Teresa Hernandez - Academia.edu (original) (raw)

Papers by Teresa Hernandez

Soil Biology & Biochemistry, 2003

Unsuitable agricultural practices together with adverse environmental conditions have led to degr... more Unsuitable agricultural practices together with adverse environmental conditions have led to degradation of soil in many Mediterranean areas. One method for recovering degraded soils in semiarid regions, is to add organic matter in order to improve soil characteristics, ...

Food Research International, 2002

In two experiments, the response of rats to feeding with diets containing grapefruit flavonoids w... more In two experiments, the response of rats to feeding with diets containing grapefruit flavonoids was examined. In the first experiment, during 8 weeks, four diets without or with 0.1, 0.2 and 0.4% extract of flavonoid from grapefruit (from 0.05 to 0.2% DM pure flavonoids) were applied. In the second experiment, during 10 days, diets with oxidised fat (100 meq O 2 /kg) and without or with 0.4% extract of flavonoid were applied. The obtained results showed that the addition of 0.1-0.4% extract of flavonoid from grapefruit did not affect the diet intake and the body weight gain of rats, and slightly increased the antioxidative potential of serum (decreased the MDA content but had no significant effect on the PGx and SOD activities). The addition strongly affected functioning of the blind gut ecosystem causing an increased filling with contents, an increase in the intestinal wall mass and pH, as well as a decrease in the microbiological activity of b-glucuronidase and an increase in the a-galactosidase activity. #

Bioresource Technology, 1999

The effects of fresh and composted urban wastes on the organic matter of an arid soil were evalua... more The effects of fresh and composted urban wastes on the organic matter of an arid soil were evaluated. The quality of the arid soil was improved with organic amendment. This improvement was more evident in soils amended with fresh residues (municipal solid waste and ...

Biology and Fertility of Soils, 1999

This paper reports the effect of the addition of the organic fraction of municipal solid waste a... more This paper reports the effect of the addition of the organic fraction of municipal solid waste at two different rates on the microbiological and biochemical properties of an arid soil after 8 years. The vegetation that appeared spontaneously just after the amendment was still present 8 years later. The organic matter fractions were higher in the amended soil than in the control soil. Amended soil showed higher values of microbial biomass C, soil basal respiration and dehydrogenase activity than control soil, which reached values near to those of the natural soils in the area. The organic amendment had a positive effect on the activity of enzymes related with C, N, P cycles, particularly when the amendment was at the highest dose. This effect could be also observed on the activity of extracted enzymes. The results indicated that the addition of urban waste could be a suitable technique with which to restore soil quality.

Biology and Fertility of Soils, 1997

Changes produced in the biological characteristics of an arid soil by the addition of various urb... more Changes produced in the biological characteristics of an arid soil by the addition of various urban wastes (municipal solid waste, sewage sludge and compost) at different doses, were evaluated during a 360-day incubation experiment. The addition of organic materials to the soil increased the values of biomass carbon, basal respiration, biomass C/total organic C ratio and metabolic quotient (qCO2), indicating the activation of soil microorganisms. These biological parameters showed a decreasing tendency with time. Nevertheless, their values in amended soils were higher than in control soil, which clearly indicates the improvement of soil biological quality brought about by the organic amendment. This favorable effect on soil biological activity was more noticeable with the addition of fresh wastes (municipal solid waste or sewage sludge) than with compost. In turn, this effect was more permanent when the soil was amended with municipal solid waste than when it was amended with sewage sludge.

Bioresource Technology, 1998

This work studied the changes in soil oxidoreductase and hydrolase activities during 360 days of ... more This work studied the changes in soil oxidoreductase and hydrolase activities during 360 days of incubation of an arid soil amended with different amounts of organic materials (fresh and composted urban organic wastes). The enzymatic activities were stimulated by such amendments. ...

Plant and Soil, 1991

The influence of composting on the fertilizing value of an aerobic sewage sludge and its action o... more The influence of composting on the fertilizing value of an aerobic sewage sludge and its action on ryegrass was studied. Soil P and K contents, cation-exchange capacity (CEC) and CEC/total organic carbon incresed with composting, while the percentage of phytotoxic substances diminished. The compost provided useful quantities of organic matter and macronutrients. The addition of uncomposted waste to the soil initially had a depressive effect on yield which disappeared after a period of incubation of this material in the soil, whereas the application of a mature compost produced yields superior to those in the control treatment.

Soil Biology & Biochemistry, 2002

The uses of many of the soils of Central Spain have changed and these changes have led frequently... more The uses of many of the soils of Central Spain have changed and these changes have led frequently to the decline of natural plant cover. In this paper we report on the organic matter fractions and the microbial activity of soils developed from different substrates (limestone and granites) in relation to plant cover decline. Speci®c indicators of microbial activity (microbial biomass carbon (MBC), basal respiration, and some oxidoreductase and hydrolase activities) were measured. These indicators decreased in value in both limestone and acid soils where plant cover had declined (from climax, tree forest, to low bush); a similar effect was observed in the labile organic matter fractions (water soluble carbon (WSC), water soluble carbohydrates and polyphenolic compounds). For some measures of microbiological activity (e.g. MBC and soil respiration) the differences in acid soils were lower than in limestone soils. For example, MBC values in limestone soils ranged from 1426 ngC g 21 in tree forest to 498 ngC g 21 in low bush; while in acid soils, these values ranged from 428 ngC g 21 in tree forest to 265 ngC g 21 in low bush. Acid soils, unlike the limestone soils, showed no relationship between plant cover decline and hydrolase activities related to the N cycle (urease and protease). In general, soil microbial activity was negatively affected by plant cover degradation. q

Communications in Soil Science and Plant Analysis, 1997

Soils from many portions of the Mediterranean region are subjected to progressive degradation as ... more Soils from many portions of the Mediterranean region are subjected to progressive degradation as a result of erosion by wind and water. As a consequence, the fertility level of these degraded soils is declining. This report studied the dehydrogenase activity of 18 soils, all of which were subjected to processes of erosion, in order to ascertain whether such activity could serve as a marker of the microbial activity of a degraded soil. The dehydrogenase activity of the soils studied was not correlated with their organic matter content, indicating that total organic matter was not representative of the microbial activity of degraded soil. An analysis of principal components showed a similar behavior between other indices of microbial activity (basal respiration and biomass carbon) and the dehydrogenase activity values. This data confirmed that dehydrogenase activity can be used as a sensitive marker of soil degradation and soil microbial activity.

Soil Biology & Biochemistry, 1994

Sununary-Thirty-six soils from twelve different arid zones from SE Spain under Mediterranean envi... more Sununary-Thirty-six soils from twelve different arid zones from SE Spain under Mediterranean environmental conditions were characterized by a range of measurements indicative of soil microbiological activity. Our aim was to relate the degradation undergone by these soils with their microbiological and enzymatic characteristics. In general, the soils studied had a low microbiological activity. These soils showed similar values of pH and low total organic-C (TOC) and available nutrient content. The behaviour of dehydrogenase activity was similar to that of CO, emission and biomass-C, with values ranging from 4 to 148 pg iodo-nitrotetrazolium formazan g-' of soil. A positive correlation was found between the above indices which, in turn, were negatively correlated with the metabolic quotient values. No correlation was found between these measurements and physical variables such as clay content, pH and WHC of the soils. However, there was a negative correlation with electrical conductivity. The values of urease, protease which hydrolyses N-a-benzoil+argininamide, protease which hydrolyses casein, phosphatase and B-glucosidase were, in general, low. There was a positive correlation between the hydrolases of the soils studied. A positive correlation was also found between hydrolases and measurements such as CO, emission, biomass-C, biomass-C-to-TOC ratio and dehydrogenase.

$Research paper thumbnail of Changes in carbon fractions during composting and maturation of organic wastes$

Environmental Management, 1991

Seven mixtures from four organic residues—an aerobic sewage sludge, a city refuse, a peat residue... more Seven mixtures from four organic residues—an aerobic sewage sludge, a city refuse, a peat residue, and a grape debris—were composted, and the changes undergone by their different carbon fractions during their composting and maturation were studied. In most cases a decrease in carbon fractions during the composting and maturation processes was observed. The extractable carbon, however, increased during maturation. Organic matter mineralization was greater in the composts with city refuse than in those with sewage sludge. The samples with peat residue showed the lowest decreases in carbon fractions. During maturation, an increase of humiclike fraction was observed, which was reflected by a decrease in the soluble carbon-precipitated carbon ratio at pH 2. Water-soluble carbon was the carbon fraction most easily degradable by microorganisms, and its amount correlated significantly with composting time in all the samples.

Soil Biology & Biochemistry, 2000

Several organic matter fractions together with biological and biochemical parameters were measure... more Several organic matter fractions together with biological and biochemical parameters were measured in a range of intensively farmed soils in SE Spanish Mediterranean region, which had been abandoned (i.e. not used in agriculture) for different periods of time. These soils were compared with adjacent natural soils that had never been used for agriculture. There was a general decline of total organic carbon (TOC), extractable humic substances, water-soluble carbon (WSC) and carbohydrates, microbial biomass and respiration with the time elapsed since abandonment. There was also a decline in plant cover in the abandoned soils. When a degraded soil was amended with municipal solid waste at rates of 6.5 and 26 kg m 22 as a potential means of remediation, TOC, humic substances, WSC, microbial biomass and respiration rates signi®cantly increased but only at the higher rate of amendment. Plant cover was signi®cantly enhanced by both rates of the amendments and was still present 10 years after the amendment. These data con®rm that agricultural soil abandonment leads to soil degradation and that the addition of urban waste could be a suitable technique with which to restore their quality. q

Communications in Soil Science and Plant Analysis, 1992

... Titre du document / Document title. Evaluation of the maturity of municipal waste compost usi... more ... Titre du document / Document title. Evaluation of the maturity of municipal waste compost using simple chemical parameters. Auteur(s) / Author(s). GARCIA C. ; HERNANDEZ F. ; COSTA F. ; AYUSO M. ; Affiliation(s) du ou des auteurs / Author(s) Affiliation(s). Cent. ...

Soil Science Society of America Journal, 1998

... as a mea-sure of microbial activity in soil, although some re-searchers have criticized this ... more ... as a mea-sure of microbial activity in soil, although some re-searchers have criticized this hypothesis (Nannipieri et al., 1990; Beyer et al ... plant residues (Hayano and Tubaki, 1985), which contributes to the release of energy for soil microbial activity (Eivazi and Zakaria, 1993). ...

El resfriado o gripe es una de las enfermedades más frecuentes. En la clínica se puede dividir en... more El resfriado o gripe es una de las enfermedades más frecuentes. En la clínica se puede dividir en dos grandes tipos: el resfriado común y el resfriado (o influenza) epidémico.