Thermodynamic parameters of enzymes in grassland soils from Galicia, NW Spain.

39: 311-319.The thermodynamic parameters of the enzymes catalase, dehydrogenase, casein-protease, a-N-benzoyl-L-argininamide (BAA)- protease, urease, Carboxymethyl (CM)-cellulase, invertase, b-glucosidase and arylsulphatase, were investigated in grassland soils from a European temperate-humid zone (Galicia, NW Spain). The effect of temperature on enzyme activity was determined at 5, 18, 27, 37, 57 and 70 1C. The temperature-dependence of the rate of substrate hydrolysis varied depending on the enzyme and soil. In general, the soil containing the least amount of organic matter (OM) showed the lowest enzyme activity for all temperatures and enzymes, whereas soils with similar OM contents showed similar levels of activity for the entire temperature range. Temperature had a noteworthy effect on the activity of oxidoreductases. Product formation in the reaction catalyzed by dehydrogenase increased with increasing temperature until 70 1C, which was attributed to chemical reduction of iodonitrotetrazolium violet (INT) at high temperatures. Catalase activity was not affected above 37 1C, which may be explained either by non-enzymatic decomposition of hydrogen peroxide or by the fact that catalase has reached kinetic perfection, and is therefore not saturated with substrate. The Arrhenius equation was used to determine the activation energy (Ea) and the temperature coefficient (Q10) for all enzymes. The values of Ea and Q10 for each enzyme differed among soils, although in general the differences were small, especially for those enzymes that act on substrates of low molecular weight. In terms of the values of Ea and Q10 and the differences established among soils, the results obtained for those enzymes that act on substrates of high molecular weight differed most from those corresponding to the other enzymes. Thus the lowest Ea and Q10 values corresponded to BAA-protease, and the highest values to CM-cellulase and casein-protease. Except for catalase in one of the soils, the values of Ea and Q10 for the oxidoreductases were similar to those of most of the hydrolases. In general, the effect of temperature appeared to be more dependent on the type of enzyme than on the characteristics of the soil. r 2006 Elsevier Ltd. All rights reserved.Peer reviewe

Hydrolitic enzyme activities in agricultural and forest soils. Some implications for their use as indicators of soil quality.

40: 2146-2155.Although a great deal of information exists about the effect of land use on soil enzyme activities, much of this is contradictory and brings into question the suitability of soil enzyme activities as indicators of how land use affects soil quality. The purpose of this study was to investigate the effect of land use on different soil biochemical properties, especially hydrolytic enzyme activities, with the aim of providing knowledge about the problems related to the use of enzymes as indicators of soil quality. The data presented derive from various studies in which a large number of soils under different types of forest or agricultural management were analysed by the same methods. All of the soil samples were characterized in terms of their main physical and chemical properties, the activity of several hydrolases, microbial biomass C and soil basal respiration. The results indicate that soil use causes a large reduction in organic matter content and that the effect on enzyme activity varies depending on the type of land use or management and the type of enzyme. Furthermore, the enzyme activities per carbon unit (specific activities) in soils affected by land use are almost always higher than in maximum quality soils (climax soils under oak vegetation or oak soils), and land use also generates greater increases in the specific activity as the C content decreases. The mechanism responsible for these increases probably involves loss of the most labile organic matter. Enzyme enrichment is not always produced to the same degree, as it varies as a function of the enzyme and the type of land use under consideration. It is concluded that the complexity of the behaviour of the soil enzymes raises doubts about the use of enzyme activities as indicators of soil degradation brought about by land use.Peer reviewe

Effect of soil use on the composition of circulating water: the Fonte Espiño river basin (Galicia, NW Spain).

En Difusse Phosphorus Loss (eds. Goswin Heckrath and Gitte H. Rubaek), págs. 397-399.Peer reviewe

Evaluation of C Stocks in Afforested High Quality Agricultural Land

18 páginas, 3 figuras, 7 tablasAfforestation of marginal land has been recommended by the Intergovernmental Panel on Climate Change (IPCC) as a means of enhancing the capacity of soil to act as a carbon (C) sink. However, the success of this practice is variable and depends on many factors, including the type of land management used. In this study, we quantified and compared the C stocks in two highly productive agricultural soils afforested with poplar 10 years before the study and in adjacent soils still used for agricultural purposes. One of the agricultural soils was sown with grass and maize in a crop rotation system and the other was alternately sown with maize (6 months) and left fallow (6 months). In all soils, we estimated the C pools associated with the live biomass (including the C extracted by harvesting in the cropped soils in the 10 years since afforestation), dead biomass, amount of fertiliser added (quantifying all inputs of C added as fertiliser in the cropped soils since the start of afforestation) and the soil organic matter (0–100 cm), to enable estimation of the total C stocks in the ecosystem. Afforestation had different effects on the various C pools. Thus, although afforestation enhanced the C sink capacity of the ecosystem when carried out on agricultural land, the degree to which this occurred varied according to previous land use. The increase in C stocks that occurred from afforestation was lower in the plots employing maize-grass rotation, compared to those with maize-fallow rotation. The ecosystem C balance was quite similar in both afforested plots (247.4 and 233.0 Mg C ha−1), while it was quite different in the cultivated plots (182.3 Mg C ha−1 in Laraño; 73.9 Mg C ha−1 in A Barca). Although at both sites the C balance was higher in the afforested plot than in the cultivated plot, the differences were much smaller in Laraño (65.1 Mg C ha−1 higher in the forested plot than in the cultivated plot) than in A Barca (159.1 Mg C ha−1 higher in the forested plot than in the cultivated plot). Our results from highly productive agricultural land are similar to previous findings on marginal land.This research was funded by the Spanish MICINN (Project No. CGL2008-01992/BTE) co-financed with ERDF funds from the EU and by the Xunta de Galicia through the RCG project IN607A 2021-06 and the Contrato-Programa CSIC-Xunta 2021–2022.Peer reviewe

Modifications of organic matter and enzymatic activities in response to change in soil use in semi-arid mountain ecosystems (southern Spain)

Soil organic matter composition and biochemical properties were determined in mountain calcimorphic Mediterranean soils under different vegetation (cultivated soils, secondary bush, high mountain bush, juniper, evergreen oak and pine) to assess the impact of soil use on the size and activity of microbial communities. Our results indicated that clearing forest leads to a general decline in the performance of soil organic carbon sequestration and associated enzymatic activities. However, when soil enzymatic activities (dehydrogenase, catalase, phosphodiesterase, β-glucosidase, urease and casein-protease) were expressed as ratios to total organic carbon (specific activities), a conspicuous increase in their activities was observed in cleared soils as compared with forest soils, suggesting enhanced hydrolytic potential in the former. In addition, the negative correlation observed between qCO 2 (metabolic quotient) and water retention at -1500 kPa, could be interpreted as an adaptive strategy against low soil moisture by microbial communities in cleared soils. This indicates the importance of describing soil quality in terms of long-term soil organic C sequestration and/or resistance of the organic matter to microbial transformation. These features were reflected in the visible and infrared spectra of humic acids, which suggested humification mechanisms involving mainly an alteration of plant macromolecules with poor incorporation of characteristic microbial metabolites in the forest soils whereas the opposite effect was observed in cleared soils. © 2012 The Authors. Journal compilation © 2012 British Society of Soil Science

Global cross-cultural validation of a brief measure for identifying potential suicide risk in 42 countries

Objectives This study aimed to examine the psychometric properties of the P4 suicide screener in a multinational sample. The primary goal was to evaluate the reliability and validity of the scale and investigate its convergent validity by analyzing its correlation with depression, anxiety, and substance use. Study design The study design is a cross-sectional self-report study conducted across 42 countries. Methods A cross-sectional, self-report study was conducted in 42 countries, with a total of 82,243 participants included in the final data set. Results The study provides an overview of suicide ideation rates across 42 countries and confirms the structural validity of the P4 screener. The findings indicated that sexual and gender minority individuals exhibited higher rates of suicidal ideation. The P4 screener showed adequate reliability, convergence, and discriminant validity, and a cutoff score of 1 is recommended to identify individuals at risk of suicidal behavior. Conclusions The study supports the reliability and validity of the P4 suicide screener across 42 diverse countries, highlighting the importance of using a cross-cultural suicide risk assessment to standardize the identification of high-risk individuals and tailoring culturally sensitive suicide prevention strategies

Cross-cultural validation and measurement invariance of anxiety and depression symptoms: A study of the Brief Symptom Inventory (BSI) in 42 countries.

Depression and anxiety are among the most prevalent mental health issues experienced worldwide. However, whereas cross-cultural studies utilize psychometrically valid and reliable scales, fewer can meaningfully compare these conditions across different groups. To address this gap, the current study aimed to psychometrically assess the Brief Symptomatology Index (BSI) in 42 countries. Using data from the International Sex Survey (N = 82,243; M <sub>age</sub>  = 32.39; SD <sub>age</sub>  = 12.52; women: n = 46,874; 57 %), we examined the reliability of depression and anxiety symptom scores of the BSI-18, as well as evaluated evidence of construct, invariance, and criterion-related validity in predicting clinically relevant variables across countries, languages, genders, and sexual orientations. Results corroborated an invariant, two-factor structure across all groups tested, exhibiting excellent reliability estimates for both subscales. The 'caseness' criterion effectively discriminated among those at low and high risk of depression and anxiety, yielding differential effects on the clinical criteria examined. The predictive validation was not made against a clinical diagnosis, and the full BSI-18 scale was not examined (excluding the somatization sub-dimension), limiting the validation scope of the BSI-18. Finally, the study was conducted online, mainly by advertisements through social media, ultimately skewing our sample towards women, younger, and highly educated populations. The results support that the BSI-12 is a valid and reliable assessment tool for assessing depression and anxiety symptoms across countries, languages, genders, and sexual orientations. Further, its caseness criterion can discriminate well between participants at high and low risk of depression and anxiety