A busca por substratos alternativos, que possam substituir produtos comerciais na produção de mudas de tomate, é de fundamental importância para a redução dos custos nessa fase inicial da cultura. Objetivou-se, com esta pesquisa, avaliar a qualidade de mudas de tomate industrial IPA 6, produzidas com substratos à base de esterco ovino. O experimento foi conduzido em viveiro da Universidade Federal Rural de Pernambuco, Unidade Acadêmica de Serra Talhada, de 16 de fevereiro a 30 de março de 2012. Utilizou-se o delineamento inteiramente casualizado, com quatro repetições. Os tratamentos avaliados foram: T1 - [substrato comercial]; T2 - [esterco ovino + areia (1:1)]; T3 - [esterco ovino + areia (2:1)]; T4 - [esterco ovino + areia (3:1)]; T5 - [esterco ovino + solo (1:1)]; T6 - [esterco ovino + solo (2:1)]; T7 - [esterco ovino + solo (3:1)]; T8 - [esterco ovino + areia + solo (1:1:1)];T9 - [esterco ovino + areia + solo (2:1:1)]; T10 - [esterco ovino + areia + solo (3:1:1)]. Os indicadores de emergência avaliados foram: percentagem, índice de velocidade e tempo médio de emergência. Analisaram-se as seguintes características de desenvolvimento: número de folhas, altura de plântula, diâmetro de caule, comprimento de raízes, massa da matéria seca da parte aérea e das raízes. O substrato comercial proporcionou melhor vigor de mudas de tomate IPA 6. Por outro lado, o uso do esterco ovino mais solo (2:1), para compor substratos alternativos constituiu-se opção viável para a produção de mudas desse cultivar.

Para obter produtos de qualidade e em quantidade ao longo do ano, é necessário o planejamento do plantio, observando a produtividade esperada, o preço praticado no comércio e os custos relativos aos fatores de produção, como despesas com mão de obra e aquisição de fertilizantes, os quais ditam o sucesso do investimento. O objetivo deste trabalho foi avaliar a rentabilidade do rabanete cv. Crimson Gigante adubado com diferentes quantidades de biomassa de flor-de-seda, em distintos tempos de incorporação ao solo e cultivado em duas épocas (outubro-dezembro e abril-julho), no semiárido de Pernambuco. O delineamento experimental utilizado em ambos os experimentos foi o de blocos completos casualizados com os tratamentos arranjados em esquema fatorial 4 × 4, com três repetições, sendo o primeiro fator: as quantidades de flor-de-seda (5,4; 8,8; 12,2 e 15,6 t ha-1 em base seca), e o segundo: os tempos de incorporação ao solo deste adubo (0, 10, 20 e 30 dias). Além da produtividade comercial de raízes e dos custos de produção, foram determinados os indicadores econômicos: renda bruta, renda líquida, taxa de retorno e índice de lucratividade. As maiores receitas bruta e líquida foram observadas com a quantidade de 15,6 t ha-1 de flor-de-seda. A incorporação da flor-de-seda 22 dias antes do plantio do rabanete foi considerada ideal à viabilidade econômica do investimento.

The sesame crop (Sesamum indicum L.) is sensitive to competition with weeds because of its low competitiveness that is directly linked to its slow initial growth. The control of weeds in the crop is an essential practice to ensure the high productivity of this oilseed. Therefore, to define the critical period of interference prevention is important to ensure efficiency and low control costs. Factors such as cultivar, environmental conditions, and cultivation system may alter the critical weed interference prevention period (CPWC). Therefore, the objective of this work was to determine the critical weed interference prevention period in two sesame cultivars. The critical weed interference prevention period for sesame cultivars, BRS Seda and CNPA G2, was defined in two years (2016 and 2017). Log-logistic regression of four parameters was used to determine the critical weed interference prevention period. The cultivar CNPA G2 was more competitive compared to the cultivar BRS Seda. The CPWC for BRS Seda was on average 67 and 52 days, whereas for CNPA G2 was 52 and 34 days, considering respectively, a loss of 5 and 10%. Weed control for BRS Seda and CNPA G2 should begin respectively between 12 and 15, and 17 and 20 days, considering a loss of 5 and 10%.

This study aimed to evaluate the emergence, growth, biomass accumulation and tolerance of peanut genotypes under salt stress. The experiment was conducted in a protected environment (greenhouse), evaluating six peanut genotypes (Tatuí, L7151, Caiapó, IAC8112, IAC881 and Havana), which were subjected to two levels of irrigation water salinity (0.5 [control] and 3.5 dS m-1), arranged in a 6 x 2 factorial scheme, in a randomized block design, with five repetitions, with two plants per plot. Plants were cultivated for 30 days after sowing in lysimeters with capacity for 0.5 dm3, filled with a mixture of non-saline, non-sodic soil and commercial substrate in 1:1 proportion on volume basis. During this period, plants were evaluated for emergence, growth, biomass accumulation, tolerance to salinity and dissimilarity. The genotypes Tatuí and L7151 are the most sensitive to salt stress in the emergence stage. Irrigation with high-salinity water reduced the growth and biomass accumulation of the peanut genotypes, and Caiapó and IAC8112 were the least affected. The classification of salinity tolerance had the following sequence: Caiapó > IAC8112 > Havana > Tatuí > IAC881 > L7151.

No abstract

The use of green manures in vegetable crop production systems has increased, but there is still a lack of information about the correct handling of the species for better use by culture. Two field experiments were conducted in Serra Talhada in the semiarid of Pernambuco state, Brazil, to evaluate the effects of amounts of biomass and times of Calotropis procera incorporation into the soil in the agronomic performance of the beetroot 'Early Wonder' in two growing seasons (fall and spring-summer). The experimental design was a randomized block in three replications. The treatments were arranged in a 4 x 4 factorial scheme, with the first factor corresponding to the quantities of C. procera biomass (5.4, 8.8, 12.2, and 15.6 Mg ha -1 on a dry basis) and the second to the times of incorporation into the soil (0, 10, 20, and 30 days before sowing of beetroot). The following characteristics were assessed in the beetroot: plant height, number of leaves per plant, root diameter, total productivity, commercial productivity, and dry mass of roots. The amount of C. procera as well as the time of incorporation and growing season directly influenced the agronomic performance of beetroot. Regardless of the assessed agronomic characteristics, increasing amounts, and decreasing the time of incorporation proportionally influenced the performance of beetroot. The best agronomic performance of the beetroot was obtained by fertilization with 15.6 Mg ha -1 of C. procera. The ideal time of incorporation of green manure coincided with the date of the sowing of beetroot. The cultivation in the fall season resulted in higher total and commercial productivity of beetroots fertilized with C. procera.

No abstract

Lettuce is a vegetable crop that requires a large supply of nutrients in a readily available form, within a short period of intense vegetative growth. The use of green manuring, with spontaneous species of the Caatinga biome, can quickly increase the organic matter content in the soil, providing nutrients for the crop. Therefore, the objective of this work was to evaluate the agron omic performance and economic profitability of lettuce fertilized with Calotropis procera in single crop under the semi-arid conditions of the state of Rio Grande do Norte, Brazil. The experimental design was a randomized complete block, with four treatments and five replicates. The treatments consisted of four amounts of C. procera biomass incorporated into the soil (10, 25, 40, and 55 t ha-1 of dry matter). The maximum agronomic efficiency of lettuce productivity was obtained for a yield of 18.16 t ha-1 , with 40.29 t ha-1 of C. procera biomass added to the soil. The maximum economic efficiency of lettuce yield was achieved by the net income of AU$3,006.50 (R$7,546.31 ha-1), provided by the production of 17.65 t ha-1 of fresh mass, with 32.20 t ha-1 of C. procera biomass added to the soil. The use of C. procera as a green manure presents agro-economic feasibility for lettuce cultivation in the semi-arid conditions of the Rio Grande do Norte state.