Produtividade de grãos e componentes de produção da canola de acordo com fontes e doses de nitrogênio

Abstract

Resumo -O objetivo deste trabalho foi avaliar a resposta da canola a fontes e doses de nitrogênio aplicadas na semeadura. O experimento foi conduzido em Latossolo Vermelho distroférrico típico, com textura muito argilosa. Utilizou-se delineamento experimental de blocos ao acaso, em arranjo fatorial 7x2, com sete doses de N em superfície na semeadura (0, 20, 40, 60, 80, 100 e 120 kg ha -1 ), duas fontes de N (sulfato de amônio e ureia) e quatro repetições. O experimento foi realizado com o híbrido Hyola 61, por dois anos, e foram avaliadas as seguintes variáveis: altura de planta, número de plantas por metro quadrado, massa de matéria seca da parte aérea, massa de síliquas por planta, massa de mil grãos, produtividade de grãos, e teores de proteína e de óleo nos grãos. As variáveis não foram influenciadas pelas fontes de N. A maior produtividade de grãos é alcançada com 88 kg ha -1 de N. Doses crescentes de N aumentam os teores de proteína e diminuem os de óleo nos grãos de canola.Termos para indexação: Brassica napus, adubação nitrogenada, sulfato de amônio, teor de óleo, teor de proteína, ureia. Grain yield and yield components in canola according to nitrogen sources and ratesAbstract -The objective of this work was to evaluate the response of canola to nitrogen sources and rates applied at sowing. The experiment was carried out on a dystroferric Red Ferralsol, with a very clayey texture. A randomized complete block design was used, in a 7x2 factorial arrangement, with seven N rates applied on soil surface at sowing (0, 20, 40, 60, 80, 100, and 120 kg ha -1 ), two N sources (ammonium sulfate and urea), and four replicates. The experiment was carried out with the Hyola 61 hybrid for two years, and the following variables were evaluated: plant height, number of plants per square meter, shoot dry matter mass, pod mass per plant, weight of a thousand grains, grain yield, and protein and oil contents in seeds. The variables were not affected by the N sources. The highest grain yield is obtained with 88 kg ha -1 N. Increasing N rates increase protein contents and reduce oil contents in canola seeds.Index terms: Brassica napus, nitrogen fertilization, ammonium sulfate, oil content, protein content, urea. IntroduçãoA canola (Brassica napus L. var. oleífera) é uma oleaginosa de inverno desenvolvida a partir do melhoramento genético da colza. Em razão dos preços vantajosos e de sua adaptabilidade às condições edafoclimáticas do Sul do Brasil, a canola vem se tornando, na região, juntamente com o milho safrinha (Zea mays L.) e o trigo (Triticum aestivum L.), uma excelente opção de cultivo de inverno, além de constituir uma sucessão adequada ao cultivo de soja (Glycine max L.).A canola é uma cultura altamente responsiva à aplicação de N (Rathke et al

Genetic variation and gain in progenies of crambe

“…The average grain yield of crambe progenies was higher than the average grain yield of canola, an oilseed crop also from Brassica family with grain yield reaching 1300 to 1700 kg ha -1 , according to studies by Kruger at al. (2011) and Kaefer et al (2014). Regarding the grain oil content, which is a relevant characteristic in crambe, Lessman (1975) observed values from 27.1 to 33.3% in lines of crambe evaluated in two years, being similar to the values obtained in this study.…”

Interception of solar radiation by the productive structures of spring canola hybrids

“…Results of interception efficiency obtained with the two higher doses of applied N are equivalent to values obtained by CHARTIER et al (1983) andFRAY et al (1996), between 70 and 80%, while the lowest doses of N (10 and 20kg ha -1 ), provided values of εi between 45 and 55%. This response can in part be attributed to limitations of N for photosynthesis (KAEFER et al, 2014), which results in a low production of reproductive structures, in comparison to higher levels of nitrogen. Thus, canola plants may increase the production of assimilates if they are well supplied in N, so producing more siliques.…”

Canola response to nitrogen sources and split application

“…Its absence limits plant growth and its availability has been associated with the increase in cell division and expansion, leaf area and photosynthesis (Bybordi, 2012). It is important to mention that higher LA is a desirable aspect in plants, because it allows the interception of greater amount of solar energy and, combined with adequate N supply, provides better conditions for converting this energy into photoassimilates (Rathke, et al, 2006;Chavarria et al, 2011;Kaefer et al, 2014).…”