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Water, Soil and Crop Management Principles for the Control of SaltsFuller, Wallace H. 07 1900 (has links)
This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.
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Micropropagation and secondary metabolites of Sclerocarya birrea.Moyo, Mack. January 2009 (has links)
Sclerocarya birrea (marula, Anacardiaceae) is a highly-valued indigenous tree in most parts of sub-Saharan Africa because of its medicinal and nutritional properties. The marula tree is adapted to the semi-arid conditions that characterise most parts of sub-Saharan Africa and renders them unsuitable for conventional crop agriculture. The unique nutritional properties of marula and its high tolerance to dry conditions provide opportunities for its development into a plantation crop. On the other hand, the demand for marula plant parts, mainly the bark and roots as medicinal remedies, poses a great threat to wild populations. In the long term, the growing demand of marula products in the food, pharmaceutical and cosmetic industries will not be sustainable from wild populations alone. Plant tissue culture technologies can be useful for in vitro manipulation and mass propagation of the plant in the process of domestication and conservation. The aims of the project were to determine the optimum conditions for seed germination, in vitro propagation and plant regeneration, and to evaluate the potential bioactivity of secondary metabolites from its renewable plant parts as an alternative option in the conservation of S. birrea.
An ex vitro seed germination study indicated that after-ripening and cold stratification are critical factors. Cold stratification (5 °C) of marula nuts for 14 days improved germination (65%) as compared to non-stratified nuts (32%). Direct shoot organogenesis was achieved from leaf explants through the induction of nodular meristemoids on Murashige and Skoog (MS) (1962) medium and woody plant medium (WPM) supplemented with 6-benzyladenine (BA) in combination with naphthalene acetic acid (NAA), indole-3-butryric acid (IBA) and indole-3-acetic acid (IAA). Induction of nodular meristemoids from 86% of the leaf cultures was achieved on a MS medium with 4.0 ìM BA and 1.0 ìM NAA. High levels (78–100%) of induction were also achieved on WPM with different concentrations of BA (1.0–4.0 ìM) and IBA (1.0–4.0 ìM). The highest conversion of nodular meristemoids into shoots on MS initiation medium was only 22% for 4.0 ìM BA and 1.0 ìM NAA. This was improved to 62% when nodular clusters were cultured in MS liquid medium. Histological studies revealed high numbers of unipolar meristematic buds developing from globular nodules. These embryo-like structures have in the past been mistaken for true somatic embryos. The initiation of high numbers of nodular meristemoids per explant provides potential for automated large-scale clonal propagation in bioreactors, in vitro phytochemical production and the development of synthetic seed technology, similar to somatic embryogenesis. Plant regeneration through nodule culture has potential for application in mass micropropagation and plant breeding of S. birrea.
Adventitious shoot and root induction are important phases in micropropagation. Plant growth regulators play an important role in these developmental processes, and the type and concentration used have major influences on the eventual organogenic pathway. Three auxins (IAA, IBA and NAA) and four aromatic cytokinins (6-benzyladenine, meta-topolin, meta-topolin riboside, and meta-methoxytopolin riboside) were evaluated for their potential to induce adventitious shoot and root formation in S. birrea shoots, hypocotyls and epicotyls. Among the evaluated cytokinins, the highest adventitious shoot induction (62%) was achieved on MS medium supplemented with meta-topolin (8.0 ìM). The lowest adventitious shoot induction (2.5%) was obtained on MS basal medium containing 2.0 ìM meta-methoxytopolin riboside. The highest adventitious shoot induction for hypocotyls was 55% on MS medium supplemented with 8.0 ìM meta-topolin. For the tested auxins, IBA induced adventitious rooting in 91% of shoots at a concentration of 4.0 ìM after 8 weeks in culture. However, the in vitro rooted plants only survived for two weeks when transferred ex vitro. A temperature of 25 °C and 16-h photoperiod were optimum for adventitious root induction. Stomatal density (number per mm2) on the abaxial leaf surfaces was higher for the 16-h photoperiod treatment (206.6 ± 15.28) compared to that for a 24-h photoperiod (134.6 ± 12.98). Normal mature stomata with kidney-shaped guard cells and an outer ledge over the stomatal pore were observed for in vitro plants growing under a 16-h photoperiod.
Total phenolic content, proanthocyanidins, gallotannins, flavonoids, and antioxidant activities of S. birrea methanolic extracts were evaluated using in vitro bioassays.
Methanolic extracts of the young stem bark and leaves contained high levels of these phytochemicals. Sclerocarya birrea young stem extracts contained the highest levels of total phenolics (14.15 ± 0.03 mg GAE g-1), flavonoids (1219.39 ± 16.62 ìg CE g-1) and gallotannins (246.12 ± 3.76 ìg GAE g-1). Sclerocarya birrea leaf extracts had the highest concentration of proanthocyanidins (1.25%). The EC50 values of the extracts in the DPPH free radical scavenging assay ranged from 5.028 to 6.921 ìg ml-1, compared to ascorbic acid (6.868 ìg ml-1). A dose-dependent linear curve was obtained for all extracts in the ferric-reducing power assay. All the extracts exhibited high antioxidant activity comparable to butylated hydroxytoluene based on the rate of â-carotene bleaching (89.6 to 93.9%). Sclerocarya birrea provides a source of secondary metabolites which have potent antioxidant properties and may be beneficial to the health of consumers.
Sclerocarya birrea young stem and leaf ethanolic extracts exhibited high bioactivity (MIC < 1.0 mg ml-1) against both Gram-positive (Bacillus subtilis and Staphylococcus aureus) and Gram-negative (Escherichia coli and Klebsiella pneumoniae) bacteria. The highest activity (MIC = 0.098 mg ml-1 and total activity = 1609.1 ml g-1) was recorded for young stem extracts against B. subtilis. The highest activity (MIC = 1.56 mg ml-1 and MFC = 1.56 mg ml-1) in the antifungal assay against Candida albicans was observed for young stem ethanolic extracts. Sclerocarya birrea extracts had moderate acetylcholinesterase (AChE) inhibition activity. The dichloromethane (DCM) and methanol (MeOH) fractions exhibited dose-dependent acetylcholinesterase inhibitory activity. The highest AChE inhibitory activities were from leaves (DCM fraction, IC50 = 0.1053 mg ml-1) and young stems (MeOH fraction, IC50 = 0.478 mg ml-1). High inhibitory activity against cyclooxygenase (COX-1 and COX-2) enzymes was observed. All extracts and fractions showed high COX-1 enzyme inhibition (90.7-100%). Petroleum ether (PE) and dichloromethane fractions also exhibited high inhibition against COX-2 enzyme (77.7-92.6%). The pharmacological activities observed suggest that S. birrea renewable plant parts (leaves and young stems) provide a substantial source of medicinal secondary metabolites. Based on these results, plant part substitution can be a practical conservation strategy for this species. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2009.
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Incorporating the Canegro sugarcane model into the DSSAT V4 cropping system model framework.Jones, Matthew Robert. 31 July 2013 (has links)
Canegro is a leading sugarcane crop simulation model and has been used extensively in agronomic research and management. The model has been under development since the late 1980s at the South African Sugarcane Research Institute (SASRI). The Decision Support System for Agrotechnology Transfer (DSSAT) is a software package containing models for a wide range of field crops, and utilities for processing, storing and analysing model inputs and outputs. Canegro was included as part of version 3.1 of DSSAT in the mid-1990s. The SASRI Canegro model was subsequently developed further, but these changes were never integrated, nor incorporated, into DSSAT. DSSAT has also developed substantially, and as of version 4 adopted a modular Cropping System Model (CSM) structure, providing numerous scientific and practical advantages over previous non-modular versions. The DSSAT-Canegro v.3 model was not modified to use this modular structure.
Following recognition of the advantages offered by DSSAT and its modular CSM, a project was initiated to incorporate the Canegro model into the DSSAT CSM. The project entailed: (i) restructuring and integrating the current Canegro plant growth and development code into the DSSAT v4 CSM modular framework, making use of its generic modules for management, soil, weather and the energy balance; (ii) verification of DSSAT CSM Canegro model results against the current SASRI version of Canegro to ensure that the new model produced similar results to the original model, for a set of simulated situations; and (iii) evaluation of the new DSSAT CSM Canegro model against experimental datasets.
The new DSSAT v4 CSM Canegro model has been verified to behave identically to the SASRI Canegro model when the water balance is not modelled and growth can occur at climatic potential rates. When the water balance is simulated but where the crop is not stressed, near identical output is produced by both models. Under water-stressed conditions, some discrepancies appear between the two models, due to differences in the calculation of reference evaporation, soil surface evaporation and runoff. Validation of the new model against data from 16 experimental crops produced root mean squared errors of 6.62 t ha-1 for stalk dry mass and 3.59 t ha-1 for sucrose mass – very similar to published values for Canegro. This project has yielded a functional, well-documented, maintainable and user-friendly version of the Canegro model, which is available for universal use via the official release of the DSSAT v4.5. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2013.
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Land suitability evaluation for rainfed agriculture using GIS : the case study of Weenen Nature Reserve, KwaZulu-Natal, South Africa.Ghebremeskel, Legesse Abraham. January 2003 (has links)
Weenen Nature Reserve (WNR) has a long history of unwise land use that resulted in severe overgrazing and soil degradation. Since 1948 several soil conservation and reclamation programs have been undertaken to halt the degradation process and regain the agricultural potential of the area. This study evaluates the current agricultural potential of the reserve under rainfed cultivation primarily based on climatic, soil, topographic and crop requirement data collected from different sources. Spatial information on each of the land resources parameters was digitally encoded in a GIS database to create thematic layers of the land resources. Crop requirement information on seven different crops that were selected as representative crops under rainfed agriculture in the area namely, maize, Sorg):mm, cotton, dry bean, soya bean, potato and cabbage was compared with the land resources parameters. The thematic layers of the land resources were then overlyed using a GIS to select areas that satisfy the crop requirements. The results showed that WNR has two major limitations in relation to its use for rainfed agriculture, namely its shallow and rocky soils and its arid climate. Consequently, the resulting land suitability maps indicate that WNR has very low suitability for all of the crops considered. Dry beans are relatively well adapted to the area followed by sorghum. Maize and soya beans are preferred over cotton. Potatoes'and cabbages are least adapted to the area because of the high temperatures during thCl/growing season. It was concluded that generally the reserve is not suitable for rainfed agriculture. However, there is a small area of land in the northern part of the reserve that can be cultivated. The rugged area in the central part of the reserve can be used for grazing with careful managemeIit. The eastern and southern parts can only be used as habitats for wildlife owing to their steep topography and inaccessibility, whereas the highly degraded areas in the western parts of the reserve should be kept under soil conservation and reclamation. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 2003.
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Growth and nutritive value of lucerne ( Medicago sativa L. ) and Melilotus ( Melilotus albus Medik. ) under saline conditionsGuerrero-Rodriguez, Juan de Dios January 2006 (has links)
Dryland salinity is a major and expanding threat to agricultural land in Australia. Animal production from forages grown on saline land is perhaps its most promising economic use. Glycophytic forage legumes have been evaluated under saline conditions mainly for agronomic characteristics and, to a lesser extent, for nutritive quality to animals. Plant growth and its nutritive quality are interrelated, but a decline in yield in response to salinity may be associated with effects on the chemical constituents of the plant since soil salinity affects plant metabolism. This research aimed to investigate changes in the components of yield and nutritive value of two legumes species. Lucerne ( Medicago sativa ) and Melilotus ( Melilotus albus ) were exposed to different levels of NaCl in the range of 0 to 110 mM NaCl. The research tested the hypothesis that the components of plant nutritive value are not as sensitive to salinity as shoot biomass production since the adaptive mechanisms of the plant lessen harmful effects of the salts. For both plant species, salinity decreased leaf and stem dry matter production, but increased leaf - to - stem ratio. In addition, salinity resulted in earlier flowering in Melilotus. Mineral composition was the most sensitive component of forage quality. Calculated sodium chloride concentrations were up to 125 g / kg DM in lucerne and 39 g / kg DM in Melilotus when irrigated with 110 mM NaCl. The concentrations of calcium and magnesium decreased in both species and approached the marginal range for animal production. Zinc concentration also decreased while potassium decreased in stems of lucerne only. The digestible organic matter ( DOMD ) in response to salinity varied between species. At the highest salt concentration, the whole shoot ( i.e., leaf and stem ) of lucerne decreased up to 4 percentage units while Melilotus increased by 6 percentage units. In lucerne, DOMD was influenced by a high concentration of soluble ash in leaf and stem and, in Melilotus, by an increase in the organic matter content of leaf and a reduction in lignin concentration in stem, which favoured higher digestibility. These results were supported by a histological study in which an increase in starch in Melilotus leaf, and a lower proportion of xylem in relation to parenchyma in stems, was measured. Crude protein concentration was not compromised and, in relation to Melilotus, coumarin concentration did not increase with salinity. In conclusion, the reduction in DM production of species with similar salt tolerance does not necessarily correspond to an equivalent reduction in nutritive value. This research represents the most detailed study into effects of salinity on glycophytic forage legumes. Results show that while some aspects of forage quality ( e.g., minerals composition and energy ) are strongly influenced by salinity, other aspects ( e.g., protein ) remain relatively unaffected. These findings have implications for development of productive grazing systems on saline agricultural land. / Thesis (Ph.D.)--School of Agriculture, Food and Wine, 2006.
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Potential oil crops : cultivation of Barbarea verna, Barbarea vulgaris and Lepidium campestre /Börjesdotter, Desirée, January 1900 (has links) (PDF)
Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv. / Härtill 4 uppsatser.
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Fornecimento de nitrogênio em cobertura no feijoeiro em sucessão à sistemas de cultivo de milho no plantio direto / Nitrogen supply in beans coverage in succession of corn crops in no-tillageCouto Junior, Pedro Afonso 06 April 2018 (has links)
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Previous issue date: 2018-04-06 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A cultura do feijoeiro é bastante exigente em nitrogênio, elemento que sofre diferentes transformações na agricultura e passível de perdas na agricultura, em função de fatores adversos. O feijão também possui função social pelo fato de ser um dos principais alimentos da dieta dos brasileiros. Sendo assim, os objetivos deste trabalho foram verificar viabilidade do consórcio de milho com Urochloa ruziziensis e Crotalária spectabilis em termos de produtividade de grãos e de palhada; e em uma segunda etapa a resposta do feijoeiro cultivado em sucessão aos sistemas de cultivo e ao fornecimento de nitrogênio em cobertura no primeiro e no segundo ano de implantação do sistema plantio direto na palha. O experimento foi conduzido ao longo das safras de 2014/2015 e 2015/2016, num Latossolo Vermelho eutroférrico, argiloso em Jaboticabal-SP, no delineamento de blocos casualizados, em esquema de parcelas sub-subdivididas, com quatro repetições. As parcelas foram constituídas pelos sistemas de cultivo de milho exclusivo, milho consorciado com Urochloa ruziziensis e milho consorciado com Crotalária spectabilis, antecessores ao cultivo do feijoeiro. As subparcelas foram compostas por combinações de fornecimento do nitrogênio em cobertura no feijoeiro, na dose de 90 kg ha-1, sendo aplicada em dose única por ocasião do surgimento do primeiro trifólio, na presença do terceiro trifólio e no pré-florescimento, e de modo parcelado com 45+45+00, 00+45+45, 30+60+00, 00+60+30, 60+30+00 e 30+30+30 nos estádios fenológicos supracitados, bem como a ausência do fornecimento de nitrogênio em cobertura e as sub-subparcelas constituídas pelas safras 2015 e 2016. Os três sistemas de cultivo de milho tiveram para a produção de palhada e recobrimento da superfície do solo valores acima de 7,0 t ha-1 e 89 %, respectivamente, viabilizando a adoção do sistema plantio direto, sendo que para a produtividade, quando consorciado com Crotalária spectabilis, houve superioridade sobre os demais sistemas de cultivo, nas duas safras. A produtividade de grãos no feijoeiro é influenciada pela forma de fornecimento de nitrogênio em cobertura e pela palhada do sistema de cultivo de milho antecessor. O fornecimento de nitrogênio em cobertura no feijoeiro como 45+45+00 e 30+60+00, após os sistemas de cultivo de milho consorciados, promovem maiores produtividades de grãos, comparativamente ao sistema de milho exclusivo. As variáveis respostas qualitativas, proteína bruta, relação de hidratação e tempo para máxima hidratação dos grãos do feijoeiro são influenciadas pelos sistemas de cultivo de milho vs safras, bem como o fornecimento de nitrogênio em cobertura vs as safras agrícolas para o tempo de cozimento. / Bean is very demanding in nitrogen, an element that undergoes different transformations in agriculture and is susceptible to losses due to adverse factors. It also has a social function because beans are one of the main foods in Brazilians diet. Thus, the objectives of this work were to verify the viability of the maize consortium with Urochloa ruziziensis and Crotalária spectabilis in terms of grain productivity and straw; and in a second step verify the response of the bean cultivated in succession to the cropping systems and to the nitrogen supply in the first and second year of implantation of the no - tillage system in the straw. The experiment was conducted during the 2014/2015 and 2015/2016 harvests in a clayey Red Latosol at Jaboticabal-SP, in a randomized complete block design with four replications. The plots consisted of exclusive corn cultivation systems, maize intercropped with Urochloa ruziziensis and corn intercropped with Crotalária spectabilis, predecessors to bean cultivation. The subplots were composed of nitrogen supply combinations in bean cover, at a dose of 90 kg ha-1, being applied in a single dose at the time of the first trifolium, in the presence of the third trifolium and in the pre-flowering, and 45+45+00, 00+45+45, 30+60+00, 00+60+30, 60+30+00 and 30+30+30 in the phenological stages mentioned above, as well as in the absence of the supply of and the sub-subplots constituted by the 2015 and 2016 crops. The three maize cropping systems had values above 7.0t ha-1 and 89%, for the production of straw and covering of the soil, respectively, making it possible the adoption of the no-tillage system, and for productivity, the consortium with Crotalária spectabilis was better than the other cropping systems, in the two harvests.The bean productivity is influenced by the way of nitrogen supply in coverage and by the straw of the predecessor maize crop system. The nitrogen supply in bean cover as 45+45+00 and 30+60+00, after intercropped corn systems, promoted higher productivity, compared to the exclusive corn system. The qualitative variables, crude protein, hydration and time ratio for maximum hydration of bean grains are influenced by maize cropping systems vs harvests, as well as the nitrogen supply in cover vs agricultural harvests for the cooking time.
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Efektivní využití fytomasy v ochranném pásmu NP Podyjí / Effective use of phytomass in the protected area of the National Park PodyjíFORMANOVÁ, Petra January 2014 (has links)
The objective of the thesis is to evaluate the possibility of the effective use of waste and phytomass specifically grown for energy purposes in the protected area of National Park Podyjí. The task was to characterize the source of phytomass in this environmentally sensitive area. The data were collected by studying documents, visits to enterprises and institutions, and personal consultations with business and other stakeholders. The result of this work is a brief assessment of the production potential and the factors influencing its development. Due to the nature of the territory, to suggest measures for efficient use of land for the production of energy phytomass with regard to the attitudes of farmers and the authority of nature and landscape.
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Efeito residual do lodo de esgoto na cultura de cenoura (Daucus carota L.) : aspectos socioeconomicos e de fertilidadeCíntya Rodrigues Monte 00 March 2009 (has links)
No description available.
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Uplatnění meziplodin jako stabilizujícího prvku proti erozním splachům / Application of intercropping as a stabilizing element against erosion washes awayKUKAČKA, Vladislav January 2010 (has links)
The thesis was focused on the application of theorethical knowledge about catch crops and their influence on water erosion in practice. Its task is to evaluate the effect of the inclusion of catch crops in crop rotation in light of occurance and extent of water erosion on the example of agricultural enterprise ZEPHYR Františkovy Lázně, s.r.o. The task is also assessment of the possible combinations of crops and catch crops and suggestion for their use in middlegrowth period. The universal equation for calculation of erosion wash by Wischmeier and Smith was used to evaluate and calculate an erosion parameters for a given locality. The result of this thesis is reduction of soil loss by 26 % on lands with catch crop usage as a stabilizing element, compared to the classic conservative rotation of crops.
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