Date of Defense
18-11-2025 9:30 AM
Location
Building F3, Room 223
Document Type
Thesis Defense
Degree Name
Master of Science in Horticulture
College
College of Agriculture and Veterinary Medicine
Department
Integrative Agriculture
First Advisor
Dr. Elke Gabriel Neumann
Keywords
Fruit trees, plant nutritional status, arbuscular mycorrhizal fungi, biofertilizers, citrus, micronutrient deficiency
Abstract
Domestic cultivation of fruits can greatly contribute to food security and supply of residents with healthy but highly perishable products. However, in the area of Al Ain, the cultivation of dicotyledonous fruit trees at the commercial scale is relatively uncommon, due to risks associated with the impact of the harsh environmental conditions on plant performance. The present study aimed at investigating to which extent mineral nutrient deficiency is responsible for the poor performance of fruit trees during the warm summer season. A five year old fruit tree plantation at the UAEU Research Farm in Al Foah served as study site. The plantation involved sixteen dicotyledonous and commercially relevant fruit tree species. The youngest fully developed leaves of these plants were sampled and analyzed for concentrations of mineral nutritional elements. In addition, root and soil samples were taken from the plant rooting zone to assess the extent of arbuscular mycorrhiza (AM) fungal root colonization and the number of AM fungal spores in the soil. Results revealed a sufficient supply status with cations and P for most plants, and a moderate to low N nutritional status. Plants of all species were severely Zn deficient, and all sampled citrus species and pomegranate showed deficiency of Mn. Plant species that were best able to maintain adequate nutritional status during the hot summer months were mulberry, sidr, and table grapes, and lime. Micronutrient deficiency was identified as a likely reason for poor performance of fruit trees at the Al Foah site. Evaluation of the plant fertilization and irrigation practices revealed a rather low N, P, and K input via the applied manure, and it is recommended to provide plants with additional mineral or organic fertilizer to improve nutrient supply, especially with N. Further recommended is regular foliar application of chelated Zn, Mn and Ni. The irrigation water supply to plantations of fig, almond, citrus species, pomegranate, grapes, and plums was found to be excessive, potentially leading to nutrient leaching from the irrigation basins, and high carbon footprints. It is recommended to base the irrigation water supply on estimation of the potential evapotranspiration in the future. The analysis of AM fungal root colonization of the fruit trees revealed high AM colonization of mango, mulberry, and citrus species. Other mycotrophic species, such as fig, sidr, and pomegranate, however, were not colonized at all. The previous use of the site for ghaf tree plantation did not encourage AM fungal root colonization in fruit trees grown at the same site. It is possible that AM fungi were introduced to the site with the root bales of the fruit trees at the time of planting. Since AM fungi can greatly enhance plant performance in stressful environments and facilitate acquisition of P and micronutrients, it was recommended to inoculate the nonmycorrhizal fruit trees in Al Foah with a biofertililzer containing AM fungal propagules.
Included in
NUTRITIONAL STATUS AND ENDOMYCORRHIZAL ROOT COLONIZATION OF VARIOUS FRUIT TREE SPECIES GROWN IN THE OPEN FIELD IN AL AIN, UAE
Building F3, Room 223
Domestic cultivation of fruits can greatly contribute to food security and supply of residents with healthy but highly perishable products. However, in the area of Al Ain, the cultivation of dicotyledonous fruit trees at the commercial scale is relatively uncommon, due to risks associated with the impact of the harsh environmental conditions on plant performance. The present study aimed at investigating to which extent mineral nutrient deficiency is responsible for the poor performance of fruit trees during the warm summer season. A five year old fruit tree plantation at the UAEU Research Farm in Al Foah served as study site. The plantation involved sixteen dicotyledonous and commercially relevant fruit tree species. The youngest fully developed leaves of these plants were sampled and analyzed for concentrations of mineral nutritional elements. In addition, root and soil samples were taken from the plant rooting zone to assess the extent of arbuscular mycorrhiza (AM) fungal root colonization and the number of AM fungal spores in the soil. Results revealed a sufficient supply status with cations and P for most plants, and a moderate to low N nutritional status. Plants of all species were severely Zn deficient, and all sampled citrus species and pomegranate showed deficiency of Mn. Plant species that were best able to maintain adequate nutritional status during the hot summer months were mulberry, sidr, and table grapes, and lime. Micronutrient deficiency was identified as a likely reason for poor performance of fruit trees at the Al Foah site. Evaluation of the plant fertilization and irrigation practices revealed a rather low N, P, and K input via the applied manure, and it is recommended to provide plants with additional mineral or organic fertilizer to improve nutrient supply, especially with N. Further recommended is regular foliar application of chelated Zn, Mn and Ni. The irrigation water supply to plantations of fig, almond, citrus species, pomegranate, grapes, and plums was found to be excessive, potentially leading to nutrient leaching from the irrigation basins, and high carbon footprints. It is recommended to base the irrigation water supply on estimation of the potential evapotranspiration in the future. The analysis of AM fungal root colonization of the fruit trees revealed high AM colonization of mango, mulberry, and citrus species. Other mycotrophic species, such as fig, sidr, and pomegranate, however, were not colonized at all. The previous use of the site for ghaf tree plantation did not encourage AM fungal root colonization in fruit trees grown at the same site. It is possible that AM fungi were introduced to the site with the root bales of the fruit trees at the time of planting. Since AM fungi can greatly enhance plant performance in stressful environments and facilitate acquisition of P and micronutrients, it was recommended to inoculate the nonmycorrhizal fruit trees in Al Foah with a biofertililzer containing AM fungal propagules.