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Doctoral Thesis
DOI
https://doi.org/10.11606/T.11.2020.tde-20200111-143520
Document
Author
Full name
Robinson Antonio Pitelli
E-mail
Institute/School/College
Knowledge Area
Date of Defense
Published
Piracicaba, 1981
Supervisor
Title in Portuguese
Competição por nutrientes entre a cultura do arroz e a comunidade infestante. efeitos do espaçamento e da fertilização nitrogenada
Keywords in Portuguese
ARROZ
COMPETIÇÃO
NUTRIENTES
PLANTAS INFESTANTES
Abstract in Portuguese
Objetivou-se estudar os efeitos das diferenças de 0,40 m e 0,60 m e das doses de 2.4, 4.8 e 7.2 g de N/m de sulco sobre a competição por nitrogênio, fósforo , potássio, cálcio, magnésio, cobre, ferro, manganês e zinco entre a comunidade infestante e a cultura do arroz de sequeiro (Oryza sativa L. c.v. IAC 25). O experimento foi instalado em solo Latossol Vermelho escuro fase arenosa. Coletou-se a parte aérea das plantas de arroz e das plantas daninhas no perfilhamento e no florescimento da cultura. Analisou-se, ainda, o grão de arroz beneficiado. Nas condições em que foi desenvolvida a presente pesquisa pode-se concluir que: 1) A competição imposta pelas plantas daninhas reduziu os acúmulos de matéria seca e de nutrientes na parte aérea e nos grãos de arroz. A redução da produção de grãos foi da ordem de 60%; 2) os acúmulos de matéria seca e de nutrientes pela comunidade infestante não foram alterados pelo espaçamento e pela fertilização nitrogenada; 3) as participações do arroz e da comunidade infestante no total da matéria seca acumulada no sistema foram equilibradas; 4) a comunidade infestante e a cultura divergiram no recrutamento dos recursos minerais do solo. O arroz apresentou teores mais elevados de fósforo, cobre, manganês e zinco. Os teores de nitrogênio, potássio, cálcio, magnésio e ferro foram maiores na comunidade infestante; 5) a intensidade de influência das plantas daninhas em relação aos teores dos elementos no arroz foi maior no espaçamento de 0,60 m e dependeu do nível.de exigência dos competidores em relação aos elementos.
Title in English
Nutrient weed competition in upland rice crop. row spacing and nitrogen fertilization effects.
Abstract in English
The purpose of this work was the study of the row spacing, from 0.40 to 0.60 m, and nitrogen doses, 2.4, 4.8 and 7.2 g of N/m of row, effects on the weed competition for nitrogen, phosphorus, potassium, calcium, magnesium" copper, iron, manganese and zinc, in upland rice crop (Oryza sativa L. cv. IAC 25). The experiment was instalated in a "Latossol Vermelho Escuro fase arenosa" soil. The rice plants and weed shoots were coleted in the tillering and flowering crop phases, and chemically analizated. The rice grains were also analizated. In our experimental conditions the following conclusions seams to hold: 1) The weed competition reduced the accumulation of dry matter, nutrients in shoot and in the rice grains. The yield was reduced about 60 per cent; 2) the dry matter and nutrient accumulation in the weed community had not been affected by crop row spacing and nitrogen fertilization: 3) the relative dry matter distribuition between the rice crop and weed community in the total dry matter of the system were equilibrated; 4) there were differences in the mineral uptake by the weeds and rice crops. The levels of phosphorus, copper, manganese and zinc were higher in rice plants. Contrasting, the levels of nitrogen, potassium, calcium, magnesium and iron that were higher in the weed community; 5) the degree of the effects of the weed competition in relation to the levels of nutrients were higher in 0,60 m spacing. The effect was dependent of the nutricional requeriment levels of each element by the competidors.
 
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Publishing Date
2020-01-11
 
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