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The Arctic is warming at twice the global average, which may impact agricultural production in Greenland. Therefore knowledge of the functional properties of Greenlandic soil resources is necessary. The relative soil gas diffusivity [the soil gas diffusion coefficient (D p)-free-air diffusion coefficient (D o) ratio] is the chief parameter controlling gas transport in soils. Predictions of D p /D o are needed to estimate root zone aeration and terrestrial greenhouse gas fluxes. We used existing models to analyze the D p /D o of soils from Greenlandic fields and a pore connectivity index (C ip) to infer their degree of structural development and identify the main parameters controlling D p /D o. In total, 201 × 3 intact 100-cm 3 soil samples were sampled across six fields with clay and organic C contents of 0.016 to 0.089 and 0.016 to 0.105 kg kg −1 , respectively. The D p /D o was measured with the one-chamber nonsteady-state method at soil water potentials between-10 and-1,000 cm H 2 O. Accurate determination of total porosity (Φ) was ensured by calibrating a particle density model on 129 samples. The soils exhibited a less developed structure and highly tortuous pore networks, resulting in low D p /D o as a function of air-filled porosity (ε). Density-corrected models with air saturation (ε/Φ) reduced the RMSE. Furthermore, C ip at-1,000 cm H 2 O soil water potential increased linearly with dry bulk density (ρ b), suggesting that ρ b is a key controller of D p /D o , which is important for planning cultivation practices for Southern Greenlandic soils. Lastly, we found that an air saturation >35% is required for adequate soil aeration. Abbreviations: CF, coarse fraction; C ip , pore connectivity index; D o , diffusion coefficient of oxygen in free air; D p , oxygen soil gas diffusion coefficient; D p /D o , relative soil gas diffusivity; GDC, generalized density-corrected model;

The soil specific surface area (SSA) affects soil physical and chemical properties. Numerous studies applied visible near-infrared spectroscopy (Vis-NIRS) to estimate clay content (particles < 2 µm). Since SSA is better defined and more directly related to particle size distribution and mineralogy than clay content, predictions of SSA from Vis-NIRS are expected to be better than that for clay. Thus, the aims of this study were to (i) test the feasibility of using Vis-NIRS for SSA determination, (ii) compare the predictive ability of Partial Least Squares (PLS) model of SSA with that of clay, (iii) identify important wavelengths using interval Partial Least Squares (iPLS) regression, and to test if the application of iPLS improves the predictive ability of the models. A total of 550 soil samples with a wide range in SSA (3-437 m 2 g-1) and clay content (1-83%) was divided into a calibration and a validation set. The PLS models had similar predictive ability for SSA (ratio of performance to interquartile range, RPIQ = 1.7) and clay content (RPIQ = 1.6). utilizing iPLS led to only limited improvement in the prediction accuracy (RPIQ of 1.8 and 1.7 for SSA and clay content, respectively), yet decreased the number of relevant wavelengths and indicated a higher specificity of SSA over the broader spectral response of clay. The important wavelengths for SSA and clay predictions were indicative of the organo-mineral content and its interactions, including spectral response from not only iron oxides and minerals but also organic matter due to masking effect of the non-complexed organic carbon on the mineral phases of some of the soils. Abbreviations: EGME, ethylene glycol monoethyl ether; iPLS, interval partial least squares; OM, organic matter; PC, principal component; PCA, principal component analysis; PLS, partial least squares; RPIQ, ratio of performance to interquartile range; RMSEP, root mean squared error of prediction; SOC, soil organic carbon; SSA, soil specific surface area; vis-NIRS, visible near-infrared spectroscopy. T he soil specific surface area (SSA) is a basic soil property and indicates the surface area per unit mass of soil. It affects physical and chemical properties of the soil and is important for processes such as water retention and movement, ion exchange reactions, contaminant adsorption, microbial attachment, nutrient dynamics, soil aggregation, and irrigation management (Pennell, 2002). The SSA can vary greatly depending on the soil type and the method used for its determination. Different soils present differences in mineralogical and organic composition as well as in particle-size distribution resulting in large variations in the amount of available reactive surfaces. For instance, soils rich in clay and organic matter can have SSA of up to 8 × 10 5 m 2 kg-1 , whereas the SSA for sandy soils can be as low as 1 × 10 3 m 2 kg-1 (Pennell, 2002). Due to the importance of SSA, there is a worldwide interest and need for its accurate determination. Although SSA is measured routinely by scientists, a...

The tribe Microteryini Hoffer, 1955 is proposed a junior synonym of Discodini Hoffer, 1954. The genus Aschitus Mercet is newly defined and a key is provided to females of 20 Palaearctic species. In new limits Aschitus includes the genera Anicetellus Szelényi and Viggiania Trjapitzin as junior synonyms, and 18 speeies are transferred to Aschitus as combs. n., viz. submetallicus Szelenyi from Anicetellus, aeneiventris (Walker), barbarus (Dalman), hemipterus (Nikolskaja), lichtensiae (Howard), matritensis (Mercet), triozae (André), zarina (Walker) from Encyrtus, axius (Trjapitzin), carpathicus (Hoffer) (nom. praeocc., = hofferi nom. n.), ilus (Trjapitzin), itylus (Trjapitzin), narzykulovi (Sharipov), problematicus (Hoffer), sugonjaevi (Trjapitzin) from Microterys, carpathicus (Hoffer), mongolicus (Myartseva) and naiacocci (Trjapitzin) from Paraphaenodiscus. Aschitus balcanicus sp. n. is described from Greece and Yugoslavia. Lectotypes are designated for Encyrtus barbarus Dalman, Metallon usticorne Erdös and Microterys nikolskajae Erdös. Aschitus hofferi nom. n. is proposed as a replacement name for Mícroterys carpathicus Hoffer, 1977.