ABSTRACT Cowpea bean is a socioeconomically important legume that contribute to generate employment and income. This species presents great grain variability, and the commercial subclass black eye stands out as a very appreciated grain in Brazil and abroad, thus requiring the development of new cultivars. The objective of this work was to evaluate and select lineages of commercial black eye cowpea, based on simultaneous, and direct selection. First, 105 progenies and four controls were evaluated using the Federer's augmented block design. Seventy-seven progenies, selected from this evaluation-first selection cycle-and four controls were evaluated in three environments, using a simple 9×9 lattice design. Based on this evaluation, the second selection cycle was possible, resulting in 24 progenies. The gain by direct selection was lower than the predicted gain for grain yield in the first cycle, indicating that the selection was not effective. This result was probably due to the reduced genetic variability caused by the selection pressure. In the second cycle, the predicted and observed gains were similar, indicating that much of the expected gain was observed. The predicted and observed gains, with simultaneous selection based on the rank sum selection index, were similar in the first and second cycle. The simultaneous and direct selections resulted in genetic gains for grain yield in the two selection cycles, making it possible the selection of high grain yield lineages. | RESUMO O feijão-caupi é uma leguminosa socioeconomicamente importante, contribuindo com a geração de emprego e renda. É uma espécie que apresenta grande variabilidade para o tipo de grão, sendo a subclasse comercial fradinho a que se destaca por ser um grão muito apreciado no Brasil e no exterior, demandando o desenvolvimento de novas cultivares. Este trabalho foi realizado com o objetivo de avaliar e selecionar linhagens de feijão-caupi tipo comercial fradinho, baseada na seleção simultânea e seleção direta. Inicialmente foram avaliadas 105 progênies e quatro testemunhas, utilizando o delineamento Blocos Aumentados de Federer. A partir desta avaliação foram selecionadas 77 progênies (primeiro ciclo de seleção), e quatro testemunhas que foram avaliadas em três ambientes, utilizando o delineamento látice simples 9x9. Fundamentado nessa avaliação, foi possível realizar o segundo ciclo de seleção, resultando em 24 progênies. Pela seleção direta, o ganho realizado foi inferior ao ganho predito para produtividade no primeiro ciclo, indicando que a seleção não foi efetiva, provavelmente devido à redução da variabilidade genética ocasionada pela pressão de seleção. No segundo ciclo, os ganhos realizado e predito foram bem próximos, indicando que grande parte do ganho esperado foi concretizado. Para os ganhos com a seleção simultânea baseados no Índice de Soma de Ranks, os valores de ganho predito e realizado foram semelhantes no primeiro e segundo ciclo. As seleções, simultânea e direta, possibilitaram a obtenção de ganhos genéticos para produtividade nos dois ciclos de seleção, possibilitando a seleção de linhagens de alta produtividade.

Cowpea bean is a socioeconomically important legume that contribute to generate employment and income. This species presents great grain variability, and the commercial subclass black eye stands out as a very appreciated grain in Brazil and abroad, thus requiring the development of new cultivars. The objective of this work was to evaluate and select lineages of commercial black eye cowpea, based on simultaneous, and direct selection. First, 105 progenies and four controls were evaluated using the Federer's augmented block design. Seventy-seven progenies, selected from this evaluation-first selection cycle-and four controls were evaluated in three environments, using a simple 9×9 lattice design. Based on this evaluation, the second selection cycle was possible, resulting in 24 progenies. The gain by direct selection was lower than the predicted gain for grain yield in the first cycle, indicating that the selection was not effective. This result was probably due to the reduced genetic variability caused by the selection pressure. In the second cycle, the predicted and observed gains were similar, indicating that much of the expected gain was observed. The predicted and observed gains, with simultaneous selection based on the rank sum selection index, were similar in the first and second cycle. The simultaneous and direct selections resulted in genetic gains for grain yield in the two selection cycles, making it possible the selection of high grain yield lineages.

ABSTRACT The objective of this work was to evaluate the biomass production and antioxidant enzymatic system activity of irrigated forage sorghum with saline aquaculture effluent under different leaching fractions. The experiment was conducted in the Caatinga Experimental Field of the Embrapa Semiarido, in Petrolina, State of Pernambuco, Brazil. The experimental design was a complete randomized block in a split-plot arrangement with four replications, consisting of three forage sorghum varieties (Volumax, F305 and Sudan) and four leaching fractions (0, 5, 10 and 15%). The vegetal materials were collected when the plants were at the soft-dough stage. The biomass production and activity of the enzymes superoxide dismutase, catalase and ascorbate peroxidase were evaluated. Irrigation with saline aquaculture effluent with leaching fraction of 15% results in low salinity level in the root zone and higher biomass production of forage sorghum Sudan and F305, in semiarid conditions. The antioxidant system was activated in the three sorghum varieties to prevent accumulation of reactive oxygen species, with the synchrony between the enzymes superoxide dismutase and catalase resulting in a better productive response of the varieties Sudan and F305. | RESUMO Objetivou-se com este trabalho avaliar o desempenho da cultura do sorgo forrageiro irrigado com efluente salino da piscicultura sob diferentes frações de lixiviação em relação à produção de biomassa e a atividade do sistema enzimático antioxidativo. O estudo foi realizado no Campo Experimental Caatinga, pertencente à Embrapa Semiárido, em Petrolina - PE. O delineamento experimental foi blocos ao acaso, com quatro repetições, em parcelas subdivididas, composto por três variedades de sorgo forrageiro (Volumax, F305 e Sudão) e quatro frações de lixiviação (0; 5; 10 e 15%). A coleta do material vegetal foi realizada quando os grãos da porção central da panícula apresentaram aspecto leitoso a pastoso. Foi avaliada a produção de biomassa e a atividade das enzimas superóxido dismutase, catalase e ascorbato peroxidase. O uso de 15 % de fração de lixiviação para irrigação com efluentes salinos da piscicultura proporciona um menor nível de salinidade da zona radicular e promove uma melhor produção de biomassa do sorgo forrageiro Sudão e F305 em condições semiáridas. O sistema antioxidativo foi ativado nas três variedades de sorgo para evitar o acúmulo de ROS, sendo a sincronia entre as enzimas superóxido dismutase e catalase que refletiu numa melhor resposta produtiva das variedades Sudão e F305.

The objective of this work was to evaluate the biomass production and antioxidant enzymatic system activity of irrigated forage sorghum with saline aquaculture effluent under different leaching fractions. The experiment was conducted in the Caatinga Experimental Field of the Embrapa Semiarido, in Petrolina, State of Pernambuco, Brazil. The experimental design was a complete randomized block in a split-plot arrangement with four replications, consisting of three forage sorghum varieties (Volumax, F305 and Sudan) and four leaching fractions (0, 5, 10 and 15%). The vegetal materials were collected when the plants were at the soft-dough stage. The biomass production and activity of the enzymes superoxide dismutase, catalase and ascorbate peroxidase were evaluated. Irrigation with saline aquaculture effluent with leaching fraction of 15% results in low salinity level in the root zone and higher biomass production of forage sorghum Sudan and F305, in semiarid conditions. The antioxidant system was activated in the three sorghum varieties to prevent accumulation of reactive oxygen species, with the synchrony between the enzymes superoxide dismutase and catalase resulting in a better productive response of the varieties Sudan and F305.

RESUMO No Nordeste do Brasil, a cotonicultura de fibra colorida tem se destacado como uma das atividades agrícolas de expressiva importância, devido a sua fibra possuir várias aplicações na indústria, e ser uma cultura absorvedora de mão-de-obra. Neste contexto, objetivou-se com este trabalho avaliar o crescimento, o consumo hídrico, a eficiência no uso da água e a produção do algodoeiro cv. BRS Rubi de fibra colorida em função da irrigação com águas salinas e doses de nitrogênio, em experimento desenvolvido em lisímetros sob condições de casa de vegetação em Neossolo Regolítico Eutrófico de textura franco-arenosa em Campina Grande-PB. As plantas foram irrigadas com água de condutividade elétrica da água - CEa de 5,1; 6,1; 7,1; 8,1 e 9,1 dS m-1 e adubadas com doses de nitrogênio - DN de 65; 100; 135; 170 e 205 mg de N kg-1 de solo, no delineamento em blocos inteiramente casualizados, com três repetições. A irrigação com águas de CEa acima de 5,1 dS m-1 prejudicou o crescimento, o consumo hídrico e a eficiência no uso da água do algodoeiro cv. BRS Rubi; dentre os órgãos, o sistema radicular do algodoeiro foi menos afetado pelo o estresse salino em comparação com a parte aérea; a adubação nitrogenada não mitigou o efeito deletério do estresse salino sobre o crescimento, consumo hídrico, eficiência no uso da água e a produção do algodoeiro; a interação entre a salinidade da água e a adubação nitrogenada exerceu efeitos positivos na massa total de sementes e de pluma, sendo os maiores valores obtidos nas plantas irrigadas com CEa de 7,6 e 7,5 dS m-1 e dose de 65 mg N kg-1 de solo. | ABSTRACT In Northeast Brazil, the cultivation of colored fiber cotton has stood out as one of the agricultural activities of expressive importance because its fiber has various applications in the industry and it is a labor-demanding crop. In this context, this study aimed to evaluate the growth, water consumption, water use efficiency and production of the colored fiber cotton cv. ‘BRS Rubi’, as a function of saline water irrigation and nitrogen (N) doses. The experiment was conducted in lysimeters, under greenhouse conditions, in eutrophic Regolithic Neosol, with a sandy loam texture, in Campina Grande-PB, Brazil. The plants were irrigated using water with electrical conductivities (ECw) of 5.1, 6.1, 7.1, 8.1 and 9.1 dS m-1 and fertilized with N doses (ND) of 65, 100, 135, 170 and 205 mg N kg-1 soil, in a completely randomized block design, with three replicates. Irrigation using water with an ECw above 5.1 dS m-1, hampered growth, water consumption and water use efficiency of ‘BRS Rubi’ cotton. Among the organs, the cotton root system was less affected by the salt stress in comparison to the shoots. N fertilization did not mitigate the deleterious effect of salt stress on cotton growth, water consumption, water use efficiency and production. The interaction between water salinity and N fertilization had positive effects on total weight of seeds and lint, and the highest values were obtained in plants irrigated with water of ECw 7.6 and 7.5 dS m-1 and ND of 65 mg N kg-1 of soil.

In Northeast Brazil, the cultivation of colored fiber cotton has stood out as one of the agricultural activities of expressive importance because its fiber has various applications in the industry and it is a labor-demanding crop. In this context, this study aimed to evaluate the growth, water consumption, water use efficiency and production of the colored fiber cotton cv. ‘BRS Rubi’, as a function of saline water irrigation and nitrogen (N) doses. The experiment was conducted in lysimeters, under greenhouse conditions, in eutrophic Regolithic Neosol, with a sandy loam texture, in Campina Grande-PB, Brazil. The plants were irrigated using water with electrical conductivities (ECw) of 5.1, 6.1, 7.1, 8.1 and 9.1 dS m-1 and fertilized with N doses (ND) of 65, 100, 135, 170 and 205 mg N kg-1 soil, in a completely randomized block design, with three replicates. Irrigation using water with an ECw above 5.1 dS m-1, hampered growth, water consumption and water use efficiency of ‘BRS Rubi’ cotton. Among the organs, the cotton root system was less affected by the salt stress in comparison to the shoots. N fertilization did not mitigate the deleterious effect of salt stress on cotton growth, water consumption, water use efficiency and production. The interaction between water salinity and N fertilization had positive effects on total weight of seeds and lint, and the highest values were obtained in plants irrigated with water of ECw 7.6 and 7.5 dS m-1 and ND of 65 mg N kg-1 of soil.

RESUMO Tendo como objetivo responder ao questionamento de como o raleamento da cobertura vegetal de uma floresta tropical seca, caatinga, pode interferir no coeficiente de escoamento superficial, desenvolveu-se este estudo em três anos hidrológicos (2008, 2011 e 2013). O experimento foi conduzido no município de Iguatu no estado do Ceará, Brasil. No ano de 2008 a cobertura vegetal era caatinga em regeneração há 30 anos. A vegetação foi submetida ao manejo de raleamento em 2009, 2011 e 2013, eliminando-se as árvores com diâmetro inferior a 10 cm a altura do peito. Para investigar a resposta hidrológica em função da altura pluviométrica diária, tendo-se por base a distribuição de frequência acumulada, os eventos foram divididos em três classes pluviométricas (CP): CP ≤ 30 mm, 30 < CP ≤ 50 mm e CP > 50 mm. Para identificar se os coeficientes de escoamento gerados antes e após o raleamento da vegetação apresentavam diferenças significativas, aplicou-se o teste “t” de Student ao nível de 1%. Antes do raleamento (2008), a CP ≤ 30 mm registrou o maior percentual do coeficiente de escoamento diferindo estatisticamente ao nível de 1% de significância dos outros anos. Para eventos de grande magnitude (CP > 50 mm), os resultados apontam que o escoamento apresenta uma maior dependência das características da chuva e das condições de umidade do solo. O maior desenvolvimento do estrato herbáceo devido ao raleamento resultou em uma redução do fluxo do escoamento superficial. | ABSTRACT The objective of this work was to assess the effect of vegetation on the runoff coefficients of a Caatinga dry tropical forest before and after thinning. Thus, an experiment was conducted with evaluations in three hydrological years (2008, 2011 and 2013) in Iguatu, State of Ceará, Brazil. In 2008, the vegetation consisted of a 30-year regenerating Caatinga forest. The vegetation was subjected to thinning in 2009, 2011 and 2013, removing trees with less than 10-cm diameter at breast height. Hydrological responses were evaluated as a function of daily precipitation water depths, based on cumulative frequency distribution, by dividing precipitation events into three classes (CP) (CP≤30, 30<CP≤50 and CP>50 mm). Significant differences between runoff coefficients before and after vegetation thinning were assessed through the Student's t-test (p<0.01). Before thinning (2008), CP≤30 mm showed the highest runoff coefficient, differing statistically (p<0.01) from the other years. The results of precipitation events of great magnitude (CP>50 mm) indicate that the runoff is greatly dependent on rainfall characteristics and soil moisture conditions. The greater development of herbaceous vegetation due to thinning reduced the surface runoff.

The objective of this work was to assess the effect of vegetation on the runoff coefficients of a Caatinga dry tropical forest before and after thinning. Thus, an experiment was conducted with evaluations in three hydrological years (2008, 2011 and 2013) in Iguatu, State of Ceará, Brazil. In 2008, the vegetation consisted of a 30-year regenerating Caatinga forest. The vegetation was subjected to thinning in 2009, 2011 and 2013, removing trees with less than 10-cm diameter at breast height. Hydrological responses were evaluated as a function of daily precipitation water depths, based on cumulative frequency distribution, by dividing precipitation events into three classes (CP) (CP≤30, 30<CP≤50 and CP>50 mm). Significant differences between runoff coefficients before and after vegetation thinning were assessed through the Student's t-test (p<0.01). Before thinning (2008), CP≤30 mm showed the highest runoff coefficient, differing statistically (p<0.01) from the other years. The results of precipitation events of great magnitude (CP>50 mm) indicate that the runoff is greatly dependent on rainfall characteristics and soil moisture conditions. The greater development of herbaceous vegetation due to thinning reduced the surface runoff.

RESUMO As atividades das enzimas do complexo enzimático SSF (solid-state fermentation) adicionado à ração antes e após o processo de extrusão e a influência no desempenho de tilápias do Nilo (Oreochromis niloticus) foram avaliadas. Foram selecionadas as seguintes enzimas para análise: b-glicosidase, pectinase, xilanase, endoglucanase, amilase, protease e fitase. Os peixes foram submetidos a cinco tratamentos: ração sem adição de enzima, com adição de 400 ppm de SSF antes da extrusão, com 800 ppm de SSF antes da extrusão, 400 ppm de SSF adicionados “on top” após a extrusão e 800 ppm de SSF adicionados “on top” após a extrusão. O experimento teve um delineamento inteiramente casualizado com quatro repetições, contendo sete peixes por aquário. O peso médio inicial foi de 10,37 g ± 0,95, sendo alimentados quatro vezes ao dia, até a saciedade, durante 56 dias. Avaliou-se: peso inicial, peso final, ganho de peso, conversão alimentar, sobrevivência, taxa de crescimento específico e composição corporal. Os resultados foram comparados utilizando-se ANOVA e teste de Tukey a p<0.05. Todas as enzimas perderam atividade enzimática parcial ou total quando submetidas ao processo de extrusão, exceto a fitase. Não foram observadas diferenças entre a sobrevivência, parâmetros de qualidade da água e a composição corporal. A inclusão “on top” proporcionou um melhor rendimento, observado através de melhorias no peso final, ganho de peso e conversão alimentar. Concluiu-se que, 800 ppm de SSF deve ser adicionado "on top", após a extrusão, para proporcionar um melhor desempenho em tilápias, e consequentemente a eficiência financeira da produção. | ABSTRACT Enzyme activity in solid-state fermentation complex added to diets before and after extrusion process and its influence on Nile tilapia (Oreochromis niloticus) performance were evaluated. The following enzymes were analyzed: b-glucosidase, pectinase, xylanase, endoglucanase, amylase, protease, and phytase. The fish were fed five experimental diets: a control diet (without enzyme), two test diets supplemented before extrusion (400 and 800 ppm SSF), and two test diets after extrusion or “on top” (400 and 800 ppm SSF). The experiment had a completely randomized design with four replicates and seven fish per tank. Average initial weight was 10.37 ± 0.95 g, and fish were fed four times a day to satiation for 56 days. The following performance parameters were evaluated: final weight, weight gain, feed conversion, survival, specific growth rate, and body composition. The results were compared using ANOVA and Tukey’s test at p<0.05. All the enzymes showed partial or total losses of activity when subjected to the extrusion process, except phytase. No differences were observed for survival, water quality parameters, and body composition. On-top inclusion provided a better performance, which is observed through increases in final weight, weight gain, and feed conversion. As a result, 800 ppm of enzyme complex SSF should be added "on top", that is after extrusion, to improve tilapia performance and, consequently, contribute to the fish farming financial efficiency.

Enzyme activity in solid-state fermentation complex added to diets before and after extrusion process and its influence on Nile tilapia (Oreochromis niloticus) performance were evaluated. The following enzymes were analyzed: b-glucosidase, pectinase, xylanase, endoglucanase, amylase, protease, and phytase. The fish were fed five experimental diets: a control diet (without enzyme), two test diets supplemented before extrusion (400 and 800 ppm SSF), and two test diets after extrusion or “on top” (400 and 800 ppm SSF). The experiment had a completely randomized design with four replicates and seven fish per tank. Average initial weight was 10.37 ± 0.95 g, and fish were fed four times a day to satiation for 56 days. The following performance parameters were evaluated: final weight, weight gain, feed conversion, survival, specific growth rate, and body composition. The results were compared using ANOVA and Tukey’s test at p<0.05. All the enzymes showed partial or total losses of activity when subjected to the extrusion process, except phytase. No differences were observed for survival, water quality parameters, and body composition. On-top inclusion provided a better performance, which is observed through increases in final weight, weight gain, and feed conversion. As a result, 800 ppm of enzyme complex SSF should be added "on top", that is after extrusion, to improve tilapia performance and, consequently, contribute to the fish farming financial efficiency.

RESUMO O feijão-caupi (Vigna unguiculata [L.] Walp.) é uma das mais importantes leguminosas produzidas em regiões tropicais e subtropicais do mundo, principalmente nos países em desenvolvimento da África, América Latina e Ásia. Para um grande segmento da população mundial é a principal fonte de proteínas, calorias, fibras alimentares, minerais e vitaminas. Possui ainda compostos bioativos, destacando-se os compostos fenólicos. É produzido no Norte e Nordeste, consumido também em outras regiões do país e apresenta grande importância para os agricultores que sobrevivem desta cultura. O objetivo do presente estudo foi identificar e quantificar os compostos fenólicos no feijão-caupi, cultivar BRS Xiquexique. Tal determinação permitirá conhecer características funcionais do feijão-caupi, como fonte de antioxidantes, o que será de primordial importância para agregar valor funcional e nutricional a este alimento e ampliar as formas de consumo. Os extratos foram analisados por CLAE em equipamento modelo LC-20AT, com injetor manual. Para as análises foram preparadas soluções padrões com os ácidos fenólicos puros, tais como: ácido gálico, quercetina, ácido cafeico, ácido clorogênico, ácido ferúlico, ácido p-cumárico, catequina e epicatequina. Foram identificados catequina (2,07 ± 0,329 mg 100 g-1), epicatequina (0,48 ± 0,130 mg 100 g-1), ácido gálico (67,19 ± 6,200 mg 100 g-1), ácido ferúlico (32,07 ± 0,753 mg 100 g-1) e ácido clorogênico (3,08 ± 0,489 mg 100 g-1) em concentrações importantes. Concluiu-se que a cultivar BRS Xiquexique contêm compostos funcionais, destacando-se o ácido gálico e o ácido ferúlico com maiores teores, comprovando o potencial antioxidante do feijão-caupi. | ABSTRACT Cowpea (Vigna unguiculata [L.] Walp.) is one of the most important legumes produced in tropical and subtropical regions throughout the world, especially in the developing countries in Africa, Latin America, and Asia. It is the main source of protein, calories, dietary fiber, minerals, and vitamins for a large segment of the world population. Cowpea is also a potential functional food with a range of bioactive compounds, including phenolic compounds. This legume is grown mainly in the North and Northeast regions of Brazil, but is also consumed in other regions, and is thus important for the farmers who depend on this crop for income. This study identified and quantified phenolic compounds in the cowpea cultivar BRS Xiquexique. Such quantification reveals the functional characteristics of cowpeas, mainly as a source of antioxidants, which will be essential to add value to this food and to expand its forms of consumption. The extracts were analyzed using an HPLC model LC-20AT, equipped with a manual injector. For the HPLC analysis, standard solutions were prepared with pure phenolic acids such as gallic acid, quercetin, caffeic acid, chlorogenic acid, ferulic acid, p-coumaric acid, catechin, and epicatechin. The major phenolic compounds identified were catechin (2.07± 0.329 mg 100 g-1), epicatechin (0.48 ± 0.130 mg 100 g-1), gallic acid (67.19 ± 6.200 mg 100 g-1), ferulic acid (32.07 ± 0.753 mg 100 g-1), and chlorogenic acid (3.08 ± 0.489 mg 100 g-1). We observed that the BRS Xiquexique cultivar contains functional phenolic compounds, especially gallic acid and ferulic acid, demonstrating the antioxidant potential of cowpea.

Cowpea (Vigna unguiculata L. Walp.) is one of the most important legumes produced in tropical and subtropical regions throughout the world, especially in the developing countries in Africa, Latin America, and Asia. It is the main source of protein, calories, dietary fiber, minerals, and vitamins for a large segment of the world population. Cowpea is also a potential functional food with a range of bioactive compounds, including phenolic compounds. This legume is grown mainly in the North and Northeast regions of Brazil, but is also consumed in other regions, and is thus important for the farmers who depend on this crop for income. This study identified and quantified phenolic compounds in the cowpea cultivar BRS Xiquexique. Such quantification reveals the functional characteristics of cowpeas, mainly as a source of antioxidants, which will be essential to add value to this food and to expand its forms of consumption. The extracts were analyzed using an HPLC model LC-20AT, equipped with a manual injector. For the HPLC analysis, standard solutions were prepared with pure phenolic acids such as gallic acid, quercetin, caffeic acid, chlorogenic acid, ferulic acid, p-coumaric acid, catechin, and epicatechin. The major phenolic compounds identified were catechin (2.07± 0.329 mg 100 g-1), epicatechin (0.48 ± 0.130 mg 100 g-1), gallic acid (67.19 ± 6.200 mg 100 g-1), ferulic acid (32.07 ± 0.753 mg 100 g-1), and chlorogenic acid (3.08 ± 0.489 mg 100 g-1). We observed that the BRS Xiquexique cultivar contains functional phenolic compounds, especially gallic acid and ferulic acid, demonstrating the antioxidant potential of cowpea.

ABSTRACT Nitisols are livelihood sources of agricultural and socio-economic development in several underdeveloped countries worldwide, including Brazil. Brazilian Nitisols are usually associated with basaltic rocks found in the Southern and Southeastern regions of the country. However, Nitisols derived from basalt also occur on the southern coast of Pernambuco state, a region under full urban, agricultural, and industrial development. Aiming to understand the relationship between climate and attributes of Nitisols from the southern coast of Pernambuco, we performed morphological descriptions, physical and chemical analyzes, iron selective extraction, and soil mineralogy (sand, silt, and clay) for three basaltic soil profiles along a land slope. The results suggest a strong weathering of the profiles due to climate conditions, besides a great loss of basic cations and xanthization process, resulting in the natural genesis of acric Nitisols with yellowish coloration, which has not been yet cataloged for this soil order in the Brazilian taxonomic system. In addition, there is a variation for physical attributes of Nitisols along the slope. | RESUMO Os Nitossolos dão suporte ao desenvolvimento agrícola e socioeconômico de muitos países subdesenvolvidos do mundo, incluindo o Brasil. Os Nitossolos brasileiros estão geralmente associados às rochas basálticas das regiões Sul e Sudeste. Entretanto, Nitossolos derivado de basalto também ocorrem na costa sul de Pernambuco, uma região em pleno desenvolvimento urbano, agrícola e industrial. Objetivando compreender as relações entre o clima e os atributos dos Nitossolos da costa sul de Pernambuco, foram realizadas descrições morfológicas, análises físicas e químicas, extrações seletivas de ferro e a determinação da mineralogia das frações areia, silte e argila de três perfis derivados de basalto ao longo de uma vertente. Os resultados demonstram que o clima da região implica em forte intemperização dos perfis, em grande perda de bases e favorece o processo de xantização, resultando na singular gênese de Nitossolos com matizes amarelados e caráter ácrico, fato que até o momento ainda não foi catalogado para esta ordem no sistema taxonômico brasileiro. Os resultados também demonstram a variação dos atributos físicos dos Nitossolos ao longo da vertente.

Nitisols are livelihood sources of agricultural and socio-economic development in several underdeveloped countries worldwide, including Brazil. Brazilian Nitisols are usually associated with basaltic rocks found in the Southern and Southeastern regions of the country. However, Nitisols derived from basalt also occur on the southern coast of Pernambuco state, a region under full urban, agricultural, and industrial development. Aiming to understand the relationship between climate and attributes of Nitisols from the southern coast of Pernambuco, we performed morphological descriptions, physical and chemical analyzes, iron selective extraction, and soil mineralogy (sand, silt, and clay) for three basaltic soil profiles along a land slope. The results suggest a strong weathering of the profiles due to climate conditions, besides a great loss of basic cations and xanthization process, resulting in the natural genesis of acric Nitisols with yellowish coloration, which has not been yet cataloged for this soil order in the Brazilian taxonomic system. In addition, there is a variation for physical attributes of Nitisols along the slope.

RESUMO Os resíduos de plantas daninhas são importantes para a ciclagem de nutrientes nos agroecossistemas. A quantificação desta potencial fonte de nutrientes pode influenciar o manejo dessas plantas e as práticas de adubação. Nicandra physalodes (L.) Gaertn. (joá-de-capote) é uma planta daninha de ciclo curto com rápido crescimento e grande capacidade de acumular biomassa. Dessa forma, objetivou-se conhecer o potencial de acúmulo e ciclagem de nutrientes de N. physalodes e avaliar se o aumento de nitrogênio (N), fósforo (P) e potássio (K) no solo influenciam essas características. Utilizou-se delineamento de blocos casualizados, arranjado em parcelas subdivididas com três repetições. As parcelas foram constituídas de quatro doses crescente de N, P e K (Dose 1 - 0, 0,3 e 17,2; Dose 2 - 30, 450,3 e 75,4; Dose 3 - 60, 900,3 e 133,4 e Dose 4 - 120, 1800,3 e 249,68 mg dm-3) e as subparcelas de dez épocas de coleta das plantas (26, 33, 40, 47, 54, 61, 76, 91, 106 e 121 dias após emergência). O aumento nos níveis de N, P e K no solo proporcionou maiores produções de massa seca e acúmulo total desses macronutrientes em plantas de N. physalodes, sendo que os maiores acúmulos foram de K e N. A adubação não influenciou os teores de fibra em detergente neutro (FDN), fibra em detergente ácido (FDA) e a relação carbono/ nitrogênio da planta. N. physalodes apresenta baixa relação C/N, o que aliado aos baixos teores de FDN e FDA e ao bom acúmulo de nutrientes, sugere que o material vegetal dessa planta seja rapidamente decomposto, proporcionando uma ciclagem rápida de nutrientes no solo. | ABSTRACT Weed residues can influence nutrient cycling in agroecosystems. Quantifying this potential nutrient source may influence weed control and fertilisation practices. Nicandra physalodes (L.) Gaertn. is a weed with a short life cycle and a great ability to accumulate dry matter. Field observations suggest that N. physaloides residues are easily decomposed in soil. The objective of this study was to evaluate the effect of increasing of N, P and K doses on the growth of N. physalodes, as well as the nutrient content, chemical characteristics and C/N ratio of the weed. A randomised block design, arranged in split-plot with three replications, was utilised. The main plots were given four doses of NPK (Dose 1 - 0, 0.3 and 17.2 mg dm-3; Dose 2 - 30, 450.3 and 75.4 mg dm-3; Dose 3 - 60, 900.3 and 133.4 mg dm-3; and Dose 4 - 120, 1800.3 and 249.68 mg dm-3), and the subplots were harvested at ten time points after emergence (26, 33, 40, 47, 54, 61, 76, 91, 106 and 121 days). Higher dry matter production and N, P and K content were observed in plants grown on higher levels of fertiliser. The increase of N, P and K levels in the soil resulted in greater total accumulation of these macronutrients. The highest macronutrient contents were K and N. The treatments did not affect neutral detergent fibre (NDF), acid detergent fibre (ADF) and C/N ratio of plant. N. physalodes had low C/N ratio, low NDF and ADF levels, and great nutrient accumulation, suggesting that this plant is quickly decomposed, providing a rapid cycling of nutrients.

Weed residues can influence nutrient cycling in agroecosystems. Quantifying this potential nutrient source may influence weed control and fertilisation practices. Nicandra physalodes (L.) Gaertn. is a weed with a short life cycle and a great ability to accumulate dry matter. Field observations suggest that N. physaloides residues are easily decomposed in soil. The objective of this study was to evaluate the effect of increasing of N, P and K doses on the growth of N. physalodes, as well as the nutrient content, chemical characteristics and C/N ratio of the weed. A randomised block design, arranged in split-plot with three replications, was utilised. The main plots were given four doses of NPK (Dose 1 - 0, 0.3 and 17.2 mg dm-3; Dose 2 - 30, 450.3 and 75.4 mg dm-3; Dose 3 - 60, 900.3 and 133.4 mg dm-3; and Dose 4 - 120, 1800.3 and 249.68 mg dm-3), and the subplots were harvested at ten time points after emergence (26, 33, 40, 47, 54, 61, 76, 91, 106 and 121 days). Higher dry matter production and N, P and K content were observed in plants grown on higher levels of fertiliser. The increase of N, P and K levels in the soil resulted in greater total accumulation of these macronutrients. The highest macronutrient contents were K and N. The treatments did not affect neutral detergent fibre (NDF), acid detergent fibre (ADF) and C/N ratio of plant. N. physalodes had low C/N ratio, low NDF and ADF levels, and great nutrient accumulation, suggesting that this plant is quickly decomposed, providing a rapid cycling of nutrients.

ABSTRACT Information about the response of onion to different potassium doses may contribute to optimizing the use of fertilizers and, consequently, make the activity more profitable and environmentally sustainable. In this context, the aim of this study was to evaluate the effects of doses of potassium on onion yields. Two field experiments were carried out in the periods of September to December 2012 and April to July 2013. The experimental design used was completely randomized blocks with four replications. The treatments corresponded to the potassium doses (0, 36, 72, 108, 144 and 180 kg ha-1 of K2O). Potassium fertilization promoted an increase in the content of K in the leaf, commercial and total yield, with the maximum obtained in the dose of 180 kg ha-1 of K2O. The maximum overall and commercial yields were respectively 54.69 and 54.12 t ha-1 in the experiment of September to December 2012 and 47.39 and 46.39 t ha-1 in that of April to July 2013. | RESUMO Informações sobre a reposta da cebola a diferentes doses de potássio podem contribuir para a otimização do uso de fertilizantes e, consequentemente, tornar a atividade mais rentável e ambientalmente sustentável. Nesse contexto, o objetivo do trabalho foi avaliar os efeitos de doses de potássio na produtividade da cebola. Para isso dois experimentos de campo foram realizados nos períodos de setembro a dezembro de 2012 e abril a julho de 2013 O delineamento experimental foi em blocos casualizados completos com quatro repetições. Os tratamentos corresponderam às doses de potássio (0, 36, 72, 108, 144 e 180 kg ha-1 de K2O). A adubação potássica promoveu aumento do teor de K na folha, produtividade comercial total, com o máximo obtido na dose de 180 kg ha-1 de K2O. As produtividades máximas totais e comerciais foram respectivamente de 54,69 e 54,12 t ha-1 no experimento de setembro a dezembro de 2012 e 47,39 e 46,39 t ha-1 de abril a julho de 2013.

Information about the response of onion to different potassium doses may contribute to optimizing the use of fertilizers and, consequently, make the activity more profitable and environmentally sustainable. In this context, the aim of this study was to evaluate the effects of doses of potassium on onion yields. Two field experiments were carried out in the periods of September to December 2012 and April to July 2013. The experimental design used was completely randomized blocks with four replications. The treatments corresponded to the potassium doses (0, 36, 72, 108, 144 and 180 kg ha-1 of K2O). Potassium fertilization promoted an increase in the content of K in the leaf, commercial and total yield, with the maximum obtained in the dose of 180 kg ha-1 of K2O. The maximum overall and commercial yields were respectively 54.69 and 54.12 t ha-1 in the experiment of September to December 2012 and 47.39 and 46.39 t ha-1 in that of April to July 2013.

ABSTRACT Spatial variability of soil attributes affects crop development. Thus, information on its variability assists in soil and plant integrated management systems. The objective of this study was to assess the spatial variability of the soil apparent electrical conductivity (ECa), electrical conductivity of the saturation extract (ECse), water content in the soil (θ) and soil texture (clay, silt and sand) of a sugarcane crop area in the State of Pernambuco, Brazil. The study area had about 6.5 ha and its soil was classified as orthic Humiluvic Spodosol. Ninety soil samples were randomly collected and evaluated. The attributes assessed were soil apparent electrical conductivity (ECa) measured by electromagnetic induction with vertical dipole (ECa-V) in the soil layer 0.0.4 and horizontal dipole (ECa-H) in the soil layer 0.0-1.5 m; and ECse, θ and texture in the soil layers 0.0-0.2 m and 0.2-0.4 m. Spatial variability of the ECa was affected by the area relief, and had no direct correlation with the electrical conductivity of the saturation extract (ECse). The results showed overestimated mean frequency distribution, with means distant from the mode and median. The area relief affected the spatial variability maps of ECa-V, ECa-H, ECse and θ, however, the correlation matrix did not show a well-defined cause-and-effect relationship. Spatial variability of texture attributes (clay, site and sand) was high, presenting pure nugget effect. | RESUMO A variabilidade espacial dos atributos do solo, interferem sobre o desenvolvimento dos cultivos. Assim, o conhecimento dessa variabilidade permite o manejo integrado de solo e planta. Objetivou-se determinar a variabilidade espacial da condutividade elétrica aparente (CEa), condutividade elétrica do extrato de saturação (CEes), conteúdo de água (θ) e textura (argila, silte e areia) do solo em uma área cultivada com cana-de-açúcar, no Estado de Pernambuco. A área de estudo possui cerca de 6,5 ha e o solo da área é um Espodossolo Humilúvico órtico. As amostras de solo foram avaliadas em 90 pontos de amostragem distribuídos aleatoriamente. Foram amostrados os seguintes atributos: condutividade elétrica aparente (CEa) medida por indução eletromagnética (dipolo vertical: CEa-V e dipolo horizontal: CEa-H) nas camadas de 0,0-0,4 m e 0,0-1,5 m de profundidade respectivamente. Os demais atributos foram medidos nas camadas de 0,0-0,2 m e 0,2-0,4 m de profundidade (CEes, θ, argila, silte e areia). A variabilidade espacial da condutividade elétrica aparente do solo medida por indução eletromagnética (CEa-V e CEa-H) foi influenciada pelo relevo, não apresentando relação direta com a condutividade elétrica do extrato de saturação do solo (CEes). Os atributos em estudo apresentaram distribuição de frequência com média superestimada, com valores de média se distanciando dos valores de moda e mediana. O relevo influenciou os mapas de variabilidade espacial da CEa-V, CEa-H, CEes e θ, apesar da matriz de correlação não demonstrar relação de causa e efeito bem definida. Os atributos texturais (argila, site e areia) apresentaram elevada variabilidade espacial, apresentando efeito pepita puro (EPP).

Spatial variability of soil attributes affects crop development. Thus, information on its variability assists in soil and plant integrated management systems. The objective of this study was to assess the spatial variability of the soil apparent electrical conductivity (ECa), electrical conductivity of the saturation extract (ECse), water content in the soil (θ) and soil texture (clay, silt and sand) of a sugarcane crop area in the State of Pernambuco, Brazil. The study area had about 6.5 ha and its soil was classified as orthic Humiluvic Spodosol. Ninety soil samples were randomly collected and evaluated. The attributes assessed were soil apparent electrical conductivity (ECa) measured by electromagnetic induction with vertical dipole (ECa-V) in the soil layer 0.0.4 and horizontal dipole (ECa-H) in the soil layer 0.0-1.5 m; and ECse, θ and texture in the soil layers 0.0-0.2 m and 0.2-0.4 m. Spatial variability of the ECa was affected by the area relief, and had no direct correlation with the electrical conductivity of the saturation extract (ECse). The results showed overestimated mean frequency distribution, with means distant from the mode and median. The area relief affected the spatial variability maps of ECa-V, ECa-H, ECse and θ, however, the correlation matrix did not show a well-defined cause-and-effect relationship. Spatial variability of texture attributes (clay, site and sand) was high, presenting pure nugget effect.