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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
221

Desempenho produtivo do milho em função dos atributos químicos do solo, tendo em vista a intensificação ecológica / Production performance of maize in function of soil chemical attributes, in view of the ecological intensification

VALE, Clemeson Cardoso 30 April 2014 (has links)
Submitted by Daniella Santos (daniella.santos@ufma.br) on 2017-12-06T15:15:55Z No. of bitstreams: 1 ClemesonVale.pdf: 2633941 bytes, checksum: d3b7926b71b1f8326929442dd906fefa (MD5) / Made available in DSpace on 2017-12-06T15:15:55Z (GMT). No. of bitstreams: 1 ClemesonVale.pdf: 2633941 bytes, checksum: d3b7926b71b1f8326929442dd906fefa (MD5) Previous issue date: 2014-04-30 / CAPES / The constant concerns over the unsustainable use of natural resources, coupled with rapid population growth, direct them to the productive process of maximizing resources systems to provide greater increases in production to minimize impacts to the environment yields. The objective of this research was to evaluate the performance of maize in no-tillage in legume straw depending on the spatial variability of soil chemical properties and nutrient input in a Dystrophic cohesive oxisol. The experiment was conducted in a 0.6 ha area containing two environments (without legumes and pulses) and 170 sampling points regularly dispersed (7.0 x 5.0 m) for chemical soil variability and productive maize yields. Data were initially analyzed using descriptive statistics and later by geostatistical methods. The interaction between soil chemical properties and yield of corn production was assessed by Pearson correlation to 5%. There was an increase in levels of soil chemical properties in the area with legumes compared to the area without legumes, proving the applicability of this management system to improve the chemical quality of the soil due to continuous addition of plant residues. Found the presence of spatial variability for all soil chemical properties and productive yield with spatial dependence ranged from moderate to strong, allowing reveal through thematic maps the potentialities and limitations of the production system. The productive efficiency, productivity specifically, correlated positively with calcium, sum of bases, phosphorus, potassium, base saturation and cation exchange capacity. / As constantes preocupações com o uso insustentável dos recursos naturais, juntamente com o acelerado crescimento demográfico, direcionam os sistemas produtivos ao processo de maximização dos recursos a fim de proporcionar maiores incrementos nos rendimentos produtivos com minimização dos impactos ao ambiente. O objetivo da presente pesquisa foi avaliar o desempenho produtivo do milho em sistema de plantio direto na palha de leguminosas em função da variabilidade espacial dos atributos químicos do solo e do aporte de nutrientes num Latossolo Amarelo distrocoeso. O experimento foi conduzido numa área de 0,6 ha contendo dois ambientes (sem leguminosas e com leguminosas) e 170 pontos amostrais regularmente dispersos (7,0 x 5,0 m) para determinação da variabilidade química do solo e dos rendimentos produtivos do milho. Os dados foram inicialmente analisados por meio da estatística escritiva e posteriormente por métodos geoestatísticos. A interação entre os atributos químicos do solo e o rendimento produtivo do milho foi verificada pela correlação de Pearson a 5%. Verificou-se a elevação nos teores dos atributos químicos do solo na área com leguminosas quando comparado com a área sem leguminosas, comprovando a aplicabilidade desse sistema de manejo para a melhoria da qualidade química do solo em consequência da adição continuada de resíduos vegetais. Constatou-se a presença de variabilidade espacial para todos os atributos químicos do solo e rendimento produtivo, com grau de dependência espacial que variaram de moderado a forte, o que possibilitou revelar por meio de mapas temáticos as potencialidades e limitações do sistema de produção. O rendimento produtivo, especificamente a produtividade, apresentou correlação positiva com o cálcio, a soma de bases, o fósforo, o potássio, a saturação por bases e a capacidade de troca catiônica.
222

Uso da cama de frango associada à adubação mineral no sistema de produção de grãos da região oeste do Paraná / Use of chicken manure in the production system of grains in the west region of the Paraná

Fávero, Fernando 24 August 2012 (has links)
Made available in DSpace on 2017-07-10T17:36:48Z (GMT). No. of bitstreams: 1 2012_Fernando_Favero.pdf: 1272944 bytes, checksum: 76629093052bbcbb9791607060f52856 (MD5) Previous issue date: 2012-08-24 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The production system of grains and meats in Brazil conducted the country to a ranking of the largest producers and exporters of food in the world. The integrated production of poultry generates defined quantities of waste. The chicken manure is rich in nutrients and can be so used as fertilizer in the crops. The knowledge of the responses related to the crops allows the utilization of the chicken manure in an adequate and a rational form, avoiding losses and reducing environmental impact. The objective was to evaluate the responses in the production of grains (soybeans, corn and wheat) with application of amounts of chicken manure before the winter crop, associated with mineral fertilizer (NPK). For this, an experiment was conducted in the Experimental Station of the Copacol in Cafelândia-PR with different doses of chicken manure (0, 2, 4, 6 and 8 t ha-1), and three systems of mineral fertilization (control, super phosphate simple and formulated) in the furrow of the seeding, during two years. The chicken manure was applied manually in the plots before the winter cultivation. The experimental design was defined as randomized complete block with plots subdivided in four replications. The total concentration of foliar N, P and K, yield components, biometric variables of the crop, grains' production of the cultivation and economic returns have been evaluated. After four cultivations, samples of the soil were obtained for determining its chemical properties. The chicken manure provided the increment of the contents of foliar N, P and K of the corn and soybean as well as modified the biometric variables, also increasing the yield of the grains of the studied crops. High doses of chicken manure applied before the wheat cultivation promote the lodging of the cultivation and reduction of the weight of the hectoliter, but enhancing the grains' yield. The greatest productivity of grains and the highest annual returns in the production system of the west of the Paraná were obtained with the doses of 7,39 t ha-1 yield-1 and 5,45 t ha-1 yield-1 of chicken manure, respectively. The fertilization with chicken manure increases the levels of P, K und S in the soil, where the saturation of K reduces the concentration of Cu in the soil. The chicken manure allows the partial substitution of mineral fertilizer, also promoting the highest investment return / Os sistemas de produção de grãos e carnes brasileiros levaram o país ao ranking dos maiores produtores e exportadores de alimentos do mundo. A produção integrada de aves gera diversificação e renda para as propriedades rurais, porém produzem grandes quantidades de dejetos. A cama de frango é rica em nutrientes e pode ser usada como fertilizante para as culturas. O conhecimento das respostas às culturas permite a utilização da cama de frango de forma adequada e racional, evitando perdas e reduzindo o impacto ambiental. Objetivou-se avaliar o uso de doses de cama de frango antes da cultura de inverno associadas ao fertilizante mineral (NPK) nas características agronômicas das culturas (milho 2ª safra, soja e trigo), teores de nutrientes foliares e do solo e nos aspectos econômicos do sistema de produção de grãos do oeste do Paraná. Para tanto, foi conduzido um experimento na Estação Experimental da Copacol em Cafelândia-PR com diferentes doses de cama de frango (0, 2, 4, 6 e 8 t ha-1), e três sistemas de adubação mineral (controle, super fosfato simples e formulado) no sulco de semeadura durante dois anos. A cama de frango foi aplicada manualmente nas parcelas antes do cultivo de inverno. O delineamento experimental foi em DBC com parcelas subdivididas e quatro repetições. Foram avaliados os teores de N, P e K foliares, componentes de rendimento, variáveis biométricas das culturas, produção total de grãos dos cultivos e retorno econômico. Após quatro cultivos coletaram-se amostras de solo para determinação dos atributos químicos do solo. A cama de frango proporcionou o incremento dos teores de N, P e K foliares do milho e soja, alterou as variáveis biométricas e aumentou o rendimento de grãos das culturas estudadas. A adubação com cama de frango, até 8 t ha-1 reduziu o peso do hectolitro e a complementação com adubação com P e K aumentou o acamamento das plantas de trigo. A complementação com cama de frango proporcionou maior equilíbrio nutricional às culturas de milho e soja, refletindo no rendimento de grãos. A maior produção de grãos e a maior rentabilidade anual no sistema de produção do oeste do Paraná foram obtidas com as doses de 7,39 t ha-1 ano-1 e 5,45 t ha-1 ano-1 de cama de frango, respectivamente. A adubação com cama de frango aumenta os teores de P, K e S do solo, e a saturação por K e reduz os teores de Cu no solo. A cama de frango permite a substituição da adubação mineral, além de promover o maior retorno ao investimento
223

Associação de água residuária da suinocultura e adubação mineral no cultivo de aveia-preta / Association of swine waste water and mineral fertilization on the 24 black oat cultive

Herrmann, Daniela da Rocha 16 August 2013 (has links)
Made available in DSpace on 2017-07-10T14:38:19Z (GMT). No. of bitstreams: 1 Daniela Herrmann.pdf: 621996 bytes, checksum: 8bfc3d047c704a58a12b63a71c9d3c9b (MD5) Previous issue date: 2013-08-16 / Swine wastewater (SWW) has high organic load becoming an important source of macro and micronutrients to plants, promoting the improvement of soil quality and development in several tilth. however when done without agronomic and environmental standard, can cause problems in soil, leaching of nutrients, prejudice to water resources and toxicity to plants. The objective of this work, was to evaluate the chemical in soil and leachat regarding association of swine wastewater and mineral fertilization(MF) in farming black oat. Conducted an experiment using applications of SWW associated or not with MF, the treatments consisted of rates 0, 100, 200 and 300 m3ha-1 in the absence or presence MF, under field conditions. Were collected and analysis of soil and leachate in two seasons. It was observed effect associated with the wastewater and mineral fertilization on phosphorus in soil, isolated effect of mineral fertilization on the magnesium, potassium and electrical conductivity in soil and isolated effect of wastewater in the levels of pH, calcium, sodium, copper, zinc, nitrite + nitrate in soil and effect on sodium content in leachate / A água residuária da suinocultura (ARS) possui carga orgânica elevada se tornando fonte importante de macro e micronutrientes às plantas, promovendo a melhoria da qualidade do solo e do desenvolvimento em diversas culturas. Porém quando feita sem critérios agronômicos e ambientais, pode causar problemas no solo, lixiviação de nutrientes, prejuízos aos recursos hídricos e toxicidade às plantas. O objetivo deste trabalho foi avaliar os atributos químicos em solo e lixiviado frente a associação de água residuária da suinocultura e adubação mineral (AM) no cultivo de aveia-preta. Realizou-se um experimento em lisímetros de drenagem usando aplicações de ARS associadas ou não a AM, os tratamentos consistiram em doses de 0, 100, 200 e 300 m3ha-1 com ausência ou presença de AM, em condições de campo. Foram realizadas coletas e análises de solo e lixiviado em duas épocas. Observou-se efeito associado da água residuária e adubação mineral no teor de fósforo no solo, efeito isolado da adubação mineral nos teores de magnésio, potássio e condutividade elétrica no solo e efeito isolado da água residuária nos teores de pH, cálcio, sódio, cobre, zinco, nitrito + nitrato no solo e efeito no teor de sódio no lixiviado
224

Residual Soil Phosphorus in Tropical Oxisols: An Opportunity to Enhance Fertilizer Use Efficiency?

Bomeisl, Lauren 01 January 2019 (has links)
Phosphorus (P) is essential to life on Earth and often the limiting nutrient in agricultural systems. P fertilizer is thus an essential resource to maintain food security. In the last half century, agricultural intensification has led to an increase in P fertilizer consumption from 4.6 to 17.5 Tg of P/year to meet rising global food demand. Mineral P (i.e., phosphate rock) is a non-renewable resource in the context of the Anthropocene, and its price is vulnerable to global market fluctuations. Increased efficiency of P use on farms is considered the most effective strategy to conserve P. The soybean industry demands 9.7% of global P use, of which Brazil’s soy industry consumes the most, accounting for 5.8% of the world’s P2O5 use in 2014. This global source of soy production is challenged by the unique tendency of weathered tropical soils, such as Oxisols, to retain (i.e., fix) P in forms that are unavailable to crops. The accumulation of soil P due to years of P fertilization in excess of harvested P is referred to as “residual” or “legacy” P. Historical hotspots for crop production in the US and Europe have relied on residual soil P stocks to maintain yields despite reduced P inputs. Whether Brazil will be able to utilize the same strategy depends on the accessibility of residual soil P stocks when applied fertilizer P is reduced. Field research on this topic remains relatively scarce for cultivated Oxisols in tropical climates. I conducted a field trial at Tanguro Ranch in Mato Grosso, Brazil on a field that has been fertilized at standard high rates for 10 years to test whether residual soil P can be accessed by soy crops. Soy yield response differed significantly (p < 0.05) based on the interaction between fertilization treatment (0%, 50%, or 100% of standard P fertilization) and soil texture. My results highlight opportunities to enhance P fertilizer use efficiency in intensive tropical agriculture.
225

Assessment on infield spacial variability of nutrients in a uniformly managed corn (Zea Mays L.) field

Thabang, Sebuki Minah January 2011 (has links)
Thesis (Msc. (Agriculture)) --University of Limpopo, 2011 / The impact of agricultural chemicals on the environment has come under close scrutiny in the country of South Africa, for that reason, we are investigating alternative and appropriate methods for nutrients management. The objective of the study was to assess infield spatial variability of soil nutrients in a uniformly managed corn field, and (ii) to recommend method that can potentially help corn (Zea mays L.) producers in Limpopo Province to enhance grain yield with optimal utilization of resources. The study was conducted at Syferkuil agricultural experimental farm (23o50’ S; 29 o40’ E) of the University of Limpopo, in the northern semi-arid region of South Africa. Prior to planting of corn on this uniformly managed 7 ha portion of a 1 705 ha farm, the field was mapped with Ag132 Trimble differentially corrected global positioning system (DGPS) equipped with Field Rover II® GIS mapping software. Land suitability assessment for corn was conducted before planting and the field was classified for suitability as S1 based on FAO guidelines for irrigated agriculture and South African Binomial System of Soil classification. Soils and corn leaf sample parameters, including N were collected and measured from geo-referenced locations on a 40 x 40 m grid. Nutrient distribution spatial maps were produced with Surfer software 8.0. There was a significant variability (P≤0.05) of soil nutrients and pH across the corn field. Corn grain yield ranged from 2.7 to 6.3 Mg ha-1. For a land suitability class of S1 under linear irrigation in a semi-arid environment, these grain yields were considered lower. This lower grain yields can be linked to variability of soil nutrients, and pH because the field was classified suitable according to FAO guidelines. This field, with its significant variability of nutrients and pH that resulted in lower grain yields, is potentially a good field for precision agriculture IX methods of nutrient management such site-specific management zones for environmental quality and economic efficiency. Keywords: Maize, Small-scale farming, Soil nutrient management, and Spatial variability
226

Influence of lab lab (lablab purpureus) and dry bean (phaseolus vulgaris) intercrops with maize (zea mays l.) on maize grain yield and soil fertility status

Makgoga, Mahubane William January 2013 (has links)
Thesis (MSc. Agriculture (Agronomy)) -- University of Limpopo, 2013 / Maize (Zea mays L.) is the third most important cereal crop after wheat and rice in the world. Maize/legume intercropping system has become one of the solutions for food security among small scale maize producers due to unaffordability of chemical nitrogenous fertilizers and limited access to arable land. A study was conducted to determine the effect of maize/dry bean and maize/lablab intercropping on maize grain yield and soil fertility status. A field experiment was conducted during 2010/2011 and 2011/2012 growing seasons at the University of Limpopo experimental farm. Treatments included sole maize (ZM 521, an improved open pollinated variety, ex- CIMMYT), sole lablab (Rongai, indeterminate cultivar), sole dry bean (DBS 360, indeterminate Type II cultivar), maize/dry bean and maize/lablab intercrops arranged in randomized complete block design with five replications. Phosphorus (P) was applied on sole and intercropped maize at the rate of 30 kg P/ha in the form of superphosphate (10.5%P) at planting and 40 kg N/ha of nitrogen (N) was applied in the form of Limestone Ammonium Nitrate (LAN) (28%N) on both sole and intercropped maize four weeks after plant emergence. For maize and dry bean, grain yield, yield components and biomass were determined. Only biomass yield was measured for lablab. Soil samples were collected for soil analysis at the beginning and the end of the experiment The results showed that maize/lablab intercropping yielded significantly (P<0.05) lowered maize grain (1259.3 kg/ha) than sole maize and maize/dry bean intercropping which yielded maize grain of 2093.7 kg/ha and 2156.3 kg/ha, respectively. Sole dry bean yielded significantly (P <0.05) higher dry bean grain (1778.5 kg/ha) than intercropped dry bean (691.8 kg/ha). Rongai was only flowering by the time maize and dry bean matured hence only maize yield is reported for the Maize/lablab intercrop. Maize/dry bean intercropping was advantageous to sole cropping with a Land Equivalent Ratio (LER) of 1.42. The partial Land Equivalent Ratio (PLER) for maize in maize/lablab intercropping was 0.60. Dry bean was outcompeted by maize as calculated aggressivity value was positive at +0.64.The highest monetary value was achieved in sole dry bean and the lowest monetary value was found in intercrop dry bean. Soil TN, P, K, Ca, Mg and Na were reduced by both sole cropping and intercropping systems. Intercropping with lablab is likely to significantly lower maize yield under dryland conditions. Key words: dry bean, grain yield, Intercropping, lablab, maize, smallholder, soil fertility.
227

Anbau von Zwischenfrüchten - Auswertung der Versuchsanlagen 2012/13 in Sachsen

Schmidt, Anja, Gläser, Heiko 08 June 2013 (has links) (PDF)
Mit dem Anbau von Zwischenfrüchten kann die Nitratbelastung des Grundwassers reduziert oder niedrig gehalten werden. Zwischenfrüchte verbessern und erhalten die Bodenfruchtbarkeit, erhöhen die biologische Bodenaktivität und bieten Schutz vor Erosion. Auf Feldversuchsanlagen wurden Biomasseertrag, Stickstoffaufnahme und Stickstoffdynamik im Boden verschiedener Zwischenfruchtvarianten untersucht und ausgewertet. Eine Beschreibung der einzelnen Pflanzenarten und Hinweise zur Bestandesführung soll helfen, mit einer geeigneten Zwischenfruchtmischung gute Bestände zu etablieren.
228

Phosphorus fractions and rock phosphate transformations In soils from different landscape positions In northern Ghana

Abekoe, Mark Kofi 01 January 1996 (has links)
Phosphorus (P) is an essential plant nutrient and is one of the most critical elements influencing crop production throughout the world. Phosphorus deficiency is widespread in most soils of northern Ghana, and ferruginous nodules contained in some soils in the region accentuate the deficiency problem because they act as P sinks. This research focuses on P fertility status of soils in landscapes common to northern Ghana. Three sites were selected for the study and were referred to as sites 1, 2 and 3. Soils in a catenary sequence from site 1 were sampled for detailed P distributions in profiles, and surface soils from the upper, mid and lower slope positions of the other landscapes (sites 2 and 3) were used. The nature of P in the soil fines and ferruginous nodules was investigated using a modified Hedley fractionation procedure. The objective was to quantify the labile and non-labile inorganic P (Pi) and organic P (Po) in relation to pedogenic weathering processes at different slope positions at site 1. A secondary objective was to assess the P distribution in the landscapes at sites 2 and 3. The largest P fraction in both soil fines and nodules at each site was resistant non-labile P forms. Primary P (Ca-P) decreased with depth in the profile at the upper slope position but it occurred in greater quantities in C horizons of the lower slope soils. Phosphorus sorption capacity of the soil fines and nodules was determined to predict the behaviour of P fertilizers in the soils. Phosphorus sorption by the soil fines increased to a maximum in the B horizon of each profile and a t-test showed that P sorption was similar in profiles at each slope position. The P sorption capacities of uncrushed ferruginous nodules varied according to their sizes. The small nodules were more reactive and sorbed more P than the larger sizes. Fractionation of P from the nonfertilized and fertilized soils at the end of cropping and anion exchange resin (AER) extraction, revealed that there had been redistribution of P into different fractions. A comparison of P fractions of the nonfertilized soils after the AER extraction with those of the native soil P showed decreases in some native labile and non-labile P fractions. This suggested that these P fractions could be available for plant uptake. Both 50% PAPR and SSP fertilizations increased the labile Pi and NaOH extractable Pi levels in the soils. (Abstract shortened by UMI.)
229

Agricultural policy and soil fertility management in the maize-based smallholder farming system in Malawi /

Tchale, Hardwick. January 2006 (has links) (PDF)
Univ., Diss.--Bonn, 2005.
230

Phenotypic variation in host quality of pines for the European pine sawfly (Neodiprion sertifer)

Chorbadjian, Rodrigo A., January 2009 (has links)
Thesis (Ph. D.)--Ohio State University, 2009. / Title from first page of PDF file. Includes bibliographical references (p. 134-151).

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