-The objective of this work was to determine the effect of incorporation timing of the velvet bean (Stizolobium cinereum) (GM) on both organic broccoli yield and N status. Mineral N content in the soil, biologically fixed N recovery by broccoli, GM biomass decomposition and N release kinetics were also determined. Plots were fertilized with 12 Mg ha -1 of organic compost and received GM either at 0, 15, 30 or 45 days after transplant. Other treatments were compost (12 or 25 Mg ha -1 ), GM, mineral fertilizers and control (no fertilizer). The data were collected in four completely randomized blocks. GM decomposition increased mineral N content in soil as rapidly as mineral fertilizer or the supply of 25 Mg ha -1 of compost. The N half-life in GM (24 days) is smaller than the mass half-life (35 days) and the biological fixation contributed with 23.6% of N present in the aboveground biomass of broccoli. The result suggests a higher synchrony between the crop relative growth rate and N release from the GM when incorporated at crop early growth stage. The incorporation of GM until 15 days after transplanting replaces 50% of the highest compost dose, without yield loss.Index terms: Brassica oleracea, Stizolobium cinereum, biological nitrogen fixation, decomposition rate, N recovery. Época de incorporação de adubo verde para o cultivo orgânico de brócolisResumo -O objetivo deste trabalho foi determinar o efeito do momento da incorporação de mucuna-cinza (Stizolobium cinereum) (AV) sobre a produtividade e o teor de N do brócolis orgânico. Foram determinados o teor de N mineral no solo, a recuperação de N fixado biologicamente no brócolis e a cinética de decomposição da massa e liberação de N do AV. As parcelas foram fertilizadas com 12 Mg ha de composto orgânico. A meia-vida de N no AV (24 dias) é menor que a meia-vida da massa (35 dias) e a fixação biológica contribuiu com 23,6% do N da parte aérea do brócolis. Os resultados sugerem maior sincronia entre a taxa de crescimento relativo da cultura e a liberação de N do AV, quando incorporado no início do cultivo. A incorporação do AV até 15 dias depois do transplante substitui 50% da dose de composto sem perda de produtividade.Termos para indexação: Brassica oleracea, Stizolobium cinereum, fixação biológica do nitrogênio, taxa de decomposição, recuperação de nitrogênio.

Influence of the biomass of legumes on cabbage yield held in two consecutive cropsIn studies assessing the performance of crops in response to green manure generally are not considered the effect of roots. However, such effects may contribute to increase the scientific understanding towards this technique. The effect of the root and of the aboveground part of two legume species, Crotalaria juncea and Canavalia ensiformis, were evaluated on cabbage yield in two crops. The experiment was arranged in randomized blocks with 4 replications in a factorial design (2 x 3) + 2 (2 legumes species -Crotalaria juncea (sunnhemp) and Canavalia ensiformis (jack beans), 3 plant parts (root, aboveground part and the whole plant) and 2 additional treatments (mineral fertilizer 100% and 50% of recommended N). The green manure was applied to the surface. The cultivation with the aboveground part or the whole plant of sunnhemp or jack beans reduced the necessity of fertilization with mineral N in 50%, but the cabbage yield was reduced with the cultivation with the root system of jack beans. Areas with the aboveground part or the whole plant of sunnhemp or jack beans presented higher residual effects on the second crop with mineral N fertilizer. The cultivation with the roots of these legumes resulted in no residual effect different from mineral fertilizer with 50 or 100% of recommended N.

RESUMOA utilização de composto orgânico na produção de olerícolas resulta em efeitos diversos e complexos. Embora seja crescente a pesquisa voltada para a produção orgânica de olerícolas, os efeitos do composto orgânico sobre o crescimento e a produção dessas culturas são ainda pouco conhecidos cientificamente. Objetivou-se com este trabalho avaliar o crescimento e a produção de brócolis cultivado com composto orgânico e determinar a variável não destrutiva com maior correlação com o acúmulo de matéria seca. O experimento foi conduzido em Viçosa, MG (20º 45 sul 42º 51 oeste). O delineamento experimental foi o de blocos casualizados com quatro repetições em parcelas subdivididas no tempo para as variáveis de crescimento. Os tratamentos consistiram em doses de composto orgânico: 5, 10, 15, 20, 25 t ha -1 em base de massa seca, fornecidos à cultura do brócolis híbrido Domador . A maior produção, 564 g planta -1 , correspondente a 12,53 t ha -1 , foi obtida com a dose de 25 t ha -1 de composto. A área do dossel foi a variável de maior correlação com o rendimento comercial e com o acúmulo de massa seca, sendo a mais indicada para a avaliação do crescimento por método não destrutivo. O período inicial de maior acúmulo de massa seca varia com as doses de composto, sendo que na dose de 25 t ha -1 ,este período ocorreu entre 28 e 56 dias após o transplantio. As mais altas taxas de crescimento relativo foram verificadas entre a segunda e a quarta semana após o transplante. Termos para indexação:Brassica oleracea var. italica, manejo orgânico, curva de crescimento. ABSTRACTThe use of organic compost on vegetable crops production results in complex and diverse effects. Although the research on organic vegetable production has been increasing, the effects of organic compost on the growth and yield of these crops are still poorly scientifically known. This work aimed to evaluate the growth and yield of broccoli grown on organic compost, besides determining the non-destructive parameter with higher correlation to dry mass accumulation. The experiment was carried out in Viçosa, MG (20º 45 S 42º 51 W). The experiment was set up in a randomized block design with four replicates in split-plot (time) design for growth parameters. The treatments consisted of doses of organic compost: 5, 10 15 20 and 25 t ha -1 on a dry matter basis, supllied to hybrid domador . The highest broccoli yield, 564 g plant -1 , corresponds to 12,53 t ha -1 , and was obtained with the 25 t ha -1 compost dose. Canopy area presented the highest correlation with both commercial yield and dry mass accumulation and it is the best nondestructive parameter for growth evaluation. The initial period of higher dry mass accumulation varies according to the compost dose, So that the 25 t ha -1 dose, this period was between 28 and 56 days after transplant. The highest relative growth rates happened between the second and fourth week after transplant.

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RESUMOAmounts of N from green manures not absorbed in the first cycle can be absorbed by the subsequent crops. Therefore, it is important to quantify and monitor the residual effects of green manure to increase the agronomic benefits of its use in cropping systems. Our purpose was to study the residual effect of doses of the Crotalaria juncea green manure applied in broccoli crop in the zucchini-maize succession. This study was carried out in a crop succession system organized in three crops, with seven treatments and four major doses of green manure as 0, 3, 6, and 9 t ha -1. The control treatments consisted of a mineral fertilization, a treatment with 25 t ha -1 compost, and another as absolute control without organic compost or mineral fertilizer. The experimental plot consisted of five rows spaced 0.8 m with 3 m in length. The experimental design was a completely randomized block with four replications in a split-plot scheme in time for growth with variables of adjustment of statistical models by the response surface methodology. With the highest dose of green manure, the yield of zucchini plants was greater than the yield with 25 t ha -1 compost control and similar with mineral fertilizer. As for the maize yield in the dose of 9 t ha -1 green manure, the yield was superior only to absolute control. There was a residual effect of C. juncea mass, which was applied in broccoli crop for growth and yield of zucchini and maize grown in succession. The residual effect is dependent on the amount of weight of C. juncea applied, with the greatest effects in larger doses.