Agronomy and Crop Sciences Commons^™

Canopy Characteristics, Ingestive Behaviour And Herbage Intake In Cultivated Tropical Grasslands, Lynn E. Sollenberger, J. C. Burns

IGC Proceedings (1977-2023)

Compared to temperate systems, there have been few detailed assessments of canopy characteristics and associated grazing behavior in planted tropical grasslands. Reasons include the large number of forage species used in warm climates, the diversity of their morphology, research priorities emphasizing germplasm evaluation and management, and limited resources. This review describes canopy attributes of C₄ grass pastures, highlights the most important relationships between grazing behavior and these canopy characteristics, and discusses the implications of canopy characteristics and grazing behavior for long-term intake and animal performance. It is suggested that the largest differences in canopy characteristics between tropical and temperate …

Foraging Behaviour And Intake In Temperate Cultivated Grasslands, S. Prache, J. L. Peyraud

IGC Proceedings (1977-2023)

In temperate areas, grazing provides a large part of the nutrient requirements of ruminants and may be an important form of land use. In Europe, grassland occupies some 150 million hectares, and grazing provides about 60 to 75% of the nutrient requirements of cattle (Wilkins and Vidrih 2000). From the end of the 80’s, agricultural surpluses in Europe have led to production quotas and increased interest in more extensive systems. At the beginning of the 90’s, the emergence of the notion of sustainable agriculture combining economic, social (concerns in dereliction of less-favoured rural areas), and environmental issues (pollution, loss of …

A Comparative Grazing Study Of Sheep And Cattle Diet Selection On Native Pastures In Uruguay, Fabio Montossi, G. Pigurina, E. J. Berretta, I. Santamarina

IGC Proceedings (1977-2023)

An experiment was carried out during winter, spring and summer 1997, on native pastures of the basaltic region of Uruguay to evaluate the effects of different herbage mass levels (high, medium and low) on sward characteristics and on sheep and cattle diet selection and grazing behaviour. Higher herbage masses resulted in increments in herbage accumulation and sheep bite weight: winter (1880, 1513 and 610 kg DM ha-1, P < 0.01; 199, 148 and 128 mg DM/bite, P < 0.01), and summer (3046, 2175 and 1172 kg DM ha-1, P < 0.01; 214, 175 and 143 mg DM/bite, P < 0.01) for high, medium and low herbage mass levels respectively. The nutritive value of diet selected by sheep and cattle was higher than that of the herbage on offer, and higher in sheep than in cattle: winter (10.2, 15.9 and 12.5% crude protein, CP, P < 0.05; 49.2, 32.4 and 38.1% acid detergent fiber, ADF, P < 0.01, and summer (7.4, 10 and 9.5% CP, P < 0.05; 51.1, 36.8 and 43% ADF, P < 0.01) for herbage on offer, sheep and cattle diets respectively. These contrasting results found in the nutritive value were closely associated with differences in the proportions of the botanical components recorded, particularly the differential contribution of dead material. This experiment quantified the importance of diet selection in determining the nutritive value of the forage eaten by sheep and cattle on the native pastures of the basaltic region of Uruguay and established some relationships between diet selection and grazing management, involving animal selectivity ability differences (sheep versus cattle) and seasonal effects.

A Sheep And Catlle Diet Selection Study On A Fertilized Native Sward In Uruguay, Fabio Montossi, E. J. Berretta, G. Pigurina, I. Santamarina

IGC Proceedings (1977-2023)

This study was undertaken during winter, spring and summer 1997, located in the basaltic region of Uruguay to evaluate the effects of stocking rate (SR) and N and P fertilizer application on sward characteristics and on sheep and cattle diet selection and grazing behaviour. The treatments applied were: a) control (C; without fertilizer application using a SR of 0.9 stock units (SU)/ha), b) T1 (with N and P fertilizer application using a SR of 0.9 SU/ha), c) T2 (with N and P fertilizer application using a SR of 1.2 SU/ha) and d) T3 (with N and P fertilizer application using …

Ingestive Behavior Of Beef Cattle Fed Either Protein Or Energy Supplements Under A Rotational Grazing System, R. P. Manzano, Luiz Gustavo Nussio, M. P. Andreucci, K. Z. Veiga, R. Z. M. Costa

IGC Proceedings (1977-2023)

Eight Nellore bullocks were assigned to a Tanzânia grass pasture (Panicum maximum Jacq.) under a rotational grazing system, to evaluate the ingestive behavior under two different grazing residues. Stocking rate intensity was used to reach either 1000 kg DM.ha^-1 (R1) or 4000 kg DM.ha^-1 (R2) as residual targets. Three grazing days followed by 33 days resting period, composed a 36 day grazing cycle. Each grazing plot supported four animals, in a 4x4 Latin square design, within the following supplementation rates and sources: S1 = no supplement; S2 = 2,0 kg DM.day^-1 coarsely ground corn - 8 …

Changes In Pasture Growth Rate Due To Fertiliser And Grazing Management, P. Quigley, D. Chapman, J. Lamb, G. Kearney

IGC Proceedings (1977-2023)

It is imperative that sheep production systems in southern Australia continue to be refined so producers remain financially viable but at the same time the environment is not degraded. As part of a national thrust for development and promotion of better production systems, one research site has been established in Victoria where pastures and animal production are measured together with water and nutrient movement. Results for pasture growth rates over two years are presented here and will be used to develop best industry practice at completion of the project.

2022 Western Australian Crop Sowing Guide, B. Shackley, B. Paynter, J. Bucat, M. Seymour, S. Power

Bulletins 4000 -

Welcome to the 2022 edition of the Crop Sowing Guide for WA, which introduces 27 new variety releases: three wheat, nine barley (three recently accredited for malt and six currently under malt evaluation), twelve canola, two field pea and a lentil.

The Crop Sowing Guide for WA has been compiled by officers in the Department of Primary Industries and Regional Development. It provides information to support variety decisions for each of the major crops for the upcoming season.

In this edition, lupin agzones have been reduced from 8 agzones to 6 so that all varieties for each of the major …

Grains, Seeds And Hay Industry Funding Scheme Annual Report 2020/2021, Department Of Primary Industries And Regional Development, Western Australia

Biosecurity published reports

The Grains, Seeds and Hay Industry Funding Scheme (IFS) has been operating since 2010 to address biosecurity threats relevant to Western Australia’s (WA) grains, seeds and hay industry. The Scheme was established under the Biosecurity and Agriculture Management Act 2007 to enable growers to identify the pest and disease priorities at a whole-of-industry level and raise funds for activities to address these priorities.

There are currently three Industry Funding Schemes in operation. In addition to the Grains, Seeds and Hay IFS, there is a Cattle IFS and a Sheep and Goat IFS. The three IFSs operate in a similar manner. …

Identification And Validation Of High Ld Hotspot Genomic Regions Harboring Stem Rust Resistant Genes On 1b, 2a (Sr38), And 7b Chromosomes In Wheat, Shamseldeen Eltaher, Amira M.I. Mourad, P Stephen Baenziger, Stephen Wegulo, Vikas Belamkar, Ahmed Sallam

Department of Agronomy and Horticulture: Faculty Publications

Stem rust caused by Puccinia graminis f. sp. tritici Eriks. is an important disease of common wheat globally. The production and cultivation of genetically resistant cultivars are one of the most successful and environmentally friendly ways to protect wheat against fungal pathogens. Seedling screening and genome-wide association study (GWAS) were used to determine the genetic diversity of wheat genotypes obtained on stem rust resistance loci. At the seedling stage, the reaction of the common stem rust race QFCSC in Nebraska was measured in a set of 212 genotypes from F3:6 lines. The results indicated that 184 genotypes (86.8%) had different …

Interaction Of Contact Herbicides And Timing Of Dicamba Exposure On Soybean, Mason C. Castner, Jason K. Norsworthy, L. Tom Barber, Trenton L. Roberts, Edward E. Gbur

Crop, Soil and Environmental Sciences Faculty Publications and Presentations

Dicamba residues in sprayers are difficult to remove and may interact with subsequent herbicides, including contact herbicides labeled for use in soybean. Without proper tank cleanout, applicators treating dicamba-resistant and non–dicamba resistant crops are at risk of contaminating the spray solution with dicamba residue from previous applications. Experiments were conducted in Fayetteville, AR, in 2018 and 2019, with the first experiment evaluating consequences of dicamba tank contamination with contact herbicides and the second experiment addressing the impact of dicamba exposure on a glufosinate-resistant soybean cultivar relative to a contact herbicide application. Experiments for tank contamination and timing of dicamba exposure …

Response Of Mixed C4 Grasses To Various Multiple Paddock Grazing Strategies, B. E. Anderson, W. H. Schacht

IGC Proceedings (1977-2023)

The botanical composition of mixed grass pastures may change during grazing due to the various grazing period/recovery period lengths associated with multiple-paddock grazing strategies. This 4-year study compared changes in relative species composition and basal plant cover of a C₄ grass mixture grazed using a nested paddock design to simulate 2, 4, 6 and 12- paddock grazing cells in eastern Nebraska. Total basal plant cover declined from 11.6% prior to grazing to 7.3% after one year of grazing and then remained nearly constant thereafter. Neither relative species composition nor basal density were affected greatly by grazing strategy. Within grazing …

Spatial And Time Distribution Of Dairy Cattle Manure In An Intensive Pasture System, S. L. White, S. P. Washburn, L. D. King, R. E. Sheffield, J. T. Green Jr.

IGC Proceedings (1977-2023)

This study determined distribution of feces and urine from dairy cattle managed in a rotationally grazed pasture. Lactating Holsteins (n=18) and Jerseys (n=18) were grazed on a .74 ha endophyte-free fescue (Festuca arundinacea)/white clover (Trifolium repens) pasture. All cows were constantly observed for 24 h 6 times over 12 mo. Cows had access to about 54% of the paddock during the first grazing period (12 h) and had access to the entire paddock during the second grazing period (8 h). Data included: (1) all feces and urine events from eight cows, observed while in the pasture, …

Test Of A Conversion Equation To Increase The Accuracy Of Microhistological Analysis Of Herbivore Diets In The Pantanal, S. A. Santos, C. Costa, A. Pott, J. M. Alvarez

IGC Proceedings (1977-2023)

Forty forage species samples were collected in September 1999, including grass, sedges, forbs, shrubs and trees. Seven hand-compounded mixtures of known botanical composition and dry weight were prepared. Five slides of each mixture were made and 20 frequency observations were recorded per slide. Two procedures were used to determine percent composition on a dry weight basis and their values were converted to correct the proportion of the unidentifiable fragments amongst species. Estimated and actual values differed significantly (P < 0.05) in 31.7%, 34.1%, 12.2% and 12.2% of the species for frequency addition (FA), density convertion (DC), frequency addition converted (FAC) and density convertion converted (DCC), respectively. The average similarity values between estimated and observed mixture were 90.2, 86.0, 94.2 and 93.3 for FA, DC, FAC and DCC, respectively. In conclusion, food habits by microscopic analysis may be described using any of the procedures tested because they rank important forage species for herbivores.

Effects Of Herbage Allowance Upon Animal Performance And Grazing Behavior Of Strip-Grazed Heifers, Claudio F. Machado, F. Di Croce, F. Gonzalez, H. Zeballos, N. J. Auza, M. H. Wade, S. T. Morris, J. Hodgson

IGC Proceedings (1977-2023)

A trial was designed to test the effect of herbage allowance (HA) on live-weight gain (LWG) and grazing behavior of heifers during spring as part of a combined field-modeling research programme. Low HA (L) and high HA (H) of 2.5 and 5.0 kg DM herbage mass 100 kg animal LW^-1day^-1 were fed respectively. H animals grazed longer and achieved a higher LWG than L (P < 0.05). H animals left a higher residual pasture (P < 0.051) with a significantly (P < 0.05) higher content of green, clover, non-lamina and petiole of a higher digestibility and NSC, with a lower NDF content. The significance of some factors involved in these results on intake and diet selection are discussed in relation to the predictability of animal performance.

Spatial Frameworks For Robust Estimation Of Yield Gaps, Juan I. Rattalino Edreira, José F. Andrade, Kenneth G. Cassman, Martin K. Ittersum, Marloes P. Van Loon, Patricio Grassini

Department of Agronomy and Horticulture: Faculty Publications

Food security interventions and policies need reliable estimates of crop production and the scope to enhance production on existing cropland. Here we assess the performance of two widely used ‘top-down’ gridded frameworks (Global Agro-ecological Zones and Agricultural Model Intercomparison and Improvement Project) versus an alternative ‘bottom-up’ approach (Global Yield Gap Atlas). The Global Yield Gap Atlas estimates extra production potential locally for a number of sites representing major breadbaskets and then upscales the results to larger spatial scales. We find that estimates from top-down frameworks are alarmingly unlikely, with estimated potential production being lower than current farm production at some …

Factors Influencing The Yield Proportions Of Plantago Lanceolata L. And Taraxacum Officinale Web. In Lolium Perenne L. Swards, Harald Laser

IGC Proceedings (1977-2023)

Diaspores of Plantago lanceolata and Taraxacum officinale respectively were sown in established Lolium perenne swards to determine the dynamics of their yield proportions during five years. The experimental factors were forb species, variety of the grass species (= early or late flowering), N-fertilization, and sward density. The amount of nitrogen fertilizer had the most important effect on yield proportions of the forb species and also on the total dry-matter (= DM) yield. The single creation of gaps in grass swards before sowing forbs had a lasting positive effect on the Plantago lanceolata and Taraxacum officinale proportions. Peak proportions of Taraxacum …

Dynamic Of Native Pasture Influenced By Deferment Of Grazing And Fertilization, K. E. Gomes, G. E. Maraschin, J. Riboldi

IGC Proceedings (1977-2023)

Native pastures of southern Brazil cover 12 million ha and are the main forage feed resource for most domestic livestock. However, their heavy and continuous use has reduced standing biomass and the presence of good forage species, reducing animal performance and jeopardizing the ecosystem sustainability. An alternative for better use of these pastures and their preservation is grazing deferment that allow natural reseeding. The objective of this research was evaluate native pasture dynamic after six years of grazing deferments (GD) periods and soil fertilization effects by point-quadrat method every season. All pasture components were affected by GD, with prostrate grasses …

Evaluation Of Plant Functional Types Response To Grazing And Fertilizer Levels In Natural Grassland, Zélia M. S. Castilhos, V. D. Pillar

IGC Proceedings (1977-2023)

We report a study on a natural grassland experiment with the objective of finding optimal plant functional types (PFTs) for the description of vegetation response to levels of grazing (ungrazed, grazed) and fertilizer (with, without). The experiment was a split-plot design in randomized blocks, with three replications and the grazing levels in the main plots. Vegetation description was based on species composition and on 12 plant morphology attributes (life-form, growth-form, stem tissue type, leaf cross section, leaf texture, leaf dorsal epidermal surface, leaf ventral epidermal surface, spininess, leaf resistance, leaf width, plant height). Cover-abundance of species was visually estimated. By …

Mountain Pastures Structure And Its Relationship With Grazing, I. Albizu, S. Mendarte, G. Besga, I. Amezaga, M. Onaindia

IGC Proceedings (1977-2023)

The present work aims toward an approach to mountain pastures as a system of relationships in which it is needed to point out those environmental factors that reflect more clearly their structure and potential productivity. This initial step of pasture tipification is important as a previous activity before the planning and management of protected areas because these areas support an intensive pastoral activity. In order to achieve this objective a field study was conducted in two areas in the Gorbeia Natural Park (Bizkaia): Arraba and Aldamiñape, located at 900-1100 masl. In each pasture four plots were selected according to orientation …

Structure And Function Vegetation Conditions By Grazing Processes In A Humid Pampean Grassland (Argentina), O. E. Ansín, Estrella M. Oyhamburu, E. A. Hoffmann, M. A. Eirin

IGC Proceedings (1977-2023)

Expressed changes were evaluated as consequence of the cattle grazing, or their exclusion, in the structure of plant communities of the Flooding Pampa. We center our interest in the species numbers, plant cover, species diversity and forage availability. The treatments were: a) continuous grazing, b) enclosure grazing and c) controlled grazing. The enclosure grazing area was installed two years before starting the measurements. In the continuous grazing St. Augustine grass (Stenotaphrum secundatum Walt.) holds its initial cover of 64 % and dallis grass (Paspalum dilatatum Poir.) the 15 %. In the enclosure grazing S. secundatum decreased its cover …