Hydrological components of a young loblolly pine plantation on a sandy soil with estimates of water use and loss

Abstract

Abstract. Fertilizer and irrigation treatments were applied in a 7-to 10-year-old loblolly pine (Pinus taeda L.) plantation on a sandy soil near Laurinburg, North Carolina. Rainfall, throughfall, stemflow, and soil water content were measured throughout the study period. Monthly interception losses ranged from 4 to 15% of rainfall. Stemflow ranged from 0.2 to 6.5% of rainfall. Rainfall, leaf area index (LAI), basal area (BA), and the interactions of rainfall with LAI or BA influenced prediction models of throughfall, but not stemflow, on a stand level. We found significant differences due to the effects of treatments in the soil water of the top 0.5-and 1-m soil layers by the beginning of the second growing season and throughout the remainder of the study period. Average daily water use and loss from a 1-m soil layer reflected the low water-holding capacity of the sand. Soil water in a 1-m layer was rapidly depleted to within 10% of available water during periods of little or no rainfall. Irrigation did not significantly affect productivity and created a greater potential for loss of water to drainage below 1 m. On the basis of Zahner's [1966] method of soil water depletion in a sandy soil under forest cover, total drainage to below 1 m was 55% of evapotranspiration in unirrigated plots and 150% of evapotranspiration in irrigated plots. IntroductionLoblolly pine (Pinus taeda L.) is a major commercial species in the southeastern United States. Water stress is one of the factors that imposes limits to forest productivity. Teskey et al. [1987] reported unexplained declines in loblolly pine productivity in the southeast and found that productivity of intensively managed loblolly pine stands is reduced by summer temperatures and droughts in the spring and fall in east central North Carolina. Swank et al. [1972] found that rainfall interception ranged from 10 to 35 % as loblolly pine stands developed unless management practices reduced stocking and tree canopy. then depend in part on the ability of the stand to acclimate to changes in water availability, especially to water deficit periods during the growing season. Understanding how the hydrological components are affected by fertilization and irrigation and how the growth induced by these treatments affects water availability in young pine stands was the objective of the hydrological component of this study. This study should also help us understand how loblolly pine responds to water deficit periods on soils with low water-holding capacities under conditions of high evaporative demand.We quantified monthly throughfall, stemflow, and soil water in a young loblolly pine stand on a sandy soil under irrigation and fertilization treatments; tested for differences between the amounts of water reaching the soil under control, irrigated, fertilized, and irrigated + fertilized treatments; and compared treatment water use and loss by the water balance method using the measured components, and Zahner's [1966] method of soil water depletion for sandy soils. Site Description ...

Influence of soil porosity on water use in Pinus taeda

“…Six samples per site were taken at about 0.3 m depth and analyzed with the hydrometer method by the Utah State University Analytical Laboratory (Logan, Utah). At the sand site, we used silt and clay fractions averaged over 1.65 m depth as reported by Abrahamson et al (1998) for the site. Both sites received only natural precipitation at an average annual rate of 1,210 mm for the sand site and 1,150 mm at the loam site.…”

“…b at the sand site was derived by fitting Eq. 1 to moisture release data from the site (Abrahamson et al 1998). Table 1 Selected soil and plant parameters.…”

Eficiencia del uso del agua en plantaciones de Pinus radiata en Chile

“…Esta situación permitió que la cubierta herbácea sobreviviera por más tiempo (12). Bajo estas circunstancias, la tasa de transpiración de las plantaciones volvió a aumentar, porque una cantidad indeterminada de agua se reintegró a la atmósfera sin que pudiera ser aprovechada por los árboles (8,12).…”

“…La evapotranspiración total incluye el agua interceptada por el dosel, la que no es aprovechada por los árboles y, por lo tanto, no participa en su desarrollo (5,8).…”

“…Entre las climá-ticas sobresalen la radiación solar, las precipitaciones, la temperatura y la humedad del aire (5-7), mientras que en las edáficas destacan, entre otras, la capacidad de retención de agua útil del suelo y la velocidad de infiltración (8). Estas dos últimas características determinan la cantidad y el tiempo que el agua del suelo está disponible para la vegetación (9).…”