Recuperação no sistema solo-planta de nitrogênio derivado da adubação verde aplicada à cultura do repolho

Abstract

Resumo -O objetivo deste trabalho foi determinar a eficiência de recuperação, no sistema solo-planta, do nitrogênio derivado da adubação verde aplicada à cultura de repolho (Brassica oleracea). O experimento foi dividido em duas etapas: a primeira consistiu da produção de palhada de feijão-de-porco (Canavalia ensiformis), mucuna-cinza (Mucuna cinereum), e sorgo (Sorghum bicolor), em substrato enriquecido com 15 N. A segunda etapa consistiu da aplicação das palhadas marcadas com 15 N, em cobertura nos canteiros com repolho. Os tratamentos consistiram de: palha fresca de feijão-de-porco; palha fresca de mucuna-cinza; palha fresca de sorgo; mistura das palhas de mucuna, feijão-de-porco e sorgo a 1:1:1; e controle sem adubação verde. A recuperação de N no sistema solo-planta foi influenciada pelo tipo de palhada utilizado, e a eficiência de recuperação do N derivado da palhada de leguminosa variou de 9 a 16%. O tratamento com palha de feijão-de-porco é o que apresenta maior eficiência de recuperação e, portanto, a melhor sincronia da oferta de nitrogênio pela decomposição da palhada com a demanda pela cultura do repolho.Termos para indexação: adubo verde, dinâmica de nitrogênio, hortaliças, isótopos de 15 N. Recovery in the soil-plant system of nitrogen from green manure applied on cabbage cropAbstract -The objective of this work was to determine, in the soil-plant system, the recovery efficiency of N derived from green manure applied on cabbage (Brassica oleracea) crop. The experiment was divided into two stages: the first one consisted of the straw production of jack bean (Canavalia ensiformis), velvet bean (Mucuna cinereum), and sorghum (Sorghum bicolor), in substrate enriched with 15 N. The second stage consisted of the application of 15 N-labeled green manure on the cabbage beds. Treatments consisted of: fresh residues of jack bean; fresh residues of velvet bean; fresh residues of sorghum; mixture of residues of jack bean, velvet bean, and sorghum at 1:1:1; and control without green manure addition. The N recovery in the soil-plant system was influenced by the green manure species used, and the recovery efficiency of the N derived from the green manure legumes varied from 9 to 16%. The jack bean treatment shows a greater recovery efficiency of nitrogen and, therefore, the best synchrony of N supply, by straw decomposition, with the cabbage crop demand.

Changes in the stocks of C and N in organic matter fractions in soil cropped with coffee and fertilized with sunn hemp and ammonium sulfate

“…At planting, 6 g of N per plant was applied (60% of the N via ammonium sulfate and 40% as the dry matter of aboveground part of sunn hemp (C. juncea)). A recovery efficiency of 50% of mineral N was considered, implied by the application of 7.2 g of N. Regarding sunn hemp biomass and considering values reported in the literature, the recovery efficiency adopted was 25% (SEO et al, 2006;AMBROSANO et al, 2011;ARAÚJO et al, 2011), resulting in a dose of 9.6 g of N. The applied quantity of residues corresponded to 280 g of crushed residues from the aboveground part of sunn hemp, corresponding to a dose of 4.75 Mg ha -1 . The legume exhibited a concentration of 3.4% N in the dry matter, and it had been produced primarily for experimental use.…”

“…The values were less than 25% (SEO et al, 2006;AMBROSANO et al, 2011;ARAÚJO et al, 2011;DINIZ et al, 2015), whereas in the soil and the remaining material, higher amounts of N derived from the legume were recovered (ARAÚJO et al, 2005(ARAÚJO et al, , 2011SEO et al, 2006;LANGE et al, 2009).…”

Desenvolvimento de mudas de repolho pelo uso de diferentes substratos

“…A cultura do repolho é tolerante a solos ácidos e, por isso, adapta-se a pH entre 5,5 a 6,8 [2]. Além disso, o repolho é exigente em nitrogênio, fósforo e potássio [3].…”

Soil management in integrated rose production system

“…Although green fertilization has been shown to be efficient in several crops (Araújo et al, 2011), we still need more information special for flower production. Research on the integrated production of flowers is also recent, and, therefore, there is a lack of similar results for floriculture.…”