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. | 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.

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. | 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.

Maize is an important cereal and it is widely consumed in the world, both as food for humans and animals. Nitrogen (N) is a nutrient required in large quantities by maize, but unfortunately, soils are limited in meeting this need. Nodulating legumes can serve as a source of Nitrogen, because they are symbiotically associated with bacteria capable of fixing atmospheric N. Another important source of this nutrient is cattle manure, which is widely used in agriculture. The objective of the present study was to evaluate the effect of using legumes and cattle manure on the production as well as the microbial and biochemical quality of the soil used for maize cultivation. The experiment was conducted using a randomized complete block design, in a sub-subdivided plot scheme (2x4) +2, two leguminous plants (pigeon pea and macassar bean), four doses of cattle manure (0, 20, 40 and 60 t ha-1) and two controls; one with mineral fertilization and the other cultivated without the use of fertilizers. Treatment using a manure dose of 60t ha-1 and pigeon pea legume, recorded higher dry mass production per plant. The increase in manure doses was directly proportional to the length and weight of the cobs for the two legumes. The enzymatic activities were affected by the different doses and legumes, with greater results being recorded at the 60 t ha-1 dose with the macassar legume. The use of legumes with manure improved maize production as well as the microbiological and biochemical quality of soils.

Maize is an important cereal and it is widely consumed in the world, both as food for humans and animals. Nitrogen (N) is a nutrient required in large quantities by maize, but unfortunately, soils are limited in meeting this need. Nodulating legumes can serve as a source of Nitrogen, because they are symbiotically associated with bacteria capable of fixing atmospheric N. Another important source of this nutrient is cattle manure, which is widely used in agriculture. The objective of the present study was to evaluate the effect of using legumes and cattle manure on the production as well as the microbial and biochemical quality of the soil used for maize cultivation. The experiment was conducted using a randomized complete block design, in a   sub-subdivided plot scheme [(2x4) +2], two leguminous plants (pigeon pea and macassar bean), four doses of cattle manure (0, 20, 40 and 60 t ha-1) and two controls; one with mineral fertilization and the other cultivated  without the use of fertilizers. Treatment using a manure dose of 60t ha-1 and pigeon pea legume, recorded higher dry mass production per plant. The increase in manure doses was directly proportional to the length and weight of the cobs for the two legumes. The enzymatic activities were affected by the different doses and legumes, with greater results being recorded at the 60 t ha-1 dose with the macassar legume. The use of legumes with manure improved maize production as well as the microbiological and biochemical quality of soils. | O milho é um importante cereal muito utilizado no mundo, tanto como alimentação para humanos como para animais. O nitrogênio (N) é um nutriente requerido em grande quantidade pelo milho, e os solos são limitantes em atender essa necessidade. As leguminosas nodulantes podem ser utilizadas como fonte de Nitrogênio, por formarem associações simbióticas com bactérias capazes de fixar N atmosférico, outra importante fonte desse nutriente é o esterco bovino, utilizado largamente na agricultura. O objetivo do presente estudo foi avaliar o efeito do uso de leguminosas e esterco bovino na produção e qualidade microbiana e bioquímica do solo cultivado com milho. O experimento foi conduzido em delineamento de blocos ao acaso, em esquema de parcela sub-subdividida [(2x4) +2], sendo duas leguminosas (feijão guandu anão e feijão macassar), quatro doses de esterco bovino (0, 20, 40 e 60 t ha-1), mais dois tratamentos controle um com adubação mineral e outro sem o emprego de adubos. O tratamento utilizando a dose 60 t ha-1 de esterco com a leguminosa Guandu anão apresentou maior produção de massa seca por planta. O aumento das doses de esterco foi diretamente proporcional ao comprimento e peso das espigas para as duas leguminosas. As atividades enzimáticas responderam às diferentes doses e leguminosas, com maiores resultados na dose de 60 t ha-1 com a leguminosa macassar. O uso de leguminosa com esterco melhorou a produção de milho e a qualidade microbiológica e bioquímica dos solos.

Maize is an important cereal and it is widely consumed in the world, both as food for humans and animals. Nitrogen (N) is a nutrient required in large quantities by maize, but unfortunately, soils are limited in meeting this need. Nodulating legumes can serve as a source of Nitrogen, because they are symbiotically associated with bacteria capable of fixing atmospheric N. Another important source of this nutrient is cattle manure, which is widely used in agriculture. The objective of the present study was to evaluate the effect of using legumes and cattle manure on the production as well as the microbial and biochemical quality of the soil used for maize cultivation. The experiment was conducted using a randomized complete block design, in a sub-subdivided plot scheme [(2x4) +2], two leguminous plants (pigeon pea and macassar bean), four doses of cattle manure (0, 20, 40 and 60 t ha-1) and two controls; one with mineral fertilization and the other cultivated without the use of fertilizers. Treatment using a manure dose of 60t ha-1 and pigeon pea legume, recorded higher dry mass production per plant. The increase in manure doses was directly proportional to the length and weight of the cobs for the two legumes. The enzymatic activities were affected by the different doses and legumes, with greater results being recorded at the 60 t ha-1 dose with the macassar legume. The use of legumes with manure improved maize production as well as the microbiological and biochemical quality of soils. | O milho é um importante cereal muito utilizado no mundo, tanto como alimentação para humanos como para animais. O nitrogênio (N) é um nutriente requerido em grande quantidade pelo milho, e os solos são limitantes em atender essa necessidade. As leguminosas nodulantes podem ser utilizadas como fonte de Nitrogênio, por formarem associações simbióticas com bactérias capazes de fixar N atmosférico, outra importante fonte desse nutriente é o esterco bovino, utilizado largamente na agricultura. O objetivo do presente estudo foi avaliar o efeito do uso de leguminosas e esterco bovino na produção e qualidade microbiana e bioquímica do solo cultivado com milho. O experimento foi conduzido em delineamento de blocos ao acaso, em esquema de parcela sub-subdividida [(2x4) +2], sendo duas leguminosas (feijão guandu anão e feijão macassar), quatro doses de esterco bovino (0, 20, 40 e 60 t ha-1), mais dois tratamentos controle um com adubação mineral e outro sem o emprego de adubos. O tratamento utilizando a dose 60 t ha-1 de esterco com a leguminosa Guandu anão apresentou maior produção de massa seca por planta. O aumento das doses de esterco foi diretamente proporcional ao comprimento e peso das espigas para as duas leguminosas. As atividades enzimáticas responderam às diferentes doses e leguminosas, com maiores resultados na dose de 60 t ha-1 com a leguminosa macassar. O uso de leguminosa com esterco melhorou a produção de milho e a qualidade microbiológica e bioquímica dos solos.

Grape orchards are highly affected by oviposition of fruit flies on grape berries, which compromises the productivity and quality of the grapes. The goal of this study was to evaluate the susceptibility of American, European, and hybrid grape genotypes to Anastrepha fraterculus and Ceratitis capitata (Diptera: Tephritidae) under laboratory conditions (25 ± 2ºC, 60 ± 10% RH, and 14-hour photophase). The assays were conducted by evaluating oviposition preference through choice and no-choice (antibiosis) tests. The choice test was set up using circular arenas (diameter: 300 mm) with 10 grapes per genotype. The no-choice test was set up using 150 grapes per genotype which were placed inside plastic boxes (417 x 297 x 289 mm). After exposure of the grapes to one or two couples of fruit flies per genotype in choice and no-choice tests, respectively, the grapes were transferred to transparent plastic containers (750 mL). The number of eggs per grape and its viability were evaluated. The no-choice test also evaluated the biological cycle of the fruit flies. The assays were conducted in a completely randomized design with 15 replicates. The most preferred grapes for oviposition by A. fraterculus were Cabernet Sauvignon, Niagara Rosada, and BRS Cora, while C. capitata mainly preferred Isabel Precoce grapes. We observed the complete development of fruit flies in the Moscato Embrapa grapes, but this only occurred with C. capitata. All genotypes evaluated were considered susceptible to A. fraterculus and C. capitata. However, the fruit flies expressed differences in preference for oviposition and host quality.

Grape orchards are highly affected by oviposition of fruit flies on grape berries, which compromises the productivity and quality of the grapes. The goal of this study was to evaluate the susceptibility of American, European, and hybrid grape genotypes to Anastrepha fraterculus and Ceratitis capitata (Diptera: Tephritidae) under laboratory conditions (25 ± 2ºC, 60 ± 10% RH, and 14-hour photophase). The assays were conducted by evaluating oviposition preference through choice and no-choice (antibiosis) tests. The choice test was set up using circular arenas (diameter: 300 mm) with 10 grapes per genotype. The no-choice test was set up using 150 grapes per genotype which were placed inside plastic boxes (417 x 297 x 289 mm). After exposure of the grapes to one or two couples of fruit flies per genotype in choice and no-choice tests, respectively, the grapes were transferred to transparent plastic containers (750 mL). The number of eggs per grape and its viability were evaluated. The no-choice test also evaluated the biological cycle of the fruit flies. The assays were conducted in a completely randomized design with 15 replicates. The most preferred grapes for oviposition by A. fraterculus were Cabernet Sauvignon, Niagara Rosada, and BRS Cora, while C. capitata mainly preferred Isabel Precoce grapes. We observed the complete development of fruit flies in the Moscato Embrapa grapes, but this only occurred with C. capitata. All genotypes evaluated were considered susceptible to A. fraterculus and C. capitata. However, the fruit flies expressed differences in preference for oviposition and host quality. | No cultivo da videira a oviposição das moscas-das-frutas compromete a produtividade e a qualidade de bagas de uva. O objetivo desse trabalho foi avaliar a suscetibilidade de genótipos de uvas americanas, europeias e híbridas à Anastrepha fraterculus e Ceratitis capitata (Diptera: Tephritidae) em laboratório (25 ± 2ºC, 60±10% UR e fotofase de 14 horas) por meio de ensaios de preferência de oviposição com e sem chance de escolha (antibiose). No ensaio com chance de escolha foram utilizadas arenas circulares (300 mm de diâmetro) com 10 bagas por genótipo de uva. No teste sem chance de escolha foram utilizadas 150 bagas por genótipo de uva acondicionadas em caixa plástica (417 x 297 x 289 mm). Após a exposição a um ou a dois casais de moscas-das-frutas, por genótipo de uva nos testes com e sem chance de escolha, respectivamente, as bagas foram transferidas para potes plásticos transparentes (750 mL). Nos ensaios foram avaliados o número de ovos por baga e sua viabilidade. No ensaio sem chance de escolha também foi avaliado o ciclo biológico das moscas-das-frutas (teste de antibiose). Os experimentos foram conduzidos em delineamento inteiramente casualizado com 15 repetições. As bagas de uvas preferidas para oviposição por A. fraterculus foram Cabernet Sauvignon, Niágara Rosada e BRS Cora. Para C. capitata foi a Isabel Precoce. No genótipo Moscato Embrapa foi observado o desenvolvimento de ovo-adulto apenas de C. capitata. Assim, todos os genótipos foram considerados suscetíveis à A. fraterculus e C. capitata. No entanto, expressam diferenças na preferência para oviposição e na qualidade hospedeira para A. fraterculus e C. capitata.

Recurrent selection can generate successive gains for characters of economic interest without causing genetic narrowing in the population. However, it has rarely been used in breeding programs in popcorn, especially when using full-sibling progenies to generate more expressive gains. The objective of this study was to estimate the genetic gain of the UENF-14 popcorn population through recurrent selection, and verify the evolution of the gains between the selection cycles four and eight. A total of 200 full-sibling progenies were evaluated in randomized blocks arranged in eight sets within three replicates in two environments; each set containing twenty-five progenies and six controls (selection cycles 4, 5, 6 and 7 of the UENF-14, BRS-Angela and IAC-125). The average height, prolificacy, 100-grain weight, ear weight, grain yield, and grain popping expansion of the plants were evaluated. In the selection of the thirty superior progenies for the eighth cycle, the Mulamba and Mock selection index was used, which generated estimated genetic gains of 4.60 for grain yield and 3.61% for popping expansion. The grain yield increased 111.99 kg ha-1 and the popping expansion increased 1.75 mL g-1 per cycle. The evolution of the cycles resulted in an accumulated genetic gain for the main characters of economic importance, allowing the prediction of success in the continuity of the recurrent selection.

Recurrent selection can generate successive gains for characters of economic interest without causing genetic narrowing in the population. However, it has rarely been used in breeding programs in popcorn, especially when using full-sibling progenies to generate more expressive gains. The objective of this study was to estimate the genetic gain of the UENF-14 popcorn population through recurrent selection, and verify the evolution of the gains between the selection cycles four and eight. A total of 200 full-sibling progenies were evaluated in randomized blocks arranged in eight sets within three replicates in two environments; each set containing twenty-five progenies and six controls (selection cycles 4, 5, 6 and 7 of the UENF-14, BRS-Angela and IAC-125). The average height, prolificacy, 100-grain weight, ear weight, grain yield, and grain popping expansion of the plants were evaluated. In the selection of the thirty superior progenies for the eighth cycle, the Mulamba and Mock selection index was used, which generated estimated genetic gains of 4.60 for grain yield and 3.61% for popping expansion. The grain yield increased 111.99 kg ha-1 and the popping expansion increased 1.75 mL g-1 per cycle. The evolution of the cycles resulted in an accumulated genetic gain for the main characters of economic importance, allowing the prediction of success in the continuity of the recurrent selection. | A seleção recorrente embora permita sucessivos ganhos para caracteres de interesse econômico, sem provocar estreitamento genético na população, tem sido raramente utilizada em programas de melhoramento com milho-pipoca, sobretudo em se tratando da estratégia de utilização de progênies de irmãos-completos, em que são possíveis ganhos mais expressivos. O objetivo deste estudo foi estimar o ganho genético na população UENF-14, de milho-pipoca, por meio de seleção recorrente e averiguar a evolução dos ganhos entre os ciclos quatro e oito de seleção. Foram avaliadas 200 progênies de irmãos-completos, em blocos casualizados, com arranjos em sets dentro de três repetições em dois ambientes, no total de oito sets, sendo que cada set continha vinte e cinco progênies e seis testemunhas (ciclos 4, 5, 6 e 7 de seleção em UENF-14, BRS Angela e IAC 125). Avaliou-se a altura média da planta, prolificidade, peso de cem grãos, peso de espiga, produtividade de grãos e capacidade de expansão. Na seleção das trinta progênies superiores para o oitavo ciclo, foi utilizado o índice de seleção Mulamba e Mock, que proporcionou ganhos genéticos estimados de 4,60 e 3,61%, respectivamente, para produtividade de grãos e capacidade de expansão. Houve incremento de 111,99 kg ha-1 e de 1,75 mL g-1, por ciclo, para a produtividade de grãos e capacidade de expansão, nesta ordem. A evolução dos ciclos revelou ganho genético acumulado para os principais caracteres de importância econômica da cultura, possibilitando a antevisão de sucesso, na continuidade da seleção recorrente.

The banana tree is grown in an extensive tropical region throughout the world, usually by small producers. The present work had the objective of evaluating irrigation systems in banana production in the Açu-RN Valley, aiming at alternatives so that they can be recommended to farmers in the Açu Valley region. The experiment was carried out in the area of the School Farm of the IFRN Campus Ipanguaçu, located in the municipality of Ipanguaçu-RN. The experiment was carried out in a randomized complete block design with subdivided plots and eight replications. The irrigation systems were: irrigation, drip irrigation, micro sprinkler and alternative irrigation. The plots were composed of eight useful plants with spacing in double rows 4 x 2 x 2 m. Eight characteristics related to production were evaluated: bunch mass (MC); number of leaves (NP); number of fruits per cluster (NFC); mean mass of the leaves (MMP); diameter of the fruit of the second seed (DF2P); length of the fruit of the second seed (CF2P); mean fruit mass (MMF); productivity (Prod). The data were submitted to analysis of variance and the means were compared by the Tukey test at 5% of probability. In the first cycle of production the sprinkler irrigation system was the one that presented better results the productivity of the Pacovan banana tree; in the 3rd cycle the alternative irrigation system was the one that showed better results the productivity of the banana tree; where the electrical conductivity correlated with the sodium adsorption ratio in the irrigation water, contributed to a moderate limitation of use.

The banana tree is grown in an extensive tropical region throughout the world, usually by small producers. The present work had the objective of evaluating irrigation systems in banana production in the Açu-RN Valley, aiming at alternatives so that they can be recommended to farmers in the Açu Valley region. The experiment was carried out in the area of the School Farm of the IFRN Campus Ipanguaçu, located in the municipality of Ipanguaçu-RN. The experiment was carried out in a randomized complete block design with subdivided plots and eight replications. The irrigation systems were: irrigation, drip irrigation, micro sprinkler and alternative irrigation. The plots were composed of eight useful plants with spacing in double rows 4 x 2 x 2 m. Eight characteristics related to production were evaluated: bunch mass (MC); number of leaves (NP); number of fruits per cluster (NFC); mean mass of the leaves (MMP); diameter of the fruit of the second seed (DF2P); length of the fruit of the second seed (CF2P); mean fruit mass (MMF); productivity (Prod). The data were submitted to analysis of variance and the means were compared by the Tukey test at 5% of probability. In the first cycle of production the sprinkler irrigation system was the one that presented better results the productivity of the Pacovan banana tree; in the 3rd cycle the alternative irrigation system was the one that showed better results the productivity of the banana tree; where the electrical conductivity correlated with the sodium adsorption ratio in the irrigation water, contributed to a moderate limitation of use. | A bananeira é cultivada em uma extensa região tropical em todo mundo, geralmente por pequenos produtores. O presente trabalho teve o objetivo de avaliar sistemas de irrigação na produção de banana no Vale do Açu-RN, visando alternativas para que possam ser recomendados aos agricultores da região do Vale do Açu. O experimento foi realizado na área da Fazenda Escola do IFRN Campus Ipanguaçu, localizado no município de Ipanguaçu-RN. O ensaio foi conduzido por um período de três ciclos de produção, em delineamento de blocos casualizados com parcelas subdivididas e oito repetições, sendo representados por quatro sistemas de irrigação: aspersão, gotejamento, microaspersão e alternativo. As parcelas foram constituídas de oito plantas úteis com espaçamento em fileiras duplas 4 x 2 x 2 m. Foram avaliadas oito características relacionadas à produção: massa do cacho (MC); nº de pencas (NP); nº de frutos por cacho (NFC); massa média das pencas (MMP); diâmetro do fruto da segunda penca (DF2P); comprimento do fruto da segunda penca (CF2P); massa média de frutos (MMF); produtividade média (Prod). Os dados foram submetidos a análise de variância e as médias foram comparadas pelo teste de Tukey a 5% de probabilidade. No 1º ciclo de produção o sistema de irrigação por aspersão foi o que apresentou melhores resultados a produtividade da bananeira Pacovan; no 3º ciclo o sistema de irrigação alternativo foi o que mostrou melhores resultados a produtividade da bananeira; onde a condutividade elétrica correlacionada com a razão de adsorção do sódio na água de irrigação, contribuiram para moderada limitação de uso.

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.

The effects of soil compaction on crop growth and productivity have been well studied in recent years, however, studies on the physiological responses of crops to compaction are scarce. The objective of this study was to evaluate the effect of soil compaction on gas exchange, and photochemical efficiency of lima bean (Phaseolus lunatus L.) genotypes of different growth habits. The experimental design was a randomized block in a 3×4 factorial arrangement, with three lima bean genotypes (Branca-Pequena, Orelha-de-Vó and Roxinha) and four compaction levels (soil densities of 1.1, 1.3, 1.5 and 1.7 g cm-3), with four replications. The following variables were evaluated at 38 days after sowing: photosynthetic rate (A), leaf transpiration (E), stomatal conductance (gs), internal CO2 concentration (Ci), instantaneous water use efficiency (WUE), intrinsic water use efficiency (iWUE), instantaneous carboxylation efficiency (iCE) and photochemical efficiency (Fo, Fm, Fv and Fv/Fm). The data were subjected to analysis of variance at 5% probability by the F test. The genotypes showed a reduction in the photosynthetic rate with increasing soil compaction. The soil compaction affected the photochemical efficiency of the genotype Orelha-de-Vó, with the Fm and Fv fitting to the linear model, and the Fv/Fm fitting to the quadratic model. The genotype Orelha-de-Vó had the highest rate of E and gs at the soil densities of 1.24 and 1.29 g cm-3, respectively. Regarding the photosynthetic rate, the genotype Roxinha is more efficient than Branca-Pequena at the soil density of 1.7 g cm -3.

The effects of soil compaction on crop growth and productivity have been well studied in recent years, however, studies on the physiological responses of crops to compaction are scarce. The objective of this study was to evaluate the effect of soil compaction on gas exchange, and photochemical efficiency of lima bean (Phaseolus lunatus L.) genotypes of different growth habits. The experimental design was a randomized block in a 3×4 factorial arrangement, with three lima bean genotypes (Branca-Pequena, Orelha-de-Vó and Roxinha) and four compaction levels (soil densities of 1.1, 1.3, 1.5 and 1.7 g cm-3), with four replications. The following variables were evaluated at 38 days after sowing: photosynthetic rate (A), leaf transpiration (E), stomatal conductance (gs), internal CO2 concentration (Ci), instantaneous water use efficiency (WUE), intrinsic water use efficiency (iWUE), instantaneous carboxylation efficiency (iCE) and photochemical efficiency (Fo, Fm, Fv and Fv/Fm). The data were subjected to analysis of variance at 5% probability by the F test. The genotypes showed a reduction in the photosynthetic rate with increasing soil compaction. The soil compaction affected the photochemical efficiency of the genotype Orelha-de-Vó, with the Fm and Fv fitting to the linear model, and the Fv/Fm fitting to the quadratic model. The genotype Orelha-de-Vó had the highest rate of E and gs at the soil densities of 1.24 and 1.29 g cm-3, respectively. Regarding the photosynthetic rate, the genotype Roxinha is more efficient than Branca-Pequena at the soil density of 1.7 g cm -3. | Os efeitos da compactação do solo no crescimento e produtividade das culturas têm sido muito estudados nos últimos anos, porém, as respostas fisiológicas das culturas à compactação não têm recebido a devida atenção. Objetivou-se avaliar o efeito da compactação do solo nas trocas gasosas e na eficiência fotoquímica de genótipos de fava (Phaseolus lunatus L.) de diferentes hábitos de crescimento. O delineamento experimental utilizado foi em blocos casualizados no arranjo fatorial 3 × 4, sendo três genótipos de fava (Branca pequena, Orelha de vó e Roxinha) e quatro níveis de compactação (densidades de solo de 1,1; 1,3; 1,5 e 1,7 g cm-3), com quatro repetições. Aos 38 dias após a semeadura, analisaram-se as seguintes variáveis: taxa fotossintética (A), transpiração foliar (E), condutância estomática (gs), concentração interna de CO2 (Ci), eficiência instantânea no uso da água (EUA), eficiência intrínseca no uso da água (EIUA), eficiência instantânea de carboxilação (EiC) e eficiência fotoquímica (Fo, Fm, Fv e Fv/Fm). Os dados foram submetidos à análise de variância a 5% de probabilidade pelo teste F. Os genótipos apresentaram redução na taxa fotossintética com aumento da compactação do solo. Houve efeito da compactação do solo na eficiência fotoquímica apenas para o genótipo ‘Orelha de vó’, com ajustes do modelo linear para Fm e Fv, e quadrático para relação Fv/Fm. O genótipo ‘Orelha de vó’ atingiu a maior taxa de E e gs nas densidades de solo 1,24 e 1,29 g cm-3, respectivamente. Em relação a taxa fotossintética, o genótipo ‘Roxinha’ é mais eficiente que o genótipo ‘Branca pequena’ na densidade do solo de 1,7 g cm-3.

The present study aimed to assess the variations in the parameters of the exudate pH and flooding tests to evaluate the physiological quality of soybean seeds. We subjected the lots of soybean seeds to germination, emergence, exudate pH, and flooding tests. Further, water content of the seeds, first count of germination, and emergence speed index were also determined. The exudate pH test studied the variations in the soaking period and temperature, while the flooding test assessed the variations in the amount of water and temperature at different periods of immersion. The experiment design was completely randomized. The results were presented as means and were compared using the Scott-Knott test at 5% probability. The Pearson’s correlation coefficient between the exudate pH and emergence of seedlings, and also between the flooding test result and emergence of seedlings were calculated. The results of the study indicated that the exudate pH test can be used to evaluate the physiological quality of soybean seeds after 30 min of imbibition at 20 °C. Further, the flooding test was efficient in evaluating the vigor of soybean seeds after 4 h of immersion either in 50 mL of distilled water at 25 °C or in 75 mL of distilled water at 30 °C.

The present study aimed to assess the variations in the parameters of the exudate pH and flooding tests to evaluate the physiological quality of soybean seeds. We subjected the lots of soybean seeds to germination, emergence, exudate pH, and flooding tests. Further, water content of the seeds, first count of germination, and emergence speed index were also determined. The exudate pH test studied the variations in the soaking period and temperature, while the flooding test assessed the variations in the amount of water and temperature at different periods of immersion. The experiment design was completely randomized. The results were presented as means and were compared using the Scott–Knott test at 5% probability. The Pearson’s correlation coefficient between the exudate pH and emergence of seedlings, and also between the flooding test result and emergence of seedlings were calculated. The results of the study indicated that the exudate pH test can be used to evaluate the physiological quality of soybean seeds after 30 min of imbibition at 20 °C. Further, the flooding test was efficient in evaluating the vigor of soybean seeds after 4 h of immersion either in 50 mL of distilled water at 25 °C or in 75 mL of distilled water at 30 °C. | O trabalho teve como objetivo estudar variações nos parâmetros envolvidos no teste do pH do exsudato e alagamento para caracterização da qualidade fisiológica de sementes de soja. Inicialmente, foi determinado o teor de água e realizados os testes de germinação, primeira contagem, emergência e índice de velocidade de emergência. No teste do pH do exsudato foram estudadas variações no período de embebição e temperatura; e no teste de alagamento foram estudadas variações na quantidade de água e temperatura. O experimento foi realizado em delineamento inteiramente casualizado com quatro repetições, e as médias comparadas pelo teste de Scott-Knott a 5% de probabilidade. Foi estimado o coeficiente de correlação de Pearson entre os testes do pH do exsudato e alagamento com a emergência de plântulas. O teste do pH do exsudato pode ser utilizado na avaliação do potencial fisiológico de sementes de soja, sendo que este deve ser realizado na temperatura de 20 ºC por 30 minutos de embebição. O teste de alagamento é eficiente na avaliação do vigor de sementes de soja, podendo ser realizado nas combinações 25 ºC/50 mL ou 30 ºC/75 mL, durante 4 h.

Myroxylon balsamum is a valuable tropical tree; besides the good quality of its timber it also provides valuable nontimber forest products: balsam and resin. High deforestation rates in the area of distribution and the unregulated extraction of its resin and wood have led M. balsamum to be endangered or threatened. Its regeneration through seeds has been poorly studied, and there are no reports of germination and plasticity under controlled conditions. We evaluated the effect of scarification (longitudinal cut of the fruit and embryo fully exposed) and environmental factors (different levels of light intensities and changing temperatures) on seed germination and the development of seedlings. From the aforementioned, M. balsamum seeds are orthodox and show physical dormancy. In view of these characteristics, M. balsamum can be managed efficiently to initiate conservation programs and restoration in degraded land.

Myroxylon balsamum is a valuable tropical tree; besides the good quality of its timber it also provides valuable nontimber forest products: balsam and resin. High deforestation rates in the area of distribution and the unregulated extraction of its resin and wood have led M. balsamum to be endangered or threatened. Its regeneration through seeds has been poorly studied, and there are no reports of germination and plasticity under controlled conditions. We evaluated the effect of scarification (longitudinal cut of the fruit and embryo fully exposed) and environmental factors (different levels of light intensities and changing temperatures) on seed germination and the development of seedlings. From the aforementioned, M. balsamum seeds are orthodox and show physical dormancy. In view of these characteristics, M. balsamum can be managed efficiently to initiate conservation programs and restoration in degraded land. | Myroxylon balsamum é uma valiosa árvore tropical, com madeira de boa qualidade e que também fornece produtos não madeiráveis, como bálsamo e resina. As elevadas taxas de desmatamento em sua distribuição natural e a extração não regulamentada de sua resina e madeira têm levado esta espécie à ameaça de extinção. A regeneração desta espécie tem sido pouco estudada, não havendo registros sobre a germinação e plasticidade de sua semente sob condições controladas. Neste trabalho avaliou-se o efeito da escarificação (corte longitudinal do fruto, exposição do embrião, testemunha não escarificada) e de fatores ambientais (diferentes níveis de intensidades luminosas e de regimes de temperatura) na capacidade germinativa da semente e no desenvolvimento das plântulas. A semente de M. balsamum é ortodoxa e os tratamentos de escarificação promoveram sua germinação. Pode haver uma latência física. A informação derivada deste trabalho pode apoiar programas de conservação e de restauração com M. balsamum.

Sweet corn is an important crop because of its seeds with high total sugar and low starch contents. As common corn, this group requires an adequate amount of nitrogen to reach high yields. However, the studies on nitrogen and sweet corn are performed for ear yield instead of seed yield. As seeds are the main propagation method for this species, we proposed to evaluate the effects of nitrogen rates as side-dressing at different plant stages of a sweet corn seed production. Sweet corn seeds (variety BR 400) were sown in Latosol (Oxisol), and a 3×2+1 factorial scheme was designed with three nitrogen rates (40, 80, and 120 kg ha-1) at two plant stages (V6 and R1) plus the control (no nitrogen side-dressing). The evaluated variables were seed yield, protein content, P and Zn contents, germination, and vigor rates. We concluded that nitrogen applied at a rate of 120 kg ha-1 at V6 increases seed yield and maintains unaltered the protein content in seeds of sweet corn (BR 400 variety). Neither germination nor seed vigor increases when nitrogen rates are increased or administered at different stages of plant development. We also noted a slight decrease in P content or an increase in Zn content of seeds at low nitrogen rates; however, they are insufficient to promote changes in the physiological potential of sweet corn seeds.

Sweet corn is an important crop because of its seeds with high total sugar and low starch contents. As common corn, this group requires an adequate amount of nitrogen to reach high yields. However, the studies on nitrogen and sweet corn are performed for ear yield instead of seed yield. As seeds are the main propagation method for this species, we proposed to evaluate the effects of nitrogen rates as side-dressing at different plant stages of a sweet corn seed production. Sweet corn seeds (variety BR 400) were sown in Latosol (Oxisol), and a 3×2+1 factorial scheme was designed with three nitrogen rates (40, 80, and 120 kg ha-1) at two plant stages (V6 and R1) plus the control (no nitrogen side-dressing). The evaluated variables were seed yield, protein content, P and Zn contents, germination, and vigor rates. We concluded that nitrogen applied at a rate of 120 kg ha-1 at V6 increases seed yield and maintains unaltered the protein content in seeds of sweet corn (BR 400 variety). Neither germination nor seed vigor increases when nitrogen rates are increased or administered at different stages of plant development. We also noted a slight decrease in P content or an increase in Zn content of seeds at low nitrogen rates; however, they are insufficient to promote changes in the physiological potential of sweet corn seeds. | O milho doce é uma cultura importante por causa do seu tipo de sementes com índice elevado dos açúcares totais e baixo índice do amido. Como o milho comum, este necessita de quantidade adequada de nitrogênio para atingir altas produtividades, no entanto, os estudos que envolvem nitrogênio e milho doce são realizados para o rendimento das espigas e não para a produção de sementes. Como a semente é o principal método de propagação dessa espécie, foi avaliado os efeitos das doses de nitrogênio em cobertura em diferentes estádios fenológicos para produção e potencial fisiológico de sementes de milho doce. As sementes de milho doce (variedade BR 400) foram semeadas em Latossolo e um esquema fatorial de tratamento 3 × 2 + 1 foi instalado com três doses de nitrogênio 40, 80 e 120 kg ha-1 e dois estádios fenológicos (V6 e R1) mais o controle (sem nitrogênio em cobertura). Foram avaliadas a produtividade de sementes, teores de proteína, P e Zn, germinação e vigor. Como conclusão, o nitrogênio fornecido em V6 a 120 kg ha-1 aumenta a produtividade de sementes e mantém os teores de proteína inalterados. A germinação da semente e o vigor não aumentam quando as taxas de nitrogênio são acrescidas ou fornecidas em diferentes estádios fenológicos. Diminuição ligeira do teor de P ou o aumento do teor de Zn nas sementes são observados a uma dose baixa de nitrogênio entretanto não suficientes para promover alterações no potencial fisiológico das sementes do milho doce.