Soil Science Commons^™

Breeding Challenges In Apomictic Warm-Season Grasses, E C. Bashaw, P W. Voigt, B L. Burson

IGC Proceedings (1977-2023)

Efforts to breed apomictic grasses met with little success in the past, but results of more recent research show significant progress with some species and new prospects for improving apomicts. Early research uncovered the cytological basis for apospory and diplospory, found the common apomictic mechanisms in grasses, and showed that apomixis is transmitted from pannt to offspring. Discovery of sexual or partially sexual (facultative apomicts) plants in several species formerly considered obligate apomicts allowed for hybridization and genetic studies. Results of subsequent research confirmed inheritance of apomixis, and data from the more conclusive studies indicate that method of reproduction …

Deep Learning-Based Quantification Of Tall Fescue Abundance In Pastures, Rose E. Binkley, Samuel R. Revolinski, Echo Elizabeth Gotsick, Ray Smith, Zeya Wang, Katsutoshi Mizuta

Plant and Soil Sciences Faculty Publications

Accurate and rapid measurement of tall fescue abundance is essential for efficient forage management and mitigating livestock exposure to potential endophyte-related toxicity. Traditional visual estimation methods are labor-intensive and are subject to change depending on the observer doing the calculations, which limits their scalability and consistency. This study explores the application of deep learning techniques to automate and improve the classification of tall fescue abundance across pasture systems in Kentucky. Ground-truth abundance classes were evaluated using one of the traditional methods with occupancy grid and compared against estimates derived from red-green-blue images. Two convolutional neural network architectures, YouOnlyLookOnce (YOLO) and …

A Conserved Ethylene-Triggered Cell Death Mechanism May Underlie Hollow Stem Formation Across Plant Species, Mengxiao Yan, Weijuan Fan, Yinghui Meng, Jiamin Zhao, Wei Yang, Ziyin Xu, Yusen Gao, Haiyan Zhuang, Wuyu Zhou, Yuqin Wang, Qingjun Huang, Ling Yuan, Hongxia Wang, Jun Yang

Plant and Soil Sciences Faculty Publications

Hollow stems have independently evolved multiple times across the plant kingdom and play crucial roles in plant development and various environmental adaptations. However, the mechanisms underlying stem hollowness remain poorly understood. Water spinach (Ipomoea aquatica) is one of the few hollow-stemmed plants in the Convolvulaceae family (eudicot: asterid), and its hollow stems are essential for thriving in aquatic environments. Using histochemical staining and transcriptome analysis, we found that programmed cell death (PCD) is involved in cavity formation at water spinach shoot tips. Single-cell and spatial transcriptome analyses further revealed that ethylene and reactive oxygen species (ROS) likely drive …

A Simple Statistical Tool To Correct The Daily Temperature Effect On Dielectric Soil Matric Potential Sensor Readings, Sebastián Bravo Peña, Meindert Commelin, Ole O. Wendroth

Plant and Soil Sciences Faculty Publications

High-resolution time series recorded by soil water dielectric sensors are often affected by other processes. Dielectric soil matric potential sensors, such as the TEROS 21, exhibit temperature sensitivity, resulting in deviations of readings from the true value due to soil temperature fluctuations. However, methods for correcting this effect remain limited. The objective of this study was to create a straightforward, scale-based statistical approach to mitigate the influence of daily temperature oscillations on matric potential dielectric readings. The temperature sensitivity correction function (TSCF) identifies, quantifies, and smooths diurnal fluctuations caused by soil temperature dynamics. We provide a detailed description of the …

Field-Scale Evaluation Of Satellite- Derived Vegetation Indices And Image Timing For In-Season Nitrogen Management In Corn, Ana Morales-Ona, Katsutoshi Mizuta, James J. Camberato, Robert Nielsen, Yuxin Miao, Davide Cammarano, German Mandrini, Daniel Quinn

Plant and Soil Sciences Faculty Publications

Introduction: Traditional methods to determine the agronomic optimum nitrogen rate (AONR) for corn (Zea mays L.) rely on grain yield data, limiting in-season decision-making for nitrogen (N) management. Vegetation indices (VIs) derived from satellite imagery can serve as proxies for grain yield and help estimate in-season AONR, enabling timely sidedress applications. This study aimed to (1) quantify how VI–yield relationships vary during the vegetative period across fields with different tillage systems and crop residue; (2) determine whether VI–N response curves can be used to estimate AONR (AONRvi); and (3) assess the accuracy of AONRvi relative to yield-based AONR (AONRy). …

Climate Change Effects On Biomass And Greenhouse Gas Emissions Are Ameliorated By Nontoxic Endophytes In Southeastern Usa Transition Zone Tall Fescue Pastures, Rebecca Kay Mcgrail, Jonathan D. Moore, A. Elizabeth Carlisle, Jim A. Nelson, Rebecca L. Mcculley

Plant and Soil Sciences Faculty Publications

Background: The plant–microbe interaction between tall fescue and its endophyte Epichloë coenophiala can affect ecosystem responses to changing rainfall patterns and increasing temperatures. Endophyte-infected (E+) stands often exhibit improved stress tolerance and differing soil greenhouse gas (GHG) emissions compared to endophyte-free (E−) stands. However, it is unknown if mammalian nontoxic endophyte (NTE) strains introduced into some tall fescue cultivars confer differing stress tolerances or reduce soil GHG emissions.

Methods: We quantified the impact of fescue-NTE symbioses in Jesup and Texoma on biomass and GHG emissions in response to increased temperature (+3°C) and altered precipitation (50% lengthened interval between events) using …

A Global Synthesis Of Fragipan Silicon Concentrations And Relationships With Soil Physicochemical Properties As A Function Of Soil Parent Materials, Christopher Shepard

Plant and Soil Sciences Faculty Publications

Fragipans are dense, brittle subsurface horizons that restrict root growth and limit water-holding capacity. A common factor in these soils is a binding agent, potentially either phyllosilicate clay bridging, amorphous aluminosilicate/silica, or silica sorbed to Fe oxides. Others have suggested that no binding agent is present within these soil horizons and that the arrangement of individual particles is solely responsible for these horizons. In this article, a secondary data synthesis was utilized to demonstrate that silicon (Si) accumulation is a key pedogenic process in loess-derived fragipan horizons, but not in all fragipans. The average dithionite-extractable Si (Si_d) content …

Impact Of Land Use On Soil Properties, Clay Mineralogy, And Behavior Of Ammonium Across A Precipitation Gradient, Isabel Delamater

Theses and Dissertations--Plant and Soil Sciences

Like soil texture, clay mineralogy is considered a permanent or inherent characteristic of soils reflecting the influence of soil forming factors over long periods of time. Despite the importance of clay mineralogy in providing ecosystem services, much remains unknown about whether land use (native grassland sod versus no-tillage) can modify clay mineralogy under short periods of time. Furthermore, in no-tillage agroecosystems, lower crop yields are often ascribed to immobilization of added N fertilizer where inorganic nitrogen (such as ammonium) is converted to organic nitrogen. The possible role of clay mineralogy in retaining added ammonium has been overlooked in no-tillage systems. …

Genetic Engineering For Pastures, W J. Peacock

IGC Proceedings (1977-2023)

The first genetically engineered food products from horticultural production systems are now entering the mnrke< and field trials of genetically engineered crop species are well advanced. We cnn expect that a range of crop cultivars, in which gene

Grassland For Sustainable Ecosystems, Malcolm Hadley

IGC Proceedings (1977-2023)

Grasslnnds present many advantages for examining issues related to sustainability. Grasslands include planted pastures as well as a variety of natural rangelands in situations ranging from semi-arid to subhumid. Diversity is also reflected in the spectrum of grassland users and uses, for example, nomadic pastoralism, extensive ranches, intensive pastures, wildlife tourism, game hunting. And in terms of sustainability of resource management, grasslands encompass a wide range of contrasting situations and conflicts in resource use. Heavy grazing pressure associated with increasing human populations in certain tropical savannas, the implications of rural depopulation to traditional pasture management in alpine regions, and the …

Grasslands For Our World, F Riveros

IGC Proceedings (1977-2023)

The present-day role of grasslands and fodder is reviewed with respect agriculture, animal production and environmental concerns. The world's grazing lands are a finite resource and, overall, arc being badly managed; in most developing countries action is required now, before it is too late. They will continue to be a major source of animal feed for the foreseeable future; encroachment from cropping will continue locally but, for much of what is now natural pasture, exploitation by the grazing animal .will remain the major means of obtaining an economic return; the task of grassland professionals is to assist the managers of …

Human Impact On Terrestrial Ecosystems - What We Know And What We Are Doing About It, H A. Mooney

IGC Proceedings (1977-2023)

At present the impact of humankind on the Earth System is substantial and will become greater as we continue to add over 80 million people to the global population each year. Collectively the human species utilises over a third of the total fresh water that is available, as well as an equivalent amount of the total terrestrial productivity. Possil energy is being consumed at a prodigious rate and fuels, among other things, over a half a billion vehicles. To support the large human population the Earth has been greatly reconfigured with much of the land utilised for grazing and agriculture. …

Science And Information For Our Grasslands, G A. Nores, R R. Vera

IGC Proceedings (1977-2023)

This paper favours a view of grasslands, and agricultural research in general, that extends well beyond the limits of the scientific community and promotes the active involvement of scientists in current societal debates from a scientific perspective. It is argued that in developed countries environmental concerns rather than production growth will tend to dominate future social debate. In developing countries there is a need to balance agricultural growth with responsible management of natural resources. Needs for new technology go beyond improving biophysical efficiency, and involve economic and social efficiency objectives. The relevance of grassland research is assessed in terms of …

Vegetation Dynamics In Grazed Systems: A Hierarchical Perspective, D D. Briske

IGC Proceedings (1977-2023)

Grassland vegetation consists of a series of hierarchical levels including the tiller, plant, population and community which collectively influence the productivity and stability of grazed systems. These hierarchical levels may respond uniformly to influence vegetation dynamics, but frequently additional complexity is encountered by the occurrence of opposing responses between or among hierarchical levels. Consequently, it is important to con­sider responses at several hierarchical levels to achieve an accurate interpretation of vegetation dynamics to graz­ing within the community. The significance of a hierarchical perspective to vegetation management is illustrated with examples from bunchgrass dominated rangelands at the level of the individual …

Forage Conservation And Physico-Chemical Conversion, E Zimmer

IGC Proceedings (1977-2023)

The factors on which the digestibility of organic matter (dMO) of forages depend are now well-known. In temperate forages, this digestibility depends mainly on the growth stage, the rank of the growth-cycle, and the botanical species. It is constantly decreasing with advancing age, especially during the first growth-cycle. In after­math growth-cycles, high temperatures accelerate the decrease of digestibility with age. Tropical forages follow the same laws, but tropical grasses are less digestible than cool-season grasses, especially at young stages and in warm weather. This is partly due to the fact that high temperatures increase cell-wall contents and lignification, and also …

The Feeding Value Of Forages, C Demarquilly

IGC Proceedings (1977-2023)

The lower productivity of legume based swards and their instability of yield from year to year compared with nitrogen fertilised grass swards continues to be a major constraint on the integration of leguminous nitrogen fixing species into present-day farming systems. Most legume systems have a high biological nitrogen fixation (BNF) potential which is rarely attained in the· field due to limiting environmental or management factors. Enhancement of BNF through manipulation of the Rhizobium and plant components of the symbiosis must be viewed as a long-term objective. Optimisation of nitrogen fixation in the short-term may best be achieved through optimisation of …

Nitrogen Fixation, Cycling, And Utilization, P M. Murphy, M T. Sherwood

IGC Proceedings (1977-2023)

The lower productivity of legume based swards and their instability of yield from year to year compared with nitrogen fertilised grass swards continues to be a major constraint on the integration of leguminous nitrogen fixing species into present-day farming systems. Most legume systems have a high biological nitrogen fixation (BNF) potential which is rarely attained in the· field due to limiting environmental or management factors. Enhancement of BNF through manipulation of the Rhizobium and plant components of the symbiosis must be viewed as a long-term objective. Optimisation of nitrogen fixation in the short-term may best be achieved through optimisation of …

La Prairie Dans Ses Usages Multiples: Conservation Des Sols, Protection De L'Environnement, Etc., M Skouri, J Poissonet

IGC Proceedings (1977-2023)

Les terres :i paturage couvrent une partie importante de la planete et presentent une extreme diversite de situations en fonction des conditions ecologiques et des facteurs socio-economiques et culturels qui s'exercent sur ces espaces. Ces facteurs ont engendre des transformations du milieu nature] permettant d'intensifier, et :i ]'extreme, de contr61er la production vegetale de ces ecosystemes. Si le role premier de ces formations herbacees a ete d'alimenter Jes herbivores afin que l'homme en obtienne une production (viande, lait, peaux, etc.), Jes autres fonctions de ces espaces ont une importance que !'on ne peut se permettre de negliger, que ce soit …

Quickening Snow Melting In Early Spring With Black Powder In Snowy District, A Imai

IGC Proceedings (1977-2023)

Experiments were conducted during 1977-1980 to quiken snow melting in early spring with three kinds of black powders at 450 m a.s.l.,Tsunan-machi, Niigata Prefecture. Snow melting materials involved blast furnace slag, di-amido lime and calcium silicate and their effects on snow melting were compared with each other at various application rates on snow surface in late March every year. Snow melting was earlier with 600 kg/ha di-amido lime resulting from lower albedo of 25 % and it could quicken the snow-off by 10-13 days as compared to the control plot. This early snow melting induced the higher soil temperature and …

Effect Of Fertilization In Autumn Or After Wintering On Dallisgrass Production In The Following Season, T Kobayashi

IGC Proceedings (1977-2023)

To improve dallisgrass (Paspalum dilatatum Poir.) pasture productivity, the effects of autumn or spring topdressing in a field experiment and autumn nitrogen (N) application levels in a pot experiment on the regrowth and carbohydrate accumulation until winter and on the early summer production were studied. Dallisgrass pasture was topdressed in either autumn (late September) or spring (early March) at 0.5 kg/a each of N, phosphate (P2O5), and potash (K20), after the final cutting in late September 1978. Plants in pots were topdressed at the rates of 0.5, 1, 2, and 4 kg N/a, just after cutting in early October …

Selenium Pellets Administration In Cows Grazing Continuously On Low Selenium Grassland In Japan, J Jachja, N Ishida, R Kawashima, K Otsuki, K Otsuki, M Kawano, F Hosoyamada

IGC Proceedings (1977-2023)

The effectof selenium (Se) supplementation in cows upon the growth of their newborn calves under the conditions of continuous grazing in a low Se pasture were studied. The selenium status of calves which were born from selenium treated cows were higher than that in calves from untreated control cows during the suckling period. Selenium supplementation to the dams showed no significant response upon the body measurement for their calves at birth or four months of age, but significant improvement in body weight and withers height at the weaning period. When cows grazed continuously in pastures containing a selenium content of …

Plant Introduction, Seed Production And Fodder Promotion In An Integrated Livestock And Pasture Development Programme In Kerala, India, A Shamsudeen, T V. Joseph, F Von Sury

IGC Proceedings (1977-2023)

An integrated pasture development programme for the state of Kerala, in the 1500-3500 mm rainfall area of southern India, is described. Kerala's agriculture is characterized by small holdings and intensive multicrop farming systems with coconut and rice as main crops. Dairy cattle rearing is an important subsidiary for many farmers. A plant introduction programme selected Panicum maximum ( cvs. Makueni and Riversdale), Brachiaria ruziziensis and Centrosema pubescens for intercropping in coconut gardens. Desmodium intortum and D. uncinatum were introduced for the grasslands of the high ranges. B. ruziziensis, Melinis minutiflora, Setaria anceps ( cvs. Kazungula and N arok), Stylosanthes guianensis …

Development Of Legume-Based Pastures For Livestock Production In Yunnan, Peoples Republic Of China- Preliminary Studies With Trifolium Semiplosum Cv. Safari And Temperate Legume Cultivars, M J. Mathison, M/S T. Wang, Z Y. Yang, M H. Dunning, Y N. Al, Z Z. Ma, H X. Al, L W. Peng, H Yang, D C. Zhang, C G. Zhang, G R. Yang

IGC Proceedings (1977-2023)

Aiming to improve livestock production from extensive grassland areas in Yunnan Province south west China, forage cultivar evaluation experiments are in progress as part of the China-Australia Technical Co-operation Programme. Preliminary results are given from introduced temperate legumes sown in 1983 in replicated swards in cultivated and uncultivated grassland. South west monsoon climates sampled range from alpine-temperate to tropical. In alpine sites red clover and annual species e.g. vetches, persian and subterranean clovers were among top dry matter yielders in the first year on cultivated land, Annual clovers failed or were outyielded by white, red clovers and, in one locality, …

Development Of Legume- Based Pastures For Livestock Production In Yannan, Peoples Republic Of China - Preliminary Studies With Tropical Legume Cultivars, M J. Mathison, M.S T. Wang, Z Y. Yang, Y N. Ai, Z Z. Ma, H X. Al, L W. Peng, G R. Yang

IGC Proceedings (1977-2023)

As part of the Australia -China technical cooperation programme investigations to raise livestock production with improved pastures began in 1983 in Yunnan province, south west China. Preliminary results with ungrazedintroduced tropical legume cultivars sown in cultivated and uncultivated grassland are given for 2000-2500m altitude subtropical sites and a 500m alt. tropical site. Only Jotononis, silverleaf and greenleaf desmodiums were productive in the second year at subtropical sites. At the tropical site annual lab lab produced most dry matter in the first year. Most perennial species grew well there in the second year. The best cul ti vars for cultivated land …

Fodder Development In The Dry Zone Of Sri Lanka - A Pasture Scheme For Small Farms, P Berger, L R. Abeykoon, L Winkler

IGC Proceedings (1977-2023)

A pasture development scheme to improve fodder production by small farmers was introduces by the Sri Lanka - Swiss Livestock Development Project (SSLDP) in the easten dry zone of Sri Lanka. The procedure of the scheme is described. Emphasis was put on proper land selection, establishment procedures and management factors of pasture plots. To promote the scheme a subsidy is given to the farmers after inspections by the extension staff. The first experiences showed a better survival of the plots under a closer follow up. A marked decrease was observed during extreme climatical periods. It is proposed to intensify the …

Range Improvement In Tropical China: Gaopoling Model Cattle Farm, D L. Michalk, J F. Ayres, Fu Nanping, Zhu Chin-Min

IGC Proceedings (1977-2023)

New policies seek to increase beef output on China's rangeland by sowing legume-based pastures. "Model farms" provide a means of quickly transferring this technology to China. Gaopoling Model Cattle Farm was set up to improve beef production in dry tropical Hainan Island by introducing new legume species and better husbandry practices. With finance from Guangdong Province and technology from Australia, a program emphasising pasture research, performance recording of "improved" versus "traditional" cattle husbandry and commercial farm developmant was commenced in 1981. Though experimentation, recommendations for species combinations, fertilizer inputs and sowing methods were formulated for the major local soil types. …

Preliminary Fertilizer Requirements For Establishing Legume Based Pastures In The Alpine Zoone Of Yunnan, Jinjing Wang, J R. Bruce-Smith, Jixin Li, Mingliang Wang

IGC Proceedings (1977-2023)

Preliminary results of field trials designed to assess the soil fertility status for establishing improved legume based pastures in the alpine zone of Yunnan Province are presented. These trials were undertaken by a joint Chinese-Australian Project which is investigating ways to improve the livestock industry of the Province. The best treatments at one site in the North East yielded about 9000kg of total (grass + legume + weeds) pasture and 7000kg of this was attributable to clover production. At another site in the North West on the Southern Tibetan Plateau summer waterlogging confined the pasture yield to 4000kg DM. Tentative …

Preliminary Studies Of Fertilizer Requirements Of Tropical Legumes In Southern Yunnans Red River Valley, Jinjing Wang, J R. Bruce-Smith, Mingliang Wang, Jixin Li

IGC Proceedings (1977-2023)

As part of a joint Chinese-Australian Project to promote livestock development, a farm site in the lower Chinese section of Red River Valley was chosen as an area to study techniques suited to meeting these objectives through establishing and utilizing legume based tropical pastures. Preliminary results of fertilizer trials at Daliuhu Farm show that sulphur deficiency is the main nutrient problem retarding the growth of siratro and stylo legumes. The application of as little as 5, but optimally between 10 and 20kg of sulphur as gypsum Sor elemental S seems to adequately meet their growth requirements. The apparent adequate phosphate …

Studies On The Mountain Pastures Classification And Class Evaluation Of Guichou, China, Huang Weilian

IGC Proceedings (1977-2023)

The pastures of the mountain range in Guichou are a secondary succession type, which has been shaped since the forest was destroyed. They were formed by forest regressive succession; from forest to bushwood, and with further degeneration from bushes to pastures. Therefore, in the author's opinion, it is appropriate to use the secondary succession series method of geobotany to classify the mountain range pastures in southern China. This method can objectively describe the origin and developing stages of this range type, the features of the vegetation succession series in subtropical areas, and express their economic value and utilization, which form …

The Grass Hillsides Of Jiangxi Province, Fan Xie, Suehen Wang

IGC Proceedings (1977-2023)

For researching into vegetation on grass slopes, their types, characteristics, yield and prospect of application in livestock husbandry, a sampling investigation on the semi-location spot has been carried out. Jiangxi province is situated in Southeast China, belonging to the monsoon region in Southeast Asia. According to the principles of ecological condition and dominant species, the grass hillsides can be classified into 7 herbosa groups: Ischaemum ciliare grass-land on hilly land, Arundinella setosa grass-land on hilly land, Dicranopteris dichotoma grass-land on hilly land of low hills, Miscanthus sinensis grass-land on hilly land of mid-low hills, M. floridulus grass-land on hilly land …