Morphological composition and fiber partitioning along regrowth in elephant grass CT115 intended for ethanol production

Abstract Leaf share, plant age and growth season are often overlooked as modifiers of the biomass quality in energy crops. The current work studied the effect of the given factors on the biomass yield and the biomass quality in Elephant grass CT115, intended for bioethanol production, in Veracruz, Mexico. Two seasons per year, 5 months each, were tracked on a 2-weeks basis. The climate is warm wet with summer rains, 1,142 mm of annual rainfall, and 26 °C monthly temperature. From day 56 of the wet season or from day 84 of the dry season, stems accumulated 12 or 6 Mg ha−1, respectively, while green leaves increased only 1 Mg. Higher biomass quality was recorded for the leaf fraction, or for the wet season regrowth. For instance, lignin contained in stems meant twice that of leaves, whereas stems recorded 20% less lignin in the wet season as compared to the dry season. Despite holocellulose being similar between fractions or seasons, hemicellulose and cellulose showed inverse correlation, while lignin and cellulose contents were directly correlated in stems. Increasing the annual harvest of green leaves will improve biomass quality, which is known to increase biodegradability and might improve the annual ethanol yield.

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Temporal and spatial variation of fine roots in a northern Australian Eucalyptus tetrodonta savanna

Journal of Tropical Ecology ◽

10.1017/s0266467408004860 ◽

2008 ◽

Vol 24 (2) ◽

pp. 177-188 ◽

Cited By ~ 17

Author(s):

David P. Janos ◽

John Scott ◽

David M. J. S. Bowman

Keyword(s):

Fine Roots ◽

Soil Surface ◽

Dry Season ◽

Annual Rainfall ◽

Tropical Savannas ◽

Wet Season ◽

Temporal And Spatial Variation ◽

Deep Roots ◽

Temporal And Spatial ◽

Peak Abundance

Abstract:Six rhizotrons in an Eucalyptus tetrodonta savanna revealed seasonal changes in the abundance of fine roots (≤ 5 mm diameter). Fine roots were almost completely absent from the upper 1 m of soil during the dry season, but proliferated after the onset of wet-season rains. At peak abundance of 3.9 kg m−2 soil surface, fine roots were distributed relatively uniformly throughout 1 m depth, in contrast with many tropical savannas and tropical dry forests in which fine roots are most abundant near the soil surface. After 98% of cumulative annual rainfall had been received, fine roots began to disappear rapidly, such that 76 d later, less than 5.8% of peak abundance remained. The scarcity of fine roots in the upper 1 m of soil early in the dry season suggests that evergreen trees may be able to extract water from below 1 m throughout the dry season. Persistent deep roots together with abundant fine roots in the upper 1 m of soil during the wet season constitute a ‘dual’ root system. Deep roots might buffer atmospheric CO2 against increase by sequestering carbon at depth in the soil.

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Emerging opportunities for developing a diversified land sector economy in Australia’s northern savannas

The Rangeland Journal ◽

10.1071/rj18005 ◽

2018 ◽

Vol 40 (4) ◽

pp. 315 ◽

Cited By ~ 13

Author(s):

Jeremy Russell-Smith ◽

Kamaljit K. Sangha

Keyword(s):

Beef Cattle ◽

Greenhouse Gas Emissions ◽

Greenhouse Gas ◽

National Parks ◽

Dry Season ◽

Annual Rainfall ◽

Focal Region ◽

Wet Season ◽

Gas Emissions ◽

Northern Regions

We explore sustainable land sector opportunities for Australia’s 1.2 million km2 northern savanna rangelands where extensive beef cattle pastoralism is the predominant contemporary land use. Our focal region is characterised by mean annual rainfall exceeding 600 mm, ecologically bountiful wet season water availability followed by 6–8 months of surface water deficit, mostly nutrient-poor soils, internationally significant biodiversity and carbon stock values, very extensive dry season fires in pastorally unproductive settings, a sparse rural population (0.14 persons km–2) comprising a high proportion of Indigenous people, and associated limited infrastructure. Despite relatively high beef cattle prices in recent seasons and property values escalating at a spectacular ~6% p.a. over the past two decades, long-term economics data show that, for most northern regions, typical pastoral enterprises are unprofitable and carry significant debt. Pastoral activities can also incur very significant environmental impacts on soil and scarce dry season water resources, and greenhouse gas emissions, which currently are not accounted for in economic sustainability assessments. Over the same period, the conservation sector (including National Parks, Indigenous Protected Areas) has been expanding rapidly and now occupies 25% of the region. Since 2012, market-based savanna burning projects aimed at reducing greenhouse gas emissions occur over a further 25%. Returns from nature-based tourism focussed particularly on maintaining intact freshwater systems and associated recreational fishing opportunities dwarf returns from pastoralism. The growth of these latter industries illustrates the potential for further development of profitable ‘ecosystem services’ markets as part of a more environmentally and socially sustainable diversified regional land sector economy. We outline some of the imminent challenges involved with, and opportunities for developing, this new industry sector.

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Fire, growth and survivorship in a Neotropical savanna grass Andropogon semiberbis in Venezuela

Journal of Tropical Ecology ◽

10.1017/s0266467400003849 ◽

1989 ◽

Vol 5 (4) ◽

pp. 387-400 ◽

Cited By ~ 23

Author(s):

Juan F. Silva ◽

Fernando Castro

Keyword(s):

Seedling Growth ◽

Canopy Structure ◽

Structural Complexity ◽

Dry Season ◽

Root Competition ◽

Annual Rainfall ◽

Grass Species ◽

Mortality Factors ◽

Wet Season ◽

Adult Plants

ABSTRACTThis study was conducted in a woodland savanna in western Venezuela exclosed from grazing and burnt once a year towards the end of the dry season. Mean annual rainfall is 1500 mm, with a strong seasonality.Two cohorts of seedlings of Andropogon semiberbis were tagged and monitored for up to three years. Several variables such as survivorship, plant size, seedling density, fire damage and distance to the nearest adult were measured or estimated. Two burning experiments to measure survivorship before and after fire, and two seedling-growth experiments to assess competitive interference from adult plants of three grass species were performed.The highest mortality takes place during the dry season and is due to fire. This decreases as the plants get bigger due to increasing structural complexity of the clump by growth which gives added protection to the meristems. Other mortality factors such as desiccation, uprooting and shading seem to be important during the wet season, when mortality rate is relatively constant. Survivorship during the first year and after three years is strongly correlated to the size attained by the end of the first growing season.Seedling densities are rather low and do not seem to play any role in survivorship in this population. Adult interference with seedling growth decreases with distance and seems to be due to root competition, although there is a tendency toward increased foliage interference related to the canopy structure of adult plants.

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Annual foraging of the leaf-cutting ant Atta colombica in a semideciduous rain forest in Panama

Journal of Tropical Ecology ◽

10.1017/s0266467400010907 ◽

1997 ◽

Vol 13 (5) ◽

pp. 741-757 ◽

Cited By ~ 48

Author(s):

Rainer Wirth ◽

Wolfram Beyschlag ◽

Ronald J. Ryel ◽

Bert Hölldobler

Keyword(s):

Plant Material ◽

Dry Weight ◽

Green Plant ◽

Dry Season ◽

Barro Colorado Island ◽

Wet Season ◽

Green Leaves ◽

Leaf Cutting ◽

Total Dry Weight ◽

Atta Colombica

ABSTRACTIn a 1-y study of vegetation harvested by the leaf-cutting ants, Atta colombica Guérin, daily harvesting activity of two nests was observed for 24 h at c. 1-wk intervals (colony I: June 1993-June 1994; colony II: February-June 1994) on Barro Colorado Island. The average daily quantity of green leaves harvested by colony I was higher during the wet season (11.4 m2 d−1) than during the dry season (9.0 m2 d−1), but was highly variable between survey days. Total annual herbivory of green leaves was estimated to be 3,855 m2 foliage area for colony I and 1,707 m2 for colony II. Total dry weight of biomass harvested was higher in the dry season because most material collected during the wet season consisted of green leaves, while during the dry season, more than 50% of the total collected biomass was non-green plant material (stipules of Ficus sp., fruits, seeds, and flower parts of a variety of other species) which represented c. one third (111 kg y−1) of the total annual intake (370 kg y−1) of plant material. Total daily biomass intake was negatively correlated with daytime rainfall. The peak of daily foraging was affected by timing and duration of rainfall events. Highest input rates normally occurred between 15:00 and 16:00 h (colony I).Dry weight and surface area of harvested leaf fragments differed between plant species, with thicker leaves generally being cut into smaller pieces. Significant linear correlations were found between total daily harvest of fragments and the respective harvesting rate at the maximum of daily activity. High correspondence was found between estimates using this relationship and the measured daily leaf harvest of four other Atta colonies and of two colonies reported in published literature. The use of this relationship as a research tool is discussed.

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Seasonal fine fuel and coarse woody debris dynamics in north Australian savannas

International Journal of Wildland Fire ◽

10.1071/wf20073 ◽

2020 ◽

Vol 29 (12) ◽

pp. 1109

Author(s):

Cameron Yates ◽

Harry MacDermott ◽

Jay Evans ◽

Brett P. Murphy ◽

Jeremy Russell-Smith

Keyword(s):

Coarse Woody Debris ◽

Woody Debris ◽

Dynamic Modelling ◽

Dry Season ◽

Annual Rainfall ◽

Wet Season ◽

Rainfall Gradient ◽

Litter Accumulation ◽

Significant Seasonal Variation ◽

Savanna Burning

Several studies have separately explored accumulation of the dominant fuels (grass, fine litter (<6mm diameter) and coarse woody debris (CWD, 6–50mm diameter)) in north Australian savannas. We report an analysis of two longitudinal datasets describing how these three fuel components covary in abundance throughout the year in eucalypt-dominated savanna over a rainfall gradient of 700–1700mm mean annual rainfall (MAR). Our observations concur generally with previous observations that litter accumulation results in a late dry season (LDS) peak in biomass, whereas cured grassy fuels typically are seasonally invariant, and CWD inputs are associated with stochastic severe wet season storms and dry season fires. The distinct LDS litter peak contributes significantly to the potential for LDS fires to be of higher intensity, burn more fuel per unit area and produce greater emissions relative to early dry season (EDS) fires. However, Australia’s current (2018) formal savanna burning emissions avoidance methodology erroneously deems greater EDS fine fuel (grass and fine litter) biomass in four of nine designated vegetation fuel types. The study highlights the need to develop seasonally dynamic modelling approaches that better account for significant seasonal variation in fine fuel inputs and decomposition.

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Improvement of native pasture with Townsville stylo in the dry tropics of sub-coastal northern Queensland

Australian Journal of Experimental Agriculture ◽

10.1071/ea9790325 ◽

1979 ◽

Vol 19 (98) ◽

pp. 325 ◽

Cited By ~ 20

Author(s):

P Gillard

Keyword(s):

Dry Season ◽

Early Years ◽

Annual Rainfall ◽

Wet Season ◽

Heteropogon Contortus ◽

Pasture Quality ◽

Native Pasture ◽

Annual Grasses ◽

Townsville Stylo ◽

Pasture Yield

The results of a grazing experiment in which Townsville stylo was oversown into native pasture in sub-coastal northern Queensland are reported. The region receives 650 mm average annual rainfall compared with >850 mm at other experimental sites where Townsville stylo has been tested under grazing. The experiment included three treatments in a factorial combination: timber clearing or not, application of 125 kg ha-1 superphosphate or not and stocking rates of 0.4 and 0.2 beasts ha-1. The yield of Townsville stylo depended on treatments and annual rainfall but was generally low in this environment. Over the ten year period of the experiment the pastures remained dominated by Heteropogon contortus and Bothriochloa bladhii, and there was no invasion of annual grasses. Clearing of the timber increased the pasture yield by 77%. There was no regrowth of trees after clearing. Within each year cattle gained weight in the wet season, when pasture quality was high, and lost weight in the dry season, when pasture quality declined. Mean liveweight gain over all treatments was correlated (r = 0.97) with the length of the growing season. A significant response in liveweight gain to fertilizer occurred only in years of average or above rainfall when there was also a response in Townsville stylo yield. The effect was due to increased gains during the wet season; there were no differences in liveweight gain during the dry season, when Townsville stylo became decomposed. Significantly greater liveweight losses occurred on the heavily stocked treatments during the dry season of drought years. The yield of Townsville stylo in the early years of the experiment was significantly higher on the cleared treatments and there was a corresponding response in liveweight gains in the wet season during this period. Liveweight losses in the dry season were also significantly higher on the timbered treatments in years of drought. The powerful influence of climatic variation on the treatments places reservations on their practical application. The increased pasture yield from tree clearing is likely to be a benefit to cattle only in years of drought. The responses to superphosphate fertilizer only in years of high rainfall suggests that its use is unlikely to be profitable on Townsville stylo based pastures in this environment.

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Direct observations of rock moisture, a hidden component of the hydrologic cycle

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1800141115 ◽

2018 ◽

Vol 115 (11) ◽

pp. 2664-2669 ◽

Cited By ~ 78

Author(s):

Daniella M. Rempe ◽

William E. Dietrich

Keyword(s):

Land Surface ◽

Unsaturated Zone ◽

Global Climate ◽

Dry Season ◽

Annual Rainfall ◽

Recent Theory ◽

Wet Season ◽

Soil Thickness ◽

Moisture Storage ◽

Pass Through

Recent theory and field observations suggest that a systematically varying weathering zone, that can be tens of meters thick, commonly develops in the bedrock underlying hillslopes. Weathering turns otherwise poorly conductive bedrock into a dynamic water storage reservoir. Infiltrating precipitation typically will pass through unsaturated weathered bedrock before reaching groundwater and running off to streams. This invisible and difficult to access unsaturated zone is virtually unexplored compared with the surface soil mantle. We have proposed the term “rock moisture” to describe the exchangeable water stored in the unsaturated zone in weathered bedrock, purposely choosing a term parallel to, but distinct from, soil moisture, because weathered bedrock is a distinctly different material that is distributed across landscapes independently of soil thickness. Here, we report a multiyear intensive campaign of quantifying rock moisture across a hillslope underlain by a thick weathered bedrock zone using repeat neutron probe measurements in a suite of boreholes. Rock moisture storage accumulates in the wet season, reaches a characteristic upper value, and rapidly passes any additional rainfall downward to groundwater. Hence, rock moisture storage mediates the initiation and magnitude of recharge and runoff. In the dry season, rock moisture storage is gradually depleted by trees for transpiration, leading to a common lower value at the end of the dry season. Up to 27% of the annual rainfall is seasonally stored as rock moisture. Significant rock moisture storage is likely common, and yet it is missing from hydrologic and land-surface models used to predict regional and global climate.

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Effects of climate change on future extreme rainfall indices over Thailand

Global NEST Journal ◽

10.30955/gnj.001227 ◽

2014 ◽

Vol 16 (2) ◽

pp. 306-315

Keyword(s):

Extreme Rainfall ◽

Dry Season ◽

Southern Region ◽

Andaman Sea ◽

Annual Rainfall ◽

Reference Period ◽

Wet Season ◽

Dry Spell ◽

The Future ◽

Projected Changes

<div> <p>Extreme rainfall indices were calculated based on daily rainfall data derived from the outputs of MM5-RCM simulations. Projected changes of these indices in the future (2020s) under the IPCC Special Report on Emissions Scenarios (SRES) A1B compared to the reference period (1990s) were analyzed. Before calculating the indices, the raw outputs from the MM5-RCM were adjusted in order to reduce biases as part of the bias-correction process. The validation demonstrates that the average and cycle of annual rainfall in the reference period are reproduced reasonably in the bias-corrected MM5-RCM results. The projected changes of the rainfall indices suggest that in the future most areas of northern, western, and northeastern Thailand will become wetter in the wet season and drier in the dry season. Central and eastern Thailand will become drier in the wet season while in the dry season rainfall will become more intense, and rainy days will become more scattered with a higher number of heavy rainfall days. In the south, the length of the wet spell will be decreased in the Southern Andaman Sea area and increased in East-Southern Region. The dry spell will likely be shorter throughout the southern region for all seasons.  </p> </div> <p> </p>

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The seasonal changes of the gut microbiome of the population living in traditional lifestyles are represented by characteristic species-level and functional-level SNP enrichment patterns

BMC Genomics ◽

10.1186/s12864-021-07372-0 ◽

2021 ◽

Vol 22 (1) ◽

Author(s):

Xue Zhu ◽

Jiyue Qin ◽

Chongyang Tan ◽

Kang Ning

Keyword(s):

Gut Microbiome ◽

Seasonal Changes ◽

Dry Season ◽

Urban Setting ◽

Snp Analysis ◽

Wet Season ◽

Human Gut ◽

Human Gut Microbiome ◽

Genome Level ◽

Prevalent Species

Abstract Background Most studies investigating human gut microbiome dynamics are conducted on humans living in an urban setting. However, few studies have researched the gut microbiome of the populations living traditional lifestyles. These understudied populations are arguably better subjects in answering human-gut microbiome evolution because of their lower exposure to antibiotics and higher dependence on natural resources. Hadza hunter-gatherers in Tanzania have exhibited high biodiversity and seasonal patterns in their gut microbiome composition at the family level, where some taxa disappear in one season and reappear later. Such seasonal changes have been profiled, but the nucleotide changes remain unexplored at the genome level. Thus, it is still elusive how microbial communities change with seasonal changes at the genome level. Results In this study, we performed a strain-level single nucleotide polymorphism (SNP) analysis on 40 Hadza fecal metagenome samples spanning three seasons. With more SNP presented in the wet season, eight prevalent species have significant SNP enrichment with the increasing number of SNP calling by VarScan2, among which only three species have relatively high abundances. Eighty-three genes have the most SNP distributions between the wet season and dry season. Many of these genes are derived from Ruminococcus obeum, and mainly participated in metabolic pathways including carbon metabolism, pyruvate metabolism, and glycolysis. Conclusions Eight prevalent species have significant SNP enrichments with the increasing number of SNP, among which only Eubacterium biforme, Eubacterium hallii and Ruminococcus obeum have relatively high species abundances. Many genes in the microbiomes also presented characteristic SNP distributions between the wet season and the dry season. This implies that the seasonal changes might indirectly impact the mutation patterns for specific species and functions for the gut microbiome of the population that lives in traditional lifestyles through changing the diet in wet and dry seasons, indicating the role of these variants in these species’ adaptation to the changing environment and diets.

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Seasonal Climate Impacts on Vocal Activity in Two Neotropical Nonpasserines

Diversity ◽

10.3390/d13070319 ◽

2021 ◽

Vol 13 (7) ◽

pp. 319

Author(s):

Cristian Pérez-Granados ◽

Karl-L. Schuchmann

Keyword(s):

Air Temperature ◽

Daily Rainfall ◽

Climatic Conditions ◽

Dry Season ◽

Climate Impacts ◽

Calling Behavior ◽

Wet Season ◽

Focal Species ◽

Calling Activity ◽

Vocal Activity

Climatic conditions represent one of the main constraints that influence avian calling behavior. Here, we monitored the daily calling activity of the Undulated Tinamou (Crypturellus undulatus) and the Chaco Chachalaca (Ortalis canicollis) during the dry and wet seasons in the Brazilian Pantanal. We aimed to assess the effects of climate predictors on the vocal activity of these focal species and evaluate whether these effects may vary among seasons. Air temperature was positively associated with the daily calling activity of both species during the dry season. However, the vocal activity of both species was unrelated to air temperature during the wet season, when higher temperatures occur. Daily rainfall was positively related to the daily calling activity of both species during the dry season, when rainfall events are scarce and seem to act as a trigger for breeding phenology of the focal species. Nonetheless, air temperature was negatively associated with the daily calling activity of the Undulated Tinamou during the wet season, when rainfall was abundant. This study improves our understanding of the vocal behavior of tropical birds and their relationships with climate, but further research is needed to elucidate the mechanisms behind the associations found in our study.

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