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University of California Davis (2021)

Sustaining Alfalfa Forage Production with Limited Water Resources

Gull, Umair

Titre : Sustaining Alfalfa Forage Production with Limited Water Resources

Auteur : Gull, Umair

Université de soutenance : University of California Davis

Grade : Doctor Philosophy (PhD) 2021

Résumé partiel
Variability in climatic conditions and uncertainty in water supply brings challenges for sustainable irrigated forage production. Alfalfa (Medicago sativa L.), one of the major forage crops worldwide, is affected due to its high water demands for successful irrigated production. To address the challenge of sustaining forage yields in a changing climate, we designed three studies to understand the yield response of alfalfa under different irrigation systems and with varying water deficits. We also examined the usefulness of aerial imagery to understand the yield and quality variability in the field as affected by drought. In study 1, the potential of sub-surface drip irrigation (SDI) combined with reduced irrigation for improving forage yield, quality, and water productivity of alfalfa under water deficit conditions in California’s Central Valley was explored. In study 2, we examined the two overhead irrigation systems : low elevation spray application (LESA) and mobile drip irrigation (MDI) for producing alfalfa and the impacts of deficit irrigation using these two technologies on alfalfa production, quality, and productivity. In study 3, we examined the ability of aerial imagery, specifically, multispectral and LiDAR imaging technologies to understand yield and quality variability on a field scale with differential drought treatments. Study 1 was conducted at Kearney Agricultural Research and Extension Center (Parlier, CA) from 2016-2019 using randomized complete block (RCB) design on sandy loam soil while study 2 and 3 were conducted during 2019 and 2020 at Davis, CA using split plot randomized complete block design on a clay-loam soil. In Study 1, we found that there were no significant differences between SDI and flood irrigation systems over two years of study. In small-plot studies, it is likely that flood irrigation techniques are advantageous due to smaller checks, an advantage that may disappear when larger fields are considered- thus advantages of these systems should be viewed at scale. In addition, the SDI plots had maintenance issues in the later part of the study, a common problem with SDI. But SDI had the advantage of applying water to more closely match crop evapotranspiration demands while flood seems slightly stressed during the growth cycle due to less frequent irrigation.

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Page publiée le 23 janvier 2023