ALBERT

Description: In Europe, the establishment of short rotation coppice (SRC) systems for biomass production has been expanding in the last decades. Several studies have considered the impacts of SRC on soil properties; many have focused on studying its effect on biochemical properties while only a few have addressed physical and hydraulic properties. This study reports the assessment of soil physical and hydraulic properties on two SRC sites on sandy soils planted with 3-year-old poplar trees and an adjacent conventional agricultural field in Western Slovakia. All sites contain a comparable sandy loam soil texture and both SRC fields differed only in the groundwater accessibility. Water infiltration experiments were conducted in the field with subsequent sampling of the upper topsoil (0–5 cm depth). The samples were further processed in the laboratory to obtain the water retention and hydraulic conductivity functions of the soil covering a wide range of soil pore saturation. These hydraulic functions were fitted by using the bimodal version of Kosugi-Mualem’s hydraulic model to estimate the pore-size distribution (PSD) of the soils. The comparison between the SRC field neighboring the agricultural field and the latter showed similar hydraulic soil properties such as the topsoil water retention. However, macropore content, bulk density (BD) and infiltration capacity differed under SRC particularly in the tree row. Analogously, the two SRC fields showed similar topsoil water contents. Other soil properties differed presenting an increased macropore content and higher BD in the SRC field with distant groundwater connection. Our findings suggest that the SRC management may influence the topsoil properties.

Description: Early above- and belowground biomass fractionation, root diameter composition and allocation of cumulated fine root length per total leaf area of Populus clones have been measured for a pre-assessment of the risk for plantation establishment during spring drought conditions. Four clones of Populus × euramericana, and one P. nigra × P. maximowiczii clone (cv. Max 3), were planted in sandy mix substrate and were exposed to one normal and one deficit watering regime over 65-day greenhouse experiments conducted during early summer. The P. × euramericana hybrids showed plasticity of their root biomass fractions. Although clone Max 3 was among the productive clones, even under deficit watering, it was not able to respond plastically to deficit watering. It showed no increase in the root biomass fraction and no increase in the ratio of cumulated fine root length per total leaf area. Therefore, the clone Max 3 should not be planted under high risk for spring drought. Planting the investigated P. × euramericana clones under water deficit likely involves a lower risk, but clone differences within this group must be considered. It can be concluded that the water deficit response of biomass allocation to roots and of the ratio of fine root length per unit leaf area is suitable traits to improve drought risk assessments that are based on yield response of poplar clones to drought. Percent plant loss data and the yield at the end of the first SRC rotation will be suitable to verify the present greenhouse assessment.

Description: The water use by short rotation coppices (SRC) has been a focus of ongoing research in the last decades. Nevertheless, investigations that consider site factors and present long-term monitoring of the components of the water balance are rare. This research quantified the tree-based transpiration in the 4th growing season of uncoppiced 1st rotational hybrid poplar stands (Populus deltoides Bart. ex Marsh × P. nigra L. “AF2”) in western Slovakia. The aim of the study was to determine the influence of meteorological and soil-related site conditions on transpiration rates. Three experimental plots were located in the Morava River floodplains, on loamy sand-textured soils with different groundwater accessibilities: higher, low, and fluctuating groundwater level. We measured sap flow (Heat Ratio Method), volumetric water content, matric potential, groundwater level, and meteorological variables throughout the growing season in 2019. The results indicated that transpiration in the three sites was almost constant during that period, which was characterized by distinct conditions. The average cumulative transpiration at the site with a higher groundwater level (1105 mm) was larger than at the site with a lower groundwater level (632 mm) and the site with fluctuating groundwater (863 mm). A principal component analysis (PCA) and correlation analysis identified that the contribution of meteorological and soil-related site variables to transpiration differed among the sites. Soil water availability and groundwater accessibility are critical variables for the water use of poplar SRC. We concluded that the combination of site conditions needs to be reconsidered for the expansion of sustainable short rotation plantations in Europe.

Description: This dataset contains measurements of soil moisture, soil matric potential, soil temperature, groundwater depth, and throughfall from the study area of the project Dendromass4Europe. Three poplar SRC stands were selected according to a gradient of groundwater accessibility: S5-N (higher groundwater level), S4-D (low groundwater level), and S2-F (fluctuating groundwater level). On each of the selected sites one soil profile was excavated and prepared for the installation of soil sensors. The aim of the study was to determine the influence of meteorological and soil-related site conditions on tree transpiration rates in poplar SRC stands. Soil moisture was measured with frequency domain reflectometry (FDR) sensors, with 51 mm rods. Soil matric potential and soil temperature were measured with Tensiomark sensors of a length of 125 mm, with a ceramic head. The soil profiles were excavated on May 2018 and sensors were installed as follows: four pairs of sensors of soil moisture and matric potential at 0.3 m soil depth, three pairs at 0.6 m soil depth, and two pairs at 0.9 m soil depth. In the horizontal plane, the distance between sensors was 0.15 m; the distance between pairs was 0.3 m. At the site with fluctuating groundwater level (S2-F), at 0.9 m soil depth, high gravel content prevented the installation of matric potential sensors. On each site, a groundwater well was excavated at a distance of three meters from the soil pit. The fluctuations in groundwater level were recorded with a KELLER pressure sensor. Throughfall collectors were built at 1 m height above ground. The measurements started in June 2018 (in the case of fluctuations of groundwater level: December 2018) with a resolution of 15 minutes until middle of March 2020 (16.03.2020) and after that with a resolution of 60 minutes until end of May 2022 (31.05.2022).

Description: This dataset contains measurements of global radiation, precipitation, air temperature, relative humidity, air pressure, wind speed and wind direction from the study area of the project Dendromass4Europe. The aim of the study was to determine the influence of meteorological and soil-related site conditions on tree transpiration rates in poplar short rotation coppices plantations. In June 2018 a meteorological station was installed. The measurements started in June 2018 with a resolution of 30 minutes until end of May 2022 (31.05.2022). Three poplar SRC stands were selected according to a gradient of groundwater accessibility: S5-N (higher groundwater level), S4-D (low groundwater level), and S2-F (fluctuating groundwater level). On each of the selected sites one soil profile was excavated and prepared for the installation of soil sensors. The meteorological station was located southwest from the experimental sites. The distance from the meteorological station to the experimental sites was: 9.56 km to site S5-N (higher groundwater table), 9.82 km to site S4-D (low groundwater level), and 6.57 km to site S2-F (fluctuating groundwater table).

Description: This dataset contains measurements of sap velocity and sap flow from the study area of the project Dendromass4Europe. Three poplar SRC stands were selected according to a gradient of groundwater accessibility: S5-N (higher groundwater level), S4-D (low groundwater level), and S2-F (fluctuating groundwater level). On each of the selected sites four trees were selected according to the tree diameter at breast height distribution.The aim of the study was to quantify the water use of clone "AF2" on sites with contrasting groundwater conditions. For the sap measurements a SFM1 sap device (Heat Ratio Method) was used at 20-minutes resolution in 2019 and 30-minutes resolution in 2021. In 2019 the sensors were installed in April and the measurements were conducted throughout the growing season until end of September. In 2021, measurements started in July and concluded in September. No measurements were conducted in growing season 2020.

Description: This dataset contains measurements of sap flow from the study area of the project Dendromass4Europe. Three poplar SRC stands were selected according to a gradient of groundwater accessibility: S5-N (higher groundwater level), S4-D (low groundwater level), and S2-F (fluctuating groundwater level). On each of the selected sites four trees were selected according to the tree diameter at breast height distribution.The aim of the study was to quantify the water use of clone "AF2" on sites with contrasting groundwater conditions. For the sap measurements a SFM1 sap device (Heat Ratio Method) was used at 20-minutes resolution in 2019 and 30-minutes resolution in 2021. In 2019 the sensors were installed in April and the measurements were conducted throughout the growing season until end of September. In 2021, measurements started in July and concluded in September. No measurements were conducted in growing season 2020.