Thesis (MScAgric)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: Three different pasture mixtures were established under irrigation at the Elsenburg research farm with the aim of devising nitrogen (N) management strategies for pastures in the Winelands sub-region of South Africa. The pasture mixtures were as follows: i) a mixed grass pasture consisting of perennial ryegrass (Lolium perenne), tall fescue (Festuca arundinaceae) and cocksfoot (Dactylis glomerata); ii) a grass-clover pasture consisting of perennial ryegrass, tall fescue, cocksfoot and red and white clover (Trifolium pratense and Trifolium repens); and iii) a grass-lucerne pasture consisting of perennial ryegrass, tall fescue and lucerne (Medicago sativa). The effect of fertiliser N on selected nutritive characteristics was also evaluated. The grass-legume pastures were subjected to two management strategies: the once-off application of N and the consecutive application of N over the autumn-early spring period. The reaction of the mixed grass pasture to applied N was mostly characterised by an interaction between the season of N application and N application rate. The productivity of the pasture in terms of the primary dry matter production (PDMP) and the total dry matter production (TDMP) was highest in spring and summer with the application of 60 – 80 kg N ha-1, and decreased in autumn and winter. There was a strong response of the winter residual dry matter production (RDMP) to N, which indicated that not all applied N was utilised during the first regrowth cycle, which might present a risk of nitrate being leached below the root zone. The botanical composition of the mixed grass pasture was determined by season of N application, and not N application rate. The tall fescue content was low over all seasons, presumably due to poor establishment and strong competition from accompanying species. In the cooler months perennial ryegrass and tall fescue was the dominant species, while in the warmer months cocksfoot was the main species. Nitrogen application also had a significant effect on the quality of the pasture, most notably the crude protein (CP) content. The response of the CP content was characterised by a strong interaction between season of N application and N application rate. Crude protein levels in excess of 22 % were recorded in autumn and winter with the application of 40 – 80 kg N ha-1. Other characteristics remained within the expected range. The response of the grass-clover and grass-lucerne pastures in terms of productivity and nutritive characteristics were mainly determined by the season of N application, and not N application rate. Productivity tended to be highest in autumn and early spring for both the once-off and the consecutive N application strategies, emphasizing the effect of temperature on pasture growth. The effect of season of N application and the N application rate on the botanical composition of the respective pastures were inconsistent over the two years of the study. The clover content tended to decrease in response to increasing rates of N, while the grass fraction was stimulated. Lucerne productivity decreased from autumn through winter and reached minimum levels in early spring, and was unaffected by fertiliser N rate. The legume component in both the grass-clover and grass-lucerne pastures remained above recommended levels of 20 – 40 % for optimum animal production, even when N was applied consecutively. The nutritive characteristics measured (dry matter (DM) content, CP, in vitro organic matter digestibility (IVOMD)) remained within the expected range, except the total CP content which was very high in the first year (> 30 %), although N application rate did not have a significant effect. Based on these findings, preliminary recommendations for N fertilisation (on low carbon soils) for a mixed grass pasture is 40 kg N ha-1 during autumn and winter and 60 kg N ha-1 in spring and summer. Based on the poor response of the grass-legume pastures to applied N it is doubtful whether fertilisation will lead to an economical advantage, but low rates of approximately 40 kg N ha-1 could be beneficial in a grass-clover pasture during autumn and late winter/early spring based on the relatively strong response of PDMP to N during this period. / AFRIKAANSE OPSOMMING: Drie verskillende weidingsmengsels is onder besproeiing te Elsenburg proefplaas gevestig met die doel om stikstof (N) bestuurstrategieë te ontwikkel vir aangeplante weidings in die Wynland distrik van die Wes-Kaap van Suid Afrika. Die weidingsmengsels was as volg: i) ‘n gemengde gras weiding bestaande uit meerjarige raaigras (Lolium perenne), langswenkgras (Festuca arundinaceae) en kropaargras (Dactylis glomerata), ii) ‘n gras-klawer weiding bestaande uit meerjarige raaigras, kropaargras, langswenkgras, wit - en rooi klawer (Trifolium pratense en Trifolium repens), en iii) ‘n gras-lusern weiding bestaande uit meerjarige raaigras, langswenkgras en lusern (Medicago sativa). Die effek van stikstof bemesting op sekere kwaliteitsaspekte van die onderskeie weidings was ook geëvalueer. Die gras-peulplant weidings was onderworpe aan twee bestuurstrategieë, naamlik die eenmalige toediening van N en die agtereenvolgende toediening van N bemesting tydens die herfs – lente periode. Die reaksie van die gemengde gras weiding op N bemesting was hoofsaaklik gekenmerk deur ‘n interaksie tussen die N bemestingspeil en die seisoen van N toediening. Die produktiwiteit van die weidings i.t.v. die primêre droeëmateriaal produksie (PDMP) en die totale droeëmateriaal produksie (TDMP) was die hoogste in die lente en somer met die toediening van 60 – 80 kg N ha-1 en het in herfs en winter afgeneem. Daar was n sterk respons van die winter residuele droeëmateriaal produksie (RDMP) teenoor N, wat aandui dat nie alle toegediende N tydens die eerste hergroei periode benut was nie en dus ‘n moontlike risiko van loging inhou. Die botaniese samestelling van die gemengde gras weiding was deur die seisoen van N toediening bepaal, en nie die N bemestingspeil nie. Die langswenkgras inhoud was baie laag in alle seisoene, vermoedelik a.g.v. swak vestiging en sterk kompetisie van gepaardgaande spesies in die mengsel. Tydens die koeler seisoene van die jaar was meerjarige raaigras en langswenkgras die dominerende spesies, terwyl kropaargras tydens die warmer maande gedomineer het. Stikstof toediening het ook ‘n betekenisvolle effek op die kwaliteit van die weiding gehad, veral die ru-proteien (RP) inhoud. Die respons van RP was weereens gekenmerk deur ‘n betekenisvolle interaksie tussen die seisoen van N toediening en die N peil. Ru- proteien vlakke hoër as 22% was tydens herfs en winter waargeneem met die toedieningspyle van 40 – 80 kg N ha-1. Ander kwaliteits- eienskappe het binne normale perke gebly. Die respons van die gras-klawer en gras-lusern weidings in terme van produktiwiteit en kwaliteitseienskappe was hoofsaaklik deur die seisoen van N toediening bepaal, en nie deur die N bemestingspeil nie. Die produktiwiteit was die hoogste tydens herfs en vroeë lente vir beide die eenmalige en die herhaalde N toedieningsstrategieë. Hierdie bevindinge beklemtoon die belangrike effek van temperatuur op die groei en produksie van weidingsgewasse. Die effek van seisoen van N toediening en N peil op die botaniese samestelling van die gras-peulgewas weidings was inkonsekwent oor die twee jare van die studie. Die klawer-fraksie was geneig om af te neem soos wat die N peil toegeneem het, terwyl die gras-fraksie toegeneem het. Die lusern-inhoud het van herfs tot lente afgeneem en was ongeaffekteer deur die N peil. Die peulgewas-inhoud van beide weidingsmengsels was deurentyd hoër as die voorgeskrewe minimum vlak van 20 – 40%, selfs met opeenvolgende N-toediening. Die kwaliteitseienskappe gemeet in die studie (droeëmateriaal (DM) inhoud, RP en in vitro organiese materiaal verteerbaarheid (IVOMV)) het binne normale perke gebly, behalwe die totale ru-proteien (TRP) inhoud wat baie hoog was tydens die eerste jaar (>30%), alhoewel dit nie deur die N peil beinvloed was nie. Aan die lig van bogenoemde bevindinge is die voorlopige aanbeveling vir N- bemesting (op lae koolstof gronde) van ‘n gemengde grasweiding 40 kg N ha-1 tydens die herfs en winter en 60 kg N ha-1 tydens lente en somer. Gebasseer op die swak respons van die gras-peulgewas weidings op toegediende N, is dit twyfelagtig of N toediening enige ekonomiese voordeel vir die boer sal inhou. Gebaseer op die relatiewe sterk respons van die gras-klawer PDMP op toegediende N tydens herfs en laat winter/vroeë lente kan dit moontlik voordelig wees om lae N-vlakke van ongeveer 40 kg ha-1 tydens hierdie seisoene toe te dien.

The work was conducted in Santa Maria, RS, Brazil, with the objective of to evaluate an elephantgrass pasture (Pennisetum purpureum Schum.) var. Merckeron Pinda, under rotational grazing, during the agricultural year of 2002. The elephantgrass was established in lines separated by three meters, at October of 2001 on a 0,33 ha area. Organic fertilization was used in form of swine (70 kg/ha of N) and bovine (30kg/ha of N) manure applied at October of 2001 and January of 2002, respectively. During the agricultural year two experimentations were performed, one at summer period (January 16th until April 17th of 2002) and another in winter period (June 12th until October 14th of 2002). The area was divided in two paddocks. In summer period the pasture was constituted by elephantgrass (at lines) and spontaneous growing species (in the space between lines). The utilization period of pasture was from 01/16 until 04/17/2002, being performed six grazings along the time, three in each paddock. The occupation time in each paddock was of one day. The minor resting period was of 33 and the greater of 45 days. In the winter period it was sown, in the space between lines, 110 kg/ha of black oat (Avena strigosa). Seven grazings were performed in this period between 06/12 and 10/14/2002, being three at a paddock and four in another. The occupation time in each paddock was of one day. The minor resting period was of 29 and the greater of 51 days. In both experimentations it was used animals of Holstein breed. The experimental design utilized was randomized blocks in the summer as much as the winter period. The treatments were the grazings performed during the time, and replications the paddocks. The data had been submitted to the analysis of regression with aid of statistical package SAS (1997). Preceding the entrance of the animals in the pasture, samplings of the same one for determination of the dry matter (DM) availability and of the botanical and framework composition were carried through. In the utilization of the pasture for the animals, samples of grazing simulation were collected for posterior analysis of crude protein (CP), fiber in neutral detergent (FND) and dry matter in vitro digestibility (DMIVD). In the summer period the average availability of pasture was of 8257 kg/ha of DM, where the participation of elephantgrass was of 32.5%. The average content of CP, FND and DMIVD of the pasture was of 11.52, 64.15 and 56.67%, respectively. The stocking rate was 2161 kg of live weight/ha. In the winter period the average availability of the pasture was of 3278 kg/ha of DM. The average content of CP, FND and DMIVD of the pasture was of 15.6, 58.6 and 63.92%, respectively. The stocking rate was 1024 kg of live weight/ha / O trabalho foi conduzido no município de Santa Maria (RS), com o objetivo de estudar uma pastagem de capim-elefante, (Pennisetum purpureum Schum.) cultivar Merckeron Pinda, sob pastejo rotacionado, durante o ano agrícola de 2002. O capim-elefante foi implantado em linhas com 3 m de afastamento, em outubro de 2001 em área de 0,33 ha. Utilizou-se adubação orgânica na forma de chorume de suínos (70 kg/ha de N) e de esterco de bovinos (30 kg/ha de N) aplicados em outubro de 2001 e janeiro de 2002, respectivamente. Durante o ano agrícola foram realizadas duas experimentações, sendo uma no período estival (16 de janeiro a 17 de abril de 2002) e outra no período hibernal (12 de junho a 14 de outubro de 2002). A área foi dividida em dois piquetes. No período estival a pastagem era composta pelo capim-elefante (nas linhas) e por espécies de crescimento espontâneo (nas entrelinhas). O período de utilização da pastagem foi de 16/01 a 17/04/02, sendo realizados seis pastejos ao longo do período, três em cada piquete. O tempo de ocupação em cada piquete foi de um dia. O menor período de descanso foi de 33 e o maior de 45 dias. No período hibernal semeou-se, nas entrelinhas, 110 kg/ha de aveia preta (Avena strigosa). No período foram realizados sete pastejos entre 12/06 e 14/10/02, sendo três em um piquete e quatro no outro. O tempo de ocupação em cada piquete foi de um dia. O menor período de descanso foi de 29 e o maior de 51 dias. Nas duas experimentações utilizou-se animais da raça Holandesa. O delineamento experimental foi de blocos ao acaso tanto no período estival quanto no hibernal. Os tratamentos constaram dos pastejos efetuados no decorrer do tempo, e as repetições os piquetes. Os dados foram submetidos à análise de regressão com auxílio do pacote estatístico SAS (1997). Antecedendo a entrada dos animais na pastagem, eram realizadas amostragens da mesma para determinação da disponibilidade de matéria seca (MS) e da composição botânica e estrutural. Quando da utilização da pastagem pelos animais, eram coletadas amostras de simulação de pastejo para posterior análise de proteína bruta (PB), fibra em detergente neutro (FDN) e digestibilidade in vitro da matéria seca (DIVMS). No período estival a disponibilidade média da pastagem foi de 8257 kg/ha de MS, sendo que a participação do capim-elefante foi de 32,5%. O teor médio de PB, FDN e DIVMS da pastagem foi de 11,52; 64,15 e 56,67%, respectivamente. A carga animal foi 2161 kg de PV/ha. No período hibernal a disponibilidade média da pastagem foi de 3278 kg/ha de MS. O teor médio de PB, FDN e DIVMS da pastagem foi de 15,6; 58,6 e 63,92%, respectivamente. A carga animal foi 1024 kg de PV/ha

Made available in DSpace on 2016-04-26T19:39:30Z (GMT). No. of bitstreams: 1 2008- Elias Melo de Miranda.pdf: 858590 bytes, checksum: fe12f644fd0dbcad694f77bd0dea494b (MD5) Previous issue date: 2008-02-21 / This study was conducted at Embrapa Agrobiologia experimental area, in Serop?dica municipality, Rio de Janeiro State, with the objective of evaluating the association of arbuscular mycorrhizal fungi (AMF) with the foraging peanut (Arachis pintoi) in four situations of cultivation. The first study examined the association of peanuts with autochthonous AMF, from soil samples collected in Rio Branco municipality state of Acre, in areas of this legume as a single crop, and intercropped with pasture and coffee, as well as in secondary and primary forest. The AMF species were identified, determined the spore density and the root colonization rates, and then calculated the indexes of diversity. The other experiments were performed under greenhouse conditions, assessing the peanut seedlings response to inoculation with AMF species. The second study aimed to select the AMF effective in promoting growth of seedlings originating from seeds, and rooting of stolons in polystyrene trays, in substrate of low fertility, without additional fertilizer. In the third, it was investigated the response of seedlings propagated by rooting of stolons in condition of increasing doses of phosphorus. In the fourth study, the goal was to select AMF species that could improve the peanut forage performance cultivated in consortium with Brachiaria decumbens. The AMF species used were: Glomus etunicatum, Glomus clarum, Gigaspora margarita, Scutellospora heterogama, Acaulospora morrowiae and Entrophospora colombiana. It was assessed, among other variables, the dry matter production of shoots and roots. The analysis of the autochthonous community of AMF in agrosystems with A. Pintoi, notably in the monocrop system, indicated that this legume was a good host of AMF species, being useful to increase the density of spores and diversity of these organisms in the agrosystems. The analysis of the AMF community in the pastures intercropped with A. pintoi showed that this legume helped to increase the density of spores and diversity of species of AMF in the agrosystems. AMF species of greatest efficiency in promoting growth and nutrition of seedlings of A. Pintoi originated from seeds were E. colombiana, G. margarita, G. clarum, and A. morrowiae. However, for the seedlings originated of the rooting of stolons in polystyrene trays and without additional fertilization, it was not possible to detect a benefit of the mycorrhization. Though, these seedlings responded to the phosphate fertilization, and the response was most pronounced when inoculated with efficient AMF. In the intercropped cultivation, the treatments of inoculation were beneficial for both plant components of the system, and the A. Pintoi plants colonized by G. Clarum were most efficient to compete with the brachiaria grass. / Este trabalho foi realizado na ?rea experiemntal da Embrapa Agrobiologia em Serop?dica - RJ, com o objetivo de avaliar a associa??o de fungos micorr?zicos arbusculares (FMAs) com o amendoim forrageiro (Arachis pintoi) em quatro situa??es de cultivo. O primeiro estudo avaliou a associa??o do A. pintoi com FMAs aut?ctones, a partir de amostras de solo coletado em Rio Branco, AC, em ?reas de monocultivo e de cons?rcio desta leguminosa com gram?neas e cafeeiro, assim como em ?reas de capoeira e mata. As esp?cies de FMAs foram identificadas, determinada a densidade de esporos e as taxas de coloniza??o radicular e, ent?o, calculados ?ndices de diversidade. Os demais ensaios foram realizados em condi??es de casade- vegeta??o, avaliando-se a resposta das mudas de amendoim ? inocula??o com esp?cies de FMAs. O segundo estudo teve o objetivo de selecionar os FMAs mais eficientes em promover o crescimento de mudas originadas de sementes e do enraizamento de estol?es em bandejas de isopor, em substrato de baixa fertilidade natural, sem aduba??o suplementar. No terceiro, foi investigada a resposta de mudas propagadas por enraizamento de estol?es a doses crescentes de f?sforo. No quarto estudo, o objetivo foi selecionar esp?cies de FMAs que melhorassem o desempenho do amendoim forrageiro na condi??o de cons?rcio com Brachiaria decumbens. As esp?cies de FMAs estudadas foram: Glomus etunicatum, Glomus clarum, Gigaspora margarita, Scutellospora heterogama, Acaulospora morrowiae e Entrophospora colombiana, sendo avaliada, entre outras vari?veis, a produ??o de mat?ria seca da parte a?rea e de ra?zes. A an?lise da comunidade de FMAs aut?ctones nos agrossistemas com A. pintoi, notadamente em seu monocultivo, mostrou que esta leguminosa foi uma boa hospedeira de esp?cies de FMAs, contribuindo para aumentar a densidade de esporos e a diversidade destes organismos nos agrossistemas. As esp?cies de FMA de maior efici?ncia em promover o crescimento e nutri??o de mudas de A. pintoi originadas de sementes foram E. colombiana, G. margarita, G. clarum e A. morrowiae. Por?m, nas mudas originadas do enraizamento de estol?es, nas bandejas de isopor e sem fertiliza??o suplementar, n?o foi poss?vel detectar benef?cio da micorriza??o. Entretanto, estas mudas responderam ? fertiliza??o fosfatada, sendo esta resposta mais acentuada quando foram micorrizadas com FMAs eficientes. No cultivo consorciado, os tratamentos de inocula??o foram ben?ficos para ambas as plantas do sistema e as plantas de A. pintoi colonizadas por G. clarum foram mais eficientes em competir com a braqui?ria.

A study was developed simultaneously in Southwestern of Paraná and the Depressão Central of Rio Grande do Sul, to evaluate the production, structural and botanical components, nutritive value and morphogenetic character (exclusively in Paraná) in pastures of Coastcross-1 and Tifton 85 mixed with forage peanut (0, 25, 50 and 75% of implanted area). The experimental design was factorial (three factors), distributed in a randomized block design with three replications, the factors were cultivars (2), the percentage of area located in the legume (4) and evaluation periods. Forage production was higher for cv. Tifton 85, particulary in the second crop year, however, showed no effect of the increase of forage peanut in deployment of pastures. The increasing area implanted with legumes decreased participation of fractions leaf blade, stem and dead material in pastures. In Paraná, the use of 75% of the area planted with forage peanut promoted approximate 30% of total massa forage legume, unlike Rio Grande do Sul, with the same percentage of inclusion did not exceed 15%. The increasing presence of the forage peanut mass in the system increased the nutritive value of the pasture. In Paraná, the cv. Coastcross-1 showed better nutritive value compared to Tifton 85, and, the inclusion of forage peanut positively changed the crude protein in the leaf blades of grasses studied, from the second year of establishment. The number of green leaves, growth and senescence rate were similar among cultivars, but, cv. Coastcross-1 showed a higher number of expanded leaves and leaf appearance rate and lower phyllochron and leaf lifespan. Lower average daily heat accumulation decreases the development of grasses studied, although more pronounced in cv. Tifton 85. / Desenvolveu-se um estudo simultaneamente no Sudoeste do Paraná e na Depressão Central do Rio Grande do Sul, com o objetivo de avaliar a produção, os componentes estruturais e botânicos, o valor nutritivo e as características morfogênicas (exclusivamente no Paraná) de pastagens de Coastcross-1 e Tifton 85 consorciadas com amendoim forrageiro (0, 25, 50 e 75% de área implantada). O delineamento experimental foi o fatorial (três fatores), distribuídos em blocos ao acaso com três repetições, os fatores foram as cultivares (2), o percentual de área implantada com do amendoim forrageiro (4) e os períodos de avaliação. A produção total de forragem foi superior para o cv. Tifton 85 em especial no segundo ano agrícola, no entanto, não apresentou efeito do acréscimo de amendoim forrageiro no plantio das pastagens. A crescente área implantada com a leguminosa diminuiu a participação das frações lâmina foliar, colmo + bainha e material morto nas pastagens. No Paraná, a utilização de 75% da área com plantio com o Arachis pintoi promoveu participação próxima a 30% de leguminosa na massa de forragem total, diferentemente do Rio Grande do Sul, que com mesmo percentual de inclusão não ultrapassou 15%. A crescente presença do amendoim forrageiro na massa de forragem das pastagens consorciadas, elevou o valor nutritivo do pasto. No Paraná a cv. Coastcross-1 apresentou melhor valor nutritivo quando comparado ao Tifton 85, e a inclusão de amendoim forrageiro estolonífero alterou positivamente o teor de PB nas lâminas foliares das gramíneas estudadas, a partir do segundo ano de estabelecimento. O número de folhas verdes, folhas em crescimento e a taxa de senescência foram similares entre as cultivares estudadas, porém, a cv. Coastcross- 1 apresentou maior número de folhas expandidas, maior taxa de aparecimento foliar, mas menor filocrono e tempo de vida de folha. A menor média de acúmulo térmico diário diminuiu o desenvolvimento das gramíneas estudadas, porém de forma mais acentuada na cv. Tifton 85.

The vegetative and reproductive development of balansa clover (Trifolium michelianum Savi.) were quantified in relation to the environmental drivers of each phenophase in field and controlled environments. In a grazed experiment over 6 years, balansa clover sown with cocksfoot (Dactylis glomerata) contributed 1.6 t DM/ha/year, or ~20% of the total DM production. However, grazing management for increased seed production during flowering in the establishment year strongly influenced balansa clover regeneration. The earliest closed plot (September) averaged between 2.2 and 4.3 t DM/ha/year of balansa clover across all six years. In an incubator, balansa clover required 29°Cd for germination with an optimum temperature of 14°C and a maximum of 40°C. The base temperature for germination was 0°C. A field experiment determined that 38°Cd were required for emergence with an optimum soil temperature (Topt) of 8.5°C. The time from emergence until the first leaf appeared, the phyllochron and timing of axillary leaf appearance were compared with perennial ryegrass (Lolium perenne) and white clover (Trifolium repens L.). The rate of each was found to increase linearly with temperature. The balansa clover cultivar ‘Frontier’ required 97°Cd from sowing for the first leaf to appear, had a phyllochron of 47°Cd and secondary leaves appeared after 490°Cd. For each vegetative stage, the base temperature was 2.5°C. The timing of flower appearance depended on the quantity and direction of change of the photoperiod at emergence. A balansa clover plant, cv. ‘Bolta’, which emerged on 1 December into an increasing photoperiod of 15.6 hours flowered after 574°Cd (Tbase = 2.5°Cd) or 58 days after emergence. In contrast, if the plant emerged on 16 January into a similar but decreasing photoperiod it took 1503°Cd or 227 days to flower. This length of time became progressively shorter until remaining constant after the shortest day. In contrast, ‘Frontier’ took a constant 390 and 690 °Cd in increasing and decreasing photoperiods, respectively. The time which an individual inflorescence took from pollination until seeds were physiologically mature was 250 °Cd for both ‘Bolta’ and ‘Frontier’. The re-establishment of balansa clover each year relied on a large seed set (>1000 kg/ha) in the establishment year. The continued survival of balansa clover would then depend on a similar seeding event within a 4-5 year period to maintain the seed bank. Management considerations for balansa clover persistence and survival are discussed.