Canopy Changes In Healthlands (Erica-Ulex) Grazed By Sheep Or Goats,
2024
CIATA, Spain
Canopy Changes In Healthlands (Erica-Ulex) Grazed By Sheep Or Goats, R Celaya, K Osoro
IGC Proceedings (1997-2023)
The grazing effects of sheep and goats on vegetation dominated by heaths (Erica spp) and gorse (Ulex gallii) were studied for two years. Two plots were grazed from May to October 1992 by 7 ewes or 7 does and in the following year each plot was subdivided into two subplots subsequently grazed either by sheep or by goats in a factorial design. During the first grazing season both sheep and goats reduced similarly the cover percentage of shrubs since the herbaceous content was scarce, although goats reduced more the height of the shrubs than sheep. The cover …
Effect Of Nitrogen, Phosphorus, Potassium And Cutting On The Regrowth And Insect Infestation Of A Sorghum And Berseem Clover In Egypt,
2024
Menoufia University
Effect Of Nitrogen, Phosphorus, Potassium And Cutting On The Regrowth And Insect Infestation Of A Sorghum And Berseem Clover In Egypt, M B. Attia
IGC Proceedings (1997-2023)
The objective of this study was to determine the minimum quantities of phosphorus and potassium which must be applied with varying amounts of nitrogen in order to maintain maximum hay production and minimum level of insect infestation. This was more pronounced at the higher N rates and caused a significant N x K interaction during each of these years. There was no yield response to applied phosphorus at any N rate. Relation between levels of nitrogen and infestation percentage was positive but infestation rate decreased with the increase of potassium levels while there was no relation between levels of phosphorus …
An Overview Of The Physiology And Biochemistry Of N Reserves Mobilization In Forage Species,
2024
Universite de Caen, France
An Overview Of The Physiology And Biochemistry Of N Reserves Mobilization In Forage Species, F Le Dily, A Ourry, J Boucaud
IGC Proceedings (1997-2023)
Recent works focusing on the physiological and biochemical events associated to perennial forages sustainability (re-growth after defoliation, winter survival), provided evidence that vegetative storage proteins (VSPs, ca proteins stored in remaining organs and specifically mobilized) were key organic compounds for shoot regrowth. Attempts to elucidate environmental conditions involved in VSPs deposit ability of different species are under progress today. In contrast, mechanisms of spring- or cut-induced proteolysis are investigated at a lesser extend. This contribution is an opportunity to summarize our knowledge of N-reserves mobilization and to set the question of VSPs breakdown regulation.
Intraspecific Competition In Lucerne And Relationships With Reserve Availability,
2024
INRA, I.R.B.A, France
Intraspecific Competition In Lucerne And Relationships With Reserve Availability, Jean Christophe Avice, Alain Ourry, Gilles Lemaire, Jeffrey J. Volenec, Jean Boucaud
IGC Proceedings (1997-2023)
Below-ground reserves are thought to provide an indication of a forage potential for shoot regrowth after defoliation. The aim of this work was to re-evaluate the causal relationships existing between organic reserves (non-structural carbohydrates and N reserves) and shoot regrowth of alfalfa. The variations brought about by cultivar differences (cv Lodi or Europe), length of the previous regrowth period (30 or 45 d), or by intraspecific competition for light within a dense canopy, were studied. Field grown plants were harvested at weekly intervals, and separated as dominant, intermediate and suppressed plants. Shoot regrowth yield was determined and taproot were analyzed …
Seasonal Fluctuations Of Vegetative Storage Proteins And Starch Concentrations In Stolons Of Trifolium Repens L.,
2024
Universite Caen cedex, France
Seasonal Fluctuations Of Vegetative Storage Proteins And Starch Concentrations In Stolons Of Trifolium Repens L., V Bouchart, A Ourry, J C. Simon, J Boucaud
IGC Proceedings (1997-2023)
The seasonal pattern of nitrogen, starch and vegetative storage protein (VSP) concentrations was studied in the stolons of two Trifolium repens L. genotypes (cv Aran and Rivendel). Maximum concentrations of starch were found in summer months; its hydrolysis occurred in winter, at the time, where VSP and nitrogen were accumulated. The decrease of nitrogen and VSP concentrations occurred during spring, and an inverse relationship was found between VSP concentrations in stolons and mean temperatures. The causal implications of starch and VSP availability on spring regrowth potential are discussed in relation with regulatory mechanism inducing VSP synthesis.
Cynodon Dactylon Control In Conservation Tillage Systems,
2024
INIA La Estanzuela
Cynodon Dactylon Control In Conservation Tillage Systems, A Rios, J M. Sanz
IGC Proceedings (1997-2023)
Bermudagrass (Cynodon dactylon L. PERS.) is the most important weed in Uruguay. With the development of conservation tillage systems, chemical control of bermudagrass becomes essential. The objective of this research was to evaluate, in a long term integrated program, bermudagrass chemical control during the first year of a pasture. Application of glyphosate and no-tillage seeding of the pasture took place during fall. A 70% reduction of underground part of the weed was detected. The chemical control, together with a conservation tillage system and an adequate pasture management allowed an important reduction in bermudagrass level for the first year pasture. …
Legume Seedling Development In No Till Pasture Establishment,
2024
Buenos Aires University
Legume Seedling Development In No Till Pasture Establishment, J L. Rossi, V A. Deregibus
IGC Proceedings (1997-2023)
The objective of this study was to compare no-till and conventional seeding of pasture and their effects on legume establishment. The presence of residue cover reduced legume seedling establishment and weed population under no-till seeding. The reduction in establishment was associated with the physical impediment of the residue cover and the decay of seedling vigor when passing through that cover.
Water Relations In Berseem Cultivars Under Drought Stress,
2024
Instituto Sperimentale Colture Foraggere
Water Relations In Berseem Cultivars Under Drought Stress, A Iannucci, A Rascio, M Russo, P Martiniello
IGC Proceedings (1997-2023)
Berseem clover (Trifolium alexandrinum L.) is a crop of particular interest in semi-arid regions, used for herbage and hay productions. However, its seed yield is reduced by drought stress that occurs during seed filling. In this study five cultivars (Axi, Big Bee, Lilibeo, Sacromonte and Saniros) subjected to four irrigation frequencies in controlled environment, were compared for their physiological responses to subsequent water stress period (3 days). Some parameters (leaf water potential (), osmotic potential (þ), relative water content (RWC) and gravimetric soil water content (GSWC)) related to plant water status were recorded. Plants subjected to previous periods of …
Modelling The Effect Of A Variable Light Extinction Coefficient And Leaf Dispersion On Light Partitioning Between Species In A Grass-Clover Mixture,
2024
Wageningen Agricultural University
Modelling The Effect Of A Variable Light Extinction Coefficient And Leaf Dispersion On Light Partitioning Between Species In A Grass-Clover Mixture, M Nassiri, A Elgersma
IGC Proceedings (1997-2023)
Light partitioning in a grass-clover mixture was studied using a general competition model. The model assumes a fixed extinction coefficient (k) and no leaf dispersion. This was compared with modelling the effect of different k of both species over height as well as the effect of type of leaf dispersion. These new assumptions led to a better estimation of the light partitioning between both species. For grass the effect of variable k and leaf dispersion was similar and in both cases the total absorbed light was lower than under default conditions. For clover the new assumptions led to a higher …
Ecotypic Adaptation Of Medicago Polymorpha Along A Gradient In Central Chile: Growth And Seed Production,
2024
INIA, Chile
Ecotypic Adaptation Of Medicago Polymorpha Along A Gradient In Central Chile: Growth And Seed Production, A Del Pozo, C Ovalle, J Avendano
IGC Proceedings (1997-2023)
Relative growth rate, total dry weight and seed yield on 19 accessions of burr medic (Medicago polymorpha L.) from different bioclimatic conditions, were assessed at Cauquenes (35°58’;72°17’W) in the subhumid mediterranean region. The accessions were sown in microplots over raised beds during two years (1991 and 1992), and swards cut periodically at 2, 6 and 10 cm height. There were significant differences between accessions in both total dry weight and seed yield (P < 0.001, Table 1), but the interaction between accessions and height of cutting was not significant (P > 0.05). Total dry weight was positive correlated with days to flowering (r2 = 0.81; P > 0.01).
Effects Of Nitrogen On The Growth Of Hyparrhenia Diplandra,
2024
Brazzaville, Congo
Effects Of Nitrogen On The Growth Of Hyparrhenia Diplandra, J Nkandza
IGC Proceedings (1997-2023)
The nitrogen effects on Hyparrhenia diplandra were studied. Plants were grown on nutrient solutions of variable concentrations in nitrogen. The supplied nitrogen increased tillering, leaf production, lamina area, total dry matter accumulation and total nitrogen accumulation in lamina. A detailed examination showed that the effect on tillering was the main cause of the differences observed in dry weights between different treatments. The nitrogen supply elongated significantly the lamina and nitrogen deficiency increased its thickness; but this was not enough to compensate the loss of weight in lower nitrogen treatment. The lamina area as well as nitrogen accumulation in the lamina …
Biochemical And Isoenzyme Analysis Of Seven Pennisetum Purpureum (Schum.) Cultivars,
2024
Instituto Biologico
Biochemical And Isoenzyme Analysis Of Seven Pennisetum Purpureum (Schum.) Cultivars, E E. Bach, V B.G. Alacantara, P B. Alcntara, E A. Veasey
IGC Proceedings (1997-2023)
This study characterized seven Pennisetum purpureum cultivars, namely cv. Anão, Bajra, Cameroon, Guaçu, Roxo, Taiwan A-144 and Uruckwami, through biochemical analysis, including protein, glucose and fructose contents, and polyacrylamide gel electrophoresis using the esterase system, by sampling 30, 60, 90, 120 and 150 dayold leaves. Cultivar Taiwan A-144 presented the highest number of nodes per stem and percentage of emerging buds. Protein concentration decreased gradually after 60 days for all cultivars, except for Anão. Cultivar Guaçu presented the highest level of glucose in 90 day old plants, whereas Cameroon presented the highest levels at 120 and 150 days. The esterase …
Effect Of Phosphorous Fertiliser On The Competition Between Two Tropical Grasses And Two Tropical Legumes,
2024
CSIRO, Australia
Effect Of Phosphorous Fertiliser On The Competition Between Two Tropical Grasses And Two Tropical Legumes, F D. Hu, R J. Jones
IGC Proceedings (1997-2023)
The effect of P fertiliser on the competition between grass and legume in four grass-legume mixtures : Urochloa mosambicensis cv. Nixon/ Stylosanthes hamata cv. Verano; Nixon/S.scabra cv. Seca; Bothriochloa pertusa cv. Bowen/Verano and Bowen/Seca were studied. Each mixture was grown in a low P, low N soil, in pots. A standard replacement series design with two P levels (0 and 10 kg/ ha equivalent) and 3 replicates were used. Seventy days after sowing, Nixon mixtures outyielded Bowen mixtures, and Verano mixtures outyielded Seca mixtures. P increased top and root yields of all mixtures but there was no significant (p …
Selection And Agronomic Characterization Of Leucaena Spp. Genotypes For Cold Tolerance. I. Dry Matter Yield.,
2024
INTA, Argentina
Selection And Agronomic Characterization Of Leucaena Spp. Genotypes For Cold Tolerance. I. Dry Matter Yield., M C. Goldfarb, J F. Casco
IGC Proceedings (1997-2023)
Biotypes of Leucaena spp (56) were evaluated in order to identify those with tolerance to low temperature and with desirable characteristics as a forage crop. Selection was done at two phases. Phase I: 92 days old seedlings (n=2800) were subjected at two temperatures treatments during 14 hours: T1= -8 °C and T2= -3 °C. Selection criteria was established as 50% of live leaves remained after treatments were applied. Phase II: Plants that survived phase I were planted at field conditions and agronomic characteristics were measured. Seventeen plants were selected from eleven different biotypes, resulting one from T1 and the rest …
Effect Of Snowtrapping And Fertilization On Production Of Crested Wheatgrass And Native Pastures In Southwest Saskatchewan,
2024
Agriculture and AgriFood Canada
Effect Of Snowtrapping And Fertilization On Production Of Crested Wheatgrass And Native Pastures In Southwest Saskatchewan, M P. Schellenberg, J Waddington
IGC Proceedings (1997-2023)
The benefits of increasing soil water with snow management and fertilizer for annual and perennial crops have been demonstrated for semiarid environments. We examined the combined effect of snow management and fertilizer on forage production. In 1985, vertical wood slat or slotted plastic snow fencing (0.7m high) were erected on crested wheatgrass (Agropyron cristatum) pasture. In 1986, five rates of fertilizer: 400, 200, 100, 50, 0 kg ha-1 nitrogen each with 50 kg ha-1 phosphorous and a sixth treatment with no fertilizer were applied to each side and type of the snowfence. A second site was selected on …
Light Quality Effects On Grass Seedling Growth And Development,
2024
Agriculture and AgriFood Canada
Light Quality Effects On Grass Seedling Growth And Development, P G. Jefferson, R Muri
IGC Proceedings (1997-2023)
The poor establishment success of Russian wildrye (Psathyrostachys juncea Fisch. Nevski) limits its use. Our hypothesis was that Russian wildrye (RWR) was more sensitive to light competition than crested wheatgrass (Agropyron desertorum Fischer ex Link) or Dahurian wildrye (Elymus dahuricus Turcz. Ex Grieseb.). Seedlings were grown under plastic filters that altered both quantity and quality of light. Tiller counts, leaf counts, leaf area, light intensity and red:farred light ratio (above and beside each seedling) were recorded each week for four weeks after planting. Seedling dry weights were determined at four weeks. Low light intensity significantly reduced tiller …
Morphogenesis And Growth Analysis Of Panicum Maximum Cultivars,
2024
Universidade Federal Vicosa
Morphogenesis And Growth Analysis Of Panicum Maximum Cultivars, A Gomide, C A.M Gomide
IGC Proceedings (1997-2023)
Four cultivars of Panicum maximum, grown in pots, were evaluated regarding their leaf appearance and elongation rates, tillering appearance rate, as well as growth indices. Differences among cultivars were found as to leaf appearance and elongation rates and tillering rates. Main tiller leaf appearance was higher relative to primary tiller in the seedling growth, only. Primary tiller showed higher leaf elongation rate in the aftermath growth. No difference among cultivars was found for drymatter yield after 52 d growth period, leaf mortality, net assimilation rate, leaf area ratio and relative growth rate.
Competitive Interactions Between Palatable And Unpalatable Grasses: Effects Of Selective Defoliations Of The Palatable Grasses,
2024
Universidad Nacional del Sur, Bahia Blanca, Argentina
Competitive Interactions Between Palatable And Unpalatable Grasses: Effects Of Selective Defoliations Of The Palatable Grasses, R A. Distel, A S. Moretto
IGC Proceedings (1997-2023)
Selective herbivory of the palatable species appears to be a dominant mechanisms contributing to species competitive replacement in grasslands. Selective herbivory of the palatable species allows unpalatable species to realize a competitive advantage within the community. To test this hypothesis we compare the competitive ability of the unpalatable grasses Stipa trichotoma or S. gyneriodes in the presence of nondefoliated and defoliated plants of the palatable grass S. clarazii. The three species are native to a temperate semiarid grassland of Argentina. The response variables estimated in S.trichotoma and S.gynerioides, at both plant and tiller levels, were higher (P < 0.05) in the presence of defoliated than in the presence of undefoliated plants of S.clarazii. These results support the hypothesis that selective herbivory of the palatable species confers unpalatable species a competitive advantages, contributing to species competitive replacement within the community.
Allelopathic Interactions Among Forage Grasses And Legumes,
2024
EMBRAPA-CPATU
Allelopathic Interactions Among Forage Grasses And Legumes, A P.S Souza Filho, T De J.D. Rodrigues, L.R. De A. Rodrigues, R A. Reis
IGC Proceedings (1997-2023)
Aqueous extracts at 10% were prepared with the shoots of the grasses Brachiaria brizantha cv. Marandú, B. decumbens, B. humidicola, and of the legumes Calopogonium mucunoides, Leucaena leucocephala, Stylosanthes guianensis cv. Mineirão. The effects of the extracts were evaluated on the germination and on the radicleelongation of the forages. The pH, the electric conductivity and the osmotic potential of the extracts were determined. The germination and radicle biossays were conducted in germination chambers, with controlled temperature and photoperiod. The pH and the presence of ions did not contribute to the effects observed. The extracts of the legumes tended …
Early Ontogenetic Responses Of Six Commercial Chloris Gayana Cultivars To Salinity,
2024
IFFIVE
Early Ontogenetic Responses Of Six Commercial Chloris Gayana Cultivars To Salinity, E Taleisnik, H Perez, G Peyrano, C Arias
IGC Proceedings (1997-2023)
Some physiological aspects relevant to pasture establishment under saline conditions were evaluated in six cultivars of Chloris gayana . Two tetraploid cultivars: Boma and Callide, and four diploid ones: Bell, Katambora, Pioneer and a local accession of Pioneer, were analyzed. The effect of salinity on seedling emergence, the number of stolons per plant and frost tolerance were evaluated in the field, while effects on germination, early vegetative growth, regrowth after clipping, ion accumulation and stolon rooting were assessed in the greenhouse. Salinity had a negative effect on seedling emergence. Saline solutions delayed or altogether inhibited germination, but seeds retained viability …
