Thesis (Ph. D.)--University of Wisconsin--Madison, 1956. / Typescript. Abstracted in Dissertation abstracts, v. 16 (1956) no. 2, p. 256. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 84-91).

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The agroforestry practice of establishing shelterbelts and/or windbreaks composed of tree and shrub species that include buffaloberry (Shepherdia argentea Nutt.), caragana (Caragana arborescens Lam.) and sea buckthorn (Hippophae rhamnoides L.) is widespread within Saskatchewan. Shelterbelts play major roles in reducing wind speed, trapping snow, improving land-use efficiency and increasing economic returns. However, the practice of alley cropping within Saskatchewan is not popular. Also, apart from the protective roles the tree species offer in shelterbelts, some species have atmospheric nitrogen (N2)-fixation capabilities through biological nitrogen fixation (BNF) that are potentially important. The simultaneous integration of trees and crops on the same land management unit may lead to competition between crops and trees for growth resources such as nutrients, soil moisture and incoming radiation, the latter leading to limited access of light for understory crops. Understanding the contributions of the trees in supplying nitrogen (N) through BNF and in modifying microclimatic conditions in the alleyways would generate information needed to know their impacts on yield and nutrition of associated crops. In order to assess the contribution of the tree species in supplying N and minimizing interspecific competition while maximizing the benefits of tree-based intercropping systems, the thesis quantified the BNF capabilities of each species under greenhouse conditions using 15N dilution techniques and assessed how much of the fixed N2 is transferred to associated triticale (Triticale hexaploide Lart.) and oats (Avena sativa L.) under field conditions. Growth and yield of oats was also studied by measuring photosynthetically active radiation (PAR) and soil moisture in a Manitoba maple (Acer negundo var. negundo L.) -oats alley cropping system at Indian Head, SK. The BNF results showed that each of the test species fixes a substantial amount of N and there was a high transfer of N to associated triticale and oats. Results from the interspecific interaction study also showed that soil moisture was the primary factor affecting oats yields followed by light, with the south-lying oat plants affected more than north-lying. It can be concluded that alley cropping systems can be a practical and beneficial agroforestry practice within Saskatchewan. However, the distance between tree rows should be wide enough to permit farm machinery operations.

Thesis (M.Sc. (Pasture Science)) -- University of Limpopo, 2014 / Forage sorghum is widely grown in South Africa as annual summer forage to supplement pasture production for sheep, beef and dairy cattle. A number of sorghum cultivars are available commercially, and periodically some cultivars are added while others are withdrawn from the market. The potential yield figures and the nutritive value of these forage sorghum cultivars are generally not known. The management practices that improve forage sorghum production and quality include the time of planting and time of harvesting. The genetic makeup of different forage sorghum cultivars also accounted for a portion of the production and quality. A field experiment was conducted at Dewageningsdrift Experimental Farm (DWD), Moloto, Gauteng and Nooitgedacht Agricultural Development Center (NGD), Ermelo, Mpumalanga to study the influence of planting date on the growth potential of different forage sorghum cultivars. Three planting dates were used: mid-December 2006, mid-January 2007 and mid-February 2007. Thirteen different cultivars were incorporated in the trial to evaluate influence of the breeding history. The cultivars were defoliated at three different stages: cut repeatedly at six weekly intervals (Dt 1), cut repeatedly when it reached a grazing stage (± 800 mm high) (Dt 2) and once at the silage stage (soft dough) (Dt 3). At DWD the average total dry matter (TDM) productions, for the six week cutting treatment (Dt 1), were 10760 kg/ha, 5195 kg/ha and 1944 kg/ha for December, January and February planting date respectively. For the same treatment, at NGT, the average TDM productions were 6396 kg/ha and 1737 kg/ha for December and January respectively. The February planting resulted in the poor germination and seedling emergency. The seedlings did not survive due to low temperatures. The minimum of 13 ºC and 11.8 ºC as well as the maximum of 24.1 ºC and 23.0 ºC in February and March were below the required germination temperature (15 ºC). The highest producers that is available in the market were Jumbo, Sentop, Piper, Kow Kandy, and Sugargraze. Defoliated repeatedly at grazing stage (Dt 2), at DWD, resulted in average TDM productions of 8541 kg/ha, 4950 kg/ha and 2683 kg/ha for December, January and February, respectively. At NGT the average TDM productions were 7769 kg/ha and 3010 kg/ha for December and January respectively. The highest producers were Jumbo, Kow Kandy, Piper, Sentop and Sugargraze. The average TDM productions at the silage stage (Dt 3), at DWD, were 17923 kg/ha, 15015 kg/ha and 2529 kg/ha for December, January and February respectively. At NGT the average TDM production iii was 11856 kg/ha and 5350 kg/ha for December and January, The highest producers were Jumbo, Sugargraze, Kow Kandy, Sentop and Kow Kandy.December planting proved to be the best planting date for optimum DM production, compared to later plantings in January and February. Keywords Forage sorghum, cultivars, planting dates, defoliation stages, grazing stage, silage

Es wird ein Überblick über mögliche Auswirkungen des Klimawandels auf den Anbau von Futterpflanzen gegeben, um daraus eventuelle Auswirkungen auf den Ackerfutterbau im Freistaat Sachsen abzuleiten.

The negative impact of climate change on agricultural production is consistently increasing all over the world. As a result of these changes, the yields of some crops have been decreasing. The main problems include frequent weather changes, especially long periods of drought accompanied by high temperatures. The aim of this diploma thesis was to assess the effect of water deficit on offshoot germination and longevity of selected species of grasses and clovers. The evaluation of resistance to water deficit was carried out using both laboratory and pot experiments. The results of these experiments were used to evaluate the drought resistance of the tested species of grasses and legumes. Based on the proven drought resistance, appropriate species and varieties have been recommended for cultivation in conditions of water deficit. The issue of drought resistance is to be paid more and more attention in the future. According to most forecasts, increasingly long periods of drought are likely to occur. For this reason, there will be the need for crops and varieties that best resist to various abiotic stresses.

Philosophiae Doctor - PhD / The lack of bioclimatically suitable forage species for livestock production in the water-limited agro-ecological areas of South Africa has resulted in significant feed shortages within these areas during the ongoing drought experienced within the country. This, in turn, has resulted in significant livestock mortalities leading to financial difficulties for the farmers and farming communities within these areas. Thus, many of the water-limited agro-ecological areas in South Africa have been declared disaster areas. These cyclic long-term droughts, as well as more common short-term droughts are expected to increase in frequency, duration and intensity under the predicted future bioclimatic conditions. Although there has been significant investment into the development of improved, better-adapted forage crops for these bioclimatically marginal agro-ecosystems, these efforts, to date, have largely been unsuccessful. Therefore, in this study, we propose to identify and evaluate species that are native to the water-limited South African agro-ecosystems and that can potentially be implemented in alternative fodder flow programs within these water-limited agro-ecological areas. / 2022

Es wird ein Überblick über mögliche Auswirkungen des Klimawandels auf den Anbau von Futterpflanzen gegeben, um daraus eventuelle Auswirkungen auf den Ackerfutterbau im Freistaat Sachsen abzuleiten.

Submitted by (edna.saturno@ufrpe.br) on 2017-04-27T12:57:30Z No. of bitstreams: 1 Hiran Marcelo Siqueira da Silva.pdf: 681757 bytes, checksum: 615f7dc1968ee600a6eb6b2a3d54b5da (MD5) / Made available in DSpace on 2017-04-27T12:57:30Z (GMT). No. of bitstreams: 1 Hiran Marcelo Siqueira da Silva.pdf: 681757 bytes, checksum: 615f7dc1968ee600a6eb6b2a3d54b5da (MD5) Previous issue date: 2013-02-28 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / The physical properties of the soil can be affected by stocking rate. When stocking rates are applied correctly can provide favorable environment for root growth. Nitrogen fertilization can also stimulate growth and root activity. Thus, the replacement nitrogen ecosystem grazing results in higher biomass production and more efficient absorption of the nutrients in the soil. Manipulation in stocking and fertilization interfere in the processes of decomposition of plant tissue affecting nutrient cycling in pasture ecosystems. The study was conducted at the Experimental Station of the Agronomic Institute of Pernambuco in Itambé for two years (2009-2010). The experimental treatments consisted of three stocking rates (2.0, 3.9 and 5.8 AU ha-1, 1 AU = 450 kg BW) and three nitrogen levels (0, 150 and 300 kg ha-1 N year-1) grazing elephant grass (Pennisetum purpureum Schum.). Treatments were replicated three times and used a randomized block design in a split plot arrangement. Therefore, the objective was to evaluate the effect of nitrogen fertilization and stocking rate on physical and chemical attributes of the soil, the root distribution in depth and decomposition of roots grazing elephant grass. For part of soil and destruction of root was determined soil bulk density, particle density, porosity, aggregate stability, infiltration rate of the soil water, the light fraction of soil organic matter, soil fertility in depth, root length density and root biomass. For the decomposition analysis, we used the simple exponential model for percentage of disappearance of biomass remaining N (%). The two stage model ("plateau linear") was used to describe ON, NIDA, N and LIG: N throughout the incubation period. The increased stocking rate resulted in higher densities of soil ranging from 1.42 to 1.58 g cm-3. The light fraction of soil organic matter decreased with increasing stocking rate. The aggregation index increased with depth with values of 42.07, 47.75 and 51.04% for the soil layers 0-2.5, 2.5-7.5 and 7.5-15 cm, respectively . Soil fertility also varied at 0-20, 20-40, 40-60, 60-80 and 80-100 cm. The root length had an effect between depths. In the 0-20 cm layer was longest of all types of roots (thin, thick and full). The decomposition of biomass in the second period (10-11) was higher in the first period (9-10). After 512 days of incubation, the biomass remaining in the first period was 40% whereas in the second period was 30%. The C: N ratio dropped to two periods over the 512 days of incubation, however, as they were passing incubation times, the C: N ratio for the second period fell faster (k = 0.00168 g g-1 day-1) compared to the first period (k = 0.00113 g g-1 day-1). The lignin content increased during the incubation time. At time zero, the lignin content in the first period was higher (~ 17%) found for the second period (~ 10%). The stabilization of lignin in the first period was only achieved after 240 days of decomposition with final value of 22%, whereas in the second period, stabilization was reached after 118 days of incubation with final value of approximately 20%. At the end of two years experimental treatments, stocking rate and nitrogen fertilization did not affect Pt, VIB and EA nor influenced the fertility of the soil, the root distribution and root residue decomposition during the trial period. Moreover, the stocking rate modified the soil density and light fraction organic matter. Nitrogen rates interfered with mineralization of N from the root stock. / As propriedades físicas do solo podem ser afetadas pela taxa de lotação animal. Quando as taxas de lotação animal são aplicadas de forma correta podem proporcionar ambiente favorável ao crescimento do sistema radicular. A adubação nitrogenada também pode estimular o crescimento e a atividade radicular. Sendo assim, a reposição nitrogenada em ecossistema de pastagem resulta em maior biomassa produzida e absorção mais eficiente dos nutrientes no solo. A manipulação na lotação e a adubação interferem nos processos de decomposição do tecido vegetal, afetando a ciclagem dos nutrientes nos ecossistemas de pastagem. O estudo foi realizado na Estação Experimental do Instituto Agronômico de Pernambuco em Itambé por dois anos (2009-2010). Os tratamentos experimentais consistiram de três taxas de lotação animal (2, 3,9 e 5,8 UA ha-1; 1 UA = 450 kg PV) e três níveis de adubação nitrogenada (0, 150 e 300 kg N ha-1ano-1) em pastagens de capim-elefante (Pennisetum purpureum Schum.). Os tratamentos foram repetidos três vezes, sendo utilizado o delineamento em blocos casualizados em arranjo de parcelas subdivididas. Sendo assim, objetivou-se avaliar o efeito da adubação nitrogenada e da taxa de lotação nos atributos físicoquímicos do solo, na distribuição de raízes em profundidade e na decomposição das raízes em pastagens de capim-elefante. Para a parte de solo e distribuição de raiz em profundidade foram determinados: a densidade do solo, densidade das partículas, porosidade total, estabilidade de agregados, infiltração básica de água no solo, a fração leve da matéria orgânica do solo, fertilidade do solo em profundidade, a densidade de comprimento de raiz e a biomassa radicular. Para a análise de decomposição, foi utilizado o modelo exponencial simples para porcentagem de desaparecimento de biomassa, N remanescente (%). O modelo de dois estágios (“plateau linear”) foi utilizado para descrever LIG, NIDA, N e LIG:N ao longo do período de incubação. O aumento da taxa de lotação resultou em maiores densidades do solo que variou de 1,42 a 1,58 g cm-3. A fração leve da matéria orgânica do solo reduziu com o aumento da lotação animal. O índice de agregação aumentou com a profundidade, com valores de 42,07, 47,75 e 51,04% para as camadas de solo 0-2,5, 2,5-7,5 e 7,5-15 cm, respectivamente. A fertilidade do solo também variou nas camadas de 0-20, 20-40, 40-60, 60-80 e 80-100 cm. O comprimento de raiz apresentou efeito entre as profundidades. Na camada de 0-20 cm houve maior comprimento de todos os tipos de raízes (fina, grossa e total). A decomposição da biomassa no segundo período experimental (10-11) foi maior ao primeiro período (9-10). Após 512 dias de incubação, a biomassa remanescente no primeiro período foi de 40%, enquanto que no segundo período foi de 30%. A relação C:N caiu para os dois períodos experimentais no decorrer dos 512 dias de incubação, no entanto, à medida que foram passando os tempos de incubação, a relação C:N para o segundo período caiu mais rapidamente (k=0,00168 g g-1 dia-1), se comparado ao primeiro período (k=0,00113 g g-1 dia-1). O teor de lignina aumentou durante o tempo incubação. No tempo zero, o teor de lignina no primeiro período foi superior (~17%) ao encontrado para segundo período (~10%). A estabilização da lignina, no primeiro período, só foi alcançada aos 240 dias de decomposição com valor final de 22%, enquanto que no segundo período a estabilização foi alcançada aos 118 dias de incubação com valor final aproximado de 20%. Ao final de dois anos experimentais os tratamentos, taxa de lotação e adubação nitrogenada não alteraram a Pt, VIB e o EA, nem tão pouco influenciaram os parâmetros de fertilidade do solo, a distribuição do sistema radicular e na decomposição do resíduo radicular no período experimental. Por outro lado, a taxa de lotação modificou a densidade do solo e a fração leve da matéria orgânica. As doses de nitrogênio interferiram na mineralização do estoque de N da raiz.