A lthough there are studies on nutrition and fertilizer recommendations for the commercial cultivation of broccoli (Brassica oleracea var. italica) and works with other types of organic fertilizers such as compost or manure (Oliveira et al., 2003;Yuri et al., 2004; Damato Junior et al., 2005), there are few studies on the effects of green manure on the growth and production of broccoli. The literature also lacks studies relating green manure doses to the production and/or growth of horticultural products.One of the few studies reports the influence of doses of organic compost (OC) on yield and quality of the "Ramoso Santana" broccoli seeds. Four compost rates (0, 30, 60, 90, and 120 t/ha) with 0.72% nitrogen and 40% organic matter were applied. The production of broccoli seeds (number and weight) per plant increased linearly with increased doses of OC (Magro et al., 2010 ABSTRACTThe recommendation for green manure (GM) in cropping systems still has little scientific support, with few studies addressing the effects of nutrient amounts from green manure on the growth and production of the crop. Our aim was to evaluate the effect of levels of Crotalaria juncea green manure on the growth, production, and efficiency of the use as well as the apparent recovery of N in broccoli crop. Seven treatments were established; the main with four doses of green manure: 0, 3, 6, and 9 t/ha on a dry matter (DM) basis, applied with 12 t/ha compost. The control treatments consisted of mineral fertilization, the treatment with 25 t/ha compost, and another as the absolute control. Comparatively, production under the absolute control was less than all other treatments with green manure doses and application of 12 t/ha compost. The production of plants grown with 25 t/ha compost was superior to that of plants grown with dose of 0 t/ha and similar to that obtained with 3 t/ha; however, it was inferior to those produced with doses of 6 and 9 t/ha green manure. The highest percentage of N recovered (REC N) by the broccoli plants was observed close to a dose of 3 t/ha green manure, with a maximum point of 37.90% (2.8 t/ha), while in larger doses of 6 and 9 t/ha showed estimated values of 31.91% and 20.49%, respectively. The physiological efficiency of the use of N (EFUN) showed an effect similar to apparent recovery of N (REC N), with higher EFUN from lowest to highest dose of green manure, that is, 3, 6, and 9 t/ha, with estimated values of 70.41, 62.45, and 26.02 g DM per g of N uptake, respectively. The mass amounts of applied C. juncea influenced positively on the growth and productivity of broccoli. The lower mass of applied green manure increases the physiological efficiency of the use of N with more apparent recovery of the applied N.Keywords: Brassica oleracea var. italica, green manure, nitrogen. RESUMO Doses de Crotalaria juncea no crescimento, produção, recuperação e eficiência de uso de N em brócolisA recomendação da adubação verde nos sistemas de cultivos ainda apresenta pouco suporte científico e poucos estudos abordam os ef...

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Cratylia argentea is a shrub legume native to tropical regions of South America where it is used for animal feed and green manure. In the absence of germination guidelines, the key aim of this study was to define the most suitable temperature for conducting germination and accelerated aging tests. The biochemical attributes of seeds were also assessed. Seeds with 10% moisture from 4 different seed lots were germinated using the between paper method in a germinator at temperatures of 20, 25, 30 and 35 °C and alternating temperatures of 20/30 °C (16 h:8 h), with daily counting until germination was stable (seven days without germination). For the accelerated aging test, two temperatures (41 and 45 °C) and six aging periods (0, 24, 48, 72, 96 and 120 h) for seeds with between 10–40 % moisture content were used. Carbohydrates (%), ethereal extract (%), crude protein (%) and macro and micronutrient contents of the seeds were measured. Results showed that C. argentea seeds consist predominantly of starch (22.67 %) and protein (26.45 %) reserves with a low percentage of lipids. For the germination test, the temperature of 30 °C is recommended, allowing greater percentage and speed of germination, with seedling evaluation at 10 and 20 days. For the accelerated aging test, aging for 48 h at 41 °C is recommended to discriminate C. argentea seed lots in terms of quality.

Volatilization of nitrogen ammonia (N-NH 3 ) and rapid incorporation of mineralized nitrogen (N) into soil organic matter fractions can reduce the efficiency of green manuring. The objective of this study was to characterize N-NH3 loss through volatilization and the changes in carbon (C) and N stocks in soil fertilized with Crotalaria juncea and ammonium sulfate during coffee plant cultivation. The N-NH 3 collectors were installed and evaluated at 1, 2, 3, 4, 5, 6, 9, 12, 15, 18, 25, 32, 67 and 123 days after their installation. Total organic carbon (TOC) and total nitrogen (TN) in the 0-5-and 5-10-cm soil layers were evaluated at 0, 60, 120, 180, 240, and 300 days after fertilization. After 9 days, 20.83 kg ha -1 (N-NH 3 ) had volatilized from the 41.88 kg haobserved at the end of the evaluation period. The TOC stock in both soil layers was 5.81 Mg ha -1 , and after 300 days, the stocks were 8.84 and 8.36 Mg ha -1 for the 0-5 and 5-10 cm layers, respectively. The TN stock in the 0-5 cm layer increased from 1.74 to 1.98 Mg ha -1 over 60 days, and then decreased. There was no time dependency in the TN stock in the 5-10 cm layer. Volatilization of N-NH 3 was rapid but low. The increase in TOC stocks was not followed by an increase in TN stocks.Key words: ammonium; green manure; organic matter N-NH 3 volatilizado e estoques de N e C de solo após adubação verde de cafeeiro RESUMO: A volatilização de N-NH 3 e a rápida incorporação do N mineralizado em frações da matéria orgânica do solo podem reduzir a eficiência da adubação verde. O objetivo do trabalho foi caracterizar as perdas por volatilização de N-NH 3 e as modificações nos estoques de C e N em solo cultivado com cafeeiro e adubado com Crotalaria juncea e sulfato de amônio. Foram instalados coletores de N-NH 3 , procedendo-se com avaliações aos 1, 2, 3, 4, 5, 6, 9, 12, 15, 18, 25, 32, 67 e 123 dias após a sua instalação. Os estoques de carbono orgânico total (COT) e nitrogênio total (NT) do solo foram avaliados, nas camadas de 0-5 e 5-10 cm, aos 0, 60, 120, 180, 240 e 300 após as adubações, sendo a primeira amostragem antes das adubações. Aos nove dias já haviam sido volatilizados (N-NH3) 20,83 kg ha -1 dos 41,88 kg ha -1 observados no final do período de avaliação. O estoque de COT em ambas as camadas era de 5,81 Mg ha -1 e após 300 dias os estoques foram de 8,84 e 8,36 Mg ha -1 , respectivamente para as camadas 0-5 e 5-10 cm. Já o estoque NT na camada 0-5 cm aumentou até os 60 dias, passando de 1,74 para 1,98 Mg ha -1 , e em seguida apresentou redução. Não houve efeito do tempo no estoque de NT na camada 5-10 cm. A volatilização de N-NH 3 é rápida, porém é baixa. O aumento nos estoques de COT não foi acompanhado por aumentos nos estoques de NT. Palavras-chave: amônia; adubo verde; matéria orgânicaVolatilized N-NH 3 , N, and C stocks in soil after green manuring of coffee crops Rev. Bras.

Um dos principais entraves à produção de sementes de soja de alta qualidade é a presença de sementes esverdeadas nos lotes, uma vez que apresentam baixa qualidade fisiológica e baixo potencial de armazenamento. Assim, é fundamental o estabelecimento de condições mais adequadas de armazenamento visando a manutenção da qualidade fisiológica de lotes contendo sementes esverdeadas. O objetivo do trabalho foi investigar os efeitos de diferentes embalagens e ambientes de armazenamento na manutenção da qualidade de lotes de sementes de soja com diferentes proporções de sementes esverdeadas. Foram utilizadas sementes de três cultivares de soja, cada uma com três lotes com diferentes proporções de sementes esverdeadas. Cultivar “A”, com 8, 21 e 40% de sementes esverdeadas; cultivar “B” com 8, 11 e 21% de sementes esverdeadas; e cultivar “C”, com 2, 8 e 12% de sementes esverdeadas. Os lotes foram inicialmente caracterizados, por meio da determinação do grau de umidade e do desempenho em testes fisiológicos e bioquímicos. Em seguida, cada lote foi submetido a seis condições de armazenamento: embalagem plástica nas temperaturas de 12 °C, 20 °C e não controlada (ambiente); e embalagem porosa, nas temperaturas de 12 °C, 20 °C e não controlada. Após 195 dias de armazenamento, as sementes foram submetidas aos mesmos testes utilizados para a caracterização da qualidade inicial, além do teste de tetrazólio. O grau de umidade das sementes, inicialmente e ao longo do armazenamento, ficou próximo de 10%. Em geral, o potencial de germinação das sementes foi mantido durante o armazenamento, porém houve redução do vigor. Para a maioria dos lotes, o armazenamento em embalagem de papel kraft a 20 °C contribuiu para manutenção de maiores níveis de vigor das sementes, conforme resultados obtidos pelo teste de envelhecimento acelerado, e maior degradação da clorofila. As atividades das enzimas CAT, POX e APX reduziram, para a maioria dos lotes, com o armazenamento. Conclui-se que ambiente com umidade relativa de 56% e temperatura de 20 °C favoreceu o desempenho fisiológico e bioquímico de sementes de soja armazenadas com teor de água de 10% em embalagem de papel kraft, independente da proporção de sementes esverdeadas. As enzimas CAT, POX e APX foram mais sensíveis para indicar redução da qualidade fisiológica das sementes após o armazenamento. Assim como a proporção de sementes esverdeadas e o desempenho inicial do lote, o teor de clorofila nas sementes é determinante para seu desempenho após o armazenamento, sendo que maiores teores de clorofila levam à redução mais drástica da qualidade das sementes. Palavras-chave: Armazenamento de sementes. Teor de clorofila. Deterioração de sementes. Glycine max (L.) Merril

Despite the potential to provide N to crops, the rapid incorporation of green manure nutrients into stable fractions of organic matter in the soil (SOM) may reduce the efficiency of green manuring. Thus, the objective of this work was to characterize the changes of C and N stocks in fractions of SOM cultivated with coffee (Coffea arabica L.) and fertilized with sunn hemp (Crotalaria juncea) and ammonium sulfate. To study the changes in organic C (OC) and total N (TN) in soil and fractions of SOM over time, soil samples were collected in the 0-5 and 5-10 cm layers, with the initial sampling done prior to the application of sunn hemp residues and ammonium sulfate. Five samples were collected every 2 months after the application of the legume and ammonium sulfate. The soil samples were submitted to densimetric and granulometric fractionation, obtaining the free light organic matter (F-LOM), particulate organic matter (POM), and organic matter associated with minerals (MAM). OC and TN stocks were then determined in soil and the SOM fractions. The changes in the stocks of OC (ΔStcC) in the soil in relation to time zero were positive in the evaluations carried out in the two layers. The fractions of SOM showed positive ΔStcC at almost all of the evaluated times. The N supplied to the soil in the form of mineral and organic fertilizer promoted an increase of 0.24 Mg ha -1 of N in the 0-5 cm layer until after 60 days. Of this total, 0.03 Mg ha -1 was associated with F-LOM, 0.07 Mg ha -1 with POM, and the remainder was associated with MAM. Nearly 60% of the N that was supplied to the soil was drawn to the stable fractions of the SOM, indicating a rapid stabilization of this nutrient in the most recalcitrant organic compartments. Despite that, the variations in N stocks of MAM became smaller over time, and eventually became negative, in relation to time zero. This indicates the mineralization of N of this compartment. In the 5-10 cm layer, no effect of time was observed in the soil TN, N-POM, or N-MAM stocks. Additionally, under the conditions of this experiment, the majority of the N supplied to the soil was rapidly incorporated into the most stable fraction of SOM, and this might can reduced the efficiency of the green manuring. ResumoApesar do potencial para fornecer N aos cultivos, a rápida incorporação dos nutrientes do adubo verde em frações estáveis da matéria orgânica do solo (MOS) pode reduzir a eficiência da adubação verde. Portanto, objetivou-se com este trabalho caracterizar as alterações temporais dos estoques de C e N em frações da matéria orgânica de solo cultivado com cafeeiro (Coffea arabica L.) e adubado com crotalária (Crotalaria juncea) e sulfato de amônio. Para estudar o comportamento do C orgânico (CO) e N total (NT) no solo e nas frações da MOS ao longo do tempo, foram coletadas amostras de solo nas camadas de 0-5 e 5-10 cm, sendo a primeira amostragem antes da aplicação dos resíduos de crotalária e sulfato de amônio. Outras cinco amostras foram coletadas a cada dois meses após a aplicação ...

This research conducted in the District of Concepción, Concepción Department, Paraguay, involved the use of a randomized complete block design consisting of four treatments and five repetitions. The general objective was to evaluate the effect of Cajanus cajan L. species with different planting densities on soil compaction and as specific objectives; measure the compaction of the soil at the beginning and end of the crop cycle, determine the soil moisture percentage as well as the root development of the species at the end of the crop cycle. The data obtained were subjected to analysis of variance (ANOVA) and the means compared through the Tukey test at 5%. Determinations of resistance to soil penetration before the crop establishment and at the end of the crop cycle were not influenced positively; except at 20 cm of density that showed difference at the end of the cycle, the soil moisture percentage was not significant and for root development highly significant differences were found. As regards the soil compaction, it was found that the biological material used with different planting densities had positive effects in the compaction of the soil. Thus, the recommended density is 114,284 plants per hectare.