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Accueil du site → Doctorat → Brésil → Caracterização da produção de biomassa de capim-elefante (Pennisetum purpureum, Schum.), cv. Cameroon, em função da adubação nitrogenada e irrigação em região semiárida

Escola Superior de Agricultura Luiz de Queiroz (USP) 2014

Caracterização da produção de biomassa de capim-elefante (Pennisetum purpureum, Schum.), cv. Cameroon, em função da adubação nitrogenada e irrigação em região semiárida

Carvalho, Guilherme Busi de

Titre : Caracterização da produção de biomassa de capim-elefante (Pennisetum purpureum, Schum.), cv. Cameroon, em função da adubação nitrogenada e irrigação em região semiárida

Biomass production characterization of elephant-grass (Pennisetum purpureum, Schum.), cv. Cameroon, related to nitrogen fertilization and irrigation in the semiarid region of Brazil

Auteur : Carvalho, Guilherme Busi de

Université de soutenance : Escola Superior de Agricultura Luiz de Queiroz (USP)

Grade : Tese de Doutorado 2014

Contexte
Due to the potential use of elephant-grass biomass as a source of renewable fuel in semi-arid regions, this study aimed to evaluate the effects of six nitrogen rates (44, 200, 400, 600, 800 and 1000 kg.ha-1) and seven irrigation levels (0, 40, 54, 100, 135, 148 and 200% of crop evapotranspiration - ETc) in seven cropping ages (46, 82, 112, 139, 169, 202 and 231 days) on elephant-grass, Cameroon cultivar, dry biomass yield (BMS, kg.ha-1), height (m) and leaf area index (LAI, m2.m-2). The trial was conducted in a Quartzipsamment soil located in Beberibe, Ceará State, Brazil, semiarid region, from May 2012 to March 2013. The nitrogen rates were the main plots and the irrigation levels comprised the subplots, according to a randomized block design with four replications. Irrigation treatments perpendicularly arranged (line source system sprynkler) and nitrogen rates were arranged in parallel to the lateral irrigation line. The experimental block consisted of 36 plots with 5 x 15 m and the treatment without irrigation (L0), with 6 nitrogen rates and 4 replications, was carried out in separate location to avoid infuence of the irrigated area. The nitrogen source was ammonium sulphate, was topdressed onto soil surface, in three split applications during the trial. The irrigation timing and management definition was performed by soil water storage capacity determination and through the Penman-Monteith-FAO crop evapotranspiration calculation. Regarding to BMS production, elephant-grass responded to nitrogen fertilization and irrigation in 7 evaluated periods, and the highest BMS (kg.ha-1.day-1) accumulation response was obtained in the combined treatment 135% ETc and 400 kg.ha-1 N at after 231 days with 239.85 kg.ha-1.day-1. Regarding to irrigation depths treatments, the elephant-grass production increased in all analyzed periods, and the largest BMS (kg.ha-1.day-1) accumulation response was found in treatment 100% ETc after 82 days with 43.46 kg.ha-1.mm-1 applied. The yield in treatments 125, 148 and 200% ETc in cutting ages from 82 to 231 days were the highest and did not differ significantly. The elephant-grass did not respond to nitrogen rates after 6 periods evaluated (82 to 231 days) however the N fertilization responded at the age of 46 days with 3.780 e 5005 kg.ha-1 de BMS between treatments of 44 e 1000 kg.ha-1 de N, respectively and the most intense BMS accumulation response was observed in treatment 800 kg.ha-1 of N at 231 days with 15,4 kg.ha-1.kg-1 N applied. The LAI and height of elephant-grass responded to water depths and did not respond to nitrogen fertilization. Both can be adopted as an elephant grass BMS yield estimation parameter from the age of 112 to 202 days after cutting, respectively. However, BMS versus LAI and LAI versus height interaction showed no correlation between the data collection periods, thus those variables should not be adopted for yield estimation purpose for this crop.

Mots clés  : Agroenergia Bioenergia Energia renovável Nitrogênio — Agroenergy Bioenergy Nitrogen Renewable energy

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Page publiée le 1er décembre 2015, mise à jour le 4 juillet 2017