Submitted by (edna.saturno@ufrpe.br) on 2017-05-17T15:31:54Z No. of bitstreams: 1 Marta Gerusa Soares da Silva.pdf: 1019521 bytes, checksum: dafe6a7ce15446dca593cbcc3e9179b2 (MD5) / Made available in DSpace on 2017-05-17T15:31:54Z (GMT). No. of bitstreams: 1 Marta Gerusa Soares da Silva.pdf: 1019521 bytes, checksum: dafe6a7ce15446dca593cbcc3e9179b2 (MD5) Previous issue date: 2010-02-26 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The aim of this study was to evaluate the dynamics of the association of „capim-de-raiz‟ (Chloris orthonoton Doell.) and „capim-milhã‟ [Brachiaria plantaginea (Link.) Hitchc.], concerning growth, persistence and production, as well to morphanatomically characterize the legume „orelha de onça‟ (Macroptilium martii Benth.). In order to evaluate the dynamics of the association „capim-de-raiz‟ and „capim-milhã‟, two experiments were carried out: I. Evaluation of deferred native pasture concerning botanical composition and forage mass; II. Growth dynamics of „capim-milhã‟ and „capim-de-raiz‟. Experiment I was conducted at the Experimental Station of IPA, in São Bento do Una - PE from 2007 to 2008 with different evaluation periods for forage mass and botanical composition. Experiment II was conducted at a greenhouse in the Animal Science Department - UFRPE, from 09.26.06 to 07.26.07. Soil blocks with the plant community were taken from native pasture area of the Experimental Station of Instituto Agronômico de Pernambuco - IPA, in São Bento do Una - PE, and placed in plastic pots remaining at a greenhouse in UFRPE. Pots were submitted to four irrigation schedules: Irrigation I - irrigation at the beginning of the experiment; Irrigation II - started two months after Irrigation I; Irrigation III - started four months after irrigation I and Irrigation IV - started six months after irrigation I. After the initial irrigation of each period, all pots were irrigated every seven days until drainage and regrowth number, seedling number, plant number and inflorescence number were evaluated. Morphanatomical characterization of „orelha de onça‟ leaf was analyzed with optical microscopy in cross-sections confectioned laminae. 10 families, 15 genera and 18 species were identified in the deferred pasture. In botanical composition from May to August 2007, „capim-milhã‟ was the main component from 60 to 90 days with 46.75 and 52.09%, respectively. In August 2007, other species participated with 57.75% of the botanical composition; at the end of evaluation in year 2008 other species occupied 100% of the composition. The highest forage mass (kg DM/ha) for „capim-milhã‟ (2.736) occurred at 90 days, for other species (3.141) and „capim-de-raiz‟ (2.701) at 120 days. In soil blocks it was observed that regrowth occurred only after 30 days of assessment for initial irrigation and the highest number of seedlings to the pots occurred at 30 days. It was observed at 60 days the largest number of grasses for irrigation III and at 90 days for irrigation IV, and that most of inflorescence appeared at 90 days. In deferred area the use of stockpiled forage should preferably take place from 60 to 90 days. The main form of establishment of „capim-de-raiz‟ was by germination and at 150 days it was observed population growth of other species. It was observed paracytic and amphistomatic stomata, simple and uniseriate hairs, palisade and spongy chlorophyll parenchyma in „orelha de onça‟ leaf blade. In stem vascular system it was observed a range of libero-ligneous beams in the internodes area, separating cortex of medulla. Foliar and stem anatomical characteristics are common to legumes. / O objetivo deste trabalho foi avaliar a dinâmica da associação capim-de-raiz (Chloris orthonoton Doell.) e capim-milhã [Brachiaria plantaginea (Link.) Hitchc.], quanto ao crescimento, persistência e produção, bem como caracterizar morfoanatomicamente a leguminosa orelha de onça (Macroptilium martii Benth.). Para avaliar a dinâmica da associação capim-de-raiz e capim-milhã, foram realizados dois experimentos: I. Avaliação de um pasto nativo diferido quanto à composição botânica e massa de forragem; II. Dinâmica do crescimento do capim-milhã e capim-de-raiz. O experimento I foi conduzido na Estação Experimental do IPA, no município de São Bento do Una - PE, de 2007 a 2008, sendo utilizados diferentes períodos para avaliação da massa de forragem e composição botânica. O experimento II foi realizado em telado no Departamento de Zootecnia - UFRPE, durante o período de 26.09.06 a 26.07.07. Cubos de solos com a comunidade vegetal foram retirados de área de pastagem nativa, da Estação Experimental do Instituto Agronômico de Pernambuco - IPA, no município de São Bento do Una - PE, e colocados em vasos plásticos permanecendo em telado da UFRPE. Os vasos foram submetidos a quatro épocas de início de irrigação: Irrigação I ¿ irrigação por ocasião da implantação do experimento; Irrigação II ¿ iniciada dois meses após a irrigação I; Irrigação III ¿ iniciada quatro meses após a irrigação I e Irrigação IV ¿ iniciada seis meses após a irrigação I. Após a irrigação inicial de cada período, todos os vasos foram irrigados a cada sete dias até drenagem e foram avaliados o número de rebrotes, número de plântulas, número de plantas e número de inflorescências. A caracterização morfoanatômica foliar da orelha de onça foi analisada em microscopia óptica em lâminas confeccionadas em secções transversais. Foram identificadas 10 famílias, 15 gêneros e 18 espécies no pasto diferido. Na composição botânica de maio a agosto de 2007, o capim-milhã foi o componente principal dos 60 aos 90 dias com 46,75 e 52,09%, respectivamente. Em agosto de 2007, outras espécies participaram com 57,75% da composição botânica; no ano de 2008 ao final da avaliação, outras espécies ocuparam 100% da composição. As maiores massas de forragem (kg de MS/ha) para o capim-milhã (2.736) foram aos 90 dias, e para outras espécies (3.141) e capim-de-raiz (2.701) aos 120 dias. Nos cubos de solo, observou-se que o rebrote ocorreu apenas aos 30 dias de avaliação para irrigação inicial e o maior número de plântulas para os vasos ocorreu aos 30 dias. Foi observado aos 60 dias o maior número de gramíneas para irrigação III e aos 90 dias para irrigação IV, e que a maioria das inflorescências surgiu aos 90 dias. Em área diferida, o aproveitamento da forragem acumulada deve ocorrer preferencialmente dos 60 aos 90 dias. A principal forma de estabelecimento foi por germinação de sementes e aos 150 dias observou-se crescimento populacional de outras espécies. Foram observados na lâmina foliar da orelha de onça estômatos paracíticos e anfiestomáticos, pelos simples e unisseriados, parênquima clorofiliano em paliçada e esponjoso. Nos sistemas vasculares do caule observou-se, nas áreas dos entrenós, uma faixa de feixes líbero-lenhosos separando o córtex da medula. As características anatômicas foliares e caulinares são comuns às leguminosas.

Thesis (Ph.D. Agriculture (Plant Production)) -- University of Limpopo, 2022 / Livestock has evolved to serve as the foundation and backbone of human well-being, and it is an important component of South Africa's agricultural sector. The small stock such as sheep (Ovis aries) in Limpopo province has remained a significant and multifunctional livelihood strategy for the majority of the rural and resource-poor people. Factors such as population growth, urbanization, rising per capita income and changes in consumer tastes and preferences are all contributing to gradual increases in livestock product consumption and demand. According to the 2019 Abstract of Agricultural Statistics, South Africa is an importer of sheep and sheep products. If the sheep production industry in the province could pursue this opportunity and realize its full production potential then increased production could stimulate economic growth and development, particularly from the communal and smallholder sector. Objective one of the study seeks to describe the demographic and socio-economic characteristics of communal and smallholder sheep farmers, identify sheep feeding practices and describe the constraints that hinder the sustainable productive growth of communal and smallholder sheep systems. Data were collected from one hundred and twenty (120) sheep farmers using a structured questionnaire across three agro-ecological zones of Limpopo province. Results revealed that overall, the majority of sheep farmers were males (78%) and farmers were above 60 years old (48%). Mean sheep flock size differed significantly between communal (24.74) and smallholder (62.36) farmers. Indigenous crossbreeds were the dominant breed kept by communal (86%) and smallholder (77%) farmers. The majority of communal and smallholder farmers (90% and 96%, respectively) reared their sheep under an extensive system with rangelands as the main source of feed. As a result, they experience a critical feed gap during June and September, the mid-winter to early spring until the first rains. The findings of the study revealed that feed shortages and diseases were ranked as the first and second production constraints by sheep farmers in both the production systems. In rangeland-dependent feeding systems, insufficient feed to meet animal demands create a feed gap, which is a critical factor that limits sheep productivity and causes xxi land degradation through overgrazing. Improved forages have been widely advocated as a critical step toward resolving this challenge. However, the adoption and utilization of improved technologies such as on-farm forage legume production by these farmers have been very low, contributing to the province's low sheep productivity. An extension of objective one of this study used primary data which was collected from a sample of 120 sheep farmers to determine the factors that influence the adoption of on-farm forage legume production and the perceived barriers to adoption by communal and smallholder sheep farmers in the Limpopo province. A Probit regression model and Principal Component Analysis (PCA) were used to analyze the data. The study revealed that the adoption of on-farm forage production by communal and smallholder sheep farmers is influenced by several factors, including gender, farming experience, knowledge of forage legume production, source of income, membership in farmer associations, access to extension services and farm size. Farmer perceived barriers to adoption of on-farm forage legume production identified by this study were low institutional support, lack of resources, lack of knowledge, shortage of water and objectives of the farmer. It is therefore recommended that intensive and high-quality extension support in partnership with industry associations and stakeholders is required for communal and smallholder farmers to improve forage technology awareness, training and promote on-farm forage production to transform communal and smallholder sheep feeding practices. In the face of climate change, identifying forage species with a high potential to mitigate winter feed gap challenges under more variable climatic conditions is critical. Trifolium and Vicia species are forage legumes well known for producing high-quality forage, particularly protein, which is deficient in the majority of feed resources used for sheep feeding during the winter season. Climate change-induced stresses from rising temperatures, which these winter annual forage legumes are likely to face, necessitate agronomic and breeding approaches to improve their adaptability. Lack of knowledge on how these climate change mitigation approaches influence the productivity of winter annual forage legumes in the Pietersburg Plateau of Limpopo province prompted objective two of this study. A three-year field experiment laid in a split-split plot design with four replications was conducted to measure the effects of planting date, cultivar and harvest stage on the physiological traits associated with biomass production, forage quality, nodulation activity and xxii nutritive value of annual clover and vetch species. The results showed that the planting date and harvest stage had a significant effect on leaf gaseous exchange and biomass production. A non-significant effect of planting date on nutritive value was observed. Intercellular CO2 concentration, transpiration rate, stomatal conductance, instantaneous water use efficiency and intrinsic water use efficiency in cultivars increased with delayed planting, while a decrease in photosynthetic rate, shoot DM, root DM and nodule DM was observed. Overall among the cultivars, Resal, Alex, Elite, Laser and Dr Baumans showed more consistency in terms of leaf gaseous exchange, biomass production and quality traits under planting date 1 and varying harvest stages. Investment in the year-round fodder flow establishment with high-quality forages is important in supporting sustainable sheep production. Forage legume-grass rotation systems are important not only for green fodder production of high crude protein, mineral and vitamin content throughout the year but also for enhanced soil fertility to reduce the nitrogen (N) fertilizer requirements. Accurate estimates of forage yields on the farm are required for fodder flow planning to ensure the seasonal distribution of fodder throughout the year. Objective three of the study was a no-tillage, short-term rotation experiment conducted to determine the growth and nutritive value of forage sorghum, planted after the winter annual forage legumes in combination with nitrogen application and to validate the performance of the APSIM-grain sorghum crop model in simulating forage sorghum growth and biomass production under different N rates. The treatments were planting date (January and February) and N source from inorganic N fertilizer (0 kg N ha-1, 60 kg N ha-1, 120 kg N ha-1, 180 kg N ha-1) and forage legume N residues (Alex, Capello, Dr Baumans, Elite, Hanka, Laser, Linkarus, Opolska, Resal and Timok) arranged in a randomized complete block design with four replicates. The findings of this study showed a significant response of forage sorghum growth and nutritive value to planting date. Delayed planting reduced plant height (11%), stem diameter (18%), LAI (6.7%), chlorophyll content (18%), NDVI (2.5%), photosynthetic rate (38%) and biomass production (8%). Delayed planting further reduced crude protein, acid detergent fiber and N yield. Nitrogen source from inorganic N at 60 kg N ha-1, 120 kg N ha-1, 180 kg N ha-1 and residual N from annual clover and vetch cultivars had a significant effect on morphological, physiological, yield and nutritive value parameters of forage sorghum. xxiii Generally, legume N residue effects on all the studied parameters of forage sorghum were similar to the inorganic N fertilizer of 60 kg N ha-1. However, the effects differed widely according to the species and cultivar of the legume. Resal, Laser, Elite Capello and Dr Baumans N residue consistently showed greater effects than other legume residues. They consistently outperformed inorganic 60 kg N ha-1 on the most measured parameters. The results confirm that annual clover-forage sorghum and vetch-forage sorghum rotation have huge potential to reduce the cost and negative environmental effects associated with inorganic N use in forage prediction systems. Regarding the evaluation of the potential of the APSIM grain legume model to simulate forage legume DM and plant height, in general, the model performed well and accurately in predicting the shoot dry matter accumulation and plant height under 0 kg N ha-1, 60 kg N ha-1 and 120 kg N ha-1. However, it underestimated both these parameters at 180 kg N ha-1 implying that the application of N up to 180 kg N ha-1 is not necessary. APSIM-grain module was able to accurately predict forage biomass production under N rates up to 120 kg N ha-1 and it is therefore considered reliable to support the N nutrition in the forage sorghum fodder production systems. / University of Limpopo, research office under the UCDP program and National Research Foundation-Thuthuka