**1. Introduction**

Achieving an efficient use of natural resources and other production factors is a common goal of many of the current policies aimed at the sustainability of human activity; irrigation of agricultural crops uses about 80% of the total freshwater available for all human activities; thus, improving irrigation efficiency is a main endeavor to provide sustainability to this vital resource availability [1, 2].

Worldwide experience indicates that projected economic returns on investments in field irrigation systems are seldom fully obtained by farmers, due to improper strategies on irrigation scheduling, lack of operational control, and limited feedback on the actual performance of irrigation systems, in terms of application efficiency and uniformity. Field irrigation system projects are generally properly designed and installed, considering soil, climate and crop characteristics, with theoretical high water application and distribution efficiencies. However, in most projects, its actual operation and maintenance strategies do not accurately include these characteristics, resulting in excessive water depths applied, generally well over actual crop water needs, unnecessary energy costs, as well as constraints on reaching potential crop yields and marketable fruit quality. Also, irrigation systems' cumulative

deterioration conditions after its installation in the field, due to lack of proper maintenance and timely spare parts replacement, result in a significant reduction of the cost effectiveness of farm investments in irrigation infrastructure [3].

Lack of operational control, limited feedback on the actual performance of irrigation systems, in terms of application efficiency and uniformity, limited use of agrometeorological and crop development data to assess crop water needs, and scant follow-up of soil water content dynamics as an indicator of the fit between actual water applied and actual water evapotranspirated by the crop, as well as limitations on human resources knowledge and training, are the major issues explaining the situation described above.

Irrigation scheduling is related to the farmers' decision process concerning "'when" to irrigate and "how much" water to apply, in order to maximize agriculture production profit. Knowledge on crop water requirements and yield responses to water, as well as specific irrigation equipment constraints, limitations relative to the water supply system, and financial and economic implications of irrigation practice, must be integrated in any rational strategy to optimize pressurized irrigation systems use [4–7].

When appropriate water application techniques (i.e., irrigation system physical characteristics) are correctly coupled with irrigation scheduling (i.e., the volume and timeliness of water applications), as well as the implementation of irrigation system proper maintenance strategies, it is possible to optimize available water for irrigation, achieve potential crop yield/quality, and reduce irrigation costs. Investing resources in an up-to-date technological, sophisticated irrigation system is not by itself enough to attain high levels of performance, if its operation and maintenance are not updated accordingly [8].

Research has made available many tools, including procedures to compute crop water requirements, simulate soil water balance, estimate the impact of water deficits on yield and evaluating the economic returns of irrigation; however, irrigation scheduling and comprehensive irrigation equipment maintenance protocols are not yet utilized by the majority of farmers. Furthermore, only limited irrigation scheduling information is utilized worldwide by irrigation system managers, extensionists, or farmer advisers. It is recognized, however, that the adoption of appropriate irrigation scheduling practices generally leads to increased yield and profit improvements for farmers, significant water and energy savings, reduced environmental impact of irrigation, and long-term sustainability of irrigated agriculture [9–13].

Integration of soil hydrodynamic characteristics, potential evapotranspiration, and crop leaf area index evolution throughout the irrigation season, with actual irrigation operation data, and soil water content periodic measurements, is needed to implement smart water management strategies, aimed to optimize the economic return of investments in irrigation equipment at the farm level, as well as to reduce its operational costs and ensure continuous optimal soil water availability conditions to crops [14].

Pressurized irrigation application equipment (drip, microjet, or microsprinkler) is a high precision machine, which allows the producer to obtain the highest productivity of their agricultural crops, and at the same time, achieve specific quality characteristics, in accordance to market demands. Like any high precision machine, its design, installation, operation, and optimal maintenance are absolutely essential to achieve the objectives of high production and high quality of any viticulture, fruit, or horticultural plantation. If the design, installation, operation and/or maintenance of the systems are not optimal, generally, its negative effects on crop production and quality are more detrimental than the incorrect use of surface irrigation, because root crop soil volume wetted by each emitter (dripper, microjet, or microsprinkler) is restricted, being essential to maintain in this restricted soil volume-specific water and nutrients, salinity, acidity (pH), and oxygen availability conditions, continuously throughout the production season [15].

**13**

*Agronomic Operation and Maintenance of Field Irrigation Systems*

farm decision-making stakeholders, and farm advisors.

**2. Irrigation scheduling interactive platform**

1 mm = 10 m3

This chapter reports the main components and actual use of an interactive, dynamic, and relational database management system (RDBMS), an irrigation scheduling platform, using structured query language (SQL) for querying, maintaining, and updating the database [16]. The platform is designed to implement smart water management strategies and techniques in the operation and maintenance of farm irrigation systems in actual plantations, fruit orchards, and vineyards irrigated by drip or microsprinkler systems [6, 11, 17, 18]. The platform allows graphic representation of relevant data and processed results, automatically updating all the information required in any time span and/or in any irrigation sector combination, using interactive, easily understandable dashboards. Specific considerations for field irrigation system maintenance are also discussed in this chapter, with an analysis on the constraints for the platform adoption by farming personnel,

The interactive platform developed integrates soil hydrodynamic characteristics relevant to irrigation scheduling, with crop water requirements, based on atmospheric evaporative demand and the evolution of crop leaf area index throughout the irrigation season, as well as with the irrigation system daily effective

tion on the evolution of soil water content is also integrated, allowing next 5 days' irrigation schedules to be automatically modified, aiming to maintain continuous soil water availability conditions to the crop, if the soil profile water content trend is increasing or decreasing with respect to a specific target range [6, 9, 11, 18–20].

The platform calculates the soil volume effectively providing water to crop roots, considering soil stratification depths and textures, and the integrated water volume stored at field capacity, calculated using the "Soil Water Characteristics Hydraulic Properties Calculator" [21], assuming that water distribution in the soil below each irrigation emitter forms an ellipsoid, with specific a, b, and c radii measured in soil observation trenches at the onset of the irrigation season [22, 23] (**Figure 1**). We have repeated soil water distribution field observations on a bimonthly basis, and for most soils, a, b, and c values remain fairly constant throughout the irrigation season.

Management of the allowed soil water depletion (MAD) by ETc [8, 9], defined as the percentage of soil water stored at field capacity in the effective soil water volume, is the threshold to initiate the next irrigation event; it considers soil root crop distribution and its water extraction pattern, rootstock relative drought resistance, as well as soil major texture class, crop value, and water costs; this threshold can

The platform is programmed to schedule irrigation based on the "*variable frequency*—*variable water depth*" approach [4, 6, 7, 9, 13]; however, a maximal irrigation time value for each irrigation cycle is defined for each soil dominant structure, to avoid water percolation in lighter soils and to avoid surface water ponding or partial soil saturation in heavier soils. Thus, during high atmospheric evaporative demand periods, irrigation water depth equivalent to daily ETc in sandy soils determines the need of several watering events or cycles throughout the day, and in clay soils, irrigation is applied in 2–3 days cycle intervals, to replace the total

/hectare) applied to each irrigated sector. Independently, informa-

/hectare, being

operation, in terms of actual water depths (expressed in mm or m3

**2.1 Soil hydrodynamic properties relevant to irrigation scheduling**

also be modified according to specific crop phenology stages [19, 20].

water depth corresponding to Σ (daily ETc since the last irrigation event).

*DOI: http://dx.doi.org/10.5772/intechopen.84997*

*Agronomic Operation and Maintenance of Field Irrigation Systems DOI: http://dx.doi.org/10.5772/intechopen.84997*

*Irrigation - Water Productivity and Operation, Sustainability and Climate Change*

deterioration conditions after its installation in the field, due to lack of proper maintenance and timely spare parts replacement, result in a significant reduction of

Lack of operational control, limited feedback on the actual performance of irrigation systems, in terms of application efficiency and uniformity, limited use of agrometeorological and crop development data to assess crop water needs, and scant follow-up of soil water content dynamics as an indicator of the fit between actual water applied and actual water evapotranspirated by the crop, as well as limitations on human resources knowledge and training, are the major issues explaining

Irrigation scheduling is related to the farmers' decision process concerning "'when" to irrigate and "how much" water to apply, in order to maximize agriculture production profit. Knowledge on crop water requirements and yield responses to water, as well as specific irrigation equipment constraints, limitations relative to the water supply system, and financial and economic implications of irrigation practice, must be integrated

When appropriate water application techniques (i.e., irrigation system physical characteristics) are correctly coupled with irrigation scheduling (i.e., the volume and timeliness of water applications), as well as the implementation of irrigation system proper maintenance strategies, it is possible to optimize available water for irrigation, achieve potential crop yield/quality, and reduce irrigation costs. Investing resources in an up-to-date technological, sophisticated irrigation system is not by itself enough to attain high levels of performance, if its operation and

Research has made available many tools, including procedures to compute crop water requirements, simulate soil water balance, estimate the impact of water deficits on yield and evaluating the economic returns of irrigation; however, irrigation scheduling and comprehensive irrigation equipment maintenance protocols are not yet utilized by the majority of farmers. Furthermore, only limited irrigation scheduling information is utilized worldwide by irrigation system managers, extensionists, or farmer advisers. It is recognized, however, that the adoption of appropriate irrigation scheduling practices generally leads to increased yield and profit improvements for farmers, significant water and energy savings, reduced environmental impact of irrigation, and long-term sustainability of irrigated agriculture [9–13].

Integration of soil hydrodynamic characteristics, potential evapotranspiration, and crop leaf area index evolution throughout the irrigation season, with actual irrigation operation data, and soil water content periodic measurements, is needed to implement smart water management strategies, aimed to optimize the economic return of investments in irrigation equipment at the farm level, as well as to reduce its operational costs and ensure continuous optimal soil water availability conditions to crops [14]. Pressurized irrigation application equipment (drip, microjet, or microsprinkler) is a high precision machine, which allows the producer to obtain the highest productivity of their agricultural crops, and at the same time, achieve specific quality characteristics, in accordance to market demands. Like any high precision machine, its design, installation, operation, and optimal maintenance are absolutely essential to achieve the objectives of high production and high quality of any viticulture, fruit, or horticultural plantation. If the design, installation, operation and/or maintenance of the systems are not optimal, generally, its negative effects on crop production and quality are more detrimental than the incorrect use of surface irrigation, because root crop soil volume wetted by each emitter (dripper, microjet, or microsprinkler) is restricted, being essential to maintain in this restricted soil volume-specific water and nutrients, salinity, acidity (pH), and oxygen availability

conditions, continuously throughout the production season [15].

the cost effectiveness of farm investments in irrigation infrastructure [3].

in any rational strategy to optimize pressurized irrigation systems use [4–7].

the situation described above.

maintenance are not updated accordingly [8].

**12**

This chapter reports the main components and actual use of an interactive, dynamic, and relational database management system (RDBMS), an irrigation scheduling platform, using structured query language (SQL) for querying, maintaining, and updating the database [16]. The platform is designed to implement smart water management strategies and techniques in the operation and maintenance of farm irrigation systems in actual plantations, fruit orchards, and vineyards irrigated by drip or microsprinkler systems [6, 11, 17, 18]. The platform allows graphic representation of relevant data and processed results, automatically updating all the information required in any time span and/or in any irrigation sector combination, using interactive, easily understandable dashboards. Specific considerations for field irrigation system maintenance are also discussed in this chapter, with an analysis on the constraints for the platform adoption by farming personnel, farm decision-making stakeholders, and farm advisors.
