Francisco Marcus Lima Bezerra

Produtividade da mamona irrigada com esgoto doméstico tratado

The castor bean (Ricinus communis L.), an oil crop of economic and social importance for the Northeast region of Brazil, can be used for biodiesel production. The experiment aimed to evaluate, at a realistic scale, the productive aspects of the castor bean irrigated with treated sewage. Microsprinkler irrigation method was selected, and the experimental set-up consisted of four repetitions and four different treatments: well water and recommended fertilization (T1); treated wastewater and recommended fertilization (T2); treated wastewater without external recommended fertilization (T3); and treated wastewater and half of recommended fertilization (T4). It was found that units irrigated with treated sewage exceeded the ones irrigated with well water in almost all variables. The highest productivities were in the treatments with wastewater and fertilization (T2) and wastewater and half of recommended fertilization (T4), reaching 1,986 and 1,412 kg ha-1, respectively. The castor seeds oil content was also investigated, no significati difference among the treatments with recommended fertilization (T1, T2 and T4) was verified. The treatment tested with effluent without recommended fertilization (T3) provided very low oil content in the seeds.

Crescimento da cultura do girassol irrigado com diferentes tipos de água e adubação nitrogenada

The objective of the present study was to evaluate the growth of sunflower crop irrigated with different water sources (both treated wastewater and well water) and application of different rates of nitrogen fertilizer. The experiment was conducted at the Research Center of Treatment and Reuse of Sewer Water located in the municipality of Aquiraz in the State of Ceara, Brazil. The statistical design consisted of a randomized block in split-plots with four replications. In the plots, the effects of two types of irrigation water on sunflower growth parameters was evaluated and in the subplots the effects of the five irrigation levels; according to the percentage of Class A Evaporation Pan (ECA),corresponding to the multiplication of ECA by factors of 0.25, 0.50, 0.75, 1.00 and 1.25 levels were determined. In splitplots, the effects of the four rates of nitrogen (25, 50, 75 and 100 kg ha-1) on the same growth parameters were evaluated. The plant height, stem diameter and number of leaves increased lineaRLy as a function of the irrigation water levels. The parameter values obtained for wastewater were consistently higher than those obtained with well water. The capitulum diameter increased in a quadratic manner as a function of the irrigation water levels and nitrogen fertilizer rates.

Trocas gasosas em plantas de girassol submetidas à deficiência hídrica em diferentes estádios fenológicos

This study evaluated gas-exchange responses of the sunflower when subjected to water deficit at different stages of growth. The experiment was carried out at Pentecost, in the state of Ceara, in a randomized-block design of time-split plots, consisting of eight plots, three subplots and four blocks. In the plots, the periods of induction of the water deficit were evaluated at different stages of growth (vegetative, flowering and production formation), which corresponded to the occurrence of the water deficit at one, two or three stages, and in the subplots, the times of evaluation of the physiological characteristics corresponded to the end of each phase (52, 68 and 110 days after sowing, DAS). The crop was irrigated at a level equivalent to100% of the reference for evapotranspiration (ETo), and the water deficit was imposed at half the level that was used in the control treatment. The periods of evaluation influenced most of the variables analysed, except for the intrinsic efficiency of the use of water. The results for leaf temperature and for the rates of photosynthesis, transpiration, stomatal conductance, concentration of internal CO2, and the immediate and intrinsic efficiency of the use of water, showed no effects in relation to the level of water deficit evaluated regardless of the period in which these were applied. Photosynthesis and transpiration decreased with the stage of development of the crop, causing reductions in the immediate efficiency of the use of water. It was therefore concluded that the crop can be irrigated at 50% of ETo throughout the complete cycle without damage to the process of photosynthesis.This study evaluated gas-exchange responses of the sunflower when subjected to water deficit at different stages of growth. The experiment was carried out at Pentecost, in the state of Ceara, in a randomized-block design of time-split plots, consisting of eight plots, three subplots and four blocks. In the plots, the periods of induction of the water deficit were evaluated at different stages of growth (vegetative, flowering and production formation), which corresponded to the occurrence of the water deficit at one, two or three stages, and in the subplots, the times of evaluation of the physiological characteristics corresponded to the end of each phase (52, 68 and 110 days after sowing, DAS). The crop was irrigated at a level equivalent to100% of the reference for evapotranspiration (ETo), and the water deficit was imposed at half the level that was used in the control treatment. The periods of evaluation influenced most of the variables analysed, except for the intrinsic efficiency of the use of water. The results for leaf temperature and for the rates of photosynthesis, transpiration, stomatal conductance, concentration of internal CO2, and the immediate and intrinsic efficiency of the use of water, showed no effects in relation to the level of water deficit evaluated regardless of the period in which these were applied. Photosynthesis and transpiration decreased with the stage of development of the crop, causing reductions in the immediate efficiency of the use of water. It was therefore concluded that the crop can be irrigated at 50% of ETo throughout the complete cycle without damage to the process of photosynthesis.

Produtividade do meloeiro sob lâmina de irrigação e adubação potássica

The main goal of this work was to evaluate the effect of the application of the four water depths and four levels of potassium fertilization applied thought drip irrigation on the yield and quality of Yellow melon (Cucumis melo L.), group Gold Mine AF 10.00. The study was carried at the Pici Campus of Ceara Federal University from Brazil. A randomized block design with two factors and four repetitions was used. The first factor represented the water depths (50; 75; 100 and 150% of the Class A pan evaporation) and the second factor represented the levels of potassium fertilization (150; 225; 300 and 450 kg ha-1). The results showed that water depths linearly affected crop productivity, while Potassium fertilization and the iteration between both factors were not significant. Maximum fruit yield (35 Mg ha-1) was obtained applying 795 mm of water (150% of the Class A pan evaporation). Fruit mass increased about 82% with the amount of water applied, while the yield increased more than 16 Mg ha-1 .

Componentes estruturais do resíduo pós-corte em capim-massai adubado com cinco doses de nitrogênio

After cut residue of Massai grass under five nitrogen fertilized levels were evaluated. A completely randomized design with five nitrogen levels (0; 150; 300; 450 and 600 mg N dm-3 of soil) and five replicates (plots) in greenhouse was used. It was evaluated the residual canopy height (RCH), the tiller population density (TPD), the total residual forage dry mass (TFDM), the residual green forage dry mass (GFDM), the senescent forage dry mass (SFDM), the residual green leaf dry mass (GLDM), the residual green culm dry mass (GCDM), leaf/culm ratio (L/C), root dry mass (RDM) and above ground/root ratio (A/R). There was square effect of nitrogen fertilization on RCH. There were crescent and linear effect of nitrogen fertilization on TFDM, GFDM and GCDM. There was square effect of nitrogen fertilization on GLDM. The values were estimated in 13.35 and 39.73 g DM/plot to TFDM; 9.71 and 24.69 g DM/plot to GFDM and 3.65 and 15.07 g DM/plot to SFDM on 0 and 600 mg N dm-3 of soil, respectively. The RDM presented positively response to the N levels. It was concluded that the nitrogen fertilizing brought benefits for all structural characteristics after cut of Massai grass.

Aplicação do "ISAREG" no manejo da irrigação na cultura da melancia no Baixo Acaraú, Ceará

The objective of this study was to apply the ISAREG software model to the irrigation management of watermelon in the Lower Acarau Irrigated Perimeter (LAIP). To this end, the soil water-balance was analysed, developing an irrigation schedule which aimed for maximum crop yield for the soil and climatic conditions of the LAIP for a specific planting date and comparing it to the irrigation scheme currently adopted by irrigators. With an aim to the practical application of ISAREG, the model was supplied monthly with climatic variables, precipitation and soil data, and information on the crop. Finally, an irrigation option available in ISAREG was selected, and a simulation of the soil water-balance was carried out. Questionnaires were used in order to get information about the irrigation scheme employed at the LAIP. The research showed that the producers of watermelon at the LAIP are not properly managing water resources. During the crop cycle, irrigators are applying an excess of about 215.2 mm of water at some periods, and a deficit of 24.2 mm to the crops in others.

Fluxo de biomassa em capim-massai durante o estabelecimento e rebrotação com e sem adubação nitrogenada

A producao de biomassa em uma pastagem pode ser incrementada com o uso de fertilizantes, principalmente os nitrogenados. Diante disso, objetivou-se, com este trabalho, avaliar o fluxo de biomassa do capim-massai, durante o estabelecimento e a rebrotacao, em casa de vegetacao, sob cinco doses de nitrogenio (0; 150; 300; 450 e 600 mg de N dm-3 de solo), em delineamento inteiramente casualizado, com medidas repetidas no tempo, e cinco repeticoes. A taxa de alongamento foliar foi incrementada pelas doses de nitrogenio (N) e o crescimento de estabelecimento apresentou maior valor, em relacao ao das rebrotacoes. A taxa de alongamento das hastes nao foi influenciada pelas doses de N. O crescimento de estabelecimento apresentou maior valor para esta variavel, em relacao ao das rebrotacoes. A taxa de senescencia foliar anterior nao sofreu influencia das doses de N, porem, foi alterada entre os ciclos de crescimento. O numero de folhas vivas por perfilho foi superior, para as maiores doses e no estabelecimento, o inverso ocorrendo para o filocrono. A dose aplicada de 600 mg dm-3 de N proporcionou um incremento de 448%, na taxa de producao de forragem, e de 455%, na taxa de acumulo de forragem, em relacao aquelas do manejo sem N. A adubacao nitrogenada proporciona respostas positivas nas variaveis do fluxo de biomassa do capim-massai.

Efluente de esgoto doméstico tratado e reutilizado como fonte hídrica alternativa para a produção de cana-de-açúcar

Com base no consumo hidrico excessivo na producao agricola e da expansao do cultivo da cana-de-acucar impulsionada pela crescente demanda de etanol, tem-se questionado em relacao a um uso mais racional da agua de irrigacao e ao reuso de agua na producao agricola. Desta forma objetivou-se, com o presente trabalho, avaliar os efeitos do reuso de efluente de esgoto domestico tratado na irrigacao da cana-de-acucar. O estudo foi conduzido no Centro de Pesquisa sobre Tratamento e Reuso de Aguas Residuarias, em Aquiraz, CE. O delineamento experimental adotado foi o de blocos ao acaso, no esquema de parcelas subdivididas, com quatro repeticoes. Nas parcelas avaliaram-se os efeitos de dois tipos de agua (agua potavel e esgoto domestico tratado); e nas subparcelas se alocaram cinco lâminas de irrigacao baseadas em percentuais da evaporacao medida em um tanque do tipo classe A (ECA). Concluiu-se que a agua residuaria proporcionou o maior potencial produtivo de colmos (272,1 Mg ha-1) e a maior densidade de plantas (126.000 plantas ha-1). O aumento das lâminas de irrigacao proporcionou incrementos no potencial produtivo e na densidade de plantas, independente do tipo de agua.

Morfologia e fitomassa do girassol cultivado com déficits hidricos em diferentes estádios de desenvolvimento

The objective of the present study was to evaluate the morphology, biomass production and biomass partition of sunflower (Multissol cultivar) when subjected to water deficit at Pentecoste, CE - Brazil. An experimental design in randomized blocks was used as split plots in time (8 x 3) with four replications, with the treatments defined by the development stage for application of water deficit vegetative, flowering and formation of production stages corresponding to the occurrence of water deficit at stages 1, 2 or 3 and three evaluation periods at 52, 68 and 110 days after sowing. The plant height, number of leaves and stem diameter were negatively influenced by the isolated effects of the water deficits and evaluation periods. The water deficits and evaluation periods interacted and affected the leaf area, dry mass of leaves, petiole, stem, head and total. The best response in terms of growth and biomass production occurred in the treatment presenting no water deficit throughout the cycle. The irrigation deficits did not change the biomass partition. The irrigation level equivalent to 50% of the ETo compromised morphology and biomass production, when applied at any development stage.

ASPECTOS PRODUTIVOS DA MELANCIEIRA SOB IRRIGAÇÃO COM DÉFICIT E DIFERENTES COBERTURAS UTILIZANDO O MODELO ISAREG

The objective of this work was to assess the pulp resistance, soluble solids and yield of watermelon fruits grown under different irrigation managements (determined by the ISAREG model) and mulches, and their interactions. After a survey carried out on local producers, two experiments were conducted, using a completely randomized block design in split-plot arrangement with four replications, in the Teaching, Research and Extension Unit (UEPE) of the Federal Institute of Ceara (IFCE), Jaguaribe-Apodi Irrigation District (DIJA), State of Ceara, Brazil. The treatments consisted of four irrigation managements in the plots, M1 (100% of the available-water capacity (AWC) of the soil), M2 (80%), M3 (60%) and M4 (average water depth used by local producers) and four mulch types in the sub-plots, without mulching (C0) with rice husk (C1), white plastic (C2) and black plastic (C3) as mulches. The results were subjected to analysis of variance, and significant results were subjected to regression (irrigation managements), average test (mulches) and trend graphs (interaction between the factors). The irrigation management practiced during the watermelon crop cycle by the local producers of the Irrigation District of Jaguaribe-Apodi (DIJA) in the State of Ceara, Brazil, is not appropriated, since they usually apply more water than the highest water depth determined by the ISAREG model (100% of the AWC). The plants grown under irrigation water depth of 365.20 mm (M1) and soils with mulches of rice husk or white plastic had the highest yields and fruits with better quality of soluble solids and pulp resistance.