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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.
41

Manejo integrado de pragas na cultura do morangueiro no sul de Minas Gerais / Integrade pest management in culture of strawberry in southern of Minas Gerais

Fernanda de Cássia Neves Esteca 17 January 2017 (has links)
O sul de Minas Gerais é a principal região produtora de morangos (Fragaria x ananassa Duch.) no Brasil. O ácaro-rajado, Tetranychus urticae Koch (Acari: Tetranychidae), é considerado uma das principais pragas do morangueiro no Brasil e em vários países. Uma prática importante na cultura do morango refere-se à cobertura de solo, usualmente realizada com filme de polietileno, porém além de ser caro gera resíduos muito persistentes no ambiente. Objetivou-se com este trabalho comparar a resistência de oito genótipos de morango (\'Albion\', \'IAC Guarani\', \'IAC Princesa Isabel\', \'Oso Grande\', IAC T-0104, IAC 12, IAC 4 e IAC 1.13) ao ácaro-rajado; determinar o efeito da cobertura de solo (com a polpa de café desidratada, conhecida como palha de café) nas pragas/ patógenos e ácaros predadores desta cultura; comparar a ocorrência de pragas, patógenos e inimigos naturais entre um cultivo orgânico e outro convencional de morango. Os resultados obtidos indicaram que \'IAC Princesa Isabel\', IAC T-0104 e IAC 12 são resistentes, IAC 1.13 e IAC 4 apresentam resistência moderada e \'IAC Guarani\', \'Oso Grande\' e \'Albion\' são suscetíveis ao ácaro-rajado. \'Oso Grande\' e \'Albion\' são bastante utilizadas pelos produtores do sul de Minas Gerais. O uso de palha de café aumentou o número de predadores edáficos, tanto no solo dos canteiros (campo) e em vasos (laboratório) como em folíolos de morangueiro. O Gamasina Proctolaelaps pygmaeus (Müller) (Melicharidae) foi visto sobre morangueiros, principalmente no período noturno. Maior número de ácaro-rajado e maior severidade de doenças foram observados em plantas cultivadas em solo coberto com polietileno. Além disso, foi maior o nível de infecção de ácaro-rajado pelo fungo Neozygites floridana (Weiser e Muma) em plantas cultivadas em solo coberto com palha de café. Não foi observada diferença significativa entre a produtividade da cultura em solo coberto com polietileno e em solo coberto com palha seca de café. Os resultados da comparação da ocorrência de ártropodes e patógenos entre sistema orgânico e convencional mostraram menor ocorrência de ácaro-rajado e predadores em cultivo de morangueiro convencional, porém ocorrência considerável de tripes, mosca-branca e mofo cinzento. A incidência de dendrofoma e mancha de pestalotia foi a mesma nos dois sistemas de cultivos. Os resultados sugerem a conveniência de se continuar o processo de desenvolvimento dos genótipos que se mostraram menos afetados pelo ácaro-rajado, para que estes possam no futuro ser utilizados pelos produtores, e a condução de estudos complementares, que avaliem o desempenho de cultivos em sistema orgânico que incorporem o uso da palha de café para a cobertura do solo. / The southern of Minas Gerais is the main region producing strawberries (Fragaria x ananassa Duch.) in Brazil. The two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae), is considered one of the main strawberry pests in Brazil and in several countries. An important practice in strawberry cultivation refers to soil cover, which is usually made with polyethylene film, but it is expensive and generates very persistent residues in the environment. The objective of this study was to compare the resistance of eight strawberry genotypes (\'Albion\', \'IAC Guarani\', \'IAC Princesa Isabel\', \'Oso Grande\', IAC T-0104, IAC 12, IAC 4 and IAC 1.13); to determine the effect of soil cover (with dehydrated coffee pulp, known as coffee straw) on the pests mites/ pathogens and predatory mites of this crop; to compare the occurrence of pests, pathogens and natural enemies between an organic and a conventional strawberry crop. The results indicated that \'IAC Princesa Isabel\', IAC T-0104 and IAC 12 are resistant, IAC 4 and IAC 1.13 are moderately resistant, and \'IAC Guarani\', \'Oso Grande\' and \'Albion\' are susceptible to the two-spotted spider mite. \'Oso Grande\' and \'Albion\' are widely used by producers in the southern of Minas Gerais. The use of coffee straw increased the number of edaphic predators, both in the soil beds (field) and in pots (laboratory) as well as in strawberry leaflets. The Gamasina Proctolaelaps pygmaeus (Müller) (Melicharidae) was seen on strawberry leaftlets, mainly in the nocturnal period. Higher numbers of the two-spotted spider mites and disease severity were observed in plants grown on soil covered with polyethylene. In addition, the level of the two-spotted spider mite infected by the fungi Neozygites floridana (Weiser and Muma) was higher in plants cultivated in soil covered with coffee straw. No significant difference was observed between yield in soil covered with polyethylene and in soil covered with dry coffee straw. The results of the comparison of the occurrence of arthropods and pathogens between the organic and conventional systems showed fewer occurrences of the two-spotted spider mites and predators in conventional strawberry cultivation, but considerable occurrence of thrips, whitefly and gray mold. The incidence of dendrophoma and leaf spots caused by pestalotia was the same in both cropping systems. The results suggest the convenience to continue the development process of the genotypes that were less affected by the two-spotted spider mite, which could be used in the future by producers, and the conduction of complementary studies to evaluate the performance of crops in organic system that incorporate the use of coffee straw as soil coverage.
42

Vliv půdní složky a rozdílného krajinného pokryvu na odtokový proces (experimentální výzkum v párových povodích Zbytiny) / Influence of soil matter and different land cover on the runoff process (experimental research in the paired catchments Zbytiny)

Královec, Václav January 2018 (has links)
The doctoral thesis deals with the evaluation of influences of causal factors that significantly affect runoff processes in landscape. The research is mainly focused on the examination of land and soil cover impacts and partially pays attention to the effects of surface drainage and snow cover. The main effort was to find out the extent of influences of each individual factor on runoff from a different type of landscape. In order to find the correct answer, a methodical approach was applied to small experimental paired catchments where the research has been continuously undergoing since the year of 2006 (the presented results have been collected for 11 years of observations). The small experimental paired catchments are located at the foothills of the Šumava Mountains and they represent small area neighbouring catchments of similar physical-geographic and hydrographic conditions. The catchments were selected as the comparative ones where the main differences are the landscape and soil cover. Moreover, the character of surface drainage is regarded to be an important variable. In the catchment area of the Zbytinský Brook, there predominates the grassland which is largely drained by the subsurface drainage system. In the catchment area of the Tetřívčí Brook the dominant cover is formed by the forest...
43

Desempenho de Leguminosas para Aduba??o Verde e sua Utiliza??o no Cultivo Org?nico de Milho e Repolho no Cerrado de Mato Grosso do Sul / Performance of Legumes for Green Manure and their use in organic cultivation of maize and cabbage at the Cerrado of Mato Grosso do Sul

Cesar, Marcius Nei Zanin 30 April 2009 (has links)
Submitted by Celso Magalhaes (celsomagalhaes@ufrrj.br) on 2018-09-11T19:30:41Z No. of bitstreams: 1 2017 - Marcius Nei Zanin Cesar.pdf: 3447328 bytes, checksum: 098490a3674208d8609db17b18d3c285 (MD5) / Made available in DSpace on 2018-09-11T19:30:41Z (GMT). No. of bitstreams: 1 2017 - Marcius Nei Zanin Cesar.pdf: 3447328 bytes, checksum: 098490a3674208d8609db17b18d3c285 (MD5) Previous issue date: 2009-04-30 / Cap. I The aim of this work is to evaluate the agronomic behavior of different legume species under cerrado conditions in Mato Grosso do Sul. Seven experiments were carried out, all of them in the experimental field of the (Ag?ncia de Desenvolvimento Agr?rio e Extens?o Rural de MS), (Agency of rural development and extension of MS). Two of these experiments referred to the performance of legumes evaluation. The first experiment was carried out during the Spring- Summer period, and the second one during the Fall- Winter period. The treatments were constituted by the legume species (Crotalaria juncea, Crotalaria ochroleuca, Crotalaria mucronata, Crotalaria reviflora, Mucuna pruriens, Mucuna aterrima, Cajanus cajan (L.) Millsp Cv Fava larga and Cv IAPAR Arat? 43 an?o, Canavalia ensiformes and Canavalia brasiliensis). The third experiment was carried out to determine the dry phytomass decomposition rate and the nitrogen release of the species that were evaluated; this happened during the Fall-Winter period, and the treatments were the mulching of the legumes cited above, except C. breviflora, which was severely attacked by Fusarium sp. The experimental design adopted was randomized blocks, with eleven treatments and nine harvest dates disposed with four replicates. The forth and the fifth experiments were carried out in the subsequent year, their aim was qualifying the Biological Nitrogen Fixation (hereinafter called BNF) and determining the isotope discrimination value ?B value?; their treatments were seven legume species previously selected due to their performances on the former experimental actions and three checks, Brachiaria decumbens, Helianthus annuus, and Zea mays cv BR 106, disposed in randomized blocks with four replicates. The sixth and the seventh experiments were carried out to evaluate the performance of the cabbage cv Astrus under organic management in no-tillage system. The treatments of the sixth experiment were maize-velvet bean intercrop. The later was sown in five different times after maize germination, mucuna alone, maize alone, spontaneous vegetation, and cultivation with conventional tillage of the soil. The treatments of the seventh experiment were maize intercropped with Crotalaria juncea, the latter was slashed, slashed and pruned, maize with basic fertilizer, maize with basic and dressing fertilizers, crotalaria alone, maize alone, spontaneous vegetation, and cultivation with conventional tillage of the soil. The experimental design adopted for both experiments was randomized blocks. The evaluation of the aerial phytomass production was determined when the legume species flowered and when the non-legume ones underwent the grain filling process. The quantification of BNF and the determination of the B value were estimated by using natural abundance 15N and the 15N dilution technique. Functional growth analyses were also carried out as well as soil cover rates, digestion time of the plant tissues, and the phytosociology were determined. On the sixth and seventh experiments the green manure contributions on the agronomic behavior of the cabbage cultivated in no-tillage system under organic management were evaluated. The results obtained have demonstrated the viability for the cultivations of these legume species at the Cerrado Biome, with the contribution of the BNF varying between 75 and 85% of the nitrogen found in the plant tissue originating from the air. They have also demonstrated the viability of using C. juncea and velvet bean when both are intercropped with maize in the mulching formation to the organic cultivation of the cabbage in no-tillage system Cap. II Two experiments were carried out to evaluate the agronomic behavior of legume species in which several components of plant growth were evaluated, such as aerial phytomass production, soil cover rate, seed production, besides phytosociology and in situ decomposition rate under cerrado conditions in Mato Grosso do Sul in two periods of the year. One experiment was carried out during the Spring-Summer period and the other one was carried out during the Fall-Winter period. Both experiments were carried out at the Centro de Pesquisa da Ag?ncia de Desenvolvimento Rural e Extens?o Rural de Mato Grosso do Sul (Mato Grosso do Sul Research center of the Agency of rural development and extension), in Campo Grande ? MS. The experimental design adopted for both was randomized blocks, formed by eleven treatments made up by the species C. juncea, C. ochroleuca, C. mucronata, C. spectabilis, C. breviflora, Mucuna aterrima, Mucuna pruriens, Canavalia brasiliensis, Canavalia ensiformis, Cajanus Cajans cv ?IAPAR an?o?, and Cajanus Cajans cv. giant broad bean. The agronomic behavior of the species that were studied was evaluated by the analysis of the stem and the leaf separately. It was observed that the aerial phytomass productions differed significantly with the species of the genus Crotalaria, showing the best results. Crotalaria juncea stands out with 14.16 Mg ha-1, followed by the Cajanus cajan cv. Fava larga with 11.58 Mg ha-1; there were no significant differences among the species of prostrate habit, mucunas and Brazilian jackbean (Canavalia brasiliensis). The later obtained 3.56 Mg ha-1 and the former did 2.85 Mg ha-1. Regarding seed production, the best performances were obtained during the Fall-Winter period for all legume species, except jack bean and feij?o-bravo (Capparis flexuosa), both obtained similar performances on the two periods of sowing, probably because they might be more tolerant to the drought stress. Regarding the decomposition rate, the results have revealed that the decomposition constants and the residue half-lives had different behaviors on the species that were studied; the Crotalaria species obtained higher decomposition rates when compared to the other species, differentiated behaviors were also noticed on the stem and on the leaf. The C. juncea, jack bean, and the two species of mucuna obtained higher soil cover rate, which reflected a higher suppression of spontaneous plants Cap. III Two experiments related to the quantification of BNF and the determination of the isotope discrimination, ?B value?, in legume species previously selected were simultaneously carried out in the experimental field of the AGRAER-MS, in Campo Grande-MS, during the Spring/Summer period in the 2005/2006 year of production. The experimental design adopted was randomized blocks, formed by ten treatments made up by the species C. juncea, C. ochroleuca, C. mucronata, C. spectabilis, velvet bean, Brazilian jackbean, and Pigeon pea; there have been also, as checks, Sunflower, Maize, and Brachiaria species. The aerial phytomass productions were determined when each legume species flowered and when the non-legume ones underwent the grain filling process. With the samples of legumes and check plants, the quantities of N and the BNF were estimated by using the 15N dilution technique. Afterwards, when the BNF values were known, they were applied to the equation used in natural abundance 15N with the aim of estimating the B value. Regarding the aerial phytomass production, the Pigeon pea had the best performance, followed by the C. ochroleuca, reaching averages of 16.24 Mg ha-1 against 14.44 Mg ha-1. The legume species behaved similarly to the amount of accumulated nitrogen; the Pigeon pea, C. ohcroleuca, and C. mucronata reached values of 346.57 kg ha-1, 333.25 kg ha-1, and 277.35 kg ha- 1 respectively, and they deserve a distinction. Regarding the %BNF, it was observed that the 15N dilution technique could not be applied in all the species that were studied since the cycle of most legumes species was different from the checks; in this way, the checks were not appropriate because the technique demands that legumes and checks grow simultaneously and under the same conditions. However, to the varieties which were more precocious that the checks, the BNF value must be at least between 73 to 87%. Just on the specie C. mucronata it was possible to estimate the BNF and the B value with the rigor that the applied isotopic methodologies demand. The B value of this specie was -3.69. Cap. IV The aim of this study is to evaluate the agronomic behavior of the cabbage in no-tillage system under organic management and the contribution of the prior cultivation of two legumes with different growing habits intercropping with maize in the mulching formation. Both experiments were carried out in the experimental field of AGRAER-MS, in Campo Grande-MS. The first experiment was the maize-C. juncea intercrop, the latter was managed, slashed, pruned, and slashed afterwards; besides the cultivation of single maize, single C. juncea, cultivation with conventional tillage of the soil with and without fertilization with equivalent amounts of 100 Kg N ha-1 at planting and sidressed 30 days after the maize cultivation, making up eight treatments with four replications in randomized blocks. The dry matter productions in the aerial part of the cover crops and the spontaneous vegetation were evaluated. Agronomic characteristics that were evaluated on the cabbage: productivity, commercial standard, fresh and dry weight, besides the dry phytomass of the prior cultivation. On this experiment it was possible to verify better yields regarding the fresh weight and head diameter when we used single, pruned C. juncea maize with basic fertilizer, and maize with base and dressing fertilizers, reaching a fresh weight over 1.0 Kg and heads diameter over 10 cm. Regarding maize and cabbage productivity, they were not influenced by the different kinds of intercrop systems; there were no significant statistic difference of treatments, which also reflected on the dry matter production of the prior cultivations. On the second experiment, the experimental design which was adopted was randomized blocks, with nine treatments and four replicates. The treatments were: maize-velvet bean intercrop, the later was planted in five different times: after the maize germination, maize alone, mucuna alone, cultivation with conventional tillage of the soil, and fallow with spontaneous vegetation, making up a total number of nine treatments. The parameters that were evaluated were similar to the ones of the former experiment.The cabbage production showed the most promising yield 2.06 Kg of head average weight and when cultivated as a sequential crop to the maize-velvet bean intercrop sown 15 days after the maize germination, differing significantly from the other treatments. When we analyzed the maize productivities, we noticed fall of productivity around 29% when it was intercropped with velvet bean at 15 and 30 days after its germination when it was compared to the other prior cultivations in which the intercrop system was used. / Cap. I O presente trabalho teve como finalidade avaliar o comportamento agron?mico de diferentes esp?cies de leguminosas nas condi??es do cerrado de Mato Grosso do Sul. Foram conduzidos sete experimentos, todos no campo experimental da Ag?ncia de Desenvolvimento Agr?rio e Extens?o Rural de MS, sendo que dois deles foram referentes ? avalia??o do desempenho das leguminosas. O primeiro foi instalado no per?odo de primavera-ver?o e o segundo no outonoinverno. Os tratamentos foram constitu?dos das esp?cies de leguminosas Crotal?ria juncea, Crotal?ria ochroleuca, Crotal?ria mucronata, Crotal?ria reviflora, Mucuna pruriens, Mucuna aterrima, Cajanus cajan (L.) Millsp cv Fava larga e Cv IAPAR Arat? 43 an?o, Canavalia ensiformes e Canavalia brasiliensis. O terceiro experimento foi realizado para determinar a taxa de decomposi??o da fitomassa seca e libera??o de nitrog?nio das esp?cies avaliadas, realizado no per?odo de outono-inverno, com os tratamentos constituindo-se da palhada das leguminosas descrita acima, exceto C. breviflora, pois a leguminosa sofreu ataque severo de Fusarium sp. O delineamento experimental foi em blocos ao acaso, com onze tratamentos e nove ?pocas de coleta distribu?dos em quatro repeti??es. O quarto e o quinto experimentos foram realizados no ano subsequente e tiveram como finalidade quantificar a Fixa??o Biol?gica de Nitrog?nio (FBN) e determinar o valor de discrimina??o isot?pica ?Valor B?, tendo como tratamentos sete esp?cies de leguminosas previamente selecionadas pelos seus desempenhos nas a??es experimentais anteriores e tr?s testemunhas, Brachiaria decumbens, Helianthus annuus e Zea mays cv BR 106, dispostos em blocos ao acaso com quatro repeti??es. O sexto e o s?timo experimentos foram conduzidos para avaliar o desempenho do repolho cv Astrus sob manejo org?nico em sistema plantio direto, sendo que o sexto experimento teve como tratamentos cons?rcio milho x mucuna cinza, sendo esta semeada em cinco ?pocas diferentes, ap?s germina??o do milho, mucuna em monocultivo, milho em monocultivo, vegeta??o espont?nea e cultivo com preparo convencional do solo. O s?timo experimento teve como tratamentos milho consorciado com Crotal?ria juncea, sendo esta ro?ada, ro?ada e podada, milho com aduba??o de base, milho com aduba??o de base e cobertura, crotal?ria em monocultivo, milho em monocultivo, vegeta??o espont?nea e cultivo com preparo convencional do solo. O delineamento experimental adotado em ambos os experimentos foi o de blocos ao acaso. A avalia??o da produ??o de fitomassa a?rea foi determinada por ocasi?o do florescimento para as esp?cies de leguminosas e de enchimento de gr?os para as n?o-leguminosas. A quantifica??o da FBN e determina??o do valor ?B? foram estimadas utilizando-se a t?cnica de abund?ncia natural 15N e da dilui??o isot?pica de 15N. Foram tamb?m realizadas an?lises funcionais de crescimento, bem como determinadas as taxas de cobertura do solo, tempo de decomposi??o dos tecidos vegetais e a fitossociologia. No sexto e no s?timo experimentos, foram avaliadas as contribui??es da aduba??o verde no desempenho agron?mico do repolho cultivado em sistema de plantio direto, sob manejo org?nico. Os resultados obtidos demonstraram a viabilidade do cultivo destas leguminosas no bioma cerrado, com a contribui??o da FBN, variando entre 75 e 85% do nitrog?nio encontrado no tecido vegetal proveniente do ar. Tamb?m, demonstraram a viabilidade do uso da C. juncea e M. cinza quando cultivadas em cons?rcio com milho para obten??o de palhada ao cultivo org?nico do repolho em sistema plantio direto. Cap. II Dois experimentos foram conduzidos para avaliar o comportamento agron?mico de esp?cies de leguminosas, onde foram avaliados diferentes componentes do crescimento vegetal, como produ??o fitomassa a?rea, taxa de cobertura de solo, produ??o de sementes, al?m da fitossociologia e taxa de decomposi??o ?in situ?, nas condi??es do cerrado de Mato Grosso do Sul, em duas ?pocas do ano. Os experimentos foram conduzidos no Centro de Pesquisa da Ag?ncia de Desenvolvimento Agr?rio e Extens?o Rural de Mato Grosso do Sul, localizado em Campo Grande - MS, sendo um no per?odo de primavera-ver?o e outro no outono-inverno. Em ambos, o delineamento experimental adotado foi o de blocos ao acaso, formado de onze tratamentos constitu?dos das esp?cies C. juncea, C. ochroleuca, C. mucronata, C. spectabilis, C. breviflora, Mucuna aterrima, Mucuna pruriens, Canavalia brasiliensis, Canavalia ensiformis, Cajanus Cajans cv. IAPAR an?o e Cajanus Cajans cv. fava larga gigante. O comportamento agron?mico das esp?cies estudadas foi avaliado analisando-se separadamente haste e folha. Observou-se que as produ??es de fitomassa a?rea diferiram de forma significativa com as esp?cies do g?nero crotal?ria, obtendo-se melhores desempenhos. Destacam-se a Crotal?ria juncea com 14,16 Mg ha-1, seguida do Guandu cv fava-larga com 11,58 Mg ha-1; entre as esp?cies de h?bito prostrado, n?o houve diferen?as significativas, mucunas e o feij?o-bravo-do Cear?, sendo que esse obteve 3,56 Mg ha-1 contra 2,85 Mg ha-1 da M. preta. Com rela??o ? produ??o de sementes, os melhores desempenhos foram obtidos no per?odo de outono-inverno para todas as leguminosas, com exce??o do feij?o-de-porco e feij?o-bravo, que obtiveram desempenhos semelhantes nas duas ?pocas de semeadura, provavelmente, por serem mais tolerantes ao estresse h?drico. No tocante ? taxa de decomposi??o, os resultados revelaram que as constantes de decomposi??o e tempo de meia-vida tiveram comportamentos diferentes para as esp?cies estudadas, com esp?cies de crotal?ria obtendo maiores velocidades de decomposi??o quando comparadas ?s demais esp?cies, notou-se tamb?m comportamentos diferenciados para haste e folha. A C. juncea, feij?o de porco e as duas esp?cies de mucuna obtiveram maior taxa de cobertura de solo, o que refletiu em uma maior supress?o da vegeta??o de ocorr?ncia espont?nea Cap III Foram conduzidos simultaneamente dois experimentos relacionados ? quantifica??o da FBN e determina??o do valor de discrimina??o isot?pica, valor ?B?, em esp?cies de leguminosas previamente selecionadas. Os experimentos foram conduzidos no campo experimental da AGRAER-MS, localizado em Campo Grande-MS, no per?odo de primavera-ver?o, no ano agr?cola 2005/06. O delineamento estat?stico utilizado foi o de blocos ao acaso, constitu?dos de dez tratamentos, sendo este compostos pelas esp?cies C. juncea, C. ochroleuca, C. mucronata, C. spectabilis, Mucuna cinza, Feij?o-bravo-do-cear? e Guandu fava larga; e como testemunhas as esp?cies Girassol, Milho e Braqui?ria. Por ocasi?o do florescimento de cada esp?cie de leguminosa e enchimento de gr?os das n?o-leguminosas, foram determinadas as produ??es de fitomassa a?rea. A partir das amostras de leguminosas e plantas testemunhas, estimaram-se as quantidades de N e a FBN, para tanto usando a t?cnica de dilui??o isot?pica de 15N . Posteriormente, conhecendo-se os valores de FBN, aplicou-se aos mesmos a equa??o utilizada na t?cnica de abund?ncia natural de 15N com a finalidade de estimar o valor B. Com rela??o ? produ??o de fitomassa a?rea, o Guandu fava larga obteve melhor desempenho seguido da C. ochroleuca, atingindo m?dias de 16,24 Mg ha -1 contra 14,44 Mg ha-1. Para a quantidade de nitrog?nio acumulada as esp?cies de leguminosas se comportaram de maneira semelhante, com destaque para o Guandu fava larga, C. ohcroleuca e C. Mucronata, atingido valores de 346,57 kg ha-1, 333,25 kg ha-1 e 277,35 kg ha-1 respectivamente. No tocante ? %FBN, observou-se que a t?cnica de dilui??o isot?pica de 15N n?o poderia ser aplicada para todas as esp?cies estudadas, uma vez que a maioria das esp?cies de leguminosas teve ciclo diferenciado das testemunhas, desta forma, as testemunhas n?o foram apropriadas, visto que a t?cnica exige que tanto as leguminosas como as testemunhas cres?am nas mesmas condi??es e de forma simult?nea. Contudo, para as variedades mais precoces que as testemunhas, o valor de FBN deve estar no m?nimo entre 73 a 87%. Somente na esp?cie C. Mucronata, foi poss?vel estimar a FBN e o valor B com o rigor que exigem as metodologias isot?picas aplicadas. O valor B para esta esp?cie foi de -3,69. Cap. IV O presente estudo teve o objetivo de avaliar o desempenho agron?mico do repolho em sistema plantio direto, sob manejo org?nico, e a contribui??o do pr?-cultivo de duas leguminosas de h?bitos de crescimento distintos em cons?rcio com milho, na forma??o de palhada. Ambos experimentos foram implantados no Campo Experimental da AGRAER, em Campo Grande-MS. O primeiro experimento consistiu no cons?rcio entre milho e C. juncea, sendo esta manejada, somente com ro?ada (taratamento 6), podada e posteriormente ro?ada (tratamento 5), al?m do cultivo do milho solteiro, C. juncea solteira, cultivo com preparo convencional do solo, com aus?ncia e presen?a de aduba??o, em quantidades equivalentes a 100 Kg N ha-1 no plantio e em cobertura 30 dias ap?s plantio do milho, perfazendo oito tratamentos com quatro repeti??es, dispostos em blocos ao acaso. Avaliaram-se as produ??es de mat?ria seca na parte a?rea das plantas de cobertura e da vegeta??o espont?nea. As caracter?sticas agron?micas avaliadas no repolho foram: produtividade, padr?o comercial, peso fresco e seco, al?m da fitomassa seca do pr?-cultivo. Neste experimento, verificaram-se melhores rendimentos quanto ao peso m?dio e di?metro da cabe?a quando se utilizaram C. juncea solteira, C.juncea ro?ada, milho com aduba??o de base e milho com aduba??o de base e cobertura, alcan?ando peso m?dio acima de 1,0 kg e di?metro das cabe?as acima de 10 cm. Quanto ? produtividade do milho e do repolho, estes n?o foram influenciados pelos diferentes tipos de cons?rcios, n?o havendo diferen?a estat?stica significativa entre os tratamentos, o que refletiu tamb?m na produ??o de mat?ria seca dos pr?-cultivos. No segundo experimento, o delineamento experimental utilizado foi o de blocos ao acaso com nove tratamentos e quatro repeti??es. Os tratamentos foram: o cons?rcio entre milho e mucuna cinza, sendo esta plantada em cinco ?pocas diferentes - ap?s a germina??o do milho, monocultivo do milho, monocultivo da mucuna, cultivo com preparo convencional do solo e pousio com vegeta??o espont?nea -, perfazendo um total de nove tratamentos. Os par?metros avaliados foram semelhantes aos do experimento anterior. A produ??o do repolho alcan?ou melhores rendimentos, 2,06 kg de peso m?dio da cabe?a; e, quando cultivado em sucess?o ao cons?rcio milho x M. Cinza, semeada aos 15 dias ap?s germina??o do milho, diferiu significativamente dos demais tratamentos. Ao se analisarem as produtividades do milho, notouse uma queda de rendimento em torno de 29% quando este foi consorciado com M. Cinza, aos 15 e 30 dias ap?s sua germina??o, ao comparar-lo aos demais pr?-cultivos utilizando-se cons?rcios

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