Effects of different amendments (organic matter and hydrogel) on the actual evapotranspiration and crop coefficient of turf grass under field conditions^*

Abstract

The irrigation schedule in arid areas has to be efficient in order to reduce losses due to evaporation and deep infiltration. Irrigation optimization poses the need to establish with precision the value of actual evapotranspiration (ETa), and the crop coefficient (Kc). The water soil availability can be increased using hydrogel and organic matter amendments, and their effects could vary ETa and Kc. The aim of this study was to determine the ETa, and Kc of an experimental site with lysimeters on the Spanish Mediterranean coast cropped with a turf grass variety, Agrostis stolonifera ‐L‐93, under field conditions, and amended with hydrogel and organic matter. Reference evapotranspiration (ET0) was determined from meteorological data (FAO‐Penman‐Monteith equation). ETa was calculated from the water balance, and Kc was obtained by dividing ETa by ET0. Kc was calculated and compared on a yearly, monthly and daily basis. In summer, the differences between amendments become manifest:Unamended lysimeter (100% sand) had Kc values (0.92‐1.16), similar to organic matter amended lysimeter (0.99‐1.17). Maximum and minimum Kc values for the hydrogel amended lysimeters (1.04‐1.52) were higher than those from the other because of the ability of this compound to retain water, which facilitated evapotranspiration. Finally, hydrogel helped to maintain the turf grass quality.

Design of a Bioretention System with Water Reuse for Urban Agriculture through a Daily Water Balance

“…The outcome of this calculation led to the determination of an experimental crop coefficient denoted as Kc e = 1.08. This determination was reported, for the case study, by Bandenay et al [31]. Incorporating this latest finding and adopting a crop coefficient value of Kc = Kc e = 1.08 enables the estimation of actual evapotranspiration (ETa).…”

“…Generally, for project or design purposes, crop evapotranspiration ETc is used, while for evaluation or real-time irrigation forecasting, actual evapotranspiration ETa is employed [35]. For this research, in the calculation of the variation in soil water storage ∆RG, the reference evapotranspiration ET 0 was used because, in this case, it was equal to the crop evapotranspiration ETc (Equation ( 3)) due to the value of Kc = kc e being equal to 1.08, which is very close to unity [31], and because ET 0PM was the value used in the experimental plot's water balance. Thus, the estimation of crop evapotranspiration for day i (ETc i ) is given by Equation ( 3), where K ci and ET 0i are, respectively, the crop coefficient for day i and the reference evapotranspiration for day i.…”

Growth, Physiology, and Productivity of Bouteloua gracilis and Cenchrus ciliaris Using Moisture Retainers under Different Planting Methods

“…The use of hydrogel as a water retainer in the soil is a good option to optimize water use and not affect other similar grass species such as Agrostis stolonifera [38]. However, a study on oil flax showed that hydrogel application together with the seed was more effective than granular applications with traditional flax sowing machine since there was insufficient water retention where the granules were placed [39].…”

A Systematic Review of the Potential of a Dynamic Hydrogel as a Substrate for Sustainable Agriculture

“…Moreover, a high bulk density value determines the compactness of the soil, hence affecting air and water movements, which could impede root growth and yield [74]. Accordingly, improving the planting medium could allow for superior gas exchange and sufficient water and nutrient supply through efficient rooting systems and mechanical support for plant growth [75,76].…”

“…The hydrogel-based method is also utilisable in vivo root phenotyping to prove the interconnected pore space filled by the nutrient-held hydrogel [76]. As WHC directly affects the percentage of pore space [73][74][75][76][77][78], the polymer could reduce irrigation requirements [25,31,73] and mitigate water limitations in particular areas. Fur-thermore, when considering fertiliser costs, adding hydrogel might be the ideal option to optimise water and nutrient employment while maintaining crop production [31,70,79].…”