Plant Pathology Commons^™

Challenges And Opportunities For Improving Eco-Efficiency Of Tropical Forage-Based Systems To Mitigate Greenhouse Gas Emissions, Michael Peters, Mario Herrero, Myles Fish, Karl-Heinz Erb, Idupulapati M. Rao, Guntur V. Subbarao, Aracely Castro, Jacobo Arango, Julian Chará, Enrique Murgueitio, Rein Van Der Hoek, Peter Läderach, Glenn Hyman, Jeimar Tapasco, Bernardo Strassburg, Birthe K. Paul, Alvaro Rincón, Rainer Schultze-Kraft, Steve Fonte, Timothy Searchinger

IGC Proceedings (1977-2023)

Forage-based livestock production plays a key role in national and regional economies, for food security and poverty alleviation. Livestock production is also considered as a major contributor to agricultural GHG emissions, however. While demand for livestock products is predicted to continue to increase, there is political and societal pressure both to reduce environmental impacts and to convert some of the pasture area to alternative uses such as crop production and environmental conservation. Thus it is essential to develop approaches for sustainable intensification of livestock systems to mitigate GHG emissions, addressing biophysical, socioeconomic and policy challenges. This paper highlights the potential …

Effects Of Rain Events On Carbon Fluxes From Biological Soil Crusts, Chunping Zhang, Xudong Li, Decao Niu, Hongrong Zhang, Hua Fu

IGC Proceedings (1977-2023)

In dry ecosystems, biological soil crusts (BSCs) have been suggested as one of the factors responsible for the large rate of annual CO₂ net uptake (Xie et al. 2009). However, most studies carried out on carbon (C) fluxes in arid and semi-arid ecosystems, such as soil respiration, have neglected the carbon fluxes from BSCs. Although BSCs are a vital component of the dry-land soil C cycle, few studies have parameterized the conditions required for photosynthesis in BSCs or determined BSCs respiration (Elbert et al. 2009, Castillo-Monroy et al. 2011). Precipitation in dry land is dominated by …

Carbon Density Distribution And Carbon Storage Estimation Under Different Grazing Degradation In The Typical Steppe, Sarula Wu, Xiangyang Hou, Yong Ding, Weibo Ren

IGC Proceedings (1977-2023)

Carbon (C) is a crucial component of living organisms on planet earth, and C cycling is an important symbol of healthy development of the biosphere (Han et al. 1999). Human activity has adversely affected the global C cycle, and contributed to an alteration of climate that will generate discernible feedbacks to all organisms and ecosystems on earth (He et al. 2008). Grasslands are one of the most widely distributed terrestrial ecosystems on the earth and it is estimated that C storage of global grassland ecosystem was 761Gt (1Gt = 09t), which accounts for about 15.2% C storage in …

Effect Of Grazing On Soil Carbon And Nitrogen In Alpine Madow, Eastern Of Tibetan Plateau, Shiqing Li, Zhenggang Guo, Xue Ran, Yuying Shen

IGC Proceedings (1977-2023)

As the grassland ecosystem in the Tibetan Plateau is very fragile, overgrazing likely leads to more serious damages to it than other ecosystems. In the past 30 years, 37% of the alpine meadows have been heavily damaged by grazing causing degradation of native vegetation, a decline in species richness and feed value, and more seriously soil erosion (Six et al. 2004). The impact of grazing on alpine grasslands appears to be hysteresis, as the soil needs more time to recover than the vegetation. So analysing the effect of grazing intensity on soil characteristics is an important way to reveal how …

Carbon Sequestration In Relation To Shrub Size In The Desert Ecosystem, Decao Niu, Hongyang Chen, Shigao Jiang, Li Liu, Hongrong Zhang, Hua Fu

IGC Proceedings (1977-2023)

Desert ecosystems have been reported as the location of the long-sought ‘missing sink’ for atmospheric carbon dioxide and as a potentially important area for carbon sequestering from fossil fuel combustion in the future (Stone 2008). Researchers have found that net uptake of carbon in the Mojave Desert ranged from 102 to 127 g C m2/yr during a 3-year period, which is equivalent to the net ecosystem production of many forest ecosystems with a much higher biomass (Luyssaert et al. 2007; Wohlfahrt et al. 2008). Shrub is the dominant plant of desert ecosystems (Gratani et al. 2011); hence, it …

Distribution Of Soil Organic Carbon Fractions As Related To Land Use And Management In The Loess Plateau, Northern China, Huige Han, Xudong Li, Decao Niu, Hua Fu

IGC Proceedings (1977-2023)

Organic C in the soil is not a uniform material but rather a complex mixture of plant, animal and microbial residues at different stages of decomposition (Post and Kwon 2000). So the dynamics of soil organic carbon (SOC) is usually described by dividing total SOC into different fractions (Six et al. 2002). Of all the different fractions, density defined fractions (light- and heavy fractions) may relate better to specific functions or processes (O’Hara et al. 2006), and the changes in SOC due to land use and management may be partly explained by the way C is allocated in …

Grazing And Soil Carbon, Rooting Around For An Effect, Helen P. King

IGC Proceedings (1977-2023)

There is considerable scientific and policy interest in the effect of different grazing methods on soil organic carbon (SOC) and general acceptance that increasing SOC by changing grazing management is possible. While overgrazing is recognised as a cause of land degradation and historical loss of SOC, a review and modelling by Conant and Paustian (2002) showed that ceasing overgrazing and stocking at appropriate levels can also increase SOC. Other reviews showed no difference in animal or pasture productivity between continuous (CG) and rotational (RG) grazing (Briske et al. 2008); and increases, decreases or no change in SOC with high, …

Long-Term Impacts Of Stocking Rate On Soil Carbon Sequestration In Arid Areas Of South Africa, Deribe G. Talore, Eyob Tesfamariam, Abubeker Hassen, Jean-François Soussana

IGC Proceedings (1977-2023)

Overstocking is one of the most important factors which results in changes of carbon stocks (Reeder and Schuman, 2002) and soil degradation, particularly in sandy soil, vulnerable to degradation through physical erosion. South African (RSA) topsoil is characterized by the low level of organic matter (Du Preez et al. 2011). Like most other African countries, little is known about the level of C sequestration under various grazing strategies in the vast dry grassland areas of RSA. It is well known that long-term studies with various stocking rate would be able to shed light on the level of C sequestration …

Soil Organic Carbon Stocks In A Brazilian Oxisol Under Different Pasture Systems, José C. Pinto, Róberson M. Pimentel, Yuri L. Zinn, Fernanda H. M. Chizzotti

IGC Proceedings (1977-2023)

Pastures are the main land use systems in the world and in Brazil they occupy 115 M ha. A major part of Brazil´s greenhouse gas emissions are due to land use change and agriculture. Livestock production comprises > 90% of methane and about 55% of CO2-equivalent emissions due to agriculture (Cerri et al. 2009). However, productive, well-managed pastures can improve degraded soils and increase soil organic carbon (SOC) stocks through humification of grass and root residues. In order to enhance pasture yields and SOC sequestration, nutrient availability in soils must also be improved, especially for N and P. This work …

Bayesian Modeling For Estimating Cattle’S Dung Position In Pasture, Rena Yoshitoshi, Nariyasu Watanabe, Kensuke Kawamura, Seiichi Sakanoue, Jihyun Lim, Taisuke Yasuda

IGC Proceedings (1977-2023)

Livestock excrement is one of the major sources of greenhouse gas (GHG) emission in pasture. As a first step in evaluating its contribution to overall GHG emissions, an understanding of excretion distribution patterns in pastures is required. Betteridge et al. (2010) describe a urine sensor that detects and logs each urination event of female sheep and cattle. The urine sensor records time and ambient temperature at one-second intervals however, patters of dung distribution are not specified. The objective of this study was to predict spatial distribution of cattle dung. The knowledge of livestock excrement position may be useful for …

Influence Of Grassland Management On Carbon Allocation In A Semiarid Temperate Steppe, Nan Liu, Y. Jun Zhang, H. Ming Kan, W. Jie Lu

IGC Proceedings (1977-2023)

Grazing lands in North China are often excessively grazed and widely degraded, while hay-making lands appear to be in relatively good condition due to grazing exclusion, but they are facing a continuous loss of nutrients in the harvested biomass. In semiarid grasslands, plant productivity and community composition are significantly altered by grazing and haying. Grazing mostly leads to negative effects on aboveground productivity, however root biomass seems to increase with moderate grazing (Gao et al. 2009; Derner et al. 2006), although responses can vary. Aboveground biomass removal can increase C3 grass dominance and productivity (Hofer and Bragg 1981). …

Land Use Intensification Effects On Soil C Dynamics In Subtropical Grazing Land Ecosystems, Maria L. Silveira, Sutie Xu, Julius Adewopo, Kanika S. Inglett

IGC Proceedings (1977-2023)

The impacts of land intensification on carbon (C) responses are important components of soil organic carbon (SOC) management. Grazing land intensification typically involves the use of highly productive plant species that can support greater grazing pressure, removal of higher proportions of site biomass and nutrients during mechanical harvest or grazing, and increased use of fertilizers, particularly N. Current improved grazing land management strategies are aimed at increasing above-ground biomass yield, with less regard for below-ground C dynamics. Because intensive management affects above- and below-ground C inputs (Schuman et al. 1999; Liu et al. 2011a,b), it can therefore have …

Research On Soil Carbon Storage Of Alpine Grassland Under Different Uses In Qinghai-Tibet Plateau, Tao Li, Youmin Gan, Lei Ji, Shujing Yang, Zhongqi Song

IGC Proceedings (1977-2023)

In recent years, with the temperature rising on the Qinghai-Tibet Plateau, studies have shown that (Shaoqing Wang et al. 1999; Yuchun Qi et al. 2003) the plateau permafrost has great potential for emissions of greenhouse gases such as carbon, nitrogen, because of the remarkable permafrost thermal sensitivity. The Qinghai-Tibet Plateau is a special geographical and ecological unit, which has an important role in global climate change. The study of soil carbon storage of grassland ecosystems in the Qinghai-Tibet Plateau and its distribution characteristics allow the evaluation of different land management. The carbon cycle response and feedback effects of …

The Effects Of Management And Vegetation On Soil Carbon Stocks In Temperate Australian Grazing Systems, Warwick B. Badgery, Helen P. King, Aaron Simmons, Brian Murphy, Andrew Rawson, Elizabeth Warden

IGC Proceedings (1977-2023)

The natural spatial variability in soil organic carbon (SOC) found under perennial pasture systems can make it difficult to determine differences between contrasting agricultural management practices. Pasture composition in large, extensively grazed paddocks can give an indication of pasture growth, utilisation and fertility that influence SOC and are a result of management over the longer-term. This paper examines SOC stocks on the central and southern tablelands of NSW, Australia (average rainfall from 615 to 915 mm and average annual temperature from 10.6 to 15.6°C) at three scales (regional, between similar sites and within site) to determine the influence of management, …

Effects Of Enclosure On Biomass, Carbon, Nutrient Storage And Allocation For Seriphidium Transiliense In A Sagebrush Desert Grassland, Zheng Wei

IGC Proceedings (1977-2023)

We hypothesized that Seriphidium transiliense in a sagebrush desert grassland could improve the storage of biomass carbon and nutrient after 3 years of enclosure. Also, we expect distinctive allocation strategies of nutrient, carbon and biomass partitioning into root (R), root crown (RC), reproductive shoot (RS) and vegetative shoot (VS) plant characteristics or modules. Therefore, the storage and allocation pattern of biomass, carbon and nutrients (N, P, K, Ca and Mg) in different modules were monitored during September and October, from 2009 to 2011. The results showed that the P content of root, the N content of reproductive shoot, the Ca …

Long-Term Field Experiment For Monitoring Soil Carbon Content In Japanese Grasslands: Initial Data From 2010 To 2012, Shoji Matsuura, Hiroshi Hibino, Reiko Kazama, Hiroyuki Sasaki, Masayuki Hojito

IGC Proceedings (1977-2023)

A long-term field experiment for monitoring soil carbon content in Japanese grasslands started in 2010 to investigate the changes in soil carbon content and the effect of composted livestock manure application. We established grassland plots with 3 levels of manure application treatment at 10 sites. Bulk density values in many sites had wide inter-replicate and inter-annual variability. It is reasonable to suppose that the variability in the bulk density reflect spatial variability of physical properties within the grasslands because the annual trends of the bulk density values were not consistent. Organic carbon concentration tended to increase yearly in the surface …

Phenotypic And Genotypic Characterization Of Aroma And Cercospora Janseana Resistance In U.S. Rice, Christopher Keith Addison

LSU Doctoral Dissertations

Rice is a staple food for over one-third of the world’s population. With the increasing population, plant breeders must continue to breed for improved varieties. The utilization of markers to applied breeding program can increase the efficiency of selection for key traits. The targeted traits for this research include grain aroma and resistance to the fungal disease narrow brown leaf spot (Cercospora janseana). Our objective was to characterize SNP diversity across the BADH2 gene in publicly available sequence data of a collection of 2,932 rice varieties was characterized to determine the number of gene haplotypes in O. sativa. …

Contrasting Impacts Of Grazing On Soil Properties And Plant Communities Between Semiarid And Temperate Rangeland Ecosystems, Eduardo Medina-Roldán, Jorge Paz-Ferreiro, J. Tulio Arredondo, Elisabeth Huber-Sannwald, Richard D. Bardgett

IGC Proceedings (1977-2023)

We discuss how grazing by large herbivores as a land use option does not necessarily involve a trade-off in terms of soil carbon (C) storage, by presenting results from field grazing gradient experiments from rangeland ecosystems under different climatic conditions in semiarid grasslands from Central Mexico and temperate ecosystems from Northern England. In general, moderate grazing pressure did not reduce soil C in both ecosystems after comparisons with long-term grazing exclusions, and moderate grazing even showed higher soil C in the semiarid area. In the semiarid area, our results are likely explained by grazing tolerance of plant species in moderate …

Palatability Of Psolarea Spp. Accessions Offered As Micro-Swards To Dairy Sheep, Mauro Decandia, Marco Acciaro, Maria Sitzia, Andrea Cabiddu, Carla Manca, Valeria Giovanetti, Giovanni Molle

IGC Proceedings (1977-2023)

Psoralea bituminosa C.H. Stirton (syn. Bituminaria bituminosa L.) is a perennial legume usually considered of low palatability because of the strong smell that can be emitted by oil glands located on its foliage. However the nutritive value of P. bituminosa in terms of forage composition and digestibility was proven similar to or even better than that of other legumes. The aerial part of this species may contain a high concentration of furano-coumarins, out of which psoralen and angelicin are the most abundant (Pecetti et al. 2007). These substances could be harmful to animals, being responsible for contact photodermatitis, in …

Is There Genetic Diversity In The ‘Leucaena Bug’ Synergistes Jonesii Which May Reflect Ability To Degrade Leucaena Toxins?, Jagadish Padmanabha, Michael J. Halliday, Stuart E. Denman, Carl K. Davis, H. Max Shelton, Chris S. Mcsweeney

IGC Proceedings (1977-2023)

Leucaena leucocephala, a nutritionally rich forage tree legume, contains a non-protein amino acid, mimosine, which is degraded by ruminal bacteria to toxic metabolites 3,4-DHP and 2,3-DHP resulting in goitre-like symptoms in animals, severely restricting weight gain. Raymond Jones, in the early 1980s, discovered the ‘leucaena bug’ in the rumen of goats in Hawaii that degraded these toxic DHP metabolites into non-toxic compounds (Jones and Lowry 1984) which was named Synergistes jonesii (Allison et al. 1992) Subsequently, a rumen inoculum containing S. jonesii was used as an ‘oral drench’ for cattle, kept in continuous culture (Klieve et al. …

Rates Of Urinary Toxin Excretion In Unprotected Steers Fed Leucaena Leucocephala, Joseph H. O’Reagain, Sam R. Graham, Scott A. Dalzell, H. Max Shelton

IGC Proceedings (1977-2023)

Leucaena (Leucaena leucocephala) is a productive, nutritious, leguminous forage tree with high capacity for ruminant live weight gain. The plant does however contain the non-protein amino acid mimosine which is degraded within the rumen to 3-hydroxy-4(1H)-pyridone (3,4-DHP) with potential to cause adverse effects on animal health and production. Stock can be protected via rumen inoculation with the bacterium Synergistes jonesii, which is capable of degrading the toxin. However surveys have demonstrated sub-clinical toxicity is persisting in Queensland herds (Dalzell et al. 2012).

Currently, testing for toxicity involves analysis of urine samples using high performance liquid chromatography …

Prevalence Of Dhp Toxicity And Detection Of S. Jonesii In Ruminants Consuming Leucaena Leucocephala In Eastern Indonesia, Michael J. Halliday, Tanda Panjaitan, Jacob Nulik, H. Dahlanuddin, Jagadish Padmanabha, Chris S. Mcsweeney, Sulaiman Depamede, Debora Kana Hau, Kurniawan, Muhammad Fauzan, Sutartha, Baiq Tutik Yuliana, Charles Pakereng, Putri Ara, Dessy Liubana, Resti G. Edison, H. Max Shelton

IGC Proceedings (1977-2023)

Leucaena leucocephala (leucaena) is a productive forage tree legume widely used in eastern Indonesia. While highly nutritious, it possesses the toxin mimosine which adversely affects animal production. In ruminants, mimosine is readily converted to the two isomers of dihydroxypyridine (3,4-DHP and 2,3-DHP) known to cause goitre, suppress appetite, and cause severe mineral deficiencies. These adverse symptoms may be partially responsible for the reluctance of some farmers to feed leucaena.

A bacterium capable of complete degradation of DHP, Synergistes jonesii, originally discovered in Hawaii in goats consuming leucaena (Jones and Megarrity 1986), was later found in Indonesia which led to …

The Efficacy Of In Vitro Synergistes Jonesii Inoculum In Preventing Dhp Toxicity In Steers Fed Leucaena-Grass Diets, Michael J. Halliday, Hayley E. Giles, Scott A. Dalzell, Chris S. Mcsweeney, H. Max Shelton

IGC Proceedings (1977-2023)

Leucaena leucocephala (leucaena) is a valuable forage tree legume for tropical animal production that contains the toxin mimosine. The breakdown products of mimosine in ruminants (3,4-DHP and 2,3-DHP) can adversely affect their health and limit weight gains (Jones and Hegarty 1984). The rumen bacterium Synergistes jonesii, introduced into Australia in 1983 was shown to completely and rapidly degrade these toxins to safe levels (Jones and Megarrity 1986). Since 1996, an in vitro produced inoculum has been made commercially available to Australian graziers (Klieve et al. 2002). Accordingly, the issue of leucaena toxicity in Australia was thought to be …

Detection Of Toxicity In Ruminants Consuming Leucaena (Leucaena Leucocephala) Using A Urine Colorimetric Test, Sam R. Graham, Scott A. Dalzell, Graham L. Kerven, H. Max Shelton

IGC Proceedings (1977-2023)

Leucaena (Leucaena leucocephala), a productive leguminous shrub for feeding ruminant livestock, contains the toxic amino acid, mimosine which post- ingestion is converted to 3,4-DHP and 2,3-DHP, isomers of dihydroxy-pyridone. While DHP generally does not exhibit acute toxic symptoms, it has been suggested that it is an appetite suppressant that reduces animal live weight gain (Jones 1994). With no observable symptoms, subclinical toxicity is difficult to detect (Phaikaew et al. 2012). In 1982 the DHP-degrading rumen bacterium named Synergistes jonesii was introduced into Australia as a potential solution to DHP toxicity as it spreads easily throughout cattle herds …

Diurnal Urinary Excretion Of Dhp In Steers Fed Leucaena Leucocephala, Hayley E. Giles, Michael J. Halliday, Scott A. Dalzell, H. Max Shelton

IGC Proceedings (1977-2023)

Leucaena (Leucaena leucocephala) contains the toxin mimosine which is quickly degraded by rumen microorganisms to isomers of dihydroxypyridine (DHP). DHP is detrimental to animal production, causing reduced thyroid hormones, reduced weight gain, goiter and severe deficiencies in essential minerals (Tsai and Ling 1971; Hammond 1995). There are several methods of testing for exposure to DHP toxicity but the simplest is the colorimetric urine spot test (Graham et al. 2013). Several researchers have noted high variability in the excretion of DHP among animals on similar leucaena diets (Dalzell et al. 2012; Phaikaew et al. 2012) and …

Relationships Between Goat Foraging Behaviour And Pastoral Value In High Bassin Zone Of Mandrare Rangeland In Southern Of Madagascar, A. J. M. Randrianariveloseheno, J. N. Rakotozandriny, R. Daccord

IGC Proceedings (1977-2023)

Goats have particular anatomical behaviour for browsing leaves to satisfy their energy requirements. In rangelands, available shrubs, leaves and biomass resources influence ruminant’s activities and rhythms such as foraging, walking, resting, ruminating and drinking. At semi-arid areas, this study aimed to determine how shrubs interact with pasture value to effect goat foraging behaviour.

Relative Preference, Palatability And Intake Of Stylosanthes Scabra Accessions Adapted In Pretoria, Thamsanqa D. E. Mpanza, Abubeker Hassen, Ned E. F. Donkin

IGC Proceedings (1977-2023)

Inadequate supply of forage particularly during dry season is the major constraint in livestock production in sub-Saharan Africa (Anele et al. 2011). Poor management of the available feeds, seasonal variability in weather and climate changes may contribute to the high fluctuation of forage quality and quantity between season and years (Sultan et al. 2008). To improve livestock production in sub-Sahara Africa there is a need to improve feed deficiencies both in quantity and quality. Stylosanthes scabra cv. Seca was evaluated for dry season feed supplementation, and was found to be adaptive and productive under subtropical climate of Gauteng …

Modelling The Effect Of Maize Silage And Winter Oat Forage Crop On Cow-Calf Systems In Argentina, Horacio Berger, Claudio F. Machado, Carolina Zabala, Catalina Fernandez Rosso, Julio C. Burges

IGC Proceedings (1977-2023)

Cow-calf systems in the flooding Pampa - Argentina, are facing increasing competition with cropping systems for resources and land. In this context, to be more competitive livestock systems require system intensification, which demands an improvement on the feedbase. Forage crops and feeding silage have been used widely on dairy and beef cattle finishing systems. The purpose of the study was to assess with a model the level of intensification that can be achieved in cow calf systems and its economic effects by incorporating maize silage and winter grazing oat crops.

Plant Traits Relevant For Multi-Functionality Of Grassland Swards For Free-Range Chicken Husbandry, Laura Breitsameter, Matthias Gauly, Nicole Wrage-Mönnig, Johannes Isselstein

IGC Proceedings (1977-2023)

The sward of the outdoor run serves multiple important functions in free-range chicken husbandry systems. Vegetation ground cover is crucial for soil conservation. Moreover, by providing a foraging enrichment it is relevant for animal welfare (Shimmura et al. 2008). Scientific knowledge of the plant-animal interactions of swards in outdoor chicken runs is only just emerging. An understanding of these will help to improve swards both in view of the conservation of an intact vegetation cover, and for fostering animal welfare.

In the present field study, we investigated: (1) the growth of a number of grassland plant species under conditions …

Relationship Between Grazing Jaw Movements And Time Per Bite In Cattle: Effect Of Sward Structure And Grazing Methods, Jean C. Mezzalira, Lidiane Fonseca, Olivier J. F. Bonnet, Carlos C. Mezzalira, Lenilson Da Fonseca Rosa, Luan C. Pagani, Teresa C. M. Genro, Paulo C. De F. Carvalho

IGC Proceedings (1977-2023)

The time per bite is the result of the interaction between mouth morphology, animal behaviour and sward structure (Laca et al. 1994). The time per bite increases with bite mass (Laca et al. 1994), but it has a constant component that is the time required to open and close the jaws, namely, the time required for one jaw movement (Hirata et al. 2010, Newman et al. 1994). In this experiment we tested the hypothesis that the time per jaw movement will remain constant independently of sward structure and grazing method.