Variable Rate Irrigation Management for Humid Climates Using a Conventional Center Pivot System

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT REQUEST OF AUTHOR.] Economic as well as water shortage pressure on agricultural use of water has placed added emphasis on efficient irrigation management. Center pivot technology has made great improvement with variable rate irrigation (VRI) technology to vary water application spatially and temporally to maximize the economic and environmental return. Proper management of VRI systems depends on correctly matching the pivot application to specific field temporal and areal conditions. There is need for a tool to accurately and inexpensively define dynamic management zones, to sense within-field variability in real time, and control variable rate water application so that producers are more willing to adopt and utilize the advantages of VRI systems. This study included tests of the center pivot system uniformity performance in 2014 at Delta Research Center in Portageville, MO. The goal of this research was to develop MOPivot software with an algorithm to determine unique management areas under center pivot systems based on system design and limitations. The MOPivot tool automates prescriptions for VRI center pivot based on non-uniform water needs while avoiding potential runoff and deep percolation. The software was validated for use in real-time irrigation management in 2018 for VRI control system of a Valley 8000 center pivot planted to corn. The water balance model was used to manage irrigation scheduling. Field data, together with soil moisture sensor measurement of soil water content, were used to develop the regression model of remote sensing-based crop coefficient (Kc). Remote sensing vegetation index in conjunction with GDD and crop growth stages in regression models showed high correlation with Kc. Validation of those regression models was done using Centralia, MO, field data in 2016. The MOPivot successfully created prescriptions to match system capacity of the management zone based on system limitations for center pivot management. Along with GIS data sources, MOPivot effectively provides readily available graphical prescription maps, which can be edited and directly uploaded to a center pivot control panel. The modeled Kc compared well with FAO Kc. By combining GDD and crop growth in the models, these models would account for local weather conditions and stage of crop during growing season as time index in estimating Kc. These models with Fraction of growth (FrG) and cumulative growing degree days (cGDD) had a higher coefficient of efficiency, higher Nash-Sutcliffe coefficient of efficiency and higher Willmott index of agreement. Future work should include improvement in the MOPivot software with different crops and aerial remote sensing imagery to generate dynamic prescriptions during the season to support irrigation scheduling for real-time monitoring of field conditions.

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ARSPivot, A Sensor-Based Decision Support Software for Variable-Rate Irrigation Center Pivot Systems: Part A. Development

Transactions of the ASABE ◽

10.13031/trans.13907 ◽

2020 ◽

Vol 63 (5) ◽

pp. 1521-1533

Author(s):

Manuel A. Andrade ◽

Susan A. O’Shaughnessy ◽

Steven R. Evett

Keyword(s):

Decision Support ◽

Supervisory Control ◽

Irrigation Scheduling ◽

Variable Rate ◽

Site Specific ◽

Sensing Systems ◽

Center Pivot ◽

Water Sensing ◽

Friendly Graphical User Interface ◽

Variable Rate Irrigation

HighlightsThe ARSPivot software seamlessly integrates site-specific irrigation scheduling methods with weather, plant, and soil water sensing systems in the operation of variable-rate irrigation (VRI) center pivot systems.ARSPivot embodies an Irrigation Scheduling Supervisory Control and Data Acquisition (ISSCADA) system that incorporates site-specific irrigation scheduling methods and automates the collection and processing of data obtained from sensing systems supporting them.ARSPivot incorporates a friendly graphical user interface (GUI) that assists in the process of setting up a computerized representation of a coupled ISSCADA VRI center pivot system and simplifies the review of irrigation prescriptions automatically generated based on sensor feedback.ARSPivot’s GUI includes a geographic information system (GIS) that relates sensed data and imported GIS data to specific field control zones.Abstract. The commercial availability of variable-rate irrigation (VRI) systems gives farmers access to unprecedented control of the irrigation water applied to their fields. To take full advantage of these systems, their operations must integrate site-specific irrigation scheduling methods that in turn should be supported by a network of sensing systems. An Irrigation Scheduling Supervisory Control and Data Acquisition (ISSCADA) system patented by scientists with the USDA-Agricultural Research Service (ARS) at Bushland, Texas, incorporates site-specific irrigation scheduling methods informed by weather, plant, and soil water sensing systems. This article introduces a software package, ARSPivot, developed to integrate the ISSCADA system into the operation of VRI center pivot systems. ARSPivot assists the operation and integration of a complex network of sensing systems, irrigation scheduling methods, and irrigation machinery to achieve this end. ARSPivot consists of two independent programs interacting through a client-server architecture. The client program is focused on automatically collecting and processing georeferenced data from sensing systems and communicating with a center pivot control panel, while the server program is focused on communicating with users through a friendly graphical user interface (GUI) involving a geographic information system (GIS). The GUI allows users to visualize and modify site-specific prescription maps automatically generated based on sensor-based irrigation scheduling methods, and to control and monitor the application of irrigation amounts specified in these recommended prescription maps using center pivots equipped for VRI zone control or VRI speed control. This article discusses the principles and design considerations followed in the development of ARSPivot and presents tools implemented in the software for the virtual design and physical operation of a coupled ISSCADA VRI center pivot system. This article also illustrates how the ISSCADA system and ARSPivot constitute a comprehensive sensor-based decision support system (DSS) for VRI management that is accessible to users without in-depth knowledge of sensing systems or irrigation scheduling methods. Keywords: Center pivot irrigation, Decision support system, Precision agriculture, Sensors, Site-specific irrigation scheduling, Software, Variable rate irrigation.n

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<i>Application of deficit irrigation management to variable rate irrigation for winter wheat in sub-arid climates</i>

10.13031/aim.201700875 ◽

2017 ◽

Author(s):

Xiumei Li ◽

Weixia Zhao ◽

Jiusheng Li ◽

Yanfeng Li

Keyword(s):

Winter Wheat ◽

Deficit Irrigation ◽

Irrigation Management ◽

Variable Rate ◽

Variable Rate Irrigation

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Variable-rate irrigation management using an expert system in the eastern coastal plain

Irrigation Science ◽

10.1007/s00271-014-0457-x ◽

2015 ◽

Vol 33 (3) ◽

pp. 167-175 ◽

Cited By ~ 13

Author(s):

K. C. Stone ◽

P. J. Bauer ◽

W. J. Busscher ◽

J. A. Millen ◽

D. E. Evans ◽

...

Keyword(s):

Expert System ◽

Coastal Plain ◽

Irrigation Management ◽

Variable Rate ◽

Variable Rate Irrigation

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Potential Water Conservation Using Site-Specific Variable Rate Irrigation

Applied Engineering in Agriculture ◽

10.13031/aea.13108 ◽

2019 ◽

Vol 35 (6) ◽

pp. 881-888

Author(s):

Kenneth C Stone ◽

Philip J Bauer ◽

Gilbert C Sigua

Keyword(s):

Water Conservation ◽

Irrigation Management ◽

Field Capacity ◽

Weather Conditions ◽

Variable Rate ◽

Water Usage ◽

Site Specific ◽

Management Zones ◽

Water Holding ◽

Variable Rate Irrigation

Abstract. Site-specific variable-rate irrigation (VRI) systems can be used to spatially manage irrigation within sub-field-sized zones and optimize spatial water use efficiency. The goal of the research is to provide farmers and consultants a tool to evaluate the potential benefits of implementing VRI. The specific objective of this research is to evaluate the potential water savings using VRI management compared with uniform irrigation management to maintain soil water holding capacity above 50% depletion using two irrigation scenarios: 1) a standard 12.5 mm irrigation per application; and 2) an application to refill the soil profile to field capacity. A 21-year simulation study was carried out on a selected field with varying degrees of soil and topographic variability. The simulated field had 12 soil mapping units with water holding capacities in the top 0.30-m ranging from 42 to 70 mm. The 21-year simulation covering all weather conditions for each soil produced only two significantly different irrigation management zones for scenario 1, and for scenario 2 only one management zone. However, when the 21-year period was divided into periods with different ratios of rainfall to reference evapotranspiration, the simulations identified 1 to 5 management zones with significantly different irrigation requirements. These results indicate that variable rate irrigation system design and management should not be solely based on long term average weather conditions. Years with differing weather conditions should be used for potentially identifying management zones for VRI systems. Irrigation application depths between management zones ranged from 17 to 38 mm. However, when the actual soil areas of the study field were utilized to calculate the total volume of irrigation water applied, it resulted in an increase in water usage in the 2 and 4 management zones ranging from -1.2% to 5.8%. Water usage with VRI over uniform irrigation was greater by -1.6% to 6.8% in the 12.5 mm irrigations and by -1.2% to 2.2% for the field capacity irrigations Keywords: Management zones, Precision farming, Variable-rate irrigation, Water conservation.

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Evaluation of a hybrid remote sensing evapotranspiration model for variable rate irrigation management

10.13031/irrig.20152142641 ◽

2015 ◽

Keyword(s):

Remote Sensing ◽

Irrigation Management ◽

Variable Rate ◽

Variable Rate Irrigation

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ARSPivot, A Sensor-Based Decision Support Software for Variable-Rate Irrigation Center Pivot Systems: Part B. Application

Transactions of the ASABE ◽

10.13031/trans.13908 ◽

2020 ◽

Vol 63 (5) ◽

pp. 1535-1547

Author(s):

Manuel A. Andrade ◽

Susan A. O’Shaughnessy ◽

Steven R. Evett

Keyword(s):

Information System ◽

Decision Support ◽

Geographic Information System ◽

Soil Water ◽

Irrigation Management ◽

Plant Stress ◽

Geographic Information ◽

Variable Rate ◽

Center Pivot ◽

Water Sensing

HighlightsThe ARSPivot software facilitates variable-rate irrigation management of a center pivot irrigation system.The software embodies a system capable of generating site-specific prescription maps based on weather, plant, and soil water information.ARSPivot’s graphical user interface (GUI) incorporates easy-to-use geographic information system (GIS) tools that help its users to make irrigation management decisions.Abstract. The ARSPivot software was developed for the seamless operation of a complex network consisting of a variable-rate irrigation (VRI) center pivot system and an Irrigation Scheduling Supervisory Control and Data Acquisition (ISSCADA) system that interfaces with weather, plant, and soil water sensing systems. ARSPivot’s graphical user interface (GUI) incorporates a built-in geographic information system (GIS) that maps a center pivot system and facilitates the analysis of data relevant to its operation. The GIS was developed following a minimalistic approach with the objective of making its geospatial data analysis tools accessible to a wide range of users (farmers, irrigation consultants, and researchers). The post-harvest analyses of two experiments carried out in the Texas High Plains during the summers of 2016 and 2017 using a three-span VRI center pivot are presented to illustrate the advantages of using ARSPivot as a decision support tool and how its GIS tools help its users make better informed decisions regarding irrigation management. In these experiments, the north-northwest (NNW) portion of a field planted with corn (Zea mays L.) was irrigated using VRI zone control, and the south-southeast (SSE) portion was irrigated using VRI speed control. Experimental plots in the NNW portion were assigned one of three irrigation levels (80%, 50%, or 30% replenishment of soil water depletion to field capacity in the top 1.5 m), and their irrigation was scheduled using either a plant stress-based algorithm implemented in the ARSPivot software or manual weekly neutron probe (NP) readings. Plots in the SSE portion were assigned a single irrigation level of 80%, and their irrigation was scheduled using either the plant stress method or a two-step hybrid approach in which soil water sensing was combined with the plant stress method to determine irrigation depths. Soil water sensing data for the ISSCADA system were provided by NP readings during the 2016 season and by sets of time-domain reflectometers (TDRs) installed at depths of 15, 30, and 45 cm during the 2017 season. No significant differences were found during either season in terms of mean dry grain yield and crop water productivity (CWP) obtained from plots irrigated at the 80% level in both sides of the field, regardless of the irrigation scheduling method or the type of VRI application method used for irrigation. No significant differences were found during either season between mean dry grain yield and CWP of plots in the NNW portion irrigated using the plant stress-based method and NP readings at the 80% irrigation level. The lack of significant differences documented the potential of the ARSPivot system as a plant and soil water sensing-based decision support software for site-specific irrigation management of corn using a VRI center pivot system. Keywords: Center pivot irrigation, Decision support system, Geographic information system, Precision agriculture, Software.

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