Plant Sciences Commons^™

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 (1997-2023)

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 (1997-2023)

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 (1997-2023)

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 (1997-2023)

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 (1997-2023)

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 (1997-2023)

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 …

Impacts Of Invasive Rats On Hawaiian Cave Resources, Francis G. Howarth, Fred D. Stone

International Journal of Speleology

Although there are no published studies and limited data documenting damage by rodents in Hawaiian caves, our incidental observations during more than 40 years of surveying caves indicate that introduced rodents, especially the roof rat, Rattus rattus, pose significant threats to vulnerable cave resources. Caves, with their nearly constant and predictable physical environment often house important natural and cultural features including biological, paleontological, geological, climatic, mineralogical, cultural, and archaeological resources. All four invasive rodents in Hawai‘i commonly nest in cave entrances and rock shelters, but only the roof rat (Rattus rattus) habitually enters caves and utilizes areas …

Comparative Proteomics Of Root Apex And Root Elongation Zones Provides Insights Into Molecular Mechanisms For Drought Stress And Recovery Adjustment In Switchgrass, Zhujia Ye, Sasikiran Reddy Sangireddy, Chih-Li Yu, Dafeng Hui, Kevin Howe, Tara Fish, Theodore W. Thannhauser, Suping Zhou

Agricultural and Environmental Sciences Faculty Research

Switchgrass plants were grown in a Sandwich tube system to induce gradual drought stress by withholding watering. After 29 days, the leaf photosynthetic rate decreased significantly, compared to the control plants which were watered regularly. The drought-treated plants recovered to the same leaf water content after three days of re-watering. The root tip (1cm basal fragment, designated as RT1 hereafter) and the elongation/maturation zone (the next upper 1 cm tissue, designated as RT2 hereafter) tissues were collected at the 29th day of drought stress treatment, (named SDT for severe drought treated), after one (D1W) and three days (D3W) of re-watering. …

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 (1997-2023)

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 (1997-2023)

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 (1997-2023)

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 (1997-2023)

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 (1997-2023)

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 (1997-2023)

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 (1997-2023)

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 (1997-2023)

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 (1997-2023)

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 (1997-2023)

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 …

The State Of Sustainable Agriculture And Agroecology Research And Impacts: A Survey Of U.S. Scientists, Marcia Delonge, Tali Robbins, Andrea Basche, Lindsey Haynes-Maslow

Department of Agronomy and Horticulture: Faculty Publications

A growing body of research suggests that although sustainable agriculture, particularly agroecology, can address challenges such as those related to climate change, ecosystem services, food insecurity, and farmer livelihoods, the transition to such systems remains limited. To gain insight into the state of U.S. sustainable agriculture and agroecology, we developed a 28-question mixed-method survey that was administered to scientists in these fields. Respondents (N=168) represented diverse locations, institutions, and career stages. They offered varied definitions of sustainable agriculture, with 40% considering economic and social well-being to be core components. Respondents identified the amount and duration of public research funding as …