Plant Pathology Commons^™

Grass Vegetation Dynamics In Wetlands With Different Utilization, Dorai Pandian Kannan

IGC Proceedings (1977-2023)

The land-use patterns, combined with the biotic interactions, are likely to substantially affect the grass community of tropical wetlands. However, we need more information to understand the vegetation cover and, particularly, the diversity of grasses in the protected sites, where the naturally occurring interactions with extreme complexity. Hence a thorough understanding of these interactive effects on grass dynamics would help develop wildlife management guidelines to predict the grass-woody herbs and other associated vegetation. In light of this, a beta vegetation survey and diversity analysis in two varying wetland ecosystems of natural mountain streams and temporary ponds. Grass communities occurred along …

Mechanisms Of Ecosystem Carbon Exchange In Response To Grazing Rates In Two Hydrologically Contrasting Growing Seasons In A Desert Steppe, Y. X. Jin, D. S. Tian, Q. Wu, Y. H. Wang, G. D. Han

IGC Proceedings (1977-2023)

Chronic grazing affects grassland soil processes and plant community composition, which may create novel patterns of net ecosystem carbon exchange (NEE) under the mediation of precipitation. Here, we report results from a 14-year field manipulative experiment with four stocking rates in a Stipa breviflora desert steppe in northern China. Ecosystem carbon exchange as well as plant aboveground biomass and composition were measured in the two growing seasons (including a wet and dry growing season). Our results showed a significant interannual variation in CO₂ fluxes, heavy grazing significantly reduced NEE regardless of precipitation. Grazing-induced changes in NEE were largely attributable …

Soil C Change Over 14 Years In Grasslands Sown Into A Highly Disturbed Soil, R. D. Jackson, J. Stier

IGC Proceedings (1977-2023)

Perennial grasslands are thought to sequester C, so restoring them is touted as part of the solution for mitigating climate change. Moreover, there is growing interest among managed grassland stakeholders in selling C credits on nascent C markets. Former agricultural and municipal sites are often considered viable areas for conversion to grasslands, with types ranging from unmanaged prairies with diverse plant communities to monocultures in highly managed urban environments. We sowed five perennial plant communities into an area that had undergone massive soil disturbance five years previous during conversion from row crop agriculture to C3 turf. We found that soils …

Length Of Multi-Year Precipitation And Primary Production Relationships Vary Regionally Across Grasslands In The Central U.S., A. R. Hudson, D. P.C. Peters

IGC Proceedings (1977-2023)

Grasslands in the central United States span large temperature and aridity gradients and regionally differ in their drivers of water availability. These differences likely determine how drought event periodicity and duration can influence grassland growth, and are important to consider as global warming changes energy and water distribution across these systems. Here, we explored frequency patterns in annual grassland plant growth (aboveground net primary productivity (ANPP)) and precipitation (PPT) relationships for over 20 years at six long-term research sites spatially distributed across the central grassland region. We identified the periods (>1 year) these relationships are strongest- and when they …

Community Asynchrony Increased Its Stability By Mediating The Relationship Of Diversity–Stability Relationships In Loess Plateau, China, Fujiang Hou, Xiaojuan Huang, Jing Zhang

IGC Proceedings (1977-2023)

Extreme weather such as heavy rainfall and drought are threatening the global grassland and its potential to mitigate climate change. Therefore, understanding the drivers that promote the stability of grassland ecosystems is considered to be critical to mitigate the adverse effects of climate change on grasslands. Here, we use precipitation addition (PA) + grazing experiment to explain how species richness, aboveground biomass, species asynchrony, functional group level stability, drought tolerance and grazing tolerance can maintain grassland productivity stability. The results showed that grazing counteracted the promoting effect of rainfall on vegetation to a certain extent, and weakened the sensitivity of …

Nutrient Balances Of Rewetted Fens – Groundwater Lysimeter Results, J. Hoysagk, M. Pesch, F. Eulenstein, A. Behrendt

IGC Proceedings (1977-2023)

With the raising of groundwater levels to protect fens and the climate, there may be a risk of nutrients, such as nitrogen or potassium, leaching into the groundwater. Great amounts of nutrients, which are accumulated largely by peat forming plants like Phragmites australis and Carex spec., are conveyed into rewetted fens through high amounts of introduced water. Nitrogen leaching into the groundwater is very low even at the beginning of flooding and there is no sudden, pronounced leaching. Only a portion of potassium is taken up by plants whereas the rest might be found in the groundwater. Increasing nutrient inputs …

Carbon Storage And Sequestration Under Different Stocking Rates In A Eurasian Desert Steppe In China, G. D. Han, C. P. Gao, C. W. Han, Q. Wu, A. M. Zhu, Z. W. Gao, Y. Y. Dou

IGC Proceedings (1977-2023)

The research on carbon source/sink of terrestrial ecosystem is an important part of global climate change. Under the sustainable grazing management, the carbon storage in grassland ecosystem will increase, which promotes the carbon sequestration in the grassland area. In order to understand the carbon sequestration in grazing system of desert steppe, a sheep grazing experiment for completely random block design was conducted in desert steppe. There were 4 stocking rates and 3 replications in this experiment. The effects of annual precipitation and stocking rate on the carbon sequestration of desert steppe were compared. The stocking rate treatments were as follows: …

Enclosure Rather Than Topography Enhances The Soil Ecological Stoichiometry In Typical Steppe On The Loess Plateau, China, Zhaoxia Guo, Fujiang Hou, Jiao Ning

IGC Proceedings (1977-2023)

Grassland is one of the largest terrestrial ecosystems in the world, a large part of which is distributed in varied topography. And grazing and enclosure are the main ways to use this part. Grazing changes the soil structure through feeding, trampling and excreta return, thus affects the soil nutrients. The aspect mainly affects soil temperature and moisture by affecting solar radiation. The slope affects soil nutrients by affecting surface runoff. Water and temperature are the main factors affecting soil nutrients. We carried out to explore the effect of enclosure years and topography on soil ecological stoichiometry. The results showed that: …

Activity Budget And Foraging Patterns Of Nubian Giraffes (Giraffa Camelopardalis Camelopardalis) In Lake Nakuru National Park, Kenya, Consolata G. Gitau, J. S. Mbau, R. K. Ngugi, A. B. Muneza, E. Ngumbi

IGC Proceedings (1977-2023)

How animals decide to spend their time has a key impact on their survival and reproduction. These behavioral decisions are shaped by ecological and environmental factors, such as seasonal changes. Foraging patterns show how an animal chooses to forage in its environment as influenced by resource availability, competition, and predation risk. Giraffe activity budget has been investigated in populations across Africa and found to be influenced by body size, diet composition, and sex. The activity budget and foraging patterns of Nubian giraffes vary considerably between ecosystems. The Nubian giraffe, a subspecies of the Northern giraffe species (Giraffa Camelopardalis) …

Ecosystem Services Provided By Overseeding Aeschynomene Into Bahiagrass Pastures In South Florida, J. Garzon, João M. B. Vendramini, Maria L. S. Silveira, José C. B. Dubeux Jr., H. L. Liao, Lynn E. Sollenberger, H. M. S. Da Silva, V. C. Gomes, H. M. R. Oliveira, A. Erhunmwunse

IGC Proceedings (1977-2023)

Aeschynomene (Aeschynomene americana L.) is a warm-season annual legume commonly overseeded into warm-season perennial grass pastures in tropical and subtropical regions. Although aeschynomene usually increases forage production and nutritive value, there is limited information about the ecosystem services provided by this legume. The objective of these studies was to evaluate the effects of overseeding aeschynomene into bahiagrass (Paspalum notatum Flüggé) pastures on nutrient dynamics and microbial N-cycling gene abundances. The studies were conducted in Ona, FL, from April to March 2019-2020 and 2020-2021. Treatments were the split-plot arrangement of two forage systems treatments (overseeding aeschynomene into bahiagrass or …

Evaluation Of Restoration Of Damaged Ecosystems On Soil Nematode Communities And Their Functions In The Desert Steppe Open-Pit Mining Area Of Inner Mongolia, Zhiwei W. Gao, G. D. Han, G. G. Zhang

IGC Proceedings (1977-2023)

In view of the general lack of analysis of the ecological restoration effects of underground soil in the desert grassland ecological restoration projects in Inner Mongolia, this study selected the most representative open-pit quarries, open-pit iron mines and open-pit coal mines in the desert steppe. Using high-throughput sequencing technology, nematode community composition, diversity, and function were analyzed to determine the response of nematodes to different ecological restoration methods in damaged areas of coal mines. In open-pit coal mines, for slope rehabilitation, vegetation blanket restoration exhibited more favorable effects than those exhibited by vegetation bag restoration and natural restoration. For rehabilitation …

Surface-Soil Aggregation And Organic C And N Fractions Under Paired Grassland And Cropland Sites In The Southeastern Usa, Alan J. Franzluebbers, S. Van Vliet, M. H. Poore

IGC Proceedings (1977-2023)

Grasslands are expected to deliver ecosystem services by sequestering soil organic C, improving soil health and water quality, and minimizing soil erosion. Data to support these ecosystem services from contemporary managed grasslands are relatively scant, and so on-farm measurements would help bolster assessment across more diverse environmental settings. This study was conducted to compare soil properties from paired landuse of croplands and grasslands in a diversity of Major Land Resource Areas – the Piedmont, Blue Ridge, and Blackland Prairie of the southeastern USA. Four separate pastures on three collaborating farms were sampled at depth of 0-10 cm. Four samples from …

Forage Response And Economic Benefits To Weed Management In Grasslands, E. S. Flynn, S. Ingram, B. B. Sleugh

IGC Proceedings (1977-2023)

A common question among managers of grazing operations is “At what level of weed pressure does it become economical to apply herbicides on pastures?” Unfortunately, there isn’t just one answer to this question as production goals and practices differ between operations and even within an operation over time. Regardless, the real question being ask is if weed control will increase profit per acre.

There are three basic avenues that may be taken to improve profit per acre through weed control. The first is to increase the carrying capacity of the grazing operation by controlling weeds and replacing them with desirable …

Evaluation Of Herbicides For Saltcedar Control In Southwest Kansas, W. H. Fick

IGC Proceedings (1977-2023)

Saltcedar is an invasive species along some of the major rivers and tributaries in Kansas. The objective of this study is to determine control of saltcedar in southwestern Kansas using herbicides applied to individual trees as cut-stump, basal, and foliar treatments. Cut-stump treatments were applied in 2004-2010 during the months of April or May. Basal applications with 10% triclopyr in diesel were applied between 2007-2021 during the months of August through early October. Foliar treatments were applied during 2008-2021 using 467 L/ha spray volumes during August through early October. Chi square analysis at P < 0.05 was used to compare treatments. In initial studies, imazapyr (Arsenal) at 10% v/v in water, triclopyr (Remedy) at 10% v/v in diesel, and undiluted triclopyr (Pathfinder II) provided 80- 100% control of saltcedar, and were more effective than triclopyr + 2,4-D (Crossbow) applied as a 4% v/v solution in diesel (60% control). During 2008-2010, 10% imazapyr, 50% glyphosate, glyphosate + imazapyr (0.5% + 0.5%), triclopyr at 10 or 25%, and a mixture of triclopyr + fluroxypyr (PastureGard) at 25% all provided greater than 91% control of saltcedar. Basal bark control using 10% v/v triclopyr in diesel averaged 72% control. Foliar applications with 0.5 or 1% imazapyr and 0.5% + 1% imazapyr + glyphosate all provided greater than 84% control of saltcedar treated in 2008-2011. Imazapic (Plateau) at 1% was first compared with 1% imazapyr during 2014-2016 with both treatments providing about 80% control. During 2017-2021, 1% imazapyr (82% control), 1% imazapic (79% control), and 0.5% + 0.5% imazapyr + glyphosate (92% control) were all more effective than a combination of aminopyralid (Milestone) + triclopyr applied at 239 g/L + 359 g/L (42% control). Herbicides can be applied as cutstump, basal bark, or foliar treatments for the control of saltcedar.

Effect Of Litter Addition On Amino Acid Content And Composition In Alpine Meadow Soil, Yanli L. Feng, X. Y. Li, W. Z. Zong, J. Wang

IGC Proceedings (1977-2023)

Litter plays an important role in plant-soil nutrient cycling. However, the response of soil amino acid pools to litter input is unclear. Therefore, the aim of this study was to explore the effects of litter addition on the content and composition of soil amino acids in an alpine meadow soil. Soil was amended with litter of its dominant species, Kobresia graminifolia, and incubated for four weeks. Our results show that litter addition significantly increased the exchangeable amino acid content and protease activity in the soil. These results are crucial for understanding the amino acid cycling in soil.

Germination And Seedlings Heterotrophic Growth Of Cocksfoot (Dactylis Glomerata L.) In Response To Temperature, Abraham Escobar-Gutiérrez, L. Q. Ahmed

IGC Proceedings (1977-2023)

In the context of climate change, grasslands are considered, similar to forest, as an important sink for atmospheric CO₂. However, environmental change seems to go faster than species adaptation to survive on site. Germination and heterotrophic growth are key phases for plant, and consequently, communities’ establishment and structure. They are under genetic control and affected by temperature. The objective of this study was to analyze the intra-specific variability of six accessions of Dactylis glomerata in their responses to eight constant temperatures (5 to 40˚C) during germination and initial heterotrophic growth. The novelty of this work comes from the …

Detection Of Endophyte Mycotoxins By Service Laboratories: Providing Answers For Safe Feed, J. Honneffer, M. Sulyok, V. Milojevic, A. Holman, Jennifer Duringer

IGC Proceedings (1977-2023)

. A global network of service laboratories exists to test livestock feed materials (typically grass hay and pellets) for ergovaline, ergot alkaloids and lolitrem B to ensure ‘safe feeds’ are being given to livestock. These compounds are mycotoxins produced by endophytic fungi that naturally reside in feed material. They have been purposely bred into grass species, as they enhance the plant’s survival from drought and insect predation. Unfortunately, ergovaline and other ergot alkaloids also cause vasoconstrictive effects and reproductive difficulties in livestock, resulting in a $1 million annual loss in production for the cattle industry in the USA alone. Lolitrem …

L-Grassf: A New Model For Simulating The Genetic Environment Interactions On The Reproductive Phenology Of Grasses, S. Rouet, Jean Louis Durand, D. Combes, A. Escobar Gutiérrez, D. Leclercq, R. Barillot

IGC Proceedings (1977-2023)

Predicting the reproductive phenology in perennial grasses is a major concern because it determines the quantity and quality of forage. It varies a lot depending on site, year and cultivar. Projections of future climates suggest significant changes in seasonal temperature pattern, with new combinations of temperature and photoperiod, whose consequences on the floral induction of perennial grasses are unknown. L-GrassF is a new Functional Structural Plant Model simulating genetic variability of the phenology of perennial ryegrass in order to better understand the perenniality of grasslands and better anticipate the effects of climate change. L-GrassF stems from a previous model (L-Grass) …

Sustainable Intensification Of Livestock Systems Using Forage Legumes In The Anthropocene, José C. B. Dubeux Jr., D. M. Jaramillo, E. R. S. Santos, L. Garcia, L. M. D. Queiroz, K. R. Trumpp

IGC Proceedings (1977-2023)

Sustainable intensification of livestock systems implies greater efficiency in resource utilization resulting in greater output of products and other ecosystem services per unit of resource input. Strategies to improve resource use efficiency include diversification of plant and ruminant species with complementary resource use. Forages that have root systems with contrasting architecture and exploring different soil layers with complementary use of resource acquisition (e.g., nutrients, water) could enhance primary productivity. Belowground interactions with soil microbiota (e.g., mycorrhizae) is key to enhance resource utilization. Forages with complementary canopy characteristics that helps enhancing light interception and utilization could also lead to greater resource …

Grazing Cover Crops For Soil Health In An Integrated Crop-Livestock System, Forrest E. Davis, J. Brett Rushing

IGC Proceedings (1977-2023)

. Optimizing soil health requires building an environment that creates conditions which allow for best function of the chemical, biological, and physical properties of the soil to thrive as an organism and an ecosystem. Integrated crop-livestock systems (ICLS) use a systems approach to provide improvements to soil health parameters. In the fall of 2021, a randomized complete block study was conducted at the Coastal Plain Branch Experiment Station (CPBES) in Newton, Mississippi and at the Prairie Research Unit (PRU) in Prairie, Mississippi to observe the soil health effects of grazing cereal rye cover crops in a soybean production system. Three …