Weed Science Commons^™

An Effective P Application Method For Dactylis Glomerata, M Hojito, A Nishimune, M Noshiro

IGC Proceedings (1977-2023)

There are two practical ways to apply phosphorus (P) fertil­izer on cutting type grasslands in Hokkaido, Japan. The first one is to apply P at a rate of about I 00 kg P2Os/ha in the spring (April) in one application. Some reasons for this method have been explained (Hayakawa et al., 1951). However, in some cases, it is more convenient for practical management to apply three equal amounts of P, at three different times during the year (April, June and August) the same as other fertilizers such as nitrogen or potassium. That is a second way. Grassland soil is acidified …

Distribution Of Phosphorus And Aluminum In Acidic Pasture Soils And Effects On Growth Of Subterranean Clover, M J. Mclaughlin, T R. James

IGC Proceedings (1977-2023)

In south-eastern Australia, pasture improvement and the use of superphosphate fertilizers have resulted in the gradual acidi­fication of many soils under subterranean clover pastures (Wil­liams, 1980). Despite high values of exchangeable and extract­able aluminium (and low pH) recorded in many soils, there are few reports of significant responses of clover growth to lime application in the field. In this study we examined the vertical distribution of CaCb-extractable aluminium (Al) and available phosphorus (Bray P) in pasture topsoils. We also simulated the conditions in the field sites by investigating in solution culture the response of subterranean clover to various concentrations of …

Relations Entre Facteur Hydrique, Drainage Er Evolution De La Flore Des Prairies En Lorraine, S Oberle, S Plantureux, R Bonischot, A Guckert

IGC Proceedings (1977-2023)

Une part non negligeable (plus de 50 %) des Surfaces Agri­coles lorraines est occupee par des prairies permanentes. Or, nombre de ces dernieres souffrent d'exces d'eau qui limitent gravement leur productivite. Le developpement recent d'opera­tion de drainage offre la possibilite de lever un facteur limitant et, ce faisant, d'augmenter significativement la qualite et la quantite du fourrage produit. Il convient toutefois de rappeler que Jes prairies permanentes sont constituees d'un ensemble d'especes vegetales en equilibre avec leur milieu ecologique. la perturbation de ce dernier, en !'occurrence la modification du regime hydrique, va entrainer la mise en place progressive d'un nouvel …

Influence Of Sulfur And Nitrogen On Bahiagrass, J E. Rechcigl, G G. Payne, R J. Stephenson

IGC Proceedings (1977-2023)

One of the most important forage crops grown in Florida is bahiagrass, with nearly 1 million ha grown annually. Bahia­grass is found on more acres than all other improved grass pastures combined. Average annual dry matter yields for bahiagrass range from 9 - 16 t/ha. Bahiagrass is adapted to most climatic conditions throughout the state and can be grown on upland well drained sands as well as poorly drained « flatwoods » soils. Until recently, little attention has been focused on the need for S fertilization for plant growth. This is understandable since, in the past fertilizers were contaminated with …

The Depletion Of Soil K As Affected By Fertilization Of Eragrostis Curvula Used For Hay Production, N.F G. Rethman, C C. De Witt

IGC Proceedings (1977-2023)

Eragrostis curvula is widely planted as a hay crop in the summer rainfall areas of South Africa. For many years the main yield determinants have been regarded as N and P. As a result of the depleting effect of crop removal low K status is becoming more common. The beneficial effect of K fertiliz­ation, in combination with N, has been illustrated by Miles et al. (1986) and Rethman and De Witt (1839). Information on the rate of build up and/or depletion of soil K under different fertilization regimes is, however, required to facilitate the plan­ning of fertilization strategies. The monitoring …

Studies On The Macropores Structure Of Grassland's Soil, K Sato, K Tokunaga

IGC Proceedings (1977-2023)

The purpose of this study is to examine the structure of macroporous soils which allows better aeration, water reten­tion and drainage. Previous investigations of macroporous soils have dealt with drainage (McIntyre and Sleeman, 1982), void forms (Tippkotter, 1983; Walker and Trudgill, 1983) and X-ray radiography (Rogaar, H. and R.A.H. Thiadens, 1975). Analyses of these studies have not proved sucessful to explain the effect of the soil structure as regards water retention and drainage. Therefore, the present study was designed to deter­mine the structure of macroporous soils by use of soft X-ray radiography and soil physical properties. Tokunaga et al.,(1984, 1986, …

Study Of Some Factors That Influence Upon P Fertilization On Pastures From Red Ferralitic Soil, Marta Hernandez, A R. Mesa

IGC Proceedings (1977-2023)

The importance of P for vegetal nutrition has been a topic of study for several workers. However, results obtained have not always been positive using P fertilizer due to some factors such as the content of this nutrient in the soil and its fixation capacity. This study was conducted in order to evaluate the response of guinea grass cv. Likoni and buffel grass cv. Biloela to P fertil­ization. These pastures were selected due to their favourable behaviour and the different levels of exigency to P that they pre­sent.

An International Perspective Of Dairying In New Zealand, M Murphy

IGC Proceedings (1977-2023)

It is often said that the New Zealand dairy industry is the most low­cost efficient industry of the main dairy industries world wide. I am certainly not going to put a case against the New Zealand dairy industry today but I am going to look at it from a slightly different perspective to Ireland. Is the industry low cost, efficient? How do you measure that? I nm going to give a personal view on some of the strengths and weaknesses. I am going to suggest that there are some surprising weaknesses in an otherwise extremely efficient industry and I am …

Factors Influencing The Availability Of Soil Cobalt And Its Uptake By Herbage, J E. Paterson, D A. Klessa, A Macpherson

IGC Proceedings (1977-2023)

Severe cobalt (Co) deficiency is now rare in Scotland but subclinical deficiency, although difficult to diagnose, is com­monly thought to be reducing the profitability of many sheep and beef farms (COSAC/SARI, 1982). By understanding the factors which determine herbage Co content and Co availablity to ruminants, areas at risk may be predicted and preventative measures taken. To this end, a series of field and laboratory experiments were investigated:

Co adsorption and desorption characteristic of soils. Effects of fertiliser N on herbage Co content. Response of pasture and grazing ruminants to applied Co fertiliser.

Variations Saisonnieres De La Croissance D'Une Prairie De Setaria Anceps En Guadeloupe, P Cruz, O Sobesky

IGC Proceedings (1977-2023)

La production des cultures fourrageres en zones tropicales est frequemment modifiee par des effets saisonniers. Le deficit hydrique, la photoperiode et la temperature peuvent etre a l'origine de ces variations mais seulement le premier facteur peut etre controle a l'echelle d'une parcelle. L'effet de la photo­periode est bien connu sur des plantes stoloniferes comme le Pangola, lequel reduit fortement sa croissance pendant la saison de jours courts (Salette, 1971; Cruz et al., 1989). Parmi certaines plantes a talles (Crespo, 1986) des variations plus fai­bles sont rapportees mais sans faire la part de l'effet des basses temperatures. L'objectif de ce travail …

Relationships Between Root Morphology And Nutrient Uptake In Winter-Flooded Mediterranean Grasslands, A J. Hernandez, J Pastor

IGC Proceedings (1977-2023)

One of the functions of roots directly related to the environ­ment is that of uptake. However, since legume are worse competitors than grasses for nutrients and water, root mor­phology may be an important factor in this competition in grassland systems. This has been very interesting for the study of the dynamics of flooded pastures in West-Central Spain. Their main root characteristics were studied in a previous paper (Hernandez and Pastor, 1988). Now we intend to approach the knowledge of the relationships between root morphology and nutrient uptake.

Effect Of Soil Moisture On The Growth And Development Of Seedlings Of Some Grass Species, J Jargiello, Wanda Harkot

IGC Proceedings (1977-2023)

Soil moisture in the upper layer is one of the fundamental factors favouring successful grass seeding. In our country, especially difficult conditions of germination and growth of seedlings can be observed on muck-peat soils, particularly on those of degraded, easily drying muck (Kowalczyk and Okruszko, 1973). Studies ofRoguska-Wasilewska (1960) point out that the grass ventilation system is not the same in all the species, which differentiates their resistance to soil overdrying. The aim of the studies was to determine the effect of muck­peat soil moisture in its upper layer on some morphological features of seedlings of some grass species and …

The Above Ground And Root Production Of Grass On Different Soils, Sophia Toth

IGC Proceedings (1977-2023)

The total DM production of grass involves the above ground and root yields. The special literature mainly focuses on utiliza­ble grass yields while details of root production are less avail­able. The latter data show that grass annually produces large amounts of root improving the soil characteristics thereby. Very few results are available of the DM yield of grass on different soils under uniform ecological conditions. In Hungary soils under grass show a fairly diversified pic­ture, ranging from sands to heavy clay soils (solonchak, solonetz). In our experiment we investigated the effects of different soils and fertilization on the total DM …

Response Of Forage Oats To Nitrogen Fertilizer In High And Low Fertility Soils, N Moreira

IGC Proceedings (1977-2023)

Forage oats are used extensively as whole-crop in rainfed areas of Portugal as is traditional in Mediterranean areas. They are cropped with minimum inputs, and increasingly in mixtures with annual legumes such as Vivia sativa (Moreira, 1989). In addition to the fact that relatively low yields are obtained in these conditions, the oats harvested during grain filling have a very low crude protein content, which severely limits their nutritive value (Eagles et al., 1979; Abreu et al., 1982). The aim of the present study is to determine the effects of nitrogen fertilizer on whole-crop forage oats in terms of dry­matter …

Lowering Cocksfoot Yields Caused By Manganese Toxicity And Molybdenum Deficiency Caused By Acidifying Effect Of Ammonium Nitrate Application, H Gembrazewski, Urszula Sienkiewicz

IGC Proceedings (1977-2023)

In the case of cocksfoot (Dactylis glomerata L.) cultivation in monoculture or its domination as a result of high N level further regrowth yields decrease is often observed. This situ­ation also takes place on fertile soils and during years with good precipitation amounts. Similarly in pot experiments with optimal water and nutrients-N.P.K.-supply, this phenomenon also takes place. According to many research works, N application systemati­cally acidifies the treated soil. In Poland 60 % of soils are acid ones (pHKcl < 5,6). Sandy soils dominating in Poland are poor organic matter and they possess low buffering capacity. They are not resistant to acidifying effect of nitrogen fertilization which, besides bio­logical oldering of plants, can be the reason of yields lowering in further harvests. Lowering of soil reaction strongly effects micronutrients availability to plants to which its insufficiency or surplus is harmful. The problem of Mn toxicity and Mo insufficiency on acid soils is often discussed. The aim of the present research is to investigate the influence of increasing rates of commonly used N source - ammonium nitrate - on the yield and chemical composition of cocksfoot.

Rendement Des Prairies Dans Les Marais De L'Ouest De La France. Diagnostic Des Insuffisances Minerales, Y Pons, E Lafon

IGC Proceedings (1977-2023)

Situes sur la cote atlantique entre la Vilaine au Nord et la Gironde au Sud, !es Marais de l'Ouest s'etendent sur 250 000 ha environ. Ils resultent du comblement d'un golfe marin par des alluvions fluviomarines argileuses. La prairie est la production obligatoire lorsque !es contraintes hydrauliques ne sont pas maitrisables ou lorsque le cout d'amenagement est prohibitif. C'est le cas d'une part des marais "mouilles" qui sont soumis aux crues des rivieres (sols tourbeux et argileux) et d'autre part des marais desseches lorsque !es sols sont sodiques et done tres instables. L'objectif de l'etude est d'expliquer !es ecarts de …

A Time For Change- Issues Arising From The Xvii International Grassland Congress Developed World Viewpoint, Barney Foran

IGC Proceedings (1977-2023)

A number of major issues raised at the conference, if they are accepted by farmers and grassland scientists, will mean a major realignment of both the philosophy and practice of grassland science. The first of these is future world trade flows and a bleak prognosis for traded livestock products. Jf the developed world accepts that developing nations have to trade in order to develop, and trade in commodities where they have a cost advantage, this suggests that bulk production of livestock commodities will decline ln total. Thus grassland exports will have to concentrate on high value niche markets. This poses …

Congress Outlook From The Developing Countries' Perspective, Bede N. Okigbo

IGC Proceedings (1977-2023)

In this XVII International Grassland Congress, which is now successfully drawing to a close, we are all very grateful for the opportunity to participate and enjoy the hospitality of our New Zealand and Australian hosts. Above everything else, we have benefited much more from attending than we have individually contributed to its success in various ways.

Water Balance And Soil Fertility Characteristics Of Brigalow (Acacia Harpophylla) Lands Before And After Forest Clearing, Paul A. Lawrence, B A. Cowie, D Yule, P J. Thorburn

IGC Proceedings (1977-2023)

A multidisciplinary study was undertaken to investigate the changes in catchment runoff, groundwater recharge and soil fertility after the complete removal of brigalow (Acacia harpophylla) forest for buffet grass pasture. Clearing brlgalow for pasture increased runoff amount by 21 mm/year; however, runoff represented a·· small (11-14%) component of the annual water balance. An increase in groundwater recharge immediately after clearing was not sustained once the pasture was established. Clearing did not alter the annual water balance, evapotranspiration taking 90% of annual rainfall, Clearing and burning• caused a flush of plant available N, P and K but this was …

Successional Dynamics Of An Acacia Savanna In Southern Africa, C. Richard Hurt, Richard I. Yeaton

IGC Proceedings (1977-2023)

Acacia-dominated savannas iii southern Africa are ·maintained by disturbance. Wheri ihese ecosystems are managed as pastoral systems, the disturbance regime is altered, • arid the· successional sequence proceeds to broad-leafed woodland. We examined changes in woody species composition over a soil catena, and used sliccessional stages within an acacia-dominated community to develop a Markov model of the dynamics of the system. We used this model to simulate 2 management scenarios and to make predictions · of associated community changes over time.

Deforestation In Pakistan, Inayat U. Chaudhry

IGC Proceedings (1977-2023)

Pakistan's economy is agricultural and pastoral. From 1150 to 1991 its forest cover declined from an estimated 28 million ha to 4,6 million ha and population increased from 1.2 to 112 million. rn addition to. increasing population, government irrigation projects for colonisation, in road of agriculture into forestry and construction of barrages over rivers caused deforestation. This has increased soil erosion, siltation of dams and the gap in production and demand of wood: biodiversity has been adversely affected and mangrove forests have degraded. Forestation has been carried out over 220 000 ha since 1947. A network of easily accessible nurseries, …

Animal Production From Tropical Semi-Arid Savannah Woodland In Subcoastal Queensland, Australia, H G. Bishop, H J. Chamberlain, R M. Dodt, T B. Hilder, G A. Lambert, E R. Anderson

IGC Proceedings (1977-2023)

Annual live-weight gain of steers grazing on virgin tropical semi­arid poplar box (Eucalyptus populnea) savannah woodland in subcoastal central Queensland fluctuated between 59 kg/head and 200 kg/head over a 7-year period. Average live-weight gain for the 7 years was 136 kg/head/year, which is above expected levels for this vegetation type. Reasons suggested for this animal performance are the use of a stocking rate more lenient than the district average and above-average winter rainfall received during the 7 years of this demonstration project. Removing trees doubled the pasture dry matter yield, which subsequently allowed a doubling of stocking rate …

Forage Production From In Situ Herbicide Treatment Of Semi-Arid Woodlands And Scrub Regrowth, A R. Murphy, C O. Love, G W. Fossett

IGC Proceedings (1977-2023)

The response of native pastures after stem injection of eucalypt woodlands with picloram-triclopyr herbicide in 1986 was Investigated at 2 locations in Queensland over 18 months, Treatments were fenced to exclude half the plots from grazing by cattle. At Rolleston (good rainfall) dry matter grass response from grazed and ungrazed plots was 2- to 3-fold more than in untreated plots 4-18 months after treatment. At Mundubbera (low rainfall) picloram-triclopyr gave 2- to 5-fold increases in grass dry matter 3-18 months in ungrazed plots and 3-9 months in grazed plots. At both sites plclorarn-triclopyr gave quicker nnd greater grass response than …

Evaluation Of Animal Productivity And Pasture Yield After Treatment Of Brigalow (Acacia Harpopylla) Regrowth With Tebuthiuron, G W. Fossett, P C. Venamore

IGC Proceedings (1977-2023)

Brigalow (Acacia harpophylla) regrowth was aerially treated with 2.0 kg/ha tebuthiuron (Graslan TM) at Blackwater, Australia in November 1989. Control of brigalow regrowth increased in grass production 2- fold, which resulted in dramatic animal live-weight gains. The live­weight advantage of steers grazing the tebuthiuron treated area was 31 kg/head compared with similar steers grazing the control paddock at similar stocking rates. After 20 months this advantage enabled 44% of stock to be marketed at premlum prices. A subset of steers implanted with a long-term hormonal growth promotant (HGP) (Compudose400™) and grazing the tebuthiuron-treated paddock recorded a 75 kg …

Competitive Effects Of Trees On Pasture Are A Function Of Rainfall Distribution And Soil Depth, J C. Scanlan, G M. Mckeon

IGC Proceedings (1977-2023)

A pasture production model was modified to account for the effect of tree water use on pasture production in woodlands of norJhern Australia. Simulation experiments with the model indicate that competition for water explains the effect of trees on pasture production. Trees compete for water most strongly (I) in shallow soils; (2) when tree roots are shallow; and (3) when intra-seasonal dry periods reduce the amount of water available for transpiration.

Deforestation In The Savanna Context: Problems And Benefits For Pastoralism, W H. Burrows

IGC Proceedings (1977-2023)

Deforestation is discussed from a savanna perspective, rather than in the usual rain forest connotation. Reasons for removing trees and shrubs from savannas are outlined with emphasis placed on the impacts that tree clearing has on livestock production. Other benefits and possible adverse consequences of removing woody plants are detailed. It is suggested that the importance of trees ln maintafning nutrient flows in grazed savanna may be overstated. Problems that arise from clearing trees from savannas often result from a lack of preclearing planning or post-clearing management, rather than the clearing operation Itself.

Deforestation For Pasture In The Humid Tropics: Is It Economically And Environmentally Sound In The Long Term?, E Adilson Serrao, C Uhl, D C. Nepstad

IGC Proceedings (1977-2023)

During the past 5 decades, the rate of tropical forest conversion has accelerated in response to economic pressures, population growth, technological development, and prpgrammes and incentives to open land for development. Deforestation rates rose substantially through the I 980s, and were highest in Africa ( 1.7% ), followed by Asia (1.4%) and Latin America (0.9%). The greatest extent of deforestation, however, was In Latin America, especially in the Amazon, where much of the deforestation was for pasture-based cattle development. Although forest conversion for ranching has been routinely criticised because of the ecological and socioeconomic implications associated with it, cattle herds …

A Legume Ley System In Australia's Semi-Arid Tropics, R L. Mccown, K Thiagalingam, T Price, P S. Carberry, R K. Jones, N P. Dagliesh, D.C I. Peake

IGC Proceedings (1977-2023)

A large part of the Australian continent is semi-arid and tropical. While extensive beef cattle grazing is the most significant agricultural industry in this region, there Is some potential for dryland cropping. There are strong economic and- ecological reasons for exploring the possibility of a no-till tropical ley system. Work at Katherine, Northern Territory, found that a ley system based on Stylosanthes hamata cv. Verano showed considerable promise based on both contributions to dry-season animal performance and nitrogen contribution to succeeding coarse grain crops. Subsequent research and development in the wetter Douglas-Daly district of the Northern Territory has demonstrated even …

Hardseededness Of Medicago Polymorpha Under Field Conditions In The Subhumid Mediterranean Zone Of Chile, Julia R. Avendano, Alejandro L. Del Pozo, Carlos M. Ovalle

IGC Proceedings (1977-2023)

To improve knowledge in the establishment and self-regeneration of medics grown in rotation with wheat in Chile, the long-term ambiental softening of medic seed is being studied. In March, (i) 72 samples of 100 pods each, were broadcast on the soil surface In plots of 20x20 cm, surrounded by a wood frame, and (ii) 12 samples were placed in a similar way, but the pods were buried at 1-2 ·cm. /11 sitr,, or field germination was recorded, and the germinated seeds destroyed. In (i), every 2 months during the first to fourlh softening season (SS), and in (ii), each March …

Role Of Gramineous Species In Cereal-Annual Legume Farming Systems, G N. Roberts, P G. Tow, E D. Carter

IGC Proceedings (1977-2023)

Three pasture types (volunteer annual grass+medic, grass-free medic and oat+volunteer grass+medic) were compared at 2 stocking rates (8.4 and 12.6 DSE) with grazing Merino wethers. The oat variety is resistnnt to both Gaeumannomyces graminis (take-all) and Heterodem avenae (cereal cyst nematode), important root diseases of cereals. Four harvests were taken during early winter. The oat + grass + medic pasture type had a faster growth rate and maintained higher levels of available pasture on all sampling occasions (July to September). The yields of the grass and medic components were significantly reduced in the oat+grass+medic treatment from the second harvest onwards. …