Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / O SubmÃdio SÃo Francisco à um dos principais polos produtores de melÃo amarelo para o mercado interno brasileiro. Sabendo que as atividades agrÃcolas impactam o meio ambiente, este estudo objetiva avaliar os impactos ambientais, por meio da avaliaÃÃo do ciclo de vida, na produÃÃo de 1 kg de melÃo cultivado no SubmÃdio SÃo Francisco, sob dois sistemas de produÃÃo: convencional e conservacionista. Os dados referentes ao sistema de produÃÃo convencional de melÃo foram obtidos em campo, com entrevistas conduzidas no PerÃmetro Irrigado Salitre (Juazeiro-BA), jà os dados referentes aos sistemas conservacionistas foram obtidos em uma unidade experimental da Embrapa SemiÃrido (Petrolina-PE). Realizou-se uma anÃlise de sensibilidade, considerando quatro cenÃrios: C1 (transporte), C2 (embalagem) e C3 (fertilizantes) e C4 (combinaÃÃo de C1, C2 e C3). O sistema de produto em estudo abrange a produÃÃo de sementes e mudas de melÃo, a produÃÃo agrÃcola dos frutos, a embalagem e transporte do melÃo, e a produÃÃo e transporte dos insumos utilizados nestes processos. Aplicou-se o mÃtodo Recipe na avaliaÃÃo das categorias: MudanÃa ClimÃtica, AcidificaÃÃo do Solo, EutrofizaÃÃo de Ãguas Doces, EutrofizaÃÃo Marinha e Escassez HÃdrica; e o mÃtodo Usetox para avaliaÃÃo da Toxicidade. Os resultados indicaram que, em longo prazo, os sistemas conservacionistas apresentam menores impactos ambientais. Mostraram ainda que as categorias avaliadas sÃo afetadas por trÃs principais processos: transporte dos frutos, embalagem dos frutos e produÃÃo de fertilizantes. Com base na anÃlise de sensibilidade, observa-se que no cenÃrio 4 (que combina a substituiÃÃo das caixas de papelÃo, a utilizaÃÃo de um transporte misto e a supressÃo do uso de fertilizantes nitrogenados) ocorre a maior reduÃÃo dos impactos em todas categorias avaliadas. / The Creative Commons License is a leading producer of yellow melon pole for the Brazilian domestic market. Knowing that agricultural activities impact the environment, this study aims to evaluate the environmental impacts through the evaluation of the life cycle, to produce 1 kg of melon grown in Creative Commons License, under two production systems: conventional and conservation. The data relating to conventional melon production system were obtained in the field, with interviews conducted in the Irrigated Perimeter Salitre (Juazeiro-BA), since the data for the conservation systems were obtained in a experimental unit Embrapa Semi-Arid (Petrolina-PE). We performed a sensitivity analysis considering four scenarios: C1 (transport), C2 (packaging) and C3 (fertilizers) and C4 (combination of C1, C2 and C3). The product system under study covers the production of seeds and melon seedlings, agricultural production of fruits, packaging and transport of melons, and the production and transport of inputs used in these processes. Recipe applied the method in the evaluation of the categories: Climate Change, Soil Acidification, Eutrophication of Freshwater, Marine Eutrophication and Water Scarcity; and the Usetox method to assess toxicity. The results indicated that in the long run, conservationists systems have lower environmental impacts. They are shown even if the evaluated categories are affected by three main processes: transport of fruit, packaging of fruits and fertilizer production. Based on the sensitivity analysis, it is observed that the scenario 4 (combining the replacement of the cartons, the use of a mixed transport and the removal of nitrogen fertilizer use) is the greatest reduction of impacts in all categories evaluated.

Limitações nas reservas de combustíveis fósseis e a crescente concentração de gases de efeito estufa na atmosfera tem aumentado o interesse para incrementar a participação da cana-de-açúcar como fonte de biomassa para geração de energia renovável. O uso dos resíduos de colheita da cana-de-açúcar para produção de eletricidade e etanol de segunda geração foi intensificado nos últimos anos, sem haver conhecimento claro das implicações da retirada total ou parcial da palha na produtividade da cultura e qualidade do solo a médio e longo prazo. O objetivo deste estudo foi avaliar a produtividade da cana-de-açúcar, os atributos químicos e os estoques de C e N no solo sob níveis de remoção de palha em áreas com e sem rotação com crotalária. Os parâmetros produtivos da cana-de-açúcar foram avaliados em áreas experimentais localizadas em Quirinópolis/GO, Chapadão do Céu/GO, Iracemápolis/SP e Quatá/SP, enquanto os atributos químicos e os estoques de C e N do solo foram avaliados em Quirinópolis/GO e Quatá/SP, locais com solos de textura argilosa e arenosa, respectivamente. Em cada local, foram instalados dois experimentos, um com rotação com crotalária e outro sem rotação com crotalária (pousio) na renovação do canavial. Após a colheita da cana-planta, foram instalados os tratamentos de soqueira referentes aos níveis de 0, 50 e 100% de manutenção de palha. Os parâmetros produtivos foram avaliados nos dois anos seguintes, enquanto os efeitos no solo foram avaliados no final do segundo ciclo agrícola. A manutenção de palha aumentou a produtividade de colmos em três áreas (Quirinópolis/GO, Chapadão do Céu/GO e Quatá/SP) e reduziu a produtividade em um local (Iracemápolis/SP).O efeito benéfico da rotação com crotalária foi menos persistente no tempo do que a manutenção da palha. Os atributos químicos do solo foram mais influenciados pelos tratamentos no solo argiloso do que no solo arenoso. No solo argiloso, a interação da rotação com crotalária e manutenção da palha aumentou os teores de Mg e o V%, e reduziu a acidez potencial do solo. A rotação aumentou os teores de P, K nos dois solos estudados e a CTC no solo argiloso. A rotação com crotalária não afetou os estoques de C e N, enquanto que a manutenção de palha favoreceu o acumulo de C nos dois tipos de solo. / The limited fossil reserves and the growing concentration of greenhouse gases in the atmosphere, have augmented the interest for a greater participation of sugarcane as a source of biomass for renewable energy generation. The use of sugarcane harvest residues for the production of electricity and second generation ethanol has been intensifying in recent years, without having a clear understanding of the implications of total or partial removal of the straw on the crop productivity and soil quality in the medium and long term. The objective of this study was to evaluate sugarcane productivity, soil chemical attributes and C and N stocks in the soil under straw removal levels in areas with and without sunn hemp rotation. The productivity parameters of sugarcane were evaluated in experimental areas located in Quirinópolis / GO, Chapadão do Céu / GO, Iracemápolis / SP and Quatá / SP, while the chemical attributes and the soil C and N stocks were studied in Quirinópolis / GO and Quatá / SP, places with clay and sandy soils respectively. In each site, two experiments were installed, one with sunn hemp rotation and the other without sunn hemp (fallow) in the renovation of the cane field. After harvesting of the cane-plant, were installed the ratooning treatments referring to the levels of 0, 50 and 100% of straw maintenance were installed. The productive parameters were evaluated in the following two years, while the effects on the soil were evaluated at the end of the second agricultural cycle. The straw retention increased the yield of stalks in three areas (Quirinópolis / GO, Chapadão do Céu / GO and Quatá / SP) and reduced productivity in one place (Iracemápolis / SP). The beneficial effect of rotation with sunn hemp was less persistent in the time than the maintenance of the straw. The chemical attributes of the soil were more influenced by treatments in the clay soil than in the sandy soil. In the clay soil, the rotation interaction with crotalaria and straw maintenance increased the Mg and %BS, and reduced the potential acidity of the soil. The rotation increased the P, K content in the two studied soils and the CEC in the clay soil. Sunn hemp rotation did not affect soil C and N stocks, and maintenance of straw favored C accumulation in both types of soil.

Made available in DSpace on 2016-04-28T14:58:37Z (GMT). No. of bitstreams: 1 2008 - ALEXANDRE PORTO SALMI.pdf: 1554795 bytes, checksum: a6848d37084d24af12afa69b12020065 (MD5) Previous issue date: 2008-07-31 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Flemingia macrophylla is an underexploited Asian legume shrub in Brazil. International literature emphasizes its high potential as component in agroforestry systems in various regions of the tropics. The objective of this dissertation is to evaluate the potential of Flemingia macrophylla as an alternative green manure to be included in agroecological based systems. Two field experiments were conducted from December 12 2006 through December 19 2007. The first experiment was performed in Serop?dica, at sea level, and the second, in Avelar, Paty do Alferes at 500 m altitude. On both experiments twelve monthly plant samplings were performed. Variables measured included stem diameter, number of follioles, and number of branches. Besides, in the first experiment, leaf area, root volumes and biomass, number of nodules and nutrients were quantified monthly. Estimates of biological nitrogen fixation were also accomplished by natural abundance of 15N. The experimental design was a randomized complete block with 12 treatments and four replicates. A previous germination test indicated that pre-incubation with 95% sulphuric acid for 20 minutes resulted in 88% germination, whereas immersion in 90oC water, 44%. On the filed experiments, plants performed better in Serop?dica. The majority of variables were adjusted to second degree polynomial equations. Growth rates were adjusted to Gompertz model. Maximum heights were 1.8 and 1.4 m in Serop?dica and Avelar, respectively. Biomass yields reached 4.1 Mg ha-1 in Serop?dica and 2.3 Mg ha-1 in Avelar. Accumulation of N, P and K at 360 days after planting was 72.6 and 24.4 kg ha-1, respectively in Serop?dica. The highest growth rate was found between 150 and 180 days. The percentage of N derived from biological N fixation was similar at 240, 300 and 360 day after planting, averaging 76.9%, which is equivalent to 62.2 kg N ha-1 at 360 days. The results indicate that Flemingia macrophylla may provide significant amounts of biomass and nutrients, especially N, being a promising species to be included in agroecological production systems. / Flemingia macrophylla ? uma leguminosa arbustiva de origem asi?tica, pouco conhecida e utilizada no Brasil. A literatura destaca seu elevado potencial em diferentes sistemas agroflorestais em v?rias regi?es tropicais do mundo. Esta disserta??o tem como objetivo avaliar o potencial agron?mico de flemingea como alternativa de adubo verde para inclus?o em sistemas diversos de produ??o com base agroecol?gica. Para tanto, realizou-se dois experimentos em condi??es de campo, em 12/12/2006 at? 19/12/2007. O primeiro experimento foi instalado no munic?pio de Serop?dica, a 33 metros de altitude pr?ximo do n?vel do mar e o segundo, em Avelar, Munic?pio de Paty do Alferes a 500 m de altitude. Nos dois experimentos, foram feitas doze coletas mensais das plantas, onde foram determinada altura, di?metro do caule, n?mero de fol?olos e n?mero de ramifica??es. Al?m disso, no experimento I, determinou-se a ?rea foliar, volume e biomassa de ra?zes, biomassa de folhas e caule, n?mero de n?dulos e teores de nutrientes em folhas e caules. Foi ainda realizada estimativa da fixa??o biol?gica de nitrog?nio por meio da abund?ncia natural de 15N. O delineamento utilizado em ambos os experimentos foi em blocos casualizados, com 12 tratamentos (?pocas de coleta) e quatro repeti??es. O teste de germina??o indicou que o tratamento de pr?-incuba??o por vinte minutos com ?cido sulf?rico (95%), resultou em 88% de sementes germinadas, ao passo que o tratamento de imers?o em ?gua quente (90oC) resultou em 44%. Quanto aos experimentos a campo, houve melhor desempenho das plantas em Serop?dica. As alturas m?ximas foram de 1,8 e 1,4 m para Serop?dica e Avelar, respectivamente. A produ??o de biomassa aos 360 dias ap?s transplantio, chegou a valores em torno de 4,1 Mg ha-1 para Serop?dica e 2,3 Mg ha-1 para Avelar. O ac?mulo de N, P e K aos 360 DAT foi de 72,6 e 24,4 e 33 kg ha-1, respectivamente, em Serop?dica. Neste local, observou-se maior taxa de crescimento absoluto entre 150 e 180 DAT. Em rela??o ? produ??o de sementes, n?o se observou diferen?a estat?stica significativa entre os dois locais, apresentando rendimentos de 21,5 e 8,9 kg ha-1. A percentagem de N proveniente da fixa??o biol?gica foi semelhante nas tr?s ?pocas (240 DAT, 300 DAT e 360 DAT) com m?dia de 76,9 % o que equivaleu a 62,2 kg N ha-1 aos 360 DAT. Os resultados indicam que Flemingia macrophylla ? uma esp?cie que pode fornecer quantidades significativas de biomassa e nutrientes, especialmente N, sendo promissora para inclus?o em sistemas de produ??o com base agroecol?gica.

Submitted by Jorge Silva (jorgelmsilva@ufrrj.br) on 2018-08-21T19:46:40Z No. of bitstreams: 1 2009 - Carla Andreia da Cunha Martins.pdf: 6594844 bytes, checksum: 336fdb999764e447e38cb6a0c803c837 (MD5) / Made available in DSpace on 2018-08-21T19:46:40Z (GMT). No. of bitstreams: 1 2009 - Carla Andreia da Cunha Martins.pdf: 6594844 bytes, checksum: 336fdb999764e447e38cb6a0c803c837 (MD5) Previous issue date: 2009-02-28 / CNPq / Population in general is getting more interested in consuming healthy food. Alternative eco-agricultural cropping practices are being emphasized, thanks to the benefits to sustainable agricultural and environment systems. Management of organic and mineral fertilizers, in search of nutrient efficiency, is directly related to environmental, social and economical issues. As plants become more efficient to absorb nutrients, the farmer can count on better products quality and, consequently, to better economic results. The experiments described in the chapters one and two of this study were conducted, respectively, in Fazenda C?rrego Frio and in Fazenda Santo Ant?nio de Estrela, both in Nova Friburgo municipality, Rio de Janeiro State. The first one was accomplished in partnership with Pesagro-Nova Friburgo, and it aimed to evaluate the production of the arracacha (Arracacia xanthorrhiza Bancroft) plant associated with covering plants. The experimental design was of random blocks with four repetitions, and four management treatments: conventional (control), spontaneous vegetation, black oats (Avena strigosa Schreb), and consortium black oats + Villosa villosa. The arracacha variety tested in both studies was the ?Amarela de Caranda?? (AC). The results showed that in the treatments with oats and oat + Villosa villosa, the accumulation of dry mass in the plant and their parts was smallest. The production of commercial roots was higher at 12 months after the planting (MAP) for the conventional and spontaneous vegetation treatments. The second experiment aimed to evaluate the yield of the arracacha crop submitted to increasing doses of phosphorus, with two sources of the fertilizer. The experimental design was of randomly blocks with 4 repetitions and 12 treatments, that consisted of 2 phosphorous sources (simple super phosphate and rock phosphate), and 6 phosphorous doses (0 - without phosphorus - control), 40, 80, 120, 240 and 480 kg P2O5 ha-1). The largest production of total and commercial roots was verified in the treatments with rock phosphate as source of P. The highest total levels of sulfur in the plants were found in the treatments with simple super phosphate. Concerning the accumulation of total nutrients, it was observed a similarity between the two sources of phosphorous. A third experiment was conducted in a greenhouse, located in Serop?dica municipality - RJ. The experimental design was of randomly blocks with four repetitions and six treatments. The treatments consisted of increasing doses of gypsum (CaSO4H2O) as following: 12.5; 25; 50; 100; 200 kg ha-1 of S and a control without gypsum. The soil material was sampled from an Udult soil and the cultivated variety was ?Amarela de Senador Amaral? (ASA). The objective of the study was to evaluate the effect of the sulphur addition in the crop yield. There were determinate: plant dry matter weight; and the levels of N, P, K and S in the plant tissue. The highest doses of S increased the dry matter accumulated in leaves + petioles. Concerning the sulfur accumulation, it was dose dependent for the three parts of the arracacha plant. Despite the conditions in which this research was conducted (greenhouse), it was possible to conclude preliminarily that the ASA is responsive to sulphur fertilization. / O interesse pelo consumo de alimentos saud?veis vem despertando maior aten??o da popula??o. Pr?ticas altenativas de cultivo visando ? agricultura agroecol?gica v?m se destacando em fun??o da sustentabilidade dos sistemas agr?colas e ambientais. O manejo dos fertilizantes org?nicos e minerais buscando a efici?ncia de uso de nutrientes est? diretamente relacionado a quest?es de import?ncia social, econ?mica e ambiental. O melhor aproveitamento dos nutrientes pelas plantas, consequentemente, levar? a uma melhor qualidade da produ??o agr?cola e uma maior rentabilidade para o produtor rural. Os experimentos referentes aos cap?tulos um e dois foram instalados na Fazenda C?rrego Frio e na Fazenda Santo Ant?nio de Estrela, em Nova Friburgo ? RJ. O primeiro trabalho em parceria com a Pesagro-Nova Friburgo, objetivou o estudo da produ??o da mandioquinha-salsa (Arracacia xanthorrhiza Bancroft) consorciada com plantas de cobertura. O delineamento experimental foi de blocos ao acaso com quatro repeti??es e quatro tratamentos de manejo: convencional (testemunha), vegeta??o espont?nea, aveia-preta (Avena strigosa Schreb) e cons?rcio aveia-preta+ervilhaca (Vicia villosa). A variedade usada foi Amarela de Caranda? (AC). Os resultados mostraram que os ac?mulos de massa seca na planta e nas suas partes foram menores nos tratamentos com aveia e aveia + ervilhaca. A produ??o de ra?zes comerciais foi maior aos 12 meses ap?s plantio (MAP) para o tratamento convencional e vegeta??o espont?nea. O ac?mulo de nutrientes de modo geral foi maior nos tratamentos convencional e vegeta??o espont?nea aos 12 MAP. O segundo experimento objetivou avaliar a resposta da mandioquinha-salsa a doses crescentes de f?sforo, com duas fontes do fertilizante fosfatado. O delineamento experimental foi de blocos ao acaso com 4 repeti??es e 12 tratamentos, os tratamentos constaram de 2 fontes de f?sforo (superfosfato simples, SS; e fosfato de rocha, FR) e 6 doses de f?sforo (40, 80, 120, 240 e 480 kg P2O5 ha-1) e uma testemunha. A variedade usada foi AC. A maior produ??o de ra?zes totais e ra?zes comerciais foi verificada nos tratamentos com a fonte de P, FR. Os maiores teores totais de enxofre nas plantas foram encontrados nos tratamentos com SS. No ac?mulo de nutrientes totais observou-se semelhan?a nas respostas das duas fontes de f?sforo estudadas. Um terceiro estudo foi realizado em casa-de-vegeta??o no Departamento de Solos-IA da UFRRJ, em Serop?dica ? RJ. O delineamento experimental foi de blocos ao acaso com quatro repeti??es e seis tratamentos. Os tratamentos constaram de doses de gesso (CaSO4.H2O) a seguir: 12,5; 25; 50; 100; 200 kg ha-1 de S e, uma testemunha. O material de solo usado foi de um Argissolo Amarelo e a variedade cultivada foi a Amarela de Senador Amaral (ASA). O objetivo do trabalho foi avaliar a resposta da mandioquinha-salsa ? aduba??o sulfatada. As determina??es foram: peso de mat?ria seca da planta e teores de N, P, K e S no tecido vegetal. O ac?mulo de mat?ria seca de folhas + pec?olos aumentou em fun??o das doses crescentes de enxofre. Quanto ao ac?mulo de enxofre houve resposta em fun??o das doses nas tr?s partes da planta de mandioquinha-salsa. Em uma conclus?o pr?via, por ser o trabalho conduzido em casa-de-vegeta??o, a ASA responde ? aduba??o sulfatada.

On the Canadian prairies, organic production generally includes the use of annual green manure (GrM) crops, which are terminated using tillage to add nutrients and organic matter to the soil. However, in a GrM plough-down year, farmers face loss of income. As an alternative to growing traditional GrM crops, legumes can be grown alone or intercropped with cereals and harvested as green feed forage (GF) for use on-farm or for sale to other producers without depleting soil nitrogen (N) for the subsequent crop. We hypothesized that the GF system would have similar biomass, and N yield, and ultimately would return N into the soil. Furthermore, by intercropping a legume with a cereal, biological N2-fixation will be enhanced in the legume.<p> Field experiments, conducted over two years, were established at Vonda and Delisle, Saskatchewan, Canada. The experiment was conducted using a randomized complete block design (RCBD) with 16 treatments and four replicates in which field pea (<i>Pisum sativum</i> cv 40-10 silage pea), oat (<i>Avena sativa</i> L.cv AC Morgan), and triticale (X <i>Triticosecale</i> Wittmack cv Pika) were grown alone or in combination and managed as GrM or GF. Wheat and tillage fallow served as cropped and uncropped controls, respectively. The tillage fallow-control system was tilled twice in the growing season using a small tractor disc. The intercropped oat was seeded at three densities (50, 100, and 150 plants m-2) to determine whether increasing cereal density stimulated N2-fixation in the field pea.<p> The GrM system was sampled and incorporated (when the field pea was at full bloom) two weeks earlier than the GF system. Consequently, at both sites, all treatments in the GF system consistently yielded more dry matter and accumulated more N than treatments in the GrM system. At the Delisle site, where percent nitrogen derived from the atmosphere (%Ndfa) was compared, increasing cereal density did not increase N2-fixation in both management systems. However, pea in the GF system accumulated more than twice the amount of N (kg ha-1) from fixation as compared to pea in the GrM system, presumably because of the longer growth period.<p> Wheat grown following the GrM treatments produced more biomass and accumulated more N than wheat following the GF treatments. Wheat grown after the monoculture field pea as a GrM had greater yield than all treatments. As well, the GrM system returned more N to the soil than did the GF system. The extra two weeks of growth in the GF system resulted in the extraction of significant amounts of nutrients and probably moisture from the soil, which adversely affected yield and nutrient composition of the following wheat crop.<p> Although organic farmers may lose income in the plough-down year, on a longterm soil sustainability basis, the GrM system is a better option than the GF system as it returns nutrients to the soil, thus providing improved plant biomass, and N accumulation of subsequent crops. However, organic farmers growing GF for hay may benefit from the increased productivity of this system on a short-term basis. Thus, farmers pursuing GF options may need to adopt other means of sustaining soil productivity on a longer term. The tilled fallow-control system resulted in high amounts of biomass and N accumulation by the subsequent wheat crop, probably due to the fact that there were no nutrients taken up in the previous year and moisture was conserved in these treatments. However, this system may have less long-term benefits compared to the GrM regime, as no nutrients are returned through ploughing down a crop.

On the Canadian prairies, organic production generally includes the use of annual green manure (GrM) crops, which are terminated using tillage to add nutrients and organic matter to the soil. However, in a GrM plough-down year, farmers face loss of income. As an alternative to growing traditional GrM crops, legumes can be grown alone or intercropped with cereals and harvested as green feed forage (GF) for use on-farm or for sale to other producers without depleting soil nitrogen (N) for the subsequent crop. We hypothesized that the GF system would have similar biomass, and N yield, and ultimately would return N into the soil. Furthermore, by intercropping a legume with a cereal, biological N2-fixation will be enhanced in the legume.<p> Field experiments, conducted over two years, were established at Vonda and Delisle, Saskatchewan, Canada. The experiment was conducted using a randomized complete block design (RCBD) with 16 treatments and four replicates in which field pea (<i>Pisum sativum</i> cv 40-10 silage pea), oat (<i>Avena sativa</i> L.cv AC Morgan), and triticale (X <i>Triticosecale</i> Wittmack cv Pika) were grown alone or in combination and managed as GrM or GF. Wheat and tillage fallow served as cropped and uncropped controls, respectively. The tillage fallow-control system was tilled twice in the growing season using a small tractor disc. The intercropped oat was seeded at three densities (50, 100, and 150 plants m-2) to determine whether increasing cereal density stimulated N2-fixation in the field pea.<p> The GrM system was sampled and incorporated (when the field pea was at full bloom) two weeks earlier than the GF system. Consequently, at both sites, all treatments in the GF system consistently yielded more dry matter and accumulated more N than treatments in the GrM system. At the Delisle site, where percent nitrogen derived from the atmosphere (%Ndfa) was compared, increasing cereal density did not increase N2-fixation in both management systems. However, pea in the GF system accumulated more than twice the amount of N (kg ha-1) from fixation as compared to pea in the GrM system, presumably because of the longer growth period.<p> Wheat grown following the GrM treatments produced more biomass and accumulated more N than wheat following the GF treatments. Wheat grown after the monoculture field pea as a GrM had greater yield than all treatments. As well, the GrM system returned more N to the soil than did the GF system. The extra two weeks of growth in the GF system resulted in the extraction of significant amounts of nutrients and probably moisture from the soil, which adversely affected yield and nutrient composition of the following wheat crop.<p> Although organic farmers may lose income in the plough-down year, on a longterm soil sustainability basis, the GrM system is a better option than the GF system as it returns nutrients to the soil, thus providing improved plant biomass, and N accumulation of subsequent crops. However, organic farmers growing GF for hay may benefit from the increased productivity of this system on a short-term basis. Thus, farmers pursuing GF options may need to adopt other means of sustaining soil productivity on a longer term. The tilled fallow-control system resulted in high amounts of biomass and N accumulation by the subsequent wheat crop, probably due to the fact that there were no nutrients taken up in the previous year and moisture was conserved in these treatments. However, this system may have less long-term benefits compared to the GrM regime, as no nutrients are returned through ploughing down a crop.

In Manitoba, potato fields have been found to be infested with Verticillium dahliae, which can produce Vertcillium wilt disease severity of up to 90% and reduce yield. Potato producers have then an increased interest on use of green manures and organic amendments to control Verticillium wilt. The objectives of this research were to evaluate selected green manure and organic amendments for their ability to reduce propagule density of V. dahliae in soil, incidence and severity of Verticillium wilt, and to enhance potato yield in Manitoba. In addition, a second study was conducted for the purpose of studying the potential of mustard green manure and seed meal to inhibit the germination of microsclerotia. Findings suggest that composted-cattle-manure and oriental mustard seed-meal amendments have promise as an alternative strategy for the control of V. dahliae. However, only composted beef cattle manure reduced disease, increased potato yield and improved nutrient availability (P) in soil

In Manitoba, potato fields have been found to be infested with Verticillium dahliae, which can produce Vertcillium wilt disease severity of up to 90% and reduce yield. Potato producers have then an increased interest on use of green manures and organic amendments to control Verticillium wilt. The objectives of this research were to evaluate selected green manure and organic amendments for their ability to reduce propagule density of V. dahliae in soil, incidence and severity of Verticillium wilt, and to enhance potato yield in Manitoba. In addition, a second study was conducted for the purpose of studying the potential of mustard green manure and seed meal to inhibit the germination of microsclerotia. Findings suggest that composted-cattle-manure and oriental mustard seed-meal amendments have promise as an alternative strategy for the control of V. dahliae. However, only composted beef cattle manure reduced disease, increased potato yield and improved nutrient availability (P) in soil

Overall soil productivity is declining in the U.S. due to loss of soil organic matter (SOM). Decreased SOM lowers soil water storage, reduces water infiltration, slows aggregate formation, and depletes soil of nutrients. In many systems, crop nutrients are replaced by expensive synthetic fertilizers that can lead to environmental concerns. This practice is not economically or environmentally sustainable in the long term. To secure future soil use and crop production, sustainable management practices are needed to prevent further SOM depletion. Incorporating legumes into cropping systems is one alternative that can bolster soil organic C (SOC) (key indicator of SOM) and reduce N fertilizer applications through symbiotic legume N fixation. Three studies were conducted over multiple years at the Texas A&M AgriLife Research and Extension Center near Overton, TX. Annual cool- and warm-season legumes were evaluated as potential green manure crops and intercrops under grain sorghum [Sorghum bicolor (L.) Moench], high-biomass sorghum [Sorghum bicolor (L.) Moench], and annual forage cropping systems. These studies quantified legume soil moisture usage and C and N contributions to the soil and subsequent crop yields in East Texas. Primary project objectives were to maintain or maximize primary crop yields at reduced N fertilizer rates and to build SOC through the integration of legume green manures and intercrops. Green manuring cool-season legumes showed the most beneficial effect on SOC, soil total N, and crop yields; however, significant increases in yield were only detected after three years in rotation. Intercropping Iron-and-Clay cowpea (Vigna unguiculata L. [Walp]) decreased yield of both high-biomass sorghum and grain sorghum due to competitive vegetative growth. Iron-and-Clay did however improve biomass yields of high-biomass sorghum in two subsequent years when implemented as a green manure. Despite large N yields as high as 310 kg ha-1, impacts of legumes on annual forage crops was limited. Poor response was likely a result of previous field history in which a permanent warm-season grass pasture was cultivated for site preparation and mineralized SOC released substantial amounts of available N. Under low soil N conditions, legume green manures produce enough N to likely reduce N fertilizer requirements cost-effectively for subsequent crops in East Texas.

Thesis (Ph. D.)--University of Missouri-Columbia, 1996. / Typescript. Vita. Includes bibliographical references (leaves 160-168). Also available on the Internet.