soil Moisture Measurement Delta-T Devices Company Profile Origins Sales and support Established in 1971, Cambridge based Delta-T Devices specialises Delta-T has an international network of representatives who can in instruments for environmental science, in particular for soil provide local sales and service in most countries. Export sales science, agronomy, plant science, data logging, meteorology and account for more than 80% of Delta-T’s business. environmental monitoring. Delta-T has retained thousands of loyal customers all over the world Delta-T is a co-operative company, owned and managed by the who value the reliability, performance and long-term service that we members who work within it. provide. Their feedback is incorporated into many of our product Co-operative working creates a highly professional environment in designs to create a process of continuous improvement. which we all strive to make the business successful. We share a high level of commitment to the company and to our customers. Policy statement High quality products “We aim to manufacture and sell instruments for use in work beneficial to the environment and directly related to human and Delta-T is a market leader in soil moisture monitoring, with more animal welfare. As a matter of conscience, we reserve the right not than 25 years’ experience in providing researchers with innovative, to sell our instruments to people or institutions involved in military dependable soil moisture sensors. We aim to continually improve work, tobacco research, environmentally destructive practices and and extend the capabilities of our products, using the most up-to- factory farming.” date theory and technologies.
    [Show full text]
  • A Thesis Entitled Applicability of Soil Moisture Sensors in Determination
    A Thesis entitled Applicability of Soil Moisture Sensors in Determination of Infiltration Rate by Milan K C Submitted to the Graduate Faculty as partial fulfillment of the requirements for the Master of Science Degree in Civil Engineering _________________________________________ Dr. Cyndee L. Gruden, Committee Chair _________________________________________ Dr. Ashok Kumar, Committee Member _________________________________________ Dr. Liangbo Hu, Committee Member _________________________________________ Dr. Amanda Bryant-Friedrich, Dean College of Graduate Studies The University of Toledo December 2017 Copyright 2017, Milan K C This document is copyrighted material. Under copyright law, no parts of this document may be reproduced without the expressed permission of the author. An Abstract of Applicability of Soil Moisture Sensors in Determination of Infiltration Rate by Milan K C Submitted to the Graduate Faculty as partial fulfillment of the requirements for the Master of Science Degree in Civil Engineering The University of Toledo December 2017 The need for stormwater management has been heightened in urban areas due to the increase in impermeable surfaces, causing flooding, erosion and pollution of water and soil. This problem can be mitigated with a scientifically designed stormwater management system, which requires field data including soil infiltration rate. Conventional approaches to measuring infiltration are tedious, time-consuming, and do not address the need for extensive, real-time data. The main objective of this research is to develop a technique that incorporates readily available real-time soil sensor data into the Green and Ampt Infiltration Model. Initial laboratory experiments confirmed that estimates of infiltration using Green and Ampt Infiltration Model with parameters found in the literature compared well to actual laboratory measurements of infiltration.
    [Show full text]
  • Review of Novel and Emerging Proximal Soil Moisture Sensors for Use in Agriculture
    sensors Review Review of Novel and Emerging Proximal Soil Moisture Sensors for Use in Agriculture Marcus Hardie Tasmanian Institute of Agriculture, University of Tasmania, Hobart, TAS 7000, Australia; [email protected] Received: 9 November 2020; Accepted: 29 November 2020; Published: 4 December 2020 Abstract: The measurement of soil moisture in agriculture is currently dominated by a small number of sensors, the use of which is greatly limited by their small sampling volume, high cost, need for close soil–sensor contact, and poor performance in saline, vertic and stony soils. This review was undertaken to explore the plethora of novel and emerging soil moisture sensors, and evaluate their potential use in agriculture. The review found that improvements to existing techniques over the last two decades are limited, and largely restricted to frequency domain reflectometry approaches. However, a broad range of new, novel and emerging means of measuring soil moisture were identified including, actively heated fiber optics (AHFO), high capacity tensiometers, paired acoustic / radio / seismic transceiver approaches, microwave-based approaches, radio frequency identification (RFID), hydrogels and seismoelectric approaches. Excitement over this range of potential new technologies is however tempered by the observation that most of these technologies are at early stages of development, and that few of these techniques have been adequately evaluated in situ agricultural soils. Keywords: matric potential; capacitance; soil moisture probes; dielectric constant; soil humidity; soil water FDR; TDR 1. Introduction Knowledge of soil moisture is important for supporting agricultural production, catchment hydrology, flood forecasting, landslide prediction and other ecosystem services [1–3]. Globally, agriculture is the largest water user accounting for approximately 70% of total water consumption [4].
    [Show full text]
  • Understanding Soil Moisture Sensors: a Fact Sheet for Irrigation Professionals in Virginia David J
    Publication BSE-198P Understanding Soil Moisture Sensors: A Fact Sheet for Irrigation Professionals in Virginia David J. Sample, Associate Professor, Biological Systems Engineering, and Extension Specialist, Hampton Roads Agricultural Research and Extension Center James S. Owen, Assistant Professor, Horticulture, and Nursery Extension Specialist, Hampton Roads Agricultural Research and Extension Center Jeb S. Fields, Ph.D. Student, Horticulture, Virginia Tech Stefani Barlow, Former Undergraduate Student, Biological Systems Engineering, Virginia Tech Note: This publication updates and replaces “Using USGS, 87 percent of the acreage irrigated in Virginia Soil Moisture Sensors for Making Irrigation in 2010 was sprinkler-applied, and 13 percent was Management Decisions in Virginia,” Virginia microirrigated. The latter method is the more efficient Cooperative Extension publication 442-024 (out of method to apply water to individual plants. publication). A significant, but unknown portion of irrigation water Please refer to definitions in the glossary at the end of demand in Virginia is used for landscape irrigation. this publication. Terms defined in the glossary are in Landscape irrigation represents a growing proportion boldface on first use in the text. of total water use as the state population and suburban communities grow. Therefore, the potential economic In the Commonwealth of Virginia, water resources are and resource (e.g., applied water and nutrients) increasingly being scrutinized due to changing surface savings of improving irrigation water use efficiency water or groundwater availability. Access to good is significant. Maximizing irrigation water use quality water is a continuing concern, and in many efficiency depends on applying irrigation water at the communities, managing water use — particularly right time, in the right place, and in the right amount.
    [Show full text]
  • Soil Moisture Sensors
    Florida Field Guide to Low Impact Development Soil Moisture Sensors (Above left) Layout of irrigated areas showing optimal and unsuitable locations for sensor placement. (Above right) Components of an installed soil moisture sensor system. Distances between components are not representative of final installation and are meant to illustrate the connections between the sensor, the zone valve, the controller and the irrigation time clock. (Right) Two types of soil moisture probes used in typical soil moisture sensor systems. Definition: Objectives: The soil moisture sensor (SMS) is a sensor Soil moisture sensors (SMSs) measure soil connected to an irrigation system controller that moisture at the root zone and regulate the measures soil moisture content in the active root existing conventional irrigation timer, resulting zone before each scheduled irrigation event and in considerable water savings when installed and bypasses the cycle if soil moisture is above a user- used properly. A customized soil water content defined set point. Soil moisture sensors, like rain threshold is set, allowing for dryer or wetter sensors, are considered rain shut off devices, but soil condition. SMSs function similarly to rain while rain sensors measure evapotranspiration sensors by bypassing irrigation events under rainy rates, soil moisture sensors measure real time soil conditions, but by measuring soil moisture at the moisture. root zone they are more effective at minimizing irrigation when plants do not need additional water. © 2008 University of Florida—Program for Resource Efficient Communities 1 Florida Field Guide to Low Impact Development Design Considerations: Applications SMSs appear to be effective in all soil types. New construction However, there is a range in effectiveness, and Retrofits uniform performance across soil types should Commercial not be assumed.
    [Show full text]
  • Spatial Upscaling of Soil Respiration Under a Complex Canopy Structure in an Old-Growth Deciduous Forest, Central Japan
    Article Spatial Upscaling of Soil Respiration under a Complex Canopy Structure in an Old-Growth Deciduous Forest, Central Japan Vilanee Suchewaboripont 1, Masaki Ando 2, Shinpei Yoshitake 3, Yasuo Iimura 4, Mitsuru Hirota 5 and Toshiyuki Ohtsuka 1,3,* 1 United Graduate School of Agricultural Science, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan; [email protected] 2 Laboratory of Forest Wildlife Management, Faculty of Applied Biology Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan; [email protected] 3 River Basin Research Center, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan; [email protected] 4 School of Environmental Science, The University of Shiga Prefecture, Hikone, Shiga 522-8533, Japan; [email protected] 5 Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, 305-8577, Japan; [email protected] * Correspondence: [email protected]; Tel.: +81-58-293-2065 Academic Editors: Robert Jandl and Mirco Rodeghiero Received: 6 December 2016; Accepted: 24 January 2017; Published: 30 January 2017 Abstract: The structural complexity, especially canopy and gap structure, of old-growth forests affects the spatial variation of soil respiration (Rs). Without considering this variation, the upscaling of Rs from field measurements to the forest site will be biased. The present study examined responses of Rs to soil temperature (Ts) and water content (W) in canopy and gap areas, developed the best fit model of Rs and used the unique spatial patterns of Rs and crown closure to upscale chamber measurements to the site scale in an old-growth beech-oak forest.
    [Show full text]
  • Weather- and Soil Moisture-Based Landscape Irrigation Scheduling Devices
    Weather- and Soil Moisture-Based Landscape Irrigation Scheduling Devices Technical Review Report – 5th Edition U.S. Department of the Interior Bureau of Reclamation Lower Colorado Region and Technical Service Center May 2015 Mission Statements The U.S. Department of the Interior protects America’s natural resources and heritage, honors our cultures and tribal communities, and supplies the energy to power our future. The mission of the Bureau of Reclamation is to manage, develop, and protect water and related resources in an environmentally and economically sound manner in the interest of the American public. For copies of this report contact Reclamation’s Southern California Area Office in the Lower Colorado Region at 951-695-5310 or download at: http://www.usbr.gov/waterconservation/docs/SmartController.pdf. Weather- and Soil Moisture-Based Landscape Irrigation Scheduling Devices Technical Review Report – 5th Edition prepared by Southern California Area Office Lower Colorado Region Temecula, California and Water Resources Planning and Operations Support Group Technical Service Center Denver, Colorado U.S. Department of the Interior Bureau of Reclamation Lower Colorado Region and Technical Service Center May 2015 Weather- and Soil Moisture-Based Landscape Scheduling Devices Table of Contents page Introduction............................................................................................................1 Smart Irrigation Technology Overview...............................................................3 SWAT Testing ...................................................................................................3
    [Show full text]