Phytomass Production Research Articles

Interaction of Heavy Metals and Pyrene on Their Fates in Soil and Tall Fescue (Festuca arundinacea)

90-Day growth chamber experiments were performed to investigate the interactive effect of pyrene and heavy metals (Cu, Cd, and Pb) on the growth of tall fescue and its uptake, accumulation, and dissipation of heavy metals and pyrene. Results show that plant growth and phytomass production were impacted by the interaction of heavy metals and pyrene. They were significantly decreased with heavy metal additions (100-2000 mg/kg), but they were only slightly declined with pyrene spiked up to 100 mg/kg. The addition of a moderate dosage of pyrene (100 mg/kg) lessened heavy metal toxicity to plants, resulting in enhanced plant growth and increased metal accumulation in plant tissues, thus improving heavy metal removal by plants. In contrast, heavy metals always reduced both plant growth and pyrene dissipation in soils. The chemical forms of Cu, Cd, and Pb in plant organs varied with metal species and pyrene addition. The dissipation and mineralization of pyrene tended to decline in both planted soil and unplanted soils with the presence of heavy metals, whereas they were enhanced with planting. The results demonstrate the complex interactive effects of organic pollutants and heavy metals on phytoremediation in soils. It can be concluded that, to a certain extent, tall fescue may be useful for phytoremediation of pyrene-heavy metal-contaminated sites. Further work is needed to enhance methods for phytoremediation of heavy metal-organics co-contaminated soil.

Луговая растительность пойм рек Вычегда и Печора. Порядок Arrhenatheretalia R. Tx. 1931

The present study continues a series of publications of the authors on diversity of the meadow vegetation in the floodplains of the Vychegda and Pechora rivers and their tributaries (Komi Republic). The floristic classification of wet meadows of the order Molinietalia Koch 1926 was published early (Shushpanikova, Yamalov, 2013). The results of floristic classification of meadow vegetation belonging to the order Arrhenatheretalia R. Tx. 1937 are discussed in this article. Analysis was based on 383 original relevés of the meadow vegetation of the order Arrhenatheretalia made in accordance with principles of the Braun-Blanquet approach (Braun-Blanquet, 1964; Mirkin and Naumova, 1998). The studies were performed in the floodplains of the Vychegda and Pechora rivers and their tributaries (Sysola, Kazhym, Pozheg, Viled, Usa, Colva, Synya, Sebys, Ilych, Syuzyu, Shchugor). The descriptions were conducted at the study plots of 10×10 m. Plant communities of small size were described within the natural limits. A location, dimensions of community, species composition, species saturation, composition of dominant and co-dominant species, total coverage and height of grass stand, aboveground phytomass production were identified. The abundance of species in meadow communities was recorded using the J. Braun-Blanquet method: r — species occurs sporadically, + — minor species, total coverage less than 1 %, 1 — 1–5 %, 2 — 6–25 % 3 — 26–50 %, 4 — 51–75 %, 5 — 76–100 %. The assessment of environmental parameters was performed by ecological methods of L. G. Ramensky (Ramensky et al., 1956). Syntaxonomic diversity of the meadow vegetation of the order Arrhenatheretalia of the Vychegda and Pechora rivers floodplains presented by 2 unions (Cynosurion R. Tx. 1947 и Festucion pratensis Sipaylova et al. 1985), 7 associations (Festucetum ovinae Turubanova 1986, Festuco pratensis–Deschampsietum caespitosae Turubanova 1986, Anthoxantho odorati–Agrostietum tenuis Sillinger 1933, Festuceto pratensis–Dactyletum glomeratae Dymina 1989 in Korolyuk et Kiprijanova 1998, Amorio repens–Poetum pratensis ass. nov., Equiseto arvensis–Elytrigietum repentis Maraculina 2009, Elytrigio repentis–Bromopsidetum inermis Yamalov 2011. Two new communities without rank are described (Agrostis vinealis, Hypericum maculatum–Phleum pratense). Most plant associations are heterogeneous by their floristic composition and they can be divided into 10 subassociations and 5 variants. The peculiarities of the floristic composition of the above mentioned associations, as well as their distribution and ecology are discussed. The distinguished associations are well differentiated by their elevation level on the floodplains. The meadow communities of Festucetum ovinae are located on the highest floodplains in the inland zone; there is Agrostis vinealis in the streamside zone of the floodplains. The meadow communities of the ass. Anthoxantho odorati–Agrostietum tenuis are located on the low floodplains in the streamside zone. The meadow communities of the associations Festuco pratensis–Deschampsietum caespitosae, Equiseto arvensis–Elytrigietum repentis, Elytrigio repentis–Bromopsidetum inermis, Festuceto pratensis–Dactyletum glomeratae are occupied the medium level floodplains. The meadow communities of the ass. Amorio repens–Poetum pratensis are found at different locations of the floodplain; they are formed under grazing. The described meadows grow on the soils with different ecological indicators. The distinguished associations are differentiated by water level (52.2–73.0), average figures — 55.9–68.9. The meadow communities of the ass. Festucetum ovinae occupy the driest sites of the floodplain; the ass. Anthoxantho odorati–Agrostietum tenuis is located in the wettest floodplains. The meadow communities of the ass. Elytrigio repentis–Bromopsidetum inermis occupy most rich and alluvial soils. They are located on the low ridges in the middle zone of the floodplain and they are formed by annual flooding on alluvial deposits. The distinguished associations are differentiated by pH (4.2–8.0), average figures — 4.9–7.0. The meadow communities with Agrostis vinealis are occupied the most acidic soil. The meadow communities of the ass. Anthoxantho odorati–Agrostietum tenuis are located on the neutral soils. The meadow communities of the most of associations occupy slightly acidic soils. The variability of moisture varies from alternating values to high values. The greatest differences in moisture are demonstrated by the communities of associations Equiseto arvensis–Elytrigietum repentis and Elytrigio repentis–Bromopsidetum inermis located on middle manes on low and medium levels of the floodplains. The associations are differ by the scale of pasture digression in range 3.3–5.0, average figures — 3.8–4.9. The meadow communities with Agrostis vinealis have the highest rates of pasture digression (4.5–5.1). The meadow communities of the ass. Anthoxantho odorati–Agrostietum tenuis have the smallest ones (3.5–3.9). A comparison of species composition of the syntaxa in Komi Republic with communities described in other regions of the Eastern Europe and the Asian part of Russia was carried out. It was shown that the meadow communities of the Komi Republic have low species diversity. Species richness of meadow communities is less than 39 species on trial area. The meadow communities of the ass. Festuco pratensis–Deschampsietum caespitosae are the richest. 195 vascular plant species are recorded in 213 geobotanical descriptions of the order Arrhenatheretalia. The aboveground phytomass varies from 20–40 g/m2 (Festucetum ovinae) to 520 g/m2 (Festuco pratensis–Deschampsietum caespitosae).

Post-wildfire regeneration of rangeland productivity and functionality – observations across three semi-arid vegetation types in South Africa

Wildfires can have significant impacts on rangeland productivity and functionality causing substantial economic losses to affected farmers. In August 2011, such wildfires swept through the North West province of South Africa, destroying large areas of grazing and farm infrastructure. There is little information available on how the regional semi-arid rangelands respond to fire. In order to increase knowledge on short-term regeneration capacities of burned rangelands, the recovery of grass phytomass, composition and diversity as well as the frequency distribution of patch types (i.e. grass-, litter- and bare patches) were assessed in the growing season following the fire. Burned and unburned sites were compared in two regional grasslands and one savanna type receiving between 480 and 700 mm rainfall y−1. Fire significantly reduced phytomass production, and lowered the grazing capacity and potential grazing days across vegetation types. In general, grass diversity, composition and relative frequencies remained unaffected documenting an overall good regeneration potential of the grass sward. An increased proportion of bare patches and decrease of litter indicated that the post-fire environment lost functionality with respect to erosion control, nutrient cycling and water infiltration. Gained insights provide valuable baseline information for future impact assessments and research into the fire dynamics of investigated vegetation types.

EVALUATION OF DRY MATTER PRODUCTION OF MISCANTHUS SINENSIS (TATAI) IN THE CONDITIONS OF SOUTH-WESTERN SLOVAKIA

Abstract In this paper, we present the results of research of phytomass production allocated to aboveground organs, leaves and stalks, after the third growing year. The research was conducted in the field experiment conditions of Farm holding in Kolíňany. The results of the aboveground dry matter production are expressed in tonnes of dry weight produced on the area of one hectare (t.ha-1). The total dry weight of the aboveground biomass was 6.89 t.ha-1 at the end of the first growing year 2010. In the growing year 2011, it reached 15.21 t.ha-1 (an increase by 121 %.) The total dry weight of the aboveground phytomass increased by 37% compared to 2011, and it reached 20.82 t.ha-1 in the third growing year (2012). The increase of phytomass is directly proportional to off shoot circle. Average off shoot circle of individuals in the first growing year was 300 mm and the average number of stems produced in a clump was 37.60. In 2011, the average off shoot circle of individuals was 502 mm and there were 43.73 stems created in a clump. In the third growing period of 2013, the extension of the off shoot circle by 113.7% (641 mm) was registered in comparison with 2010 and the amount of 80.19 stems per clump was recorded.

Specific features of xylogenesis in Dahurian larch, Larix gmelinii (Rupr.) Rupr., growing on permafrost soils in Middle Siberia

Processes of xylem formation in Dahurian larch have been studied at three sites differing in the hydrothermal regime of soils in the permafrost zone of Middle Siberia. It has been found that the start and end dates of different phases of tree ring formation may differ between the sites by up to 14 days, depending on site conditions. The data obtained contribute to knowledge of possible changes in larch forest phytomass production and provide the possibility of predicting its dynamics under conditions of climate change.

Use of High-Yielding Bioenergy Plant Castor Bean (Ricinus communis L.) as a Potential Phytoremediator for Copper-Contaminated Soils

Copper (Cu) contamination in the environment has been increased during the years with agricultural and industrial activities. Biotechnological approaches are needed for bioremediation in these areas. The aims of this study were i) to evaluate the phytoremediation capacity of the high-yielding bioenergy plant castor bean (Ricinus communis L.) in vineyard soils (Inceptisol and Mollisol) contaminated with Cu and a Cu mining waste; ii) to characterize the castor bean as a Cu phytoremediation plant; and iii) to evaluate the nutrient uptake by castor bean. Castor bean plants cultivated in soil with toxic levels of Cu for 57 d exhibited high phytomass production, a high tolerance index of roots' fresh mass and shoots' dry mass, a high level of Cu phytoaccumulation in the roots and also, a robust capacity for Cu phytostabilization. Furthermore, castor bean plants did not significantly deplete soil nutrients (such as N, P, and Mg) during cultivation. Plants cultivated in Inceptisol, Mollisol and Cu mining waste exhibited a strong potential for Cu phytoaccumulation, with values of 5 900, 3 052 and 2 805 g ha−1, respectively. In addition, the castor bean's elevated phytomass production and strong growth in Cu-contaminated soils indicated a high level of Cu phytoaccumulation and a potential application in biofuels. These findings indicate that the castor bean is a efficient hyperaccumulator of Cu and a potential candidate plant for the phytoremediation of Cu-contaminated soil.

Sistemas de culturas com milho sob semeadura direta na região Nordeste do Brasil

A grande dificuldade de implantação da semeadura direta no Nordeste é a produção e o acúmulo de fitomassa na superfície do solo. Há necessidade de se desenvolver sistemas de culturas para região Nordeste, que produzam grandes quantidades de fitomassa, para permanecer por maior tempo na superfície, oferecendo proteção ao solo. O presente trabalho objetivou avaliar a capacidade de produção de fitomassa de diferentes sistemas de culturas e sua influencia na produtividade do milho na microrregião de Guarabira - PB. Foram instalados seis sistemas de culturas: semeadura direta com milho (SD); semeadura direta com milho + mucuna (SDM); semeadura direta com milho + guandu (SDG); semeadura direta com milho + guandu + mucuna (SDGM); semeadura direta com milho + fava (SDF) e semeadura direta com milho + fava + mucuna (SDFM), na presença e ausência de adubação mineral com N-P-K, avaliados durante 9 anos. Foram avaliados o percentual de cobertura e a quantidade de fitomassa sobre o solo, bem como a produtividade de grãos de milho. A adubação mineral e as leguminosas proporcionaram acréscimos variando entre 22% e 49% de produtividade de grãos de milho entre os sistemas de cultivo. Com o passar dos anos, os sistemas de culturas promoveram estoque de fitomassa com acréscimos de até 76% na superfície do solo e, embora a precipitação seja um fator limitante para produção de fitomassa, o uso das leguminosas e da adubação mineral com N-P-K nos sistemas de culturas facilitaram a implantação do sistema de semeadura direta na região estudada.

The turfs quality of selected Slovak varieties of the genus Festuca under the conditions without irrigation

The development of botanical composition (in % dominance) in the period 2005–2011 and growth-production process in the years 2007–2011 were evaluated in small-plots experiment with selected Slovak varieties of species of the genus Festuca. The experiment was realized under the conditions without irrigation of south-western Slovakia (locality Nitra). The data of botanical composition of turfs showed that fescue varieties were able to create well-covered vegetation (coverage 87–99 %) as early as next year after sowing in conditions without irrigation. In the next period, the differences in turf coverage between varieties were minimized. The total height of turf and average daily gain of height were the highest in F. arundinacea Schreb. varieties throughout the observed period with significant differences in year 2008 (p = 0.0239), 2009 (p = 0.0462) and 2011 (p = 0.0036). The most intensive growth had F. arundinacea Schreb. cv. Koreta (1.81 to 3.44 mm.d−1; i.e. very low to moderate intensity of growth). From point of view of aboveground phytomass production almost throughout the period were used varieties characterized by very low production of phytomass. Among years and varieties were observed differences in the ability thicken vegetation expressed as the ratio of the average daily gain of weight and average daily gain of height (W/H). F. rubra L. cv. Laroma (0.38 to 1.26 g.m−2.mm−1) and F. ovina L. cv. Grasina (0.37 to 1.54 g.m−2.mm−1) dominated in this indicator except for 2009, when higher values reached F. arundinacea Schreb. cv. Koreta and Levona (both 0.43 g.m−2.mm−1; F. rubra L. and F. ovina L. – 0.27 and 0.39 g.m−2.mm−1, respectively).

Yield and species composition of a mesic grassland savanna in South Africa are influenced by long‐term nutrient addition

AbstractSpecies composition and productivity of natural grasslands are influenced by soil nutrient status. With high resource availability, productivity is expected to increase, and competition is assumed to gain prominence with predicted exclusion of species of lower competitive ability. During 2010 and 2011 we used the dry weight rank method to measure above‐ground phytomass production of herbage in 96 plots (9 m × 2.7 m) fertilized for 60 years with two forms of nitrogen (N as limestone ammonium nitrate or ammonium sulphate at four levels: 0, 7.1, 14.1, 21.2 g m−2), phosphorus (P as superphosphate at two levels: 0, 33.6 g m−2), and lime (two levels: 0, 225 g m−2). Light attenuation was measured as the proportion of photosynthetically active radiation reaching the lower leaf layers of the grasses and the ground surface. Light conditions beneath the grass layer were reduced by nutrient addition to 30% of full sunlight but remained above 60% in non‐fertilized plots. Grass total above‐ground phytomass production increased with nutrient addition. The strongest yield responses were attained with N plus P addition. Species responses showed that Themeda triandra and Hyparrhenia hirta decreased in above‐ground phytomass production with nutrient addition while Panicum maximum, Eragrostis curvula and E. plana increased. These findings are discussed in terms of competitive interactions among species, their position in the grass canopy and their physiological tolerances to high nitrogen environments.

Desempenho agronômico de plantas de cobertura usadas na proteção do solo no período de pousio

O objetivo deste trabalho foi identificar espécies com alta produção de fitomassa, para proteção do solo no período de pousio. O experimento foi realizado com três espécies da família Leguminosae e três da família Poaceae, de 2009 a 2010, na área experimental do campus da Universidade Federal de Lavras, Minas Gerais. As espécies avaliadas foram: crotalária anagiroide (Crotalaria anagyroides), feijão‑de‑porco (Canavalia ensiformis), guandu‑anão (Cajanus cajan), aveia‑preta (Avena strigosa), sorgo (Sorghum bicolor) e milheto (Pennisetum glaucum), semeadas em cultivo solteiro e consorciado. O feijão‑de‑porco e o sorgo apresentaram as maiores taxas de cobertura do solo em cultivo solteiro, enquanto o milheto apresentou a menor. O sorgo, em cultivo solteiro e consorciado com feijão‑de‑porco e guandu‑anão, apresenta a maior produção de matéria verde e matéria seca, enquanto o guandu‑anão apresenta a menor produção de matéria verde, e a crotalária anagiroide, a menor produção de matéria seca. Por ocasião da implantação da cultura comercial, o tratamento que proporcionou a maior quantidade de palha sobre o solo foi o consórcio entre feijão‑de‑porco e sorgo.

Performance of rice seeds treated with zinc, boron, and molybdenum

The objective of this study was to assess physiological quality of seeds and the initial growth of lowland rice seedlings, cv. PUITA INTA-CL, treated with a product based on Zinc, Boron and Molybdenum. The following dosages of product were used: 0 (control), 50, 100, 150 and 200 mL.100 kg-1 seed. A completely randomized experimental design was used, with 10 treatments and four replications. Physiological quality of seeds was assessed by following tests: germination; first count of germination; and length and dry phytomass of seedlings. The initial growth was assessed at 7, 14, 21, 35, and 42 days after emergence (DAE) through plant height, leaf area and dry phytomass of aerial parts and roots. It was concluded that the treatment of rice seeds with the product containing Zinc, Boron and Molybdenum up to the dosage tested of 200 mL.100 kg-1 seed does not influence germination, first count of germination, and the dry phytomass of aerial parts and roots; however, negatively influences seedling length. In addition, it also promotes greater plant height, higher leaf area, higher production of dry phytomass of seedlings, and increase on the growth rate, until 42 DAE.

A field experiment on the use of Pistacia lentiscus L. and Scrophularia canina L. subsp. bicolor (Sibth. et Sm.) Greuter for the phytoremediation of abandoned mining areas

A two-year study has been conducted in an abandoned Pb/Zn mining site, with the aim of investigating the feasibility of phytoremediation using two native Mediterranean plants (Pistacia lentiscus and Scrophularia bicolor) and of assessing the performance of amendments able to reduce the toxic effects of heavy metals. The amendments used were compost, chemical fertilizer, and zeolites, used singly or in combination. Depending on the amendments applied, the two species showed different mortality rates in the different plots, but all produced an increase in P. lentiscus survival, while S. bicolor survival improved only when amended with zeolite or zeolite + fertilizer. Scrophularia bicolor proved to be a more efficient accumulator than P. lentiscus, especially for Pb uptake. Pistacia lentiscus accumulated metals mostly in the roots. The effect of amendments was to generally reduce the bioavailable metal fraction, especially lead, in the plots amended with compost. Pistacia lentiscus proved to be the most suitable species for phytostabilization and environmental restoration, both for its resistance to metals and high phytomass production. The experiments demonstrate that the use of compost not only encourages this kind of revegetation in degraded areas, but is also an economical option that uses a by-product of solid municipal waste treatment.

Potential of a polyculture of Arundo donax and Typha latifolia for growth and phytotreatment of wastewater pollution

Arundo donax and Typha latifolia are emergent macrophyte species that commonly reproduce in humid areas during warm months. This study investigated the growth and pollutant removal capacity of these two species planted in polyculture in a vertical flow filter bed for rural wastewater treatment. Plant shoot height was monitored and biomass production and nutrient uptake were assessed. Water physicochemical parameters were also monitored. A. donax showed higher height elongation (288 cm), phytomass production (2.4 kg dry biomass/m²) and nitrogen uptake (21.1 mg/kg DW) than did T. latifolia. Phosphorus and potassium retention was identical for both species. The macrophyte bed achieved higher removal rates for biochemical oxygen demand (BOD) (76%), chemical oxygen demand (COD) (82%), total suspended solids (TSS) (96%), total Kjeldahl nitrogen (TKN) (33%) and total phosphorus (TP) (46%), compared to an unplanted basin. The macrophyte species used were able to grow and to contribute to the rural wastewater purification in the adopted experimental constructed wetland. Key words: Arundo donax , Typha latifolia , wastewater, phytotreatment, nutrient uptake, constructed wetland.

Characterizing and evaluating successional pathways of fen degradation and restoration

The definition of restoration targets and the evaluation of restoration success require a comprehensive, ecosystem-based analysis of all successional pathways, which proceed along gradients of land use intensification and continue after implementation of restoration measures. In the presented study, such analysis was applied to fen ecosystems. Study areas were river valleys and eutrophic lakes in The Netherlands and in Schleswig-Holstein, the northernmost state of Germany. At these sites high fen degradation has taken place and restoration strategies such as “recovery of peat-forming systems” and “development of species-rich fen grasslands” have recently been pursued. Based on an indirect successional analysis, we derived characteristic shifts of abiotic (hydrodynamics, soil parameter) and biotic (species composition, phytomass production) ecosystem traits relative to increasing land use intensity. Species richness and nature conservation value (NCV) initially increased and afterwards decreased during the process of land use intensification. This floristic change was accompanied by an initial decrease and subsequent increase in system productivity. Indicators for P-availability showed the same trend and there was evidence that nutrient limitation changed initially from N- (tall sedge reeds) to P- or P/N (co)-limitation (small sedge reeds) and afterwards again to N-limitation (wet and mesic grasslands). The successional analysis documented the abiotic requirements of vegetation types and their characteristic species, and thus, allowed for the use of these ecosystem traits as indicators to evaluate the success of specific restoration targets. For example, the decrease of Scheuchzerio-Caricetea species could be related more directly to reduced light availability than to an increase of the groundwater tables. Furthermore, we calculated threshold values of these traits for the occurrence of target species. For instance, a sustainable establishment of light-demanding mesotrophic species can only be expected if the standing crop value is less than 400gm−2. In a further step, we estimated the restoration success in selected study areas by applying the findings of the successional analysis. Results showed that rewetting measures have to be carried out with caution if both restoration strategies are aspired in one specific area. Moreover, restoration success of both strategies is limited in initially highly degraded areas. Sources for target species are often missing and abiotic conditions such as nutrient levels and flooding periods are often inappropriate. Consequently, expectations for restoration success should be adapted to the realistic development potential of the individual system and a cost–benefit analysis has to be carried out to avoid unnecessary management costs.

Habitat preferences of the encroacher shrub, Seriphium plumosum

The ecology of Seriphium plumosum is not yet fully understood and therefore requires in-depth research to assist with the control of this encroacher plant. The habitat preferences of the plant were quantified for terrain morphological units in terms of soil fertility, saline/sodic conditions and soil–water relationships. The influence of S. plumosum density on grass production was also quantified. It is clear that the distribution (both occurrence and density) of S. plumosum is associated with soil characteristics. The study indicated the sensitivity of S. plumosum towards wet conditions, perennial and transient water tables, overly high soil pH, clay content, high soil fertility (organic matter and phosphate) and sodium chloride. The deeper the soil profile, the more favourable the habitat for S. plumosum, owing to a decrease in waterlogged conditions. The habitat prevalence of S. plumosum is possibly a reflection of not only climatologically wetness but also of topographic wetness. There was no clear general trend for the individual cations along the terrain units. A significant relationship was established between aboveground phytomass production loss of the grass sward and S. plumosum density. These results confirm the threat posted by S. plumosum in semiarid grassland areas, following changes in environmental characteristics.

Effects of Rates and Nutrient Ratios on Production and Quality of Phytomass at Fertiliser Application to an Alluvial Meadow

Effects of Rates and Nutrient Ratios on Production and Quality of Phytomass at Fertiliser Application to an Alluvial Meadow The research objective was to assess effects of fertiliser application rates and nutrient ratios on production and quality of grassland at an alluvial meadow. The initial sward type was Festucetum pratense association. A field trial was established in the western part of "Zvolenská kotlina" basin (altitude 350 m) and consisted of ten fertiliser treatments: zero-fertilised sward (control); fertiliser P and K application; rates of 50, 100, 150 and 200 kg N/ha at two ratios of N : P : K nutrients, namely the low N : P : K ratio (1 : 0.3 : 0.8) and the high one (1 : 0.15 : 0.4), respectively. The grassland was utilised by three cuts. Dry matter (DM) production and herbage quality were determined at each of the cuts. The yield of DM was higher with the rates of 50 and 100 kg N/ha applied at the high nutrient ratio than at the low ratio. Over the research period, the highest DM production was recorded at the treatment with the low nutrient ratio and the highest N rate applied. The content of crude protein (CP) was increasing with the rising fertiliser N rate and the increase in CP was higher at the low nutrient ratio treatments. The zero-fertilised control also provided sufficient CP content. The low nutrient ratio resulted in higher P and K content than the high one. The lowest content of P and K was recorded at the control. The highest P content was found at the treatment with the fertiliser P and K applied. The highest K content was recorded at the 2nd cut, but decreased at the 3rd cut in all the treatments. The content of Ca was rising towards the 3rd cut. The content of nutrients was higher at the treatments where the high ratio was used. The content of Mg in DM was higher at the treatments with the high nutrient ratio and the high N fertiliser rates. The content of Mg was increasing in the 2nd cut at all the treatments.

Combining satellite derived phenology with climate data for climate change impact assessment

The projected influence of climate change on the timing and volume of phytomass production is expected to affect a number of ecosystem services. In order to develop coherent and locally effective adaptation and mitigation strategies, spatially explicit information on the observed changes is needed. Long-term variations of the vegetative growing season in different environmental zones of Europe for 1982–2006 have been derived by analysing time series of GIMMS NDVI data. The associations of phenologically homogenous spatial clusters to time series of temperature and precipitation data were evaluated. North-east Europe showed a trend to an earlier and longer growing season, particularly in the northern Baltic areas. Despite the earlier greening up large areas of Europe exhibited rather stable season length indicating the shift of the entire growing season to an earlier period. The northern Mediterranean displayed a growing season shift towards later dates while some agglomerations of earlier and shorter growing season were also seen. The correlation of phenological time series with climate data shows a cause-and-effect relationship over the semi natural areas consistent with results in literature. Managed ecosystems however appear to have heterogeneous change pattern with less or no correlation to climatic trends. Over these areas climatic trends seemed to overlap in a complex manner with more pronounced effects of local biophysical conditions and/or land management practices. Our results underline the importance of satellite derived phenological observations to explain local nonconformities to climatic trends for climate change impact assessment.

Some aspects of interrelations between terrestrial ecosystems and the changing climate

Issues of interrelations between climate and land ecosystems (mainly, their basic component: vegetative land cover) are considered in the paper. The hysteresis effect, which manifests itself in the dynamics of biome boundaries, is described on both a global and a regional scale and based on data analysis of the primary production of aboveground phytomass and evaporability. The work helps reveal centers of interannual stability of the onset of phenological events throughout the territory of European Russia and study regularities in their shifts during the vegetation period. The interannual temporal variability in the onset of natural events is shown to remain within the range of climatic variables. It is established that the temporal patterns for the onset of many spring events have advanced to earlier dates over the past decades (whereas those for autumn events have shifted to later dates) and the vegetation periods have extended, e.g., by more than ten additional days in the northern part of European Russia. However, phenological responses to global warming show differences across regions and groups of organisms, which evidences that the biota responds as a whole to present-day climate changes in different ways.

Seasonal variation in the phytomass, chemical composition and nutritional value of Azolla filiculoides Lam. along the water courses in the Nile Delta, Egypt

AbstractThe present study aims to assess phenological behaviour, phytomass production, chemical composition and nutritional value of Azolla filiculoides in the water courses of the Nile Delta, Egypt. The sampling process was carried out seasonally using twenty‐five plots (each of 1 × 1 m) distributed along 15 irrigation canals and 10 drainage canals in the study area. Sprouting of A. filiculoides had its maximum activity during winter, vegetative growth during spring and summer and withering during autumn. Maximum seasonal phytomass (285.2 g DW m‐2) was found during spring. The annual mean was significantly higher in drainage canals (278.3 g DW m‐2) than in irrigation canals (144.4 g DW m‐2). The concentrations of Ca, Mg and Na in A. filiculoides from drainage canals were significantly higher than in those from irrigation canals. Regarding the type of water courses, there were no significant differences in organic contents and nutritive values between the irrigation and drainage canals. The analysis of growth characteristics indicated that A. filiculoides can grow quite well in drainage canals; its macronutrient (N, Ca, Mg, Na and Fe) contents are high enough to allow it to be used as a bio‐fertilizer. On the other hand, A. filiculoides could be considered as a ‘nutrients and heavy metals remover’ especially in drainage canals for wastewater treatment if the plant is harvested during its maximum phytomass. As feed supplement for animals, this plant could be considered as excellent forage because its high levels of carbohydrate, protein, crude fat, total digestible nutrients and the lower crude fiber contents (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Nitrate concentration in lettuce leaves depending on photosynthetic photon flux and nitrate concentration in the nutrient solution

The nitrate accumulation in plant tissues can occur due to low light availability. However, published studies have not linked nitrate accumulation to photosynthetic photon flux (PPF) measured during the growing period. This study aimed to evaluate the effect of the reduction of photosynthetic photon flux and the concentration of nitrate in the nutrient solution on agronomic characteristics and accumulation of nitrate in lettuce grown in hydroponics. The trial design was entirely randomized in a factorial scheme (4 x 2) with three repetitions, and four shading levels: 0, 30, 50, and 80% and two nitrate levels in nutrient solution: 5 and 10 mmol L-1. The dry matter production decreased directly and linearly with the reduction of light. The lowest level in nitrate solution also led to reduction in dry mass yield. The maximum accumulation of nitrate reached 966.3 mg kg-1 fresh mass, with PPF of 118 μmol/m²/s and 140 mg L-1 of N-NO3-1 (below the maximum levels recommended by the European Union), and the minimum of 200 mg kg-1 with PPF of 455 μmol/m²/s and 70 mg L-1 of N-NO3-1 in the nutrient solution. The reduction of nitrate in the nutrient solution from 140 to 70 mg L-1 led to the reduction of nitrate accumulation in shoots, but also caused a decrease in the production of phytomass of shoots, as well as reduced leaf area significantly.