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Nine remote sensing-based surface soil moisture (SSM) estimation models using images from Landsat 8, Sentinel-2 and Sentinel-1 satellites were compared. To evaluate these models, we measured SSM at 179 locations in a 50-ha sunflower field. The result showed that the Water Cloud-based model, a semi-empirical regression model, which used the synergy of Landsat 8 and Sentinel-1 data, was the best model, with an R2 of 0.73 and RMSE of 0.053 m3/m3. In sum, with the integration of images from multiple satellites, soil moisture maps with suitable spatial resolutions were retrieved that may be used for irrigation planning. [ABSTRACT FROM AUTHOR]

Island beaches, once mistakenly considered as 'ecological deserts', are actually unique ecosystems that support abundant macrofaunal communities. However, limited studies have examined the variations and determinants of macrofaunal communities across the intertidal zones on island beaches, which is crucial for shedding light on the underlying ecological processes and enhancing biodiversity conservation efforts. Here, we explored the variations in macrofaunal communities along sand physico-chemical gradient across four intertidal zones on nine representative beaches, within the largest land-bridge archipelago in eastern China. Our findings revealed that species richness, density, and Shannon-Wiener diversity of macrofaunal communities were notably higher in the lower intertidal zones, exhibiting a positive correlation with elevated levels of sand moisture (M), electrical conductivity (EC), available potassium (AK), and grain size (GS). Conversely, macrofaunal Simpson diversity displayed an inverse pattern, with heightened values observed in the vegetation zone. The Saprophagous, Predaceous, and Omnivorous groups of macrofaunal communities demonstrated an increase with higher levels of EC, AK, and M in the lower intertidal zones. Furthermore, Phytophagous group of macrofaunal communities tended to inhabit the vegetation zones characterized by elevated levels of sand total phosphorus (TP), total nitrogen (TN), and organic carbon (OC). Primarily, our findings indicate that sand nutrition, moisture, and salinity play pivotal roles in shaping the variations of macrofaunal communities on island beaches. These insights offer valuable perspectives into the holistic responses of macrofauna on island beaches to changes in sand physico-chemical properties, serving as a crucial theoretical foundation for the assessment, conservation, and restoration of island beaches.

Many ecosystems are experiencing increased fire frequencies and species invasions that can erode their resilience and cause a shift to alternative states. In the sagebrush‐steppe, a semi‐arid shrubland ecosystem in North America, restoration treatments are often implemented following wildfire to enhance their resilience to invasion. However, little is known about the long‐term effectiveness of these treatments. We investigated whether repeated restoration efforts provide greater resilience in sagebrush‐steppe communities initially dominated by species with different post‐fire regeneration traits and subjected to compounding wildfires and invasion by Bromus tectorum over 25 years.We studied 37 permanent transects (Columbia Basin, Washington, USA) in which species abundance was recorded multiple times from 1992 to 2017. We quantified community change and its relationship with fire, restoration, and moisture availability. Resilience was evaluated by quantifying community resistance and stability indices.The greatest change occurred in communities where the obligate seeding shrub Artemisia tridentata was initially common. Repeated fires led to the extirpation of this shrub and eventual dominance of B. tectorum. Herbicide applications temporarily suppressed B. tectorum post‐fire. Seeding treatments and above average precipitation initially increased native cover. Although communities where resprouting species were common showed the least change, repeated fires did lead to a gradual but substantial decline (86%) in resprouting shrubs.Synthesis and applications. Our findings show that repeated restoration efforts, together with elevated precipitation, can support native species re‐establishment in systems experiencing altered disturbance regimes and species invasions. Our unique long‐term dataset demonstrates, however, that many such interventions have short‐lived effects due to the strong 'unhelpful resilience' of highly invaded systems. This implicitly suggests that many such systems have experienced fundamental shifts in ecosystem state. The likelihood of this occurring is strongly associated with the dominant species post‐fire regeneration traits. We predict that community composition and resilience will continue to degrade in the sagebrush‐steppe unless management prioritizes fire suppression and an adaptive restoration approach that considers resource availability. [ABSTRACT FROM AUTHOR]

Variation in geographical range size among closely related species may result from differences in physiological traits, such as desiccation tolerance, that enable these species to interact with their environment or adapt to new surroundings.We tested the hypothesis that insect species with a broader geographical range have either a higher basal desiccation tolerance or mount a more plastic response than more narrowly distributed species by exposing four fruit fly species (Ceratitis capitata, Ceratitis rosa, Ceratitis cosyra and Ceratitis podocarpi) to one of three acclimation treatments (control: standard relative humidity (RH) and temperature; desiccation: standard temperature and low humidity; and temperature: low RH and high temperature) and measuring metabolic rate, activity, water loss rates and survival.The targeted physiological responses differed between species and acclimation treatments. Survival of the widely distributed C. capitata improved by up to 43% after short‐term exposure to high temperature and desiccation (35°C; 0% RH) treatment, while survival in the more narrowly distributed species only improved by 4%–30% after a desiccation treatment (25°C; 0% RH).Less water was lost by broadly distributed C. capitata through excretion after both high temperature and desiccation treatments, but only activity and respiratory water loss (RWL) were reduced after the temperature treatment, and total water loss and cuticular water loss declined after the desiccation treatment. The narrowly distributed C. rosa also lost less water through excretion after both acclimation treatments but showed reduced cuticular and RWL only after desiccation. While basal tolerance in C. cosyra was high, acclimation responses in this species and C. podocarpi were insignificant in that they did not produce a measurable survival benefit.Broadly distributed species successfully employed unique combinations of physiological strategies, with some having highly flexible responses to stressful environmental conditions, which ultimately results in beneficial acclimation to enhance survival during dry conditions. By contrast, range restricted species showed limited responses to desiccation stress. Flexible desiccation responses likely contribute to species geographical ranges in changing climate conditions. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

Natural conditions in North and Central Kazakhstan and the energy potential of chestnut soil testify to the efficiency of agriculture, especially on irrigated lands. The humus horizon of chestnut soils is 35–50 cm, and the humus content is 3.0–3.5%. The majority of the humus (75%) is contained in a half-meter layer, which emphasizes the short humus level. The phosphorus content, both gross and mobile, is very low at 0.98–0.031%. Potassium is in elevated amounts. Soils are most susceptible to the application of nitrogen–phosphorus fertilizers. According to the mechanical composition, chestnut soils are predominantly lightly loamy, light clays with substrates of souses. Salinization is low, with a salt content in the 0–100 cm soil layer of 0.10–0.20%. The mass of the arable soil layer is 1.3–1.4 g/cm3. Deep plowing and loosening of soils improve the water and nutrition regime, creating good conditions for arid agriculture. With deep autumn plowing up to 30 cm, the accumulation of sediment and spring meltwater reaches 1200–1500 m3/ha more than in spring disposal. Deep plowing ensures absorption of irrigation water, eliminates run-off during irrigation, and reduces the number of crops requiring extra irrigation. In an average dry year, at 50% water availability and 70% soil moisture content (MC), the number of irrigations is 4, and the irrigation rate is 300–470 m3/ha; at 60% MC, 2 irrigations are performed, and the irrigation rate is 600–650 m3/ha. On irrigated land, the yield of cereals is 2.8–2.6 t/ha; perennial grasses, 3.0–4.5 t/ha; potatoes, 23.2–24.1 t/ha; carrots, 35.0–40.0 t/ha; and cabbage, 50.0–75.0 t/ha. [ABSTRACT FROM AUTHOR]

On the basis of long-term meteorological data and research results in a long-term stationary experiment of 1971-2020 a retrospective analysis of changes in air temperature and precipitation in the eastern region of the central climatic zone of the Kirov region was carried out and the influence of these characteristics on the dynamics of the yield of spring cereals was estimated. It has been established that the average annual air temperature during the research period was 2.4±1.0 °C. At the same time, its stable positive trend was observed at the rate of 0.39 °С /10 years. Two decades from 2001 to 2020 were recorded as the warmest for 50 years, when the temperature was 0.7...2.6 °C above climate normal. Selyaninov hydrothermal coefficient (0.7...2.1) testifies to the contrasting conditions of humidification of the vegetation periods during the research years – from drought to excessively humidified. In a long-term experiment, the yield of spring cereals increased in the row wheat – barley – oats: 2.17±0.86, 3.04±0.61, 3.39±0.65 t/ha, respectively. Strong correlations were marked between the average yield (spring wheat) and weather conditions in June: reverse with air temperature (rр = -0.735) and direct with the amount of precipitation (rр = 0.686). It has been established that the use of phosphorus fertilizers (and their aftereffect) in combination with nitrogen-potassium fertilizers weakened the influence of weather conditions on the productivity of spring wheat: the determination coefficients (R2), which reflect the portion of variability due to weather conditions, were 0.59-0.73 for the variant without fertilizers and decreased to 0.50-0.56 when applying NP3K.

• Sand physico-chemical properties exhibited distinct changes across the intertidal zones on island beaches. • Consistent patterns of variation were observed in macrofaunal diversity and functional groups across the intertidal zones. • Variations in macrofaunal communities on island beaches were primarily influenced by sand moisture, salinity, and nutrition. • Island beaches are not ecological deserts, they require careful protection. Island beaches, once mistakenly considered as 'ecological deserts', are actually unique ecosystems that support abundant macrofaunal communities. However, limited studies have examined the variations and determinants of macrofaunal communities across the intertidal zones on island beaches, which is crucial for shedding light on the underlying ecological processes and enhancing biodiversity conservation efforts. Here, we explored the variations in macrofaunal communities along sand physico-chemical gradient across four intertidal zones on nine representative beaches, within the largest land-bridge archipelago in eastern China. Our findings revealed that species richness, density, and Shannon-Wiener diversity of macrofaunal communities were notably higher in the lower intertidal zones, exhibiting a positive correlation with elevated levels of sand moisture (M), electrical conductivity (EC), available potassium (AK), and grain size (GS). Conversely, macrofaunal Simpson diversity displayed an inverse pattern, with heightened values observed in the vegetation zone. The Saprophagous, Predaceous, and Omnivorous groups of macrofaunal communities demonstrated an increase with higher levels of EC, AK, and M in the lower intertidal zones. Furthermore, Phytophagous group of macrofaunal communities tended to inhabit the vegetation zones characterized by elevated levels of sand total phosphorus (TP), total nitrogen (TN), and organic carbon (OC). Primarily, our findings indicate that sand nutrition, moisture, and salinity play pivotal roles in shaping the variations of macrofaunal communities on island beaches. These insights offer valuable perspectives into the holistic responses of macrofauna on island beaches to changes in sand physico-chemical properties, serving as a crucial theoretical foundation for the assessment, conservation, and restoration of island beaches. [ABSTRACT FROM AUTHOR]

Pollen and diatom assemblages from well-dated sediment cores from three lakes forming a west-to-east transect across the boreal forest in northwest Ontario (Canada) were used to evaluate the timing and nature of the movement of the prairie-forest ecotone (PFE) across the Holocene. Changes in vegetation, temperature, and effective moisture were inferred from pollen and pollen-based transfer functions. Analyses indicated site-specific vegetational and climate changes across short spatial distances, with prolonged prairie-like conditions during the middle Holocene at the westernmost site. Increased reconstructed temperatures at this westernmost site occurred from ∼9000 to 3000 cal yr BP, alongside increases in diatom-inferred lake levels beginning at ∼6000 cal yr BP. The abundance of Quercus peaked concurrently with rising lake levels before declining to trace levels by ∼3000 cal yr BP. Increases in the abundance of non-arboreal pollen between ∼8500 and ∼4500 cal yr BP at the more eastern lakes suggest relatively delayed and truncated PFE influence, before the reestablishment of primarily boreal taxa by ∼4500 cal yr BP, coincident with diatom-inferred increases in lake levels. This study shows that the PFE moved both farther east and north than previously determined, but generally agrees with established patterns in vegetation from other studied regions along the PFE. [ABSTRACT FROM AUTHOR]

Soil climate is a natural resource of a certain territory and a component of the natural environment. The soil climate is very important for crop production: germination of seeds of agricultural crops, dormancy of overwintering plants and perennial grasses, growth of the root system and plants' aboveground mass during the growing season, productivity of plants. The role of the soil climate is also clearly manifested during moisture- and heat-dependant periods when moisture lack or excess and low or high temperature in the upper soil layers may have a significant influence on reaction of plants to the environmental conditions and consequently on their productivity. When studying the soil climate, it is possible to adjust it following the agricultural needs. In connection therewith, the aim of the research is to determine the quantitative characteristics of the soil climate of the Northern Black Sea region using the example of corn. The object of the research: the Northern Black Sea region. The subject of the research: soil climate. The study applies classical methods of agroclimatic calculations and generalizations. The article presents the results of agroclimatic assessment of the Northern Black Sea region's soil climate using the example of corn in relation to such criteria as soil thermal resources and moisture/moisture availability resources of an individual crop. It specifies the results of quantitative agroclimatic assessment of the thermal regime of soils with different mechanical composition across the Northern Black Sea region as per the following indicators: a) date of soil temperature transitions through 10 ºC in spring and autumn on the top of the soil and at depths of 10, 20 cm; b) duration of a warm period with the temperature above 10 ºC for soils having different mechanical composition; c) combined total of active temperatures above 10 ºC on the top of the soil and at certain depths. The research also presents the results of agroclimatic assessment of moisture/moisture availability resources within the studied territory based on the following main indicators: optimum water demand, actual water demand, evaporation rate; moisture availability coefficient; moisture index by G. Т. Selianynov and moisture index by D. І. Shashko during a warm period with temperature above 10 ºC. The paper also includes the quantitative assessment of the relationship between soil moisture reserves at different depths (0–20 cm, 0–50 cm, 0–100 cm) and productive moisture reserves at the lowest moisture content and moisture availability values for corn crops.

CO2 fluxes from wood decomposition represent an important source of carbon from forest ecosystems to the atmosphere, which are determined by both wood traits and climate influencing the metabolic rates of decomposers. Previous studies have quantified the effects of moisture and temperature on wood decomposition, but these effects were not separated from the potential influence of wood traits. Indeed, it is not well understood how traits and climate interact to influence wood CO2 fluxes. Here, we examined the responses of CO2 fluxes from dead wood with different traits (angiosperm and gymnosperm) to 0%, 35%, and 70% rainfall reduction across seasonal temperature gradients. Our results showed that drought significantly decreased wood CO2 fluxes, but its effects varied with both taxonomical group and drought intensity. Drought‐induced reduction in wood CO2 fluxes was larger in angiosperms than gymnosperms for the 35% rainfall reduction treatment, but there was no significant difference between these groups for the 70% reduction treatment. This is because wood nitrogen density and carbon quality were significantly higher in angiosperms than gymnosperms, yielding a higher moisture sensitivity of wood decomposition. These findings were demonstrated by a significant positive interaction effect between wood nitrogen and moisture on CO2 fluxes in a structural equation model. Additionally, we ascertained that a constant temperature sensitivity of CO2 fluxes was independent of wood traits and consistent with previous estimates for extracellular enzyme kinetics. Our results highlight the key role of wood traits in regulating drought responses of wood carbon fluxes. Given that both climate and forest management might extensively modify taxonomic compositions in the future, it is critical for carbon cycle models to account for such interactions between wood traits and climate in driving dynamics of wood decomposition. [ABSTRACT FROM AUTHOR]

Paleoclimate reconstructions suggest that the complex variability within the Greenland stadial 1 (GS-1) over western Europe was governed by coupled ocean and atmospheric changes. However, few works from the North Atlantic mid-latitudes document both the GS-1 onset and its termination, which are often considered as single abrupt transition events. Here, we present a direct comparison between marine (alkenone-based sea surface temperatures) and terrestrial (pollen) data, at very high resolution (28 years mean), from the southwestern Iberian shelf record D13882. Our results reveal a rather complex climatic period with internally changing conditions. The GS-1 onset (GS-1a: 12890-12720 yr BP) is marked by a progressive cooling and drying; GS-1b (12720-12390 yr BP) is the coldest and driest phase; GS-1c (12390-12030 yr BP) is marked by a progressive warming and increase in moisture conditions; GS-1 termination (GS-1d: 12030-11770 yr BP) is marked by rapid switches between cool wet, cold dry and cool wet conditions. Although hydroclimate response was very unsteady throughout the GS-1 and in particular during its termination phase, the persistence of an open temperate and Mediterranean forest in southwestern Iberia during the entire episode suggests that at least some moisture was delivered via the Westerlies. We propose coupled ocean and atmospheric mechanisms to reproduce these scenaria. Changes in the strength of the Atlantic Meridional Overturning Circulation (AMOC) as well as variations in the North Atlantic sea-ice growth have favoured the displacement of the polar jet stream's latitudinal position and contributed to a complex spatial pattern and strength of the Westerlies across western Europe. • Highlights of the Quaternary Science Reviews paper by Naughton et al.. • GS-1 in SW Iberia is a complex climatic period with four main phases. • Hydroclimate was very unsteady throughout the GS-1 event and in particular during its termination phase. • Ocean and atmospheric changes contributed to a complex spatial pattern of the Westerlies across Western Europe. [ABSTRACT FROM AUTHOR]

In the present study we assessed the sensitivity of stored seeds of the common grass Neurachne alopecuroidea R.Br. from south-western Australian sources to varying temperature and moisture conditions as a tool to anticipate potential adaptability of seeds to climate change. We examined among-population germination responses, focusing on germination of excised seeds to overcome possible dormancy imparted by the lemma and palea. We hypothesised that temperature above and below the optimum and low moisture potentials would adversely affect germination, and that conditions for successful germination would be associated with the local climate at each seed source site. Experiment 1 used a bi-directional temperature gradient plate to measure responses to constant and alternating temperatures (5–40°C). Experiment 2 examined responses to moisture availability using polyethylene glycol (PEG 8000) solutions at different temperatures. Temperature optima varied among populations with significant reductions in germination occurring only below 15°C. Germination speed and success declined with decreasing moisture availability, with greater impact at higher temperatures. Significant population variation was observed. Tolerance to temperature and moisture availability was higher than expected and some of this variation suggests adaptation to local climates across the species Western Australian distribution. We discuss these results in the context of seed use in restoration and global warming. Optimising climate resilience of restoration efforts requires an understanding of a species response to certain environmental constraints. By exploring the variation in germination in stored seeds from multiple populations of the native grass Neurachne alopecuroidea , we found that germination speed and success declined with decreasing moisture availability, with greater impact at higher temperatures. The considerable variation in germination response across the species Western Australian distribution suggests that some sites may be better seed sources for future restoration than others. [ABSTRACT FROM AUTHOR]

Intraspecific trait variation within natural populations (i.e. intra‐population trait variation, IPTV) is the basic source for selection and can have significant ecological consequences. Higher IPTV may increase a population's niche breath and benefit interspecies competition under a resource‐limited environment, thus affecting the ability of a species to move into novel habitats. However, the reciprocal influences of variation in environmental conditions and phenotypic trait expression in spreading plant populations are not clearly defined. We propose that during invasion, IPTV and its relative change in response to key resource enrichment may increase with the resource deficit of invaded sites, and that this relationship may facilitate plant invasions into resource‐limited environments. We analyzed the invasion trend, IPTV and its response to water enrichment, and moisture variability among populations of an annual grass Brachypodium hybridum in California, United States. We incorporated a genotyping‐by‐sequencing approach, a common garden experiment that had two water level treatments, and public plant and climate databases. Our hypothesis was supported by the observation that for populations that invaded sites with higher spring moisture deficit, both their seed biomass IPTV (for the water‐enriched treatment only) and relative change of the IPTV across water treatments were larger when examined in the common garden experiment. A generally north to south spreading direction was found in these B. hybridum populations, towards a drier and warmer climate exhibiting higher moisture deficit for plant growth. Our results suggest a role for interactions between IPTV (rather than trait means) and environmental resource availability in promoting plant invasions, providing new insights into the significance of IPTV in shaping plant geographic distributions. [ABSTRACT FROM AUTHOR]

The hyperarid core of the Atacama Desert represents one of the most intense environments on Earth, often being used as an analog for Mars regolith. The area is characterized by extremes in climate (e.g., temperature, humidity, UV irradiation) and edaphic factors (e.g., hyper-salinity, high pH, compaction, high perchlorates, and low moisture, phosphorus and organic matter). However, the halophytic C 4 plant Distichlis spicata appears to be one of the few species on the planet that can thrive in this environment. Within this habitat it captures windblown sand leading to the formation of unique structures and the generation of above-ground phyllosphere soil. Using a combination of approaches (e.g., X-ray Computed Tomography, TXRF, δ13C/δ15N isotope profiling, microbial PLFAs, 14C turnover, phosphate sorption isotherms) we examined the factors regulating the biogeochemical cycling of nitrogen (N), phosphorus (P) and carbon (C) in both vegetated and unvegetated areas. Our results showed that D. spicata rhizomes with large aerenchyma were able to break through the highly cemented topsoil layer leading to root proliferation in the underlying soil. The presence of roots increased soil water content, P availability and induced a change in microbial community structure and promoted microbial growth and activity. In contrast, soil in the phyllosphere exhibited almost no biological activity. Organic C stocks and recent C 4 plant derived input increased as follows: phyllosphere (1941 g C m−2; 85% recent) > soils under plants (575–748 g C m−2; 55–60%) > bare soils (491–642 g C m−2; 9–17%). Due to the high levels of nitrate in soil (>2 t ha−1) and high rates of P sorption/precipitation, our data suggest that the microbial activity is both C and P, but not N limited. Root-mediated salt uptake combined with foliar excretion and dispersal of NaCl into the surrounding area indicated that D. spicata was responsible for actively removing ca. 55% of the salt from the rhizosphere. We also demonstrate that NH 3 emissions may represent a major N loss pathway from these soil ecosystems during the processing of organic N. We attribute this to NH 3 volatilization to the high pH of the soil and slow rates of nitrification. In conclusion, we demonstrate that the extremophile D. spicata physically, chemically and biologically reengineers the soil to create a highly bioactive hotspot within the climate-extreme of the Atacama Desert. • The hyperarid core of the Atacama Desert is one of the most extreme places on Earth. • Halophytic C4 Distichlis spicata is one of the few plants capable of survival. • D. spicata reengineers the soil to create below-ground biological hotspots. • D. spicata promotes microbial activity and more efficient biogeochemical cycling. • Soil biological activity is limited by C and P availability but not N. [ABSTRACT FROM AUTHOR]

Climate change may lead to alterations in tree growth and carbon cycling. Interpreting the response of forest growth to climate change requires an understanding of the temporal and spatial patterns of seasonal climatic influences on the growth of tree species. However, the effects of climate change on pine forest dynamics in tropical region of Thailand remain poorly understood. This study develops three new tree ring-width chronologies of Pinus latteri (Tenasserim pine) in northern and northeastern Thailand and analyzes their climate-growth relationships and temporal stability. Ring-width chronologies of P. latteri at three sites showed significantly positive correlations with precipitation, relative humidity and self-calibrated Palmer Drought Severity Index (scPDSI) during the dry season (previous November to current April) and early rainy season (May−June). Conversely, significantly negative correlations were found between ring-width site chronologies and air temperatures (mean, maximum and minimum) from April to August. Therefore, our results revealed that radial growth of Tenasserim pines from northern and northeastern Thailand was mainly limited by moisture availability during the dry-to-wet transition season from April to June. Moving correlations revealed that Tenasserim pines in the lowland area of northeastern Thailand became more sensitive to moisture availability in recent 30 years (1985−2017) as compared with early period (1951−1984). Accompanying the shifted growth sensitivity to climate change, growth synchrony among trees was increasing and tree growth rates of Tenasserim pines have been declining during recent decades at two more moisture-limited sites in northeastern Thailand. Recent rapid warming and increasing drought during the transition season (April−June) together intensify climatic constrains on tree growth of Tenasserim pines in the lowland area of northeastern Thailand. Considering continued regional climate change, pine forests in tropical lowland areas may encounter intensified drought stresses, and thus, become more vulnerable to future climate change. Our results serve as an early indicator of potential effects of climate change on tropical pine species and raise concerns about sustainable managements of pine forests under a changing climate.

The morphology and size variability of pollen grains of Cedrus atlantica were investigated using a novel approach employing laser diffraction granulometry. We provide new insights into size variability and present high-quality light microscopy (LM) and scanning electron microscopy (SEM) imagery of Cedrus atlantica pollen. Grains have an average size of 59.1 ± 4.0 µm, measured on millions of grains from 91 samples. Analysis showed there is high variability of grain size within individual samples, although variability between samples is not significant. We found no significant relationships between grain size and climate (including temperature, precipitation and aridity), and suggest that grain size of fossil Cedrus pollen would not be a good proxy for climate reconstruction. Grain size may be influenced by a number of complex factors such as genome size or adaptations to support wind pollination, while variability within individual samples may result from the irregular development of pollen. The laser diffraction method produced repeatable, robust measurements on millions of pollen grains which are highly correlated with measurements taken using LM (r = 0.91, p = 0.002). Where grain size information is crucial for pollen identification, for developing isolation techniques for geochemical analysis, for investigating climatic and environmental influence, or for investigating links between genomes and grain size, particle size analysis by laser diffraction provides a reproducible and robust method for quickly determining pollen grain size on many samples. [ABSTRACT FROM AUTHOR]

Management of industrial sludge is a big challenge for developing countries. Composting is an economical and viable option to manage and treat an industrial sludge. However, efficient compost production requires nature of materials involved, process understanding and physics behind the process. We investigated the physical parameters during composting of solid pulp and paper mill sludge in 550 L rotary drum composter. Variation in physical parameters such as bulk density, volatile solids, moisture content, free air space, void ratio, ash content and particle density were analyzed over the period of composting. Bulk density was observed increasing, whereas free air space was showed declining trend and observed 52% in end compost. The particle density was observed to be increasing from 610 to 680 kg m −3 . End compost was analyzed for nutritional parameters and seen to be increasing over the period of composting. A strong relationship was found between various physical parameters. Pearson’s correlation coefficient matrix was formed between free air space, bulk density, moisture content and particle density. [ABSTRACT FROM AUTHOR]

This study investigates the relationship between historically observed changes in extreme precipitation magnitudes and temperature (Pex-T relationship) at multiple locations in Canada. The focus is on understanding the behavior of these relationships with regards to key storm characteristics such as its duration, season of occurrence, and location. To do so, three locations are chosen such that they have large amounts of moisture available near them whereas four locations are chosen such that they are located in the land-locked regions of Canada and subsequently have no nearby moisture source available on them. To investigate the effect of different storm durations on Pex-T relationship, storms of durations: 5, 10, 15, 30 min, 1, 2, 6, 12, 24 h are considered. Finally, Pex-T relationship is analyzed separately for summer and winter seasons to quantify the influence of seasons. Results indicate strong influences of storm duration, season of occurrence, and location on observed precipitation scaling rates. Drastic intensification of precipitation extremes with temperature is obtained for shorter duration precipitation events than for longer duration precipitation events, in summers than in the winters. Furthermore, in summertime, increases in the intensity of convection driven precipitation extremes is found highest at locations away from large waterbodies. On the other hand, in wintertime most drastic increases in extreme precipitation are obtained at locations near large waterbodies. These findings contribute towards increasing the current understanding of precipitation extremes in the context of rapidly increasing global temperatures. [ABSTRACT FROM AUTHOR]

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Due to their extreme aridity, high rate of UV irradiation and low soil carbon (C) content, the soils of the Atacama Desert represent one of the world's most hostile environments for microbial life and its survival. Although infrequent, climatic conditions may, however, prevail which temporarily remove these stresses and allow life to briefly flourish. In this study we investigated the response of soil microbial communities to water and C availability across an aridity gradient (semi-arid, arid, hyper-arid) within the Atacama Desert. We simulated the impact of hyper-dry spells, humid fogs and precipitation events on the activation of the microbial community and the subsequent mineralization of low (glucose) and high (plant residues) molecular weight C substrates. Our results showed that mineralization rate followed the trend: semi-arid > arid > hyper-arid. Some glucose mineralization was apparent under hyper-arid conditions (water activity, a w = 0.05), although this was 10-fold slower than under humid conditions and ca. 200-fold slower than under wet conditions. A lag phase in CO 2 production after glucose-C addition in the hyper-arid soils suggested that mineralization was limited by the low microbial biomass in these soils. No lag phase was apparent in the corresponding semi-arid or arid soils. In contrast, the breakdown of the plant residues was initially much slower than for glucose and involved a much longer lag phase in all soils, suggesting that mineralization was limited by low exoenzyme activity, particularly in the humid and hyper-dry soils. Our results also showed that microbial C use efficiency followed the trend: hyper-arid > arid > semi-arid. In conclusion, we have shown that even under hyper-arid conditions, very low levels of microbial activity and C turnover do occur. Further, the microbial communities are capable of rapidly responding to available C once water becomes more abundant, however, this response is both biomass and metabolically limited in hyper-arid soils. [ABSTRACT FROM AUTHOR]

Moisture stress is an important factor affecting field-grown cowpea in the tropics, especially in the dry seasons, and irrigation is required for successful yields. Field experiment was conducted at Teaching and Research Farm of the Department of Agricultural Engineering, Federal University of Technology, Akure, during 2014 growing season using a completely confounded design with four replicates to evaluate the impact of soil moisture stress on the yields of cowpea under four different irrigation treatments. The treatments were 100%, 80%, 60% and 40% Full Irrigation Treatment (FIT). Soil moisture contents were determined biweekly using gravimetric method. Cowpea grain and biomass yields were measured after harvest. The yield response factor (Ky) was determined to evaluate the plant response to irrigation. The point where Ky and the ratio ratio of yield reduction and evapotranspiration (ET) reduction whcih are numerically equivalent was determined. The ET production function was implemented in matrix laboratory (MATLAB) to accurately determine the optimum soil moisture and irrigation water required for cowpea production. The results of the study indicated that 100% FIT excelled all other treatments at grain yield and biomass yield, where its yield was 1.06 t ha-1, the 80%, 60% and 40% FIT produced 0.95, 0.89 and 0.71 t ha-1 respectively. The analysis of the results showed that soil moisture availability was significantly (p<0.05) affected by the irrigation treatments adopted, which in turn significantly (p=0.05) affected the cowpea grain and biomass yield. The yield obtained at 40% FIT was significantly (p<0.05) different. The yield response factor of 1.24 was obtained, showing that cowpea is sensitive to water stress. The total amount of irrigation water and moisture content that resulted to the optimum yield were 151.12 mm and 0.1082 g g-1, respectively. The result implies that 32% of total irrigation water applied during the growing season would be saved. The approach adopted, therefore, proved to be useful in estimation of possible irrigation water required for optimum production of cowpea. [ABSTRACT FROM AUTHOR]

The development of well-constrained palaeo-proxies that enable the reconstruction of past climate change is becoming an ever more important field of scientific enquiry within the palaeobotanical community, with the potential to deliver broader impacts linked to understanding of future anthropogenic climate change. One of the major uncertainties in predicting climate change is how the hydrological cycle will respond to future warming. Griener and Warny (2015, Review of Palaeobotany and Palynology 221, 138–143) suggested that pollen size might be a useful proxy for tracking moisture availability, as pollen size appears to be negatively correlated with moisture. Given the long fossil record of pollen and spores such a proxy would have broad scope and the potential to deliver much needed information. Here we set out to fully evaluate and test the robustness of this proxy. We focus on a number of key issues: controls on pollen size, data analysis, and finally proxy validation. Using this approach we find that there is little theoretical or empirical support for the original relationship proposed by Griener and Warny. Consequently it is currently premature to use pollen size as a moisture availability proxy in the fossil record. However, we recognise that the technique may have potential and conclude by offering a series of recommendations that would rigorously assess and test for a relationship between pollen size and moisture availability. [ABSTRACT FROM AUTHOR]

Aim Although ongoing climate change is expected to lead to an upward shift of tree lines in mountain areas, evidence for widespread tree line advances remains scarce, implying secondary controls on tree line dynamics at the local scale. We aim to determine if vegetation change in response to past warm periods was regionally synchronous or if local factors such as topography, geomorphology or fire caused divergent local responses. Location The Canadian Cordillera in south-eastern British Columbia (Canada). Methods We analysed post-glacial sediments from three lakes at or just below the present tree line for macrofossils, pollen and charcoal to infer past local forest composition, density, dynamics and fire disturbance. Results At two lakes (Windy and Redmountain), tree macrofossil concentrations were highest in the warmer-than-present Early Holocene (11,700-7000 cal. bp), indicating higher forest density and tree line position during this time period. At the third lake (Thunder), macrofossil concentrations were low during the Early Holocene and reached maximum values in the mid-Holocene (7000-3000 cal. bp). The divergent vegetation dynamics and species composition at Thunder Lake suggest that moisture availability may have limited the establishment of closed forests on steep south-facing slopes or shallow soils in the Early Holocene. Main conclusions Summer temperature was the main driver of tree line dynamics over millennial to decadal time-scales. Closed forests, however, occurred only in areas of adequate moisture availability, which is controlled by topography and geomorphology. We therefore expect a rapid upward shift of tree lines during the 21st century in response to warmer temperatures, but only where deep soils or favourable aspects provide sufficient moisture for tree growth. Upward forest expansion will therefore be patchy and occur first in favourable microsites. [ABSTRACT FROM AUTHOR]

The article discusses the effect of different predecessors and methods of basic treatment of soil on the magnitude and nature of the formation of soil moisture reserves in the cultivation of winter wheat on the slopes of ordinary chernozems in the Rostov oblast. Winter wheat in the experiment was cultivated after a steam clean, after winter wheat, after peas, and after corn silage. The study was conducted in four variants of primary tillage in the following crop rotations: chisel, combo, surface, and moldboard tillage. It is established that, in general, over the growing period of winter wheat, 3 of 4 years have a shortage of water supply, especially in the period from the resumption of the spring growing season to complete full ripeness. Analysis of the autumn watersupplies by variants of the main processing of the soil indicates the advantage of the chisel treatment, confirmed statistically by two predecessors-a clean pair and corn silage. The studies for the years 2011-2014 showed the close relationship of the absorption coefficient of precipitation from the reserves of productive moisture in autumn ( R = 0.94). It is revealed that the assimilation of precipitation of the cold period largely depends on soil fertility due to different stocks of productive moisture in autumn. The close relationship of grain yield with the value primary of moisture reserves in the autumn sowing of winter wheat in the soil layer of 0-150 cm is shown. [ABSTRACT FROM AUTHOR]

Understanding how UV radiation interacts with prevailing climatic conditions and litter quality to determine leaf litter decomposition is fundamental for understanding soil carbon cycling pathways and ecosystem functioning in drylands. We carried out a field manipulative experiment to investigate how litter quality (labile and nitrogen-rich Retama sphaerocarpa vs. recalcitrant and nitrogen-poor Stipa tenacissima), position (on the ground vs. standing) and different UV radiation levels (UV pass vs. UV block) affect litter decomposition rates at two semiarid Mediterranean steppes with contrasting climates (continental vs. maritime) in a fully factorial experimental design. As expected, Retama litter decomposed faster than that of Stipa, and litter placed on the ground decayed faster than standing litter. However, and surprisingly, contrasting effects of UV radiation on litter decomposition were observed between the two sites. At the continental site, UV radiation increased litter decay constants by 21% on average, although the contribution of photodegradation was larger when litter was placed on the ground rather than in standing litter. At the maritime site, decay constants were 15% larger in the absence of UV radiation regardless of litter position. Significant litter type × UV exposure radiation and litter type × position interactions indicate that photodegradation contributes more to litter decomposition under less favorable moisture and substrate availability conditions for microbial decomposers. Our results emphasize the need to consider interactions between moisture availability, litter quality and UV radiation in litter decomposition models to fully understand litter decomposition impacts on soil carbon cycling and storage in drylands under climate change. [ABSTRACT FROM AUTHOR]

Based on a study of processes developed upon desertification (salinization, solonetzization, and sand accumulation) in the soils of the Caspian Sea Lowland, it is shown that soil's water retention capacity may be used as an integral parameter of all desertification trends. It is characterized by the water retention curve (WRC). The physical sense of the use of the WRC to characterize desertification consists in the fact that it shows the capability of soil to retain moisture and soil moisture mobility and availability for plants and thus characterizes the main edaphic factors, which limit biological productivity in natural ecosystems and the agroecosystems of arid regions. The soil WRC is a constant value without seasonal fluctuations, and this makes it universal in comparison with other soil parameters that undergo seasonal variations, thus making determination of the desertification rate difficult. [ABSTRACT FROM AUTHOR]