Assessment of methods to determine soil characteristics for management and design of irrigation systems

Abstract

Irrigation system design and irrigation management require appropriate match of the soil and type of crop. In Chile, agrological reports are currently being used to determine the homogeneity of soil units and land capability classes: fruit tree production vs orchard design. Agrological studies use a number of soil characteristics, but these do not include hydrophysical properties, which are essential when zoning for irrigation. Therefore, it is necessary to establish a methodology to objectively evaluate soils, based on a quantitative analysis that includes hydrophysical parameters. In this study, different methodologies are proposed for classifying homogenous soil units based on extensive field sampling. The field data was evaluated using two methodologies: 1) the SAG-USDA Manual and 2) in situ sampling of soil's hydrophysical properties and pedotransfer models. There were differences between the methodologies regarding zoning soil properties for irrigation system design and management. The methodology based on the SAG-USDA Manual requires auxiliary data in order to provide useful maps for design and management of irrigation systems. Published pedotransfer functions should be carefully assess before their use in large-scale design, as the quality the estimations depends on the data used to derive the equations. Therefore, if field data is available, we recommend calibrating equations using well-known statistical methods such as least square. In this study, the functions obtained describe the properties of interest properly, such as the field capacity for design of micro-irrigation systems. However, predicting wilting point did not give reliable results.

Using a fuzzy logic decision system to optimize the land suitability evaluation for a sprinkler irrigation method

“…The goal offers the objective which demonstrates favored results. Irrigation land suitability analysis is given to the physical and chemical properties of soil in relation to methods of irrigation considered (Kebede and Ademe, 2016;Valdivia-Ceal et al, 2017). Most of the conducted studies have used the parametric method for land suitability analysis for irrigation methods (Albaji et al, 2008(Albaji et al, , 2010(Albaji et al, , 2015Dengiz, 2006;Hoseini and Delavari, 2016) and less frequently applied new methods based on the fuzzy logic.…”

“…The goal offers the objective which demonstrates favored results. Irrigation land suitability analysis is given to the physical and chemical properties of soil in relation to methods of irrigation considered (Kebede and Ademe, 2016; Valdivia-Ceal et al, 2017).…”

Development and Evaluation of Pedotransfer Functions to Estimate Soil Moisture Content at Field Capacity and Permanent Wilting Point for South African Soils

“…Inaccurate estimation of hydraulic properties may result in the poor modelling of the water dynamics and could give misleading overall results from a biosphere model, resulting in inefficient use and management of natural resources [12,13]. Therefore, the existing PTFs developed internationally still need to be calibrated and validated locally against measurements before they can be reliably used to estimate hydraulic properties in new sites that are located in different regions from their origins [12,[44][45][46]. However, the lack of representative information on soil hydraulic properties hinders the validation of the existing PTFs and the development of local PTFs in many countries of the world [12,24,46,47].…”

“…Therefore, the existing PTFs developed internationally still need to be calibrated and validated locally against measurements before they can be reliably used to estimate hydraulic properties in new sites that are located in different regions from their origins [12,[44][45][46]. However, the lack of representative information on soil hydraulic properties hinders the validation of the existing PTFs and the development of local PTFs in many countries of the world [12,24,46,47]. Consequently, the existing PTFs are often applied without any calibration or validation in many regions as the result of data constraints [13,46,48].…”

“…However, the lack of representative information on soil hydraulic properties hinders the validation of the existing PTFs and the development of local PTFs in many countries of the world [12,24,46,47]. Consequently, the existing PTFs are often applied without any calibration or validation in many regions as the result of data constraints [13,46,48]. Therefore, the reliability of the estimated soil hydraulic properties from the existing PTFs in regions outside their origins with different geological, climatic and soil bio-physico-chemical properties is questionable.…”