Soil C dynamics after deforestation and subsequent conversion of arable cropland to grassland in humid temperate areas.

Land use and plant-soil management influence soil organic C stocks and soil properties. This study aimed to identify the main mechanisms by which these factors alter soil organic matter (SOM) dynamics and stocks. Changes in the organic C pools and biochemical quality in different OM compartments were assessed: a) after deforestation and intensive cultivation (SOM loss) and then, b) after the conversion of cropland to grassland (SOM replenishment) in a chronosequence of recovery (1-45 years). Topsoil samples were subjected to physical fractionation to assess the distribution of free particulate OM (POM) and mineral associated OM (MAOM). SOM quality was characterized by 13C NMR spectroscopy, thermal analysis (DSC/TG), and microbial activity was monitored by isothermal microcalorimetry. Deforestation and intensive cultivation led to the loss of 80 % of the C stored in the upper mineral soil (up to 30-35 cm). The POM was almost depleted, MAOM underwent significant losses (>40 %) and all OM compounds, including the aromatic C, were affected. The large and unexpected loss of MAOM can be attributed to the low specific surface soil area and also to the labile (biodegradable) nature of the OM in this fraction. After 45 years, conversion of cropland to grassland recovered 68 % of the C lost in the mineral soil (mainly as MAOM), at an annual rate of 1.25 Mg C ha-1. The present findings showed that the persistence of long-term OM depends on how strongly organic compounds are adsorbed onto mineral surfaces (i.e., the specific surface area) and the biochemical nature of OM compounds. Adequate plant-soil management favoured the replenishment of the MAOM under these experimental conditions, and this fraction was an active pool in terms of C storage and biochemical quality. This study served to test current theories about changes in soil C fractions due to land use changes and soil-plant management.

Survey data on joint cropland management among agri-food cooperatives in Mediterranean Spanish Regions.

This dataset presents data collected from joint cropland management practices survey in agri-food cooperatives of Mediterranean Spanish Regions. The objective was to examine to what extent cooperatives offer joint services, including joint management or integral exploitation of smallholdings, for the incorporation of new professionals. Data collection was conducted to five agri-food organizations: three agri-food cooperatives federations -Castilla-La Mancha, Comunitat Valenciana, and Murcia-, two second-degree agri-food cooperatives -Anecoop and Unió Nuts-, all of them located in Mediterranean Spanish Regions. A total of 1.168 survey questionnaires were distributed between July 2020 and February 2021 across five organizations through the snowball sampling method. Data from 112 collected questionnaires were correctly answered, but 106 were selected for analysis. The dataset includes socioeconomic data, productive information, and innovative characteristics from agri-food cooperatives surveyed, all in order to be able to examine the relationship between those factors and joint cropland management practices they carry on.

Validation of a simple sample preparation method for multielement analysis of bovine serum.

Here we propose a single acid digestion (SAD) sample preparation method for ICP-MS analysis of animal serum samples to determine trace element contents. The method was evaluated in comparison with a commonly used procedure involving dilution of samples in an alkaline solution (AKD). In the SAD procedure, aliquots (1 mL) of bovine serum samples were treated at low temperature with a mixture of concentrated nitric acid and hydrogen peroxide. Trace elements (As, B, Ba, Cd, Co, Cr, Cu, Fe, Hg, Li, Mn, Mo, Ni, Pb, Sb, Se, Sr, U, and Zn) were directly determined by ICP-MS analysis of diluted solutions of samples. Both methods were sufficiently sensitive to enable quantification of most trace elements, with the exception of the AKD method for Cd, Hg and Pb. The quality of the data was verified by using certified reference material. Good results were obtained for the SAD procedure and all elements, but recoveries were unacceptable with the AKD procedure for Se (recovery: 57%), Cd (154%) and Fe (139%). Strong associations (R2>0.90, P = 0.000) between the data obtained by both methods were demonstrated for the elements considered. The proposed SAD sample preparation method produced satisfactory results for determining most toxic and essential trace elements targeted in monitoring studies.

Effect of L-arginine oral supplementation on response to myocardial infarction in hypercholesterolemic and hypertensive rats.

The well known metabolic functions of L-arginine have been recently increased with the discovery of its role as the substrate for the synthesis of nitric oxide (NO), which has emerged as an endogenous signaling molecule with potential therapeutic implications for cardiovascular disease. Steady-state levels of NO are derived in part from dietary sources. It has been reported that supplementation of L-arginine reduces atherosclerosis in rabbits and reduces the arterial pressure in hypertensive rats. Therefore, we investigated the effect of L-arginine supplementation using a group of induced hypercholesterolemic rats and a group of spontaneously hypertensive rats; the infarcted area in cardiac tissue of both groups was measured during the response to myocardial infarction in the ischemia-reperfusion model. Hypercholesterolemic rats supplemented with 170 mg kg(-1) of L-arginine showed a significant (P

Trace elements in soils and plants in temperate forest plantations subjected to single and multiple applications of mixed wood ash.

Wood ash, a by-product generated in power plants, can be used to fertilize forest plantations to replenish nutrients lost during harvesting. Although wood ash generally contains low levels of trace metals, release of some of these may occur soon after ash application in acid soils. The risk of heavy metal contamination associated with application of mixed wood ash was assessed in six Pinus radiata D. Don plantations, on two types of mineral soil differing in texture, drainage and CECe. Four of the stands received a single application of 4500 kg ha(-1) (March 2003), and in the other two stands the same treatment was applied over three consecutive years (2003-2005). Trace metal (Cd, Cr, Cu, Mn, Ni, Pb, Zn) concentrations were monitored throughout the 3 years in different components of the forest ecosystem--soil solid fraction, soil solution, tree needles, ground vegetation and different mushroom species. Repeated applications of wood ash led to moderate increases in soil extractable Mn and Zn, and Mn in all mushrooms species. However, the maximum concentrations did not reach levels potentially harmful to organisms. Concentrations of Zn, Cu and Cd decreased in some mushroom species, probably because of increased soil pH caused by the treatment. Heavy metal concentrations in tree needles and ground vegetation were not altered. Although the risk of heavy metal contamination appears to be low, the long-term effects of wood ash application must be assessed.

Vascular wall: potential target for the physicochemical effects of cis-unsaturated free fatty acids.

Diets rich in monounsaturated cis-FFA (cis FFA) are associated with a significant reduction of cardiovascular risk. Although several different mechanisms have been proposed to explain this protective effect, the biochemical processes involved have not been fully elucidated. It has been shown that upon their incorporation into the plasma membrane, cis FFA induce a marked perturbation of the lipid domains, altering membrane fluidity as well as lipid-lipid and lipid-protein interactions in the bilayer plane. During the last few years, several lines of evidence have shown that these perturbations disrupt the activity of several membrane proteins and enzymatic systems. As a result, several critical transmembrane signaling systems, including the Ins(1,4,5)P(3)/DAG/[Ca(2+)](i), the cAMP/PKA, and the voltage-operated Ca(2+) influx are strongly inhibited by cis FFA in different experimental models. Furthermore, this inhibition is associated with alterations in the timing of the cell cycle as well as in the final steps of the secretory pathway. We propose that this complex set of biological actions exerted by cis FFA at the plasma membrane may contribute to explain the protective roles that these molecules appear to exert on the vascular wall.