Submitted by Leticia Schettini (leticia@ufrrj.br) on 2016-10-25T13:23:17Z No. of bitstreams: 1 2007 - Esmeralda Aparecida Porto Lopes.pdf: 883696 bytes, checksum: f8674ae83ea197a31035a6bf14482b84 (MD5) / Made available in DSpace on 2016-10-25T13:23:17Z (GMT). No. of bitstreams: 1 2007 - Esmeralda Aparecida Porto Lopes.pdf: 883696 bytes, checksum: f8674ae83ea197a31035a6bf14482b84 (MD5) Previous issue date: 2007-03-02 / The study had the objective of evaluating height and density of crotalaria planting (Crotalaria juncea L.) as biomass indicators of production, N accumulation, and potential of nitrogen biological fixation in the plant, and its influence in the maize crop (Zea mays L.). Also to obtain a corn response pattern to green manure and equivalence to N added as ammonium sulphate fertilizer. The study was conducted in 2005 and 2006, under field conditions, in the experimental area of Embrapa Agrobiologia, Serop?dica, RJ. The soil in the experimental area was identified as a Fragiudult. In the first experiment, a randomized block with four replicates design was used to test four planting densities of crotalaria (50, 100, 150 e 200 plants m-2). In the second experiment, it was used a randomized block, and it was evaluated the corn crop response pattern to doses of 0, 75, 150, 225 and 300 kg N ha-1, applied in the form of crotalaria biomass, without incorporation in the soil. For comparing N corn response it was used as reference the N fertilizer ammonium sulphate, at 0, 38, 75, 113 and 150 kg N ha-1 dosages. In the first experiment, the height of crotalaria plants was affected by the plant densities per linear meter (15, 30, 45 and 60 pl/m), starting at 48 days after the planting. The density treatment of 15 plants presented the tallest height. The variation of crotalaria plants population did not favor differences in N accumulation, biological nitrogen fixation, ratio shoot/leaf and dry aerial biomass production of crotalaria. On average, crotalaria produced an amount of dry mass of 9.0 Mg ha-1 and accumulated 164.36 kg N ha-1, with an average height of 2.6 m. From the total of N accumulated by crotalaria, 59% derived from BNF and the remaining from the soil. This leguminous was able to add to soil, through BNF, about 97 kg N ha-1, consisting in an excellent strategy of supplying N to soil. The different crotalaria population arrangements resulted in a production of aerial dry matter and N accumulation in corn, in the milky grain stage, higher than the reference plot without N. In the second experiment, crotalaria produced an amount of dry matter of 11.5 Mg ha-1 and accumulated 328 kg N ha-1 in 112 days. Each unit of mineral-N and green manure-N resulted in an increment of 22.27 and 11.98 kg ha-1, respectively. A linear model was also adjusted for total N accumulation in corn as function of green manure-N doses (R2 = 0.64) and with Nammonium sulphate (R2 = 0.79) to 5% of significance level. Each unit of mineral-N and green manure-N resulted in an increment of 0.43 and 0.09 kg ha-1, respectively. It was concluded, through the angular coefficients of the linear regression equations, which green manure and mineral fertilizer did not presented same efficiency, neither in crotalaria dry biomass production nor in total N accumulation. Therefore, it takes twice and five times more green manure to reach the same production of dry matter and total N accumulation, respectively. / O estudo teve como objetivos avaliar a altura e a densidade de plantio de crotal?ria (Crotalaria juncea L.) como indicadores da produ??o de biomassa, acumula??o de N e potencial de fixa??o biol?gica de nitrog?nio na planta, e sua influ?ncia na cultura do milho (Zea mays L.), assim como se obter uma curva de resposta da cultura do milho ? aduba??o verde, em equival?ncia ao N na forma de sulfato de am?nio. Foram conduzidos trabalhos experimentais nos anos de 2005 e 2006, sob condi??es de campo na ?rea experimental da Embrapa Agrobiologia, Serop?dica, RJ. Os experimentos foram instalados em um Planossolo H?plico, sendo que, no primeiro experimento, utilizou-se um delineamento em blocos ao acaso, com quatro repeti??es, para testar quatro densidades de plantio de crotal?ria (50, 100, 150 e 200 plantas m-2). No segundo experimento, utilizou-se um delineamento em blocos ao acaso e avaliou-se a resposta da cultura do milho ?s doses de 0, 75, 150, 225 e 300 kg N ha-1 na forma de parte a?rea de crotal?ria, sem incorpora??o no solo, tendo como refer?ncia a resposta ? fertiliza??o com doses de 0, 38, 75, 113 e 150 kg N ha-1 na forma de N-sulfato de am?nio. No primeiro experimento, a altura da planta de crotal?ria foi afetada pelas densidades de plantas por metro linear (15, 30, 45 e 60 pl/m) a partir dos 48 dias ap?s o plantio, sendo a densidade de 15 plantas a que apresentou a maior altura. A varia??o da popula??o de plantas de crotal?ria n?o favoreceu diferen?as na acumula??o de N, fixa??o biol?gica de nitrog?nio, rela??o caule/folha e produ??o de biomassa seca a?rea pela crotal?ria. Em m?dia, a crotal?ria produziu uma quantidade de mat?ria seca de 9,0 Mg ha-1 e acumulou 164,36 kg N ha-1, com uma altura m?dia de (2,6 m). Do total de N acumulado pela crotal?ria, 59% foram derivados da FBN, sendo o restante proveniente do solo. Sendo assim, essa leguminosa foi capaz de aportar ao solo, via FBN, cerca de 97 kg N ha-1, constituindo-se em uma excelente estrat?gia de fornecimento de N ao solo. Os diferentes arranjos populacionais da crotal?ria resultaram em uma produ??o de mat?ria seca a?rea e ac?mulo de nitrog?nio no milho no est?dio de gr?o leitoso superior a testemunha n?o nitrogenada. No segundo experimento, a crotal?ria produziu uma quantidade de mat?ria seca de 11,5 Mg ha-1, acumulou 328 kg N ha-1 em 112 dias. Um no milho em fun??o das doses de N como adubo verde (R2 = 0,64) e com N-Sulfato de am?nio (R2 = 0,79) ao n?vel de 5% de signific?ncia. Para cada unidade de N mineral e Nadubo verde resultou em um incremento de (0,43 e 0,09 kg ha-1), respectivamente. Concluiuse atrav?s dos coeficientes angulares das equa??es de regress?o linear que o adubo verde e o adubo mineral n?o apresentaram a mesma efici?ncia quanto a produ??o de biomassa a?rea seca da crotal?ria nem quanto ao ac?mulo de N-total, sendo portanto necess?rio duas e cinco vezes a mais adubo verde para alcan?ar a mesma produ??o de mat?ria seca e ac?mulo de Ntotal, respectivamente.