A Summary of Water Suitability Criteria for Irrigation

Abstract

This scientific article aims to summarize the most important measurements of the quality of water for use in irrigation of various crops. The goal is to help professionals and researchers in the soil, water and environment field in the selection of appropriate alternatives to face potential problems that may occur because the use of low quality water in irrigation, which may adversely affect the characteristics of the soil and thus reduce productivity and quality of crops cultivated .The most important measurements, which are summarized in this article includes measurements of salinity risk, measurements the risks of both of soil sodicity and alkalinity ,soil permeability for water quality and the specific hazards of some toxic ions. Water class for Salinity Irrigation Water Salinity Remarks Class Description EC,(dS m-1) TDS,(ppm) C1 Low Salinity < 0.25 < 200 Used for irrigation for most crops on most soils. Some leaching required under normal irrigation practices, but excess irrigation is required in extremely low permeability soil. C2 Medium Salinity 0.25-0.75 200-500 Can be used if a moderate amount of leaching occurs. Plants with moderate salt tolerance can be grown in most instances without special practices for salinity control. C3 High Salinity 0.75-2.25 500-1500 Can't be used on soil with restricted drainage. Even with adequate drainage, special management for salinity control may be required and plants with good salt tolerance should be selected. C4 Very high Salinity > 2.25 > 1500 Not suitable for irrigation under ordinary conditions but may be used occasionally under very special circumstances .The soils must be permeable , drainage must be adequate , irrigation water must be applied in excess to provide considerable leaching , and very salt-tolerant crops should be selected. Table 2. Potential of irrigation problems based on salinity values Degree of problem Units Potential of Irrigation Problem Severe Slight to Moderate None > 3.0 0.7-3.0 < 0.7 dS/m ECw > 2000 450-2000 < 450 mg/l TDS Salt Index Researches indicated that the safety limits permitted (accepted safe limit) to salinity in irrigation water is 600 mg kg-1. When water containing salts in the range of 600 to 1200 mg.kg-1 , it is necessary to appreciated saltiness guide (Salt Index). Also, this assessment is used to predict the risk of sodic. It is defined with the relationship between mono-valent sodium ions (Total Na +) and divalent calcium ions in CaCO 3 (Total Ca 2+), which found in irrigation and the estimated, as ppm i.e., mg. l-1 and can be calculated by using the following formula for Singh (2005) : Salt index = [(Total Na +-24.5)-(total Ca 2+ in CaCO 3)] x 4.85 Water quality for irrigation according to the obtained value could be evaluated as: •Negative value, mean good water quality for use in irrigation.

Comparative Evaluation of Boron Sorption Dynamics on Zeolites in Irrigation Waters: An Isothermal Modeling Approach

“…Furthermore, equilibrium assays with natural irrigation water were conducted in order to verify the interferences/synergies with other chemical species [ 30 ]. For this, irrigation water samples were collected from a pond located on a commercial farm situated in Cuevas del Almanzora (Almería, Spain).…”

Evaluation of Agricultural Soil-Improving Zeolite for Improving Irrigation Water Quality

“…The average pH of the irrigation water before treatment was approximately 8.35. The chemical characterization of the initial samples is shown in Table 4, where the obtained values are compared with the maximum limits for irrigation water defined by the FAO [11], as well as the restrictions on water use for irrigation [11,49]. Among all identified elements, only sodium and boron presented higher usage restrictions due to their high concentrations.…”