Functional trait variation among and within species and plant functional types in mountainous Mediterranean forests

Plant structural and biochemical traits are frequently used to characterise the life history of plants. Although some common patterns of trait covariation have been identified, recent studies suggest these patterns of covariation may differ with growing location and/or plant functional type (PFT). Mediterranean forest tree/shrub species are often divided into three PFTs based on their leaf habit and form, being classified as either needleleaf evergreen (Ne), broadleaf evergreen (Be), or broadleaf deciduous (Bd). Working across 61 mountainous Mediterranean forest sites of contrasting climate and soil type, we sampled and analysed 626 individuals in order to evaluate differences in key foliage trait covariation as modulated by growing conditions both within and between the Ne, Be, and Bd functional types. We found significant differences between PFTs for most traits. When considered across PFTs and by ignoring intraspecific variation, three independent functional dimensions supporting the Leaf-Height-Seed framework were identified. Some traits illustrated a common scaling relationship across and within PFTs, but others scaled differently when considered across PFTs or even within PFTs. For most traits much of the observed variation was attributable to PFT identity and not to growing location, although for some traits there was a strong environmental component and considerable intraspecific and residual variation. Nevertheless, environmental conditions as related to water availability during the dry season and to a smaller extend to soil nutrient status and soil texture, clearly influenced trait values. When compared across species, about half of the trait-environment relationships were species-specific. Our study highlights the importance of the ecological scale within which trait covariation is considered and suggests that at regional to local scales, common trait-by-trait scaling relationships should be treated with caution. PFT definitions by themselves can potentially be an important predictor variable when inferring one trait from another. These findings have important implications for local scale dynamic vegetation models

The evolution of chemical and biological characteristics in Cambic Chernozem, under the influence of crop rotation, fertilizers and soil erosion

Investigations conducted at the Agricultural Research and Development Station of Podu-Iloaiei, Iaşi County, during 2004-2008, have followed the influence of different crop structures and different fertilization methods on crop yield, erosion and soil fertility. Within the experiment, the following rotation schemes have been followed: wheat and maize continuous cropping, 2-year rotation (wheat-maize), 3-year rotation (peas-wheat-maize) and 4-year rotation + reserve field cultivated with legumes and perennial grasses (alfalfa + Lolium or Sainfoin + Bromus). The use of 3 and 4 year- rotations with annual and perennial meliorate plants has resulted in yield increases of 25 – 30 % (632 – 768 kg/ha) in wheat and 24-28% (973-1161 kg/ha) in maize, as compared to continuous cropping. The fertilization of wheat and maize crops at the rate of N60P40+30 t/ha manure has determined the increase by 3.0 g/kg (17.9%) in the content of organic carbon from soil, as compared to the rate of N100P80. The use of peas-wheat-maize-sunflower rotation + reserve field grown with legumes and perennial grasses has contributed to the increase by 2.2 g/kg (13.4%) in the content of organic carbon. The use of 4-year rotation + reserve field cultivated with perennial grasses and legumes on slope lands, poor in organic matter has determined the increase by 47% in soil potential and by 34% in enzyme potential, as compared to wheat-maize rotation. On 11% slope lands, the use of soybean-wheat-maize rotation + two reserve fields cultivated with perennial grasses has determined the diminution of soil losses by erosion at 0.985 t/ha, and on 16% slope lands, peas-wheat-maize rotation + two reserve fields, cultivated with perennial grasses has determined the diminution in soil erosion at 1.371 t/ha. On 16% slope lands, the crop structure, which determined the diminution in mean soil losses by erosion until 1.371 t/ha/year included 20 % straw cereals, 20% annual legumes, 20% row crops and 40 % perennial grasses and legumes

Effect of municipal sewage sludge on winter rape and soybean production and heavy metal contamination of soil

Investigations conducted during 2004-2008 at the Podu-Iloaiei Agricultural Research Station have studied the influence of different rates of sewage sludge on yield and soil agrochemical characteristics. Sewage sludge was applied annually at rates of 20, 40 and 60 t/ha, together with mineral fertilizers, differentiated according to the growing plant. Applying rates of 20 t/ha DM sewage sludge resulted in the accumulation of mobile phosphate stock in soil of 58 ppm; the microelement content (mobile forms from soil) was of 19.0 ppm at Cu, 0.51 ppm at B, 149 ppm at Zn and 397 ppm at manganese. The obtained results have shown that by applying a rate of 30 t/ha of raw sewage sludge (18.5 l t/ha dry matter), the allowable maximum limits stipulated by Norm 86/278/EEC, were not exceeded. By applying rates of 60 t/ha raw sewage sludge (37 t/ha dry matter), the limits established by Norm 86/278/EEC and Order no. 49 from January 14, 2004 have been exceeded only at zinc. The application of the rates of 40 t/ha sewage sludge has resulted in increasing the degree of plant supply by mineral elements (especially, nitrogen and phosphorus). It has also resulted in a mean annual supply of 3.8 t/ha highly humificated organic matter; this explains the increase in soil humus content (after 4 years) from 2.82 to 3.79%. The use of fermented sewage sludge, at a rate of 40 t/ha, has resulted in getting mean yield increases of 65 % (1075 kg/ha), in winter rape, and of 63 % (937 kg/ha), in soybean. For slope lands degraded by erosion, sewage sludge with other organic resources may contribute to the improvement in soil characteristics. The application of rates of 20 t/ha sewage sludge DM has resulted in the accumulation of mobile phosphates in soil of 58 ppm, and the content of microelements, mobile forms from soil, was of 19.0 ppm at Cu , 0.51 ppm at B, 149 ppm at Zn and 397 ppm at manganese

Influence of different organic resources on crop yield and soil fertility in the Moldavian Plateau

Investigations conducted during 2003-2007 at the Podu-Iloaiei Agricultural Research Station have studied the influence of different sewage sludge, manure and crop residues on yield quality and quantity and soil agrochemical characteristics. Experiments were set up in a five year-crop rotation (soybean-wheat-maize-sunflower-wheat). Sewage sludge was applied annually at rates of 20, 40 and 60 t/ha, together with mineral fertilizer, differentiated according to the growing plant. The Cambic Chernozem used for experiments had a clayey-loam texture (415 g clay, 305 g loam and 280 g sand), a weakly acid reaction and a mean supply with mobile phosphorus and a very good one with mobile potassium. Applying rates of 24.6 t/ha DM sewage sludge resulted in the accumulation of mobile phosphate stock in soil of 49 ppm and the microelements content (mobile forms from soil) was of 12.4 ppm at Cu, 0.47 ppm at B, 142 ppm at Zn and 382 ppm at manganese. The combined use of mean rates of mineral fertilizers (N70P70), together with 40 t/ha manure or 6 t/ha crop residues from wheat and maize crops, has resulted in improving soil physical and chemical characteristics and getting yield increases in wheat of 2313-2214 kg/ha (136-130 %), on weakly eroded lands, and 2074-2001 kg/ha (178-172 %) on highly eroded lands, compared to the unfertilized control. Both on weakly and highly eroded lands, the mineral fertilization with lower rates than N140P100 kg/ha has determined the decrease in humus content from soil until 2.49- 3.05 %. On highly eroded lands, the humus content was kept at values of 3.42-3.49% only by the annual application of the rate of 60 t/ha manure or N70P70+ 60 t/ha manure

The change of physical and chemical characteristics in cambic chernozem, as influenced by soil erosion, in the Moldavian Plain

The analyses carried out on soil profiles, at the beginning of testing period and after 36 years, on a 16% slope, with length of 310 m, have shown that on the entire slope length, soils had a very different fertility. Soils were influenced by erosion and silting processes. On weakly eroded land, the percentage of hydrostable aggregates was comprised, according to rates and type of applied fertilizers, between 38.9 and 53.6 %; on highly eroded land, the ratio of hydrostable aggregates has increased from 34.4 in unfertilized control to 52.0% at the fertilized variant with 40 t/ha manure. On eroded slope lands, poor in organic matter and nutritive elements, applying rates of 40 t/ha manure has determined yield increases in maize of 1835-2340 kg/ha, respectively, 45.9 – 58.5 kg grains/ t of manure, compared to unfertilized control. The combined use of mean rates (N70P70) of mineral fertilizers, together with 40 t/ha manure, has improved soil physical and chemical characteristics. Yield increases were of 3150 kg/ha in wheat and 3771 kg/ha in maize, compared to unfertilized variant

Effects of long-term fertilization on the fertility of erosion-affected soils from the Moldavian Plateau

The paper presented the results of investigations concerning the influence of long-term fertilization (43 years) on some chemical characteristics of Cambic Chernozem from the Moldavian Plain and on the maize yield. On slope lands, the high rate fertilization of maize crop (N140P100) has determined, in the latest ten years, an average yield increase of 103% (3373 kg/ha), against the control, and applying a rate of N70P70+40 t/ha manure resulted in getting a very close yield increase (99%, 3258 kg/ha). The minimum supply level of mobile phosphorus in soil (37-72 ppm) in pea-wheat-maize rotation (37 ppm) was maintained in case of annual application of a rate of N100P80. The total carbon content in Cambic Chernozem from the Moldavian Plain has registered significant increases at higher rates than N140P100 and in case of organo-mineral fertilization. The annual fertilization of wheat and maize, at the rate of 70 kg N + 70 kg P2O5/ha + 6 t/ha stalks of wheat, has determined, compared to the unfertilized variant, the increase in the content of organic carbon from soil by 14.5% (2.4 g organic C/kg) on weakly eroded soils, and by 29.5% (4.2 g organic C/kg) on highly eroded soils. During the long-term fertilizing of wheat and maize with high rates of mineral fertilizers (N140P100), on highly eroded lands, the total content of carbon has increased by 16.9% (2.4 g organic C/kg soil), against the unfertilized control. Applying moderate rates of mineral fertilizers (N70P70), together with 60 t/ha manure, has determined, after 43 years of testing, the increase by 32% (5.3 g organic C/kg) in the content of organic carbon from soil, on weakly eroded soils, and by 42.3% (6.0 g organic C/kg soil) on highly eroded soils, compared to the unfertilized control. On 16% slope arable lands from the Moldavian Plateau, the mean annual soil losses by erosion, registered during 1986-2007, were of 1.640 t/ha in winter wheat, 4.618 t/ha in beans, 1.89 t/ha in the field cultivated with perennial grasses and legumes on the second year of vegetation, 9.176 t/ha in maize and 9.6 t/ha in sunflower

A review of exposure assessment methods for epidemiological studies of health effects related to industrially contaminated sites

BACKGROUND: this paper is based upon work from COST Action ICSHNet. Health risks related to living close to industrially contaminated sites (ICSs) are a public concern. Toxicology-based risk assessment of single contaminants is the main approach to assess health risks, but epidemiological studies which investigate the relationships between exposure and health directly in the affected population have contributed important evidence. Limitations in exposure assessment have substantially contributed to uncertainty about associations found in epidemiological studies. OBJECTIVES: to examine exposure assessment methods that have been used in epidemiological studies on ICSs and to provide recommendations for improved exposure assessment in epidemiological studies by comparing exposure assessment methods in epidemiological studies and risk assessments. METHODS: after defining the multi-media framework of exposure related to ICSs, we discussed selected multi-media models applied in Europe. We provided an overview of exposure assessment in 54 epidemiological studies from a systematic review of hazardous waste sites; a systematic review of 41 epidemiological studies on incinerators and 52 additional studies on ICSs and health identified for this review. RESULTS: we identified 10 multi-media models used in Europe primarily for risk assessment. Recent models incorporated estimation of internal biomarker levels. Predictions of the models differ particularly for the routes ‘indoor air inhalation’ and ‘vegetable consumption’. Virtually all of the 54 hazardous waste studies used proximity indicators of exposure, based on municipality or zip code of residence (28 studies) or distance to a contaminated site (25 studies). One study used human biomonitoring. In virtually all epidemiological studies, actual land use was ignored. In the 52 additional studies on contaminated sites, proximity indicators were applied in 39 studies, air pollution dispersion modelling in 6 studies, and human biomonitoring in 9 studies. Exposure assessment in epidemiological studies on incinerators included indicators (presence of source in municipality and distance to the incinerator) and air dispersion modelling. Environmental multi-media modelling methods were not applied in any of the three groups of studies. CONCLUSIONS: recommendations for refined exposure assessment in epidemiological studies included the use of more sophisticated exposure metrics instead of simple proximity indicators where feasible, as distance from a source results in misclassification of exposure as it ignores key determinants of environmental fate and transport, source characteristics, land use, and human consumption behaviour. More validation studies using personal exposure or human biomonitoring are needed to assess misclassification of exposure. Exposure assessment should take more advantage of the detailed multi-media exposure assessment procedures developed for risk assessment. The use of indicators can be substantially improved by linking definition of zones of exposure to existing knowledge of extent of dispersion. Studies should incorporate more often land use and individual behaviour