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New Mexico State University (2015)

Desert shrub / tree growth performance under varied irrigation treatments

Bahar Yalcin

Titre : Desert shrub / tree growth performance under varied irrigation treatments

Auteur : Bahar Yalcin

Université de soutenance : New Mexico State University

Grade : Master of Science (MS) Plant and Environmental Sciences 2015

This study evaluates the growth performance of three drought-tolerant tree/shrub species : Afghan pine (Pinus eldarica), Gambel oak (Quercus gambelii) and New Mexico locust (Robinia neomexicana). Three irrigation treatments - 40%, 60% and 80% dry down rates based on gravimetric weights - were used to determine the species’ survival in areas with low moisture content over a period of seven months in greenhouse trials and six months in field trials. The research was conducted in the greenhouse and the field at the Fabian Garcia Science Center of New Mexico State University in Las Cruces, NM. Measurements for biomass, root growth potential, soil texture analysis, plant height, plant diameter, and evapotranspiration were obtained in this study. Evapotranspiration was determined with a weighing lysimeter that was designed for the greenhouse. The greenhouse results show that biomass was greatest for all species under the 80% irrigation treatment. Afghan pine showed a higher total biomass value than both Gambel oak and New Mexico locust due to its fast growth rate. However, for root growth potential analysis, NM locust demonstrated the highest new root production. According to plant height and diameter measurements that were conducted in the greenhouse between January and July, Afghan pine showed the greatest increase in height during the first three months. In the latter four months the NM locust exceeded the Afghan pine in height. The Afghan pine had the largest diameter for the January to July duration of the greenhouse trials. In the field trials, the NM locust had the greatest biomass, although the Afghan pine had the largest diameter and height increases for the first three months of March, April, and May. In remaining three months of June, July, and August, the NM locust exceeded the Afghan pine in height and diameter. An electronic weighing lysimeter system was designed to track the greenhouse tree seedling water use. A total of 27 weighing lysimeters were used in this research project. An amplifier circuit was designed to increase the signal amplification from the load cell. The amplifier was required to increase the measurement resolution from the lysimeter. The daily readings from the lysimeter measurement system show a daily water use. The weighing lysimeter has 4 major components, a support frame, a tray with 98 growing containers, a load cell, and measurement electronics.

Présentation (NMSU Library)

Page publiée le 13 octobre 2018