Conselho Nacional de Desenvolvimento Científico e Tecnológico / The milk production systems, mostly, use the pastures as the main source of forage for cattle, usually, consisting only of grasses. This strategy simplifies the management of pastures, however, implies high production costs, notably the high use of nitrogen fertilizers. An alternative to become the pasture systems more sustainable is the introduction of forage legumes, allowing a better distribution forage mass over time and reduce fertilizer costs. Thus, the objective of this research was to evaluate of three grazing systems (GS) with elephant grass (EG), Italian ryegrass (IR) and spontaneous growing species (SGS), as GS1 (control); EG + IR + SGS + arrowleaf clover, as GS2; and EG + IR + SGS + forage peanut, as GS3; during a crop year. The elephant grass was established in rows with a distance of 4m between rows. In winter period, Ryegrass was sowed between rows of EG; and considering respective treatments the arrowleaf clover was sowed and the forage peanut was preserved. Lactating Holstein cows were used in the evaluation. Experimental design was completely randomized with three treatments (grazing systems), three replicates (paddocks) with repeated measures (grazing cycles/seasons). Eight grazing cycles were performed during the experimental period (365 days), two in each season. The forage mass, botanical composition; daily accumulation dry matter rate, production and forage intake; grazing efficiency, stocking rate and nutritive value were evaluated. Samples from hand-plucking method were collected to analyze neutral detergent fiber (NDF), crude protein (CP), in situ dry matter digestibility (ISDMD) and total digestible nutrients (TDN). The values of forage mass and stocking rate were 3.46, 3.80 and 3.91 t ha-1 and 2.89, 3.39 and 3.20 animal unit ha-1, respectively for GS. Better results were found on grazing systems mixed with forage legumes. The average of NDF, CP, ISDMD and TDN of EG were 62.4, 61.5 and 60.2 %; 16.7, 16.7 and 18.1 %; 79.6, 79.8 and 79.1 %; 71.4, 71.2 and 69.9 %; and of the forage between rows of EG were 60.3, 60.3 and 52.4 %; 13.7, 15.7 and 19.5 %; 75.0, 72.8 and 81.1 %; 67.9, 65.3 and 72.9 %, respectively for treatments. Higher value of CP, ISDMD and TDN and lower of NDF were observed for the grazing systems mixed with forage peanut, especially on winter. Better results to nutritive value of elephant grass were found on spring. / Os sistemas de produção leiteira, em sua maioria, utilizam as pastagens como base da alimentação dos animais, geralmente, constituídas apenas por gramíneas. Essa prática simplifica o manejo dos pastos, contudo, implica em custos elevados de produção, notadamente pelo uso de adubos nitrogenados. Uma alternativa para tornar os sistemas forrageiros mais sustentáveis é a introdução de leguminosas, possibilitando melhor distribuição de forragem no decorrer do tempo, além de reduzir custos com adubação. Assim, a presente pesquisa teve como objetivo avaliar três sistemas forrageiros (SF) com capim elefante (CE), azevém (AZ), espécies de crescimento espontâneo (ECE), como SF1 (testemunha); CE + AZ + ECE + trevo vesiculoso (TV), como SF2; e CE + AZ + ECE + amendoim forrageiro (AF), como SF3; durante um ano agrícola. O capim elefante foi estabelecido em linhas afastadas em 4m. No período hibernal realizou-se a semeadura do azevém entre as linhas do CE; e considerando os respectivos tratamentos o trevo vesiculoso foi semeado e o amendoim forrageiro, foi preservado. Para avaliação foram usadas vacas da raça Holandesa. O delineamento experimental utilizado foi o inteiramente casualizado, com três tratamentos (SF), três repetições (piquetes) com medidas repetidas (pastejos/estações). Durante o período experimental (365 dias) foram realizados oito pastejos, dois em cada estação. Foi avaliada a massa de forragem, composição botânica; taxa de acúmulo diário, produção e consumo de foragem; eficiência de pastejo, taxa de lotação e valor nutritivo da forragem. Amostras de simulação de pastejo foram coletadas para análise de fibra em detergente neutro (FDN), proteína bruta (PB), digestibilidade in situ da matéria seca (DISMS) e nutrientes digestíveis totais (NDT). Os valores de massa de forragem e taxa de lotação foram de 3,46; 3,80 e 3,91 t ha-1 e 2,89; 3,39 e 3,20 unidades animais ha-1, respectivamente para os SF. Melhores resultados foram obtidos nos sistemas forrageiros consorciados com leguminosas. Os valores médios para FDN, PB, DISMS, e NDT do CE foram de 62,4; 61,5 e 60,2 %; 16,7; 16,7 e 18,1 %; 79,6; 79,8 e 79,1 %; 71,4; 71,2 e 69,9 %; e para forragem presente na entrelinha foram de 60,3; 60,3 e 52,4 %; 13,7; 15,7 e 19,5 %; 75,0; 72,8 e 81,1 %; 67,9; 65,3 e 72,9 %, para os respectivos tratamentos. Maiores valores para PB, DISMS e NDT e menores para FDN foram observados no sistema forrageiro consorciado com amendoim forrageiro, em especial no inverno. Melhores resultados de valor nutritivo para o capim elefante foram obtidos na primavera.

The experiment objectified the termination of lambs to the foot of the mother in pasture cultivated of ryegrass and red clover with and without creep-feeding to the lamb. Evaluations in the performance, characteristics of carcass, production of commercial cuts and production of the components had been carried through not-carcass in the lambs kept to the foot of the mother and submitted to the alimentary treatments: PAST = pasture cultivated of ryegrass and red clover; APT = pasture cultivated of ryegrass and red clover + creep-feeding to the lamb during all the period of use of the grass; AP42 = pasture cultivated of ryegrass and red clover + creep-feeding to the lamb from 42 days after beginning of the use of the grass. For all the evaluated parameters of the grass, did not have interaction (P>0.05) between treatment and period, did not have difference between treatments (P>0.05) for the parameters evaluated in the grass. Animals that had received creep-feeding had presented greater (P<0.05) profit of daily average weight and lesser (P<0.05) number of days to reach the weight established of slaughter in relation to that they had only remained in pasture. The components carcass had not differed (P>0.05) in the alimentary treatments. The weight of slaughter of 28 kg was only reached in 43, 71 and 86% of the animals of treatments PAST, AP42 and APT, respectively. The job of creep-feeding better does not provide to quality and nor carcass yield, for the lambs slaughtered with 28kg. In handling pastures of similar form, the creep-feeding promotes additive effect on the efficiency of termination of the animals. / O experimento objetivou a terminação de cordeiros ao pé da mãe em pastagem cultivada de azevém e trevo vermelho com e sem a alimentação privativa ao cordeiro. Foram realizadas avaliações no desempenho, características de carcaça, produção de cortes comerciais e produção dos componentes não-carcaça nos cordeiros mantidos ao pé da mãe e submetidos aos tratamentos alimentares: PAST = pastagem consorciada de azevém e trevo vermelho.; APT = pastagem consorciada de azevém e trevo vermelho + alimentação privativa ao cordeiro durante todo o ciclo de uso do pasto; AP42 = pastagem consorciada de azevém e trevo vermelho + alimentação privativa ao cordeiro a partir de 42 dias após inicio da utilização do pasto. Para todos os parâmetros avaliados do pasto, não houve interação (P>0,05) entre tratamento e período, não houve diferença entre tratamentos (P>0,05) para os parâmetros avaliados no pasto. Animais que receberam alimentação privativa apresentaram maior (P<0,05) ganho de peso médio diário e menor (P<0,05) número de dias para atingir o peso estabelecido de abate em relação a aqueles que somente permaneceram em pastagem. Os componentes não carcaça não diferiram (P>0,05) nos tratamentos alimentares. O peso de abate de 28 kg foi atingido somente em 43, 71 e 86 % dos animais dos tratamentos PAST, AP42 e APT, respectivamente. O emprego da alimentação privativa não proporciona melhor qualidade e nem rendimento na carcaça, para cordeiros abatidos aos 28kg. Em pastagens manejadas de forma similar, a alimentação privativa promove efeito aditivo sobre a eficiência de terminação dos animais.

Made available in DSpace on 2014-08-20T14:33:08Z (GMT). No. of bitstreams: 1 dissertacao_rosemeri_olanda.pdf: 474088 bytes, checksum: b3ca7e189d033a5e523ce3ee94f5349e (MD5) Previous issue date: 2009-03-26 / The objective of this work was to evaluate the incorporate of arrow leaf clover cv. Yuchi for seed production in Nesting Novo Arroio Grande, Arroio Grande (RS) and the other benefits of the presence of this legume specie in agricultural and pasture system. This work was realized in seven production units where were identified three systems: beef cattle production, dairy cattle production and both. Were installed seven areas for seed production with approximately 0.25 ha. The forage production and quality were determined from cuts made in three replicates of 1.0m2 being quantified: the content and yield of dry matter, crude protein and in vitro digestibility. Phenological evaluations were made during the crop cycle and from the date of sowing these events were determined: first and sixth trifoliolade leaf, first branch, flowering start and full, and seed maturation. The yield components were evaluated such as number of plants for area, number of inflorescence for plant, number of inflorescence for area and thousand seed weight. Analysis of simple linear correlation were made between: the different yield components with seed production; the quantity of phosphor applied with yield seed, crude protein and dry matter production. The clover seed production including soil seed bank showed yield of 636 kg.ha-1 which creates an increase of 97% in the gain and showing as an alternative for nesting productions units. The forage production with high quality presents capability to change the reality of the production in agro-pastoral systems. Key Words: seed production, Trifolium vesiculosum, production systems, settlement, agrarian reform, diversified production. / O objetivo do trabalho foi avaliar a incorporação do trevo vesiculoso cv. Yuchi para produção de sementes no Assentamento Novo Arroio Grande, em Arroio Grande (RS), bem como os demais benefícios da presença desta leguminosa no sistema agropastoril. O trabalho foi realizado em sete unidades de produção, onde foram identificados três sistemas: produção de gado de corte, produção de gado de leite e misto. Foram instaladas sete áreas para produção de sementes com aproximadamente 0,25ha. A produção e a qualidade da forragem foram determinadas a partir de cortes realizados em três repetições de 1,0 m2 sendo quantificados: teor e rendimento de matéria seca, proteína bruta e digestibilidade in vitro. Avaliações fenológicas foram realizadas durante o ciclo do cultivo determinando-se a partir da data de semeadura os seguintes eventos: emergência, primeira folha trifoliolada, sexta folha trifoliolada, primeira ramificação, início e plena floração e colheita de sementes. Os componentes de rendimento avaliados foram: número de plantas por área; número de inflorescências por planta e por área e peso de mil sementes. Foram realizadas análises de correlação linear simples entre os diferentes componentes de rendimento com a produção de sementes; entre a quantidade de fósforo aplicado com o rendimento de sementes, a proteína bruta e a produção de massa seca. A produção de semente de trevo vesiculoso incluindo o banco de sementes no solo alcançou rendimento de 636 kg.ha-1, o que gerou incremento de renda de 97%, configurando-se como uma alternativa para unidades de produção de assentamentos; a produção de forragem com elevada qualidade apresenta potencialidade para alterar a realidade da produção dos sistemas agropastoris.

Made available in DSpace on 2014-08-20T14:38:47Z (GMT). No. of bitstreams: 1 tese_daiane_cristina_sganzerla.pdf: 1882299 bytes, checksum: 309cae7dd279a55786ba5efa8ee79f7a (MD5) Previous issue date: 2013-01-11 / Morphogenetic, structural and productive characteristics, were avaliated in a mixed pasture of persian clover (Trifolium resupinatum L. var. resupinatum Gib. & Belli cv. Kyambro) and italian ryegrass (Lolium multiflorum Lam cv. Comum) under different defoliation intervals. The experiment was conducted at the Embrapa Clima Temperado, Capão do Leão, RS. The treatments consisted of four defoliation intervals (determined according to the time of onset of 2,5; 3,5; 4,5 and 5,5 leaves on the persian clover) in two years of evaluation (2009 and 2010 ). We used a complete randomized blocks, with six replications. Defoliation was performed by grazing with lactating cows of the Jersey breed, under rotational stocking. The variables analyzed included: rate of leaf appearance, phyllochron, number of live leaves, dead and senescent, sward height and plant, length of branches / tillers, dry matter production, leaf area, leaf area index and rate dry matter accumulation. Higher rates of leaf appearance were found in shorter intervals between defoliation for both clover and for ryegrass. For persian clover larger intervals provided greater number live leaves. As for ryegrass, greater live leaves found in shorter intervals between defoliation. The leaf area index of pasture and persian clover was higher in the interval of 5,5 leaves in the years 2009 and 2010. In 2009 the highest values of leaf area were obtained in intervals of 3,5 and 4,5 leaves and there was no effect of the intervals between defoliation in 2010 on this variable. Higher intervals provided higher sward height and plants height and also length of tillers and branches. The dry matter yield of persian clover was higher in 2010 while for ryegrass higher production was found in 2009, and the total dry matter production was higher in the interval of 5,5 leaves. The rate of dry matter accumulation was higher in the interval of 5,5 leaves in 2009 and in the interval of 2,5 leaves in 2010. Higher intervals between defoliation provide higher LAI values, sward height and dry matter production. Morphogenetic, structural and productive characteristics of a mixture persian clover and ryegrass are modified by defoliation intervals, demonstrating the phenotypic plasticity of the species. Are recommended defoliation intervals of to 3,5 appeared leaves in a mixed pastures of persian clover and ryegrass to enable a greater number of live leaves attached to a lower stems elongation, characteristics desirable from the standpoint of animal production. / Características morfogênicas, estruturais e produtivas foram avaliadas em uma consorciação de trevo-persa (Trifolium resupinatum L. var. resupinatum Gib. & Belli cv. Kyambro) e azevém anual (Lolium multiflorum Lam cv. Comum) sob diferentes intervalos entre desfolhas. O experimento foi realizado em área da Embrapa Clima Temperado, Capão do Leão, RS. Os tratamentos corresponderam a quatro intervalos entre desfolhas (determinados em função de tempo para o surgimento de 2,5; 3,5; 4,5 e 5,5 folhas em plantas de trevo-persa) em dois anos de avaliação (2009 e 2010). Utilizou-se o delineamento de blocos completos ao acaso, com seis repetições. A desfolha foi realizada através de pastejo, com vacas em lactação da raça Jersey, sob lotação rotativa. As variáveis analisadas incluíram: taxa de aparecimento de folhas, filocrono, número de folhas vivas, mortas e senescentes, altura do dossel e de plantas, comprimento de ramificações/perfilhos, produção de matéria seca, área foliar, índice de área foliar e taxa de acúmulo de matéria seca. Maiores taxas de aparecimento de folhas foram encontradas em menores intervalos entre desfolhas tanto para trevo quanto para azevém. Para trevo-persa maiores intervalos proporcionaram maior número de folhas vivas. Enquanto para azevém, maior número de folhas vivas foi encontrado em menores intervalos entre desfolhas em 2009 e nos maiores intervalos em 2010. O índice de área foliar do trevo+azevém e do trevo-persa foi maior no intervalo de 5,5 folhas nos anos de 2009 e 2010. No ano de 2009 maiores valores de área foliar foram obtidos nos intervalos de 3,5 e 4,5 folhas e não se observou efeito dos intervalos entre desfolha sobre esta variável em 2010. Maiores intervalos entre desfolha proporcionaram maior altura do dossel e de plantas e também maior comprimento de perfilhos e ramificações. A produção de matéria seca do trevo-persa foi maior em 2010 enquanto que para azevém maior produção foi encontrada em 2009, sendo a produção de matéria seca total maior no intervalo de 5,5 folhas. A taxa de acúmulo de matéria seca foi maior no intervalo de 5,5 folhas em 2009 e no intervalo de 2,5 folhas em 2010. Intervalos entre desfolha maiores proporcionam maiores valores de IAF, altura do pasto e produção de matéria seca. As características morfogênicas, estruturais e produtivas da consorciação trevo-persa e azevém são modificadas pelos intervalos entre desfolha, demonstrando a plasticidade fenotípica das espécies. São recomendáveis períodos de descanso de até 3,5 folhas surgidas, em consorciações de trevo-persa e azevém para possibilitar um maior número de folhas vivas associadas a um menor alongamento de caules, características desejáveis do ponto de vista da produção animal.

Made available in DSpace on 2014-08-20T13:44:33Z (GMT). No. of bitstreams: 1 tese_suemar_avelar.pdf: 1994897 bytes, checksum: 7caae4c2c8711db573bbdc53ac395a0f (MD5) Previous issue date: 2013-10-05 / The seed separation based on aerodynamical properties can be carried out to remove poor nourished or empty seeds and impurities. Air separation can be used alone or in conjunction with other separation as in air screen cleaner or gravity table separators. Among equipment there is the continuous flowing blower that uses only a vertical air stream to perform seed cleaning. So, the aim of this study was to evaluate the continuous seed blower with vertical air stream on barley, crimson clover and wheat seeds cleaning and quality upgrading. Seed samples of each specie were prepared and moisture content determined. The samples were blown at following air velocities: 6 m.s-1 to 14 m.s-1 (barley), 8 m.s-1 to 13 m.s-1 (crimson clover) and 8 m.s-1 to 13 m.s-1 (wheat), in 1 m.s-1 intervals. Physical purity, the thousand seed weight and the physiological quality (germination and vigor) were quantified. It was conclude that: 1 - it is possible to cleaning barley, crimson clover and wheat seeds and quality upgrading seed lots in a continuous flowing blower with vertical airstream; 2 - the air velocity 9, 10 and 11 m.s-1 where adequate to cleaning and quality ugrading barley, crimson clover and wheat seeds, respectively in the continuous flowing blower, considering seed physical purity, germination and vigor and acceptable seed discharge percentage; 3 - there is an horizontal air velocity gradient in the continuous flowing blower plastic tube; 4 - the voltage affect the air velocity in the plastic tube at low fan velocities in the continuous flowing blower with vertical airstream. / A separação das sementes empregando como base as suas propriedades aerodinâmicas pode ser utilizada para remover sementes mal formadas e impurezas. A separação pelo ar pode ser utilizada isolada ou em conjunto com outras separações como no caso da máquina de ar e peneiras ou da mesa de gravidade, por exemplo. Dentre os equipamentos para separação utilizando apenas ar encontra-se o soprador contínuo com fluxo vertical de ar. Assim, o objetivo desse trabalho foi avaliar o soprador contínuo com fluxo vertical de ar na limpeza de sementes de cevada, trevo encarnado e trigo e no aprimoramento da qualidade fisiológica. Após a preparação das amostras de cada espécie, estas foram submetidas ao soprador regulado para velocidade do ar de 6 m.s-1 a 14 m.s-1 (cevada), 8 m.s-1 a 13 m.s-1 (trevo encarnado) e 8 m.s-1 a 13 m.s-1 (trigo), em intervalos regulares de 1 m.s-1. Avaliou-se a pureza física, o peso de mil sementes e a qualidade fisiológica. Concluiu-se que: 1 - é possível limpar sementes de cevada e trigo e aprimorar a qualidade dos lotes, utilizando soprador contínuo com fluxo vertical de ar; 2 - as velocidades do ar 9, 10 e 11 m.s-1 foram adequadas para a limpeza e aprimoramento da qualidade de sementes de cevada, trevo encarnado e trigo respectivamente em soprador continuo com fluxo vertical de ar, considerando a pureza física, germinação e o vigor e porcentagem de descarte de sementes aceitável; 3 - ocorre um gradiente horizontal da velocidade do ar no tubo plástico do soprador contínuo; 4 - a voltagem interfere na velocidade do ar no tubo plástico vertical em baixas velocidades do ventilador em soprador contínuo com fluxo vertical de ar.

Red clover (Trifolium pratense) is currently used as a green fertilizer for agriculture in northern Sweden. However, due to its low resistance against diseases and a minimal benefit to local pollinators, there is a need to find alternative native species that maximize the benefits for pollinators and agriculture. Garden lupin (Lupinus polyphyllus), another legume, is an invasive alien species in Sweden that may affect the behavior of pollinators and therefore the pollination success of local plant species. The main aim of this study was to increase the knowledge of the legumes cow vetch (Vicia cracca), garden lupin, marsh pea (Lathyrus palustris) and red clover by observing their insect visitors and potential pollinators. The work was divided into subproject 1 (delprojekt 1) and subproject 2 (delprojekt 2). Delprojekt 1 studied insect visitation frequencies in one plot where garden lupin, cow vetch and red clover grew together in Burträsk, while delprojekt 2 studied insect pollination effectivity in two plots where one plot (Fäbodsanden) contained only marsh pea and the other plot (Skäret) contained both garden lupin and marsh pea. Data were collected via field observations. In ‘delprojekt 1', both bumblebees and solitary bees showed a significantly higher visit frequency to garden lupin than to cow vetch and red clover. In ‘delprojekt 2’, flies showed a significantly higher pollination effectivity on garden lupin than on marsh pea in Skäret. Both flies and bumblebees showed a significantly higher pollination effectivity on marsh pea in Fäbodsanden than in Skäret. This indicate that visitation frequencies to cow vetch and red clover as well as pollination effectivity on marsh pea may be affected by the presence/absence of garden lupin. For future studies, examples on how to extend the knowledge even further on plant-pollinator interactions are suggested.

Charles University in Prague, Faculty of Pharmacy in Hradec Králové Department of Pharmacognosy Candidate: Hana Novotná Supervisor: PharmDr. Marie Kašparová, Ph.D. Title of diploma thesis: Secondary metabolites of plant tissue culture of Trifolium pratense L. Explant cultures are perspective sources of secondary metabolites. Nevertheless production of flavonoids and isoflavonoids by the suspension culture of Trifolium pratense L. is not high. Elicitation is one of the methods used to enhance the biosynthesis of secondary metabolites. Elicitation induces physiological changes, stimulates defensive or stress-induced reactions in plants and subsequently triggers the synthesis of secondary metabolites. The objective of this study was to observe the influence of two elicitors - abscisic acid and ascorbic acid - on the production of flavonoids and isoflavonoids by the Trifolium pratense L. suspension culture (Sprint variety). The culture was cultivated in Gamborg medium to which 2 mg.l-1 of 2,4- dichlorophenoxyacetic acid and 2 mg.l-1 of 6-benzylaminopurine were added, at the temperature of 25 řC and 16 hours light / 8 hours dark period. The best elicitation effect of abscisic acid on the production of flavonoids and isoflavonoids was observed after a 6-hour application of the highest 500 µmol.l-1...

A number of morphological, floral, rhizome, root and herbage characteristics were studied in order to describe genetic variation and environmental responses in T. ambiguum. From each of six lines, 30 genotypes were clonally progagated into five diverse edaphic and altitudinal sites and grown for one season. Comparisons of growth and form were also made between T. ambiguum, T. repens cv. 'Grasslands Huia' and Lotus pedunculatus cv. 'Grasslands Maku'. The polyploid lines were found to have larger leaves than the diploids while all the lines of T. ambiguum had larger leaves than did white clover. Tetraploid lines had longer petioles and were taller and more erect than the diploids or hexaploids. Floral initiation was found to become later as ploidy level increased but the tetraploid lines exhibited a very large variation in flowering date. The cultivar Treeline was found to produce the most herbage under all conditions although not significantly more than cultivar Prairie or C.P.I. 57353. However, as nodulation was not studied it was not possible to determine whether variety differences were due to root nodulating ability or some other genetically determined parameter. None of the T. ambiguum varieties produced as much herbage as cv. Huia or cv. Maku at any site. However, all the T. ambiguum lines performed relatively better under harsher conditions. Because a large proportion of T. ambiguum was below ground the best T. ambiguum line, cultivar Treeiine, produced equivalent total plant dry weight to cv. Huia and cv. Maku at 1200 m. a.s.l., the high altitude site. Cultivar Prairie was found to have the highest proportion of rhizomes to total plant mass bu because cv. Treeline had higher total plant dry weight both cultivars produced equivalent mean rhizome dry weight. The number of rhizomes, number of daughter plants and rhizome dry weight were all highly correlated and these three characteristics showed similar trends among varieties. Rhizome length was found to increase with ploidy level, as did rhizome internode length. However, the number of nodes was found to be higher in the diploids than in the polyploids. Cultivar Treeline was found to have a high proportion of branching nodes on its rhizomes while C.P.I. 57353 and cv. Summit had the least. Rhizome production was restricted in the Wakanui silt loam soil of high bulk density. However, herbage growth and rhizome branching was increased, probably because of the higher fertility. It was shown using factor analysis on genotypic correlations, that rhizome characteristics and herbage yields were relatively independently inherited. However, morphological characters tended to be related to herbage yields. The polyploid varieties were found to be more genetically variable than the diploids . Broad sense heritabilities were calculated for all parameters measured, and in general, morphological characteristics had higher values than agronomic characteristics. As the genetic variation within each line was higher than the variation among lines, it is apparent that selection within lines should result in the largest gains. Therefore, comparison of the mean performance of the presently highly variable lines is relatively uninformative. By sacrificing some genetic diversity, large gains could be made in performance. It is suggested that cv. Prairie be used as the basis for selecting a highly rhizomatous cultivar while cv. Treeline could be used in the selection of a cultivar with higher herbage production suitable for high country conditions. In a second trial, an established stand of cv. Treeline produced up to 13250 kg per ha for one season under good growing conditions. The management required to produce this amount of herbage was to irrigate and cut to ground level every two months. The growth rate was considerably depressed when cut monthly. It was also shown that root and rhizome yield reached 12600 kg per ha, indicating a massive reserve of assimilates, particularly useful for surviving periods of stress. Seed yields were found to be adequate, reaching levels equivalent to 500-700 kg per ha. These results were discussed in relation to earlier observations on T. ambiguum by workers in Russia, Australia, U.S.A. and New Zealand. Suggestions were made for further genetic and agronomic testing.

This study consisted of two sheep grazed dryland pasture experiments. Experiment l compared sheep production from 3-year-old cocksfoot based pastures grown in combination with white, Caucasian, subterranean or balansa clover with a ryegrass-white clover pasture and a pure lucerne forage. Sheep liveweight gain per head from each pasture treatment and the pure lucerne stand was recorded in the 2006/07 and 2007/08 seasons. The cocksfoot-subterranean clover pasture provided equal (381 kg LW/ha in 2006) or higher (476 kg LW/ha in 2007) animal production in spring and gave the highest total animal production (646 kg LW/ha) averaged across years of the five grass based pastures. However, total annual liveweight production from lucerne was higher than any grass based pasture mainly due to superior animal production during summer when lucerne provided 42-85% higher animal production than any of the grass based pastures. In Experiment 2, the effect of stocking rate (8.3 (low) and 13.9 (high) ewes + twin lambs/ha) and time of closing in spring on lamb liveweight gain, pasture production and subterranean clover seedling populations was monitored over 2 years for a dryland cocksfoot-subterranean clover and ryegrass-subterranean clover pasture in Canterbury. In both years, twin lambs grew faster (g/head/d) in spring at low (327; 385) than high (253; 285) stocking rate but total liveweight gain/ha (kg/ha/d) was greater at high (7.26; 7.91) than low (5.43; 6.38) stocking rate. Ewes also gained 0.5 and 1.5 kg/head at the low stocking rate in 2006 and 2007 respectively but lost 0.2 kg/head in 2006 and gained 0.3 kg/head at high stocking rate in 2007. Mean subterranean clover seedling populations (per m²) measured in autumn after grazing treatments in the first spring were similar at both low (2850) and high (2500) stocking rate but declined with later closing dates in spring (3850, 2950, 2100 and 1700 at 2, 4, 6, 8 weeks after first visible flower). Seedling populations measured in autumn after grazing treatments in the second spring were also unaffected by stocking rate (low 1290, high 1190) but declined with later closing dates in spring (1470, 1320 and 940 at 3, 5 and 8 weeks after first flowering, respectively). The effect of stocking rate and closing dates in spring on pasture and clover production in the following autumn was similar to the effects on seedling numbers in both years. However, clover production in the following spring was unaffected by stocking rate or closing date in the previous year at the relatively high seedling populations generated by the treatments. This was presumably due to runner growth compensating for lower plant populations in pastures that were closed later in spring. Subterranean clover runner growth in spring may not compensate in a similar manner if seedling numbers in autumn fall below 500/m². Mean annual dry matter production from cocksfoot and ryegrass pastures grown with and without annual clovers pasture production ranged from 6.4 to 12.4 t DM/ha/y but stocking rate (8.3 vs. 13.9 ewes/ha) during spring did not affect annual pasture production. Pastures overdrilled with annual clovers yielded 23-45% more dry matter production than pastures grown without annual clovers. The study confirms the important role of subterranean clover in improving pasture production and liveweight gains of sheep in dryland cocksfoot and ryegrass pastures. Lowering stocking rate from 13.9 to 8.3 ewes/ha was a less effective method of increasing seed production of subterranean clover in dryland pastures although it did lead to increased liveweight gain per head.

Diss. (sammanfattning). Uppsala : Sveriges lantbruksuniv., 2003. / Härtill 4 uppsatser.