Reginaldo Gomes Nobre

Emergência, crescimento e produção da mamoneira sob estresse salino e adubação nitrogenada

The use of saline water in agriculture is becoming a reality in many regions of the world, given the increased demand for fresh water, both for irrigated agriculture, as well as for urban and industrial supply. In this context, the aim of this research was to evaluate the effect of different salinity levels in irrigation water, associated with amounts of nitrogen fertilizer, on the emergence, growth and yield of the castor bean, cv. BRS Energia, in an experiment where plants were maintained in lysimeters under field conditions, at the CCTA / UFCG. A randomised block design in a 5 x 5 factorial with three replications was used to study the effects of five levels of electrical conductivity of the irrigation water (0.4, 1.4, 2.4, 3.4 and 4.4 dS m-1) associated with five levels of nitrogen fertilizer (50, 75, 100, 125 and 150% of the dose recommended for testing in pots). The salinity of the irrigation water from 0.4 dS m-1 affects negatively and in a linear manner the percentage of emergence (PE), the emergence speed index (IVE), plant height (AP), the stem diameter (DC), the shoot dry-weight (FSPA) and root dry-weight (FSRaiz) and the seed mass of the primary raceme (MSemRP), whereas increasing levels of nitrogen caused an increase in DC, FSPA and FSRaiz. The application of increasing doses of N reduced the effect of salinity on the DC and FSRaiz of the castor bean cv. BRS Energia.

Produção de girassol sob estresse salino e adubação nitrogenada

SUMMARY : SUNFLOWER PRODUCTION UNDER SALINE STRESS ANDNITROGEN FERTILIZATION The limited availability of low-salinity water in Brazilian semiarid region causesproducers to use water of moderate to high salinity for irrigation. In view of the increasingimportance of sunflower ( Helianthus annuus L.) in this region as a potential source of renewableenergy, this study was conducted to evaluate sunflower crops irrigated with different watersalinity levels (ECw) and fertilized with nitrogen. The experiment was conducted in a greenhouseof the Federal University of Campina Grande (UFCG), from July to October 2009, in arandomized block design, to test five ECw levels (0.5 - control, 1.6, 2.7, 3.8, and 4.9 dS m -1 )and four N rates (50, 75, 100 and 125 % of the rate recommended for pot experiments) in a5 x 4 factorial scheme, with three replications. The salinity of irrigation water and nitrogenfertilization affected the sunflower plants in independent ways. Water salinity affected the leafarea, biomass of aerial parts and roots, weight and total production of achenes and harvestindex linearly and negatively. Higher N rates on the other hand reduce the crop cycle andperiod from achene formation to physiologic maturity, and increased its mass.Index terms:

Doses de boro e água residuária na produção do girassol

The availability of water of quality has become worldwide, a major constraint to expanding agricultural frontiers. Within this context, this study aimed to evaluate the effects of boron doses and irrigation with two types of water, wastewater and municipal supply water, on yield components of sunflower (Helianthus annuus L.) cv. EMBRAPA 122/V-2000. The study was conducted in a greenhouse at the Federal University of Campina Grande, in a randomized block design, analyzed in a 5 x 2 factorial with five B of boron (0; 1.0; 2.0; 3.0 and 4.0 mg L-1) combined with two types of irrigation water (R - wastewater and AB - municipal supply water) with three replications. Statistical analysis consisted of analysis of variance (F test) and means were compared by Tukey test to compare qualitative factors at 0.05 probability. It was found that the boron levels and types of water did not affect any varieble related to production of seeds, however, irrigation with wastewater variables positively influenced the fresh and dry leaves, stem and shoot all related to forage production.

Índices fisiológicos e de crescimento de um porta-enxerto de aceroleira sob estresse salino

Na literatura ha registros de variacoes na fisiologia e no desenvolvimento de genotipos diversos em condicoes de estresse salino. Nao se encontrando informacoes nesse sentido, sobre aceroleira, conduziu-se este trabalho com o objetivo de se avaliar os efeitos da salinidade sobre o clone BV1, atraves de variaveis fisiologicas e de crescimento, na fase de formacao de porta-enxerto. Os estudos foram realizados no Campo Experimental de Pacajus (EMBRAPA), na cidade de Pacajus, CE, testando-se seis niveis de salinidade da agua de irrigacao (condutividade eletrica, variando de 0,5 a 5,5 dS m-1), preparada mantendo-se a proporcao 7:2:1 entre Na:Ca:Mg, respectivamente. O sistema radicular da aceroleira e mais sensivel a salinidade que a parte aerea, assim como a fitomassa seca total quando comparada com a area foliar. A eficiencia da aceroleira em produzir materia nova por unidade de materia preexistente, aumenta com a elevacao do nivel de salinidade da agua de irrigacao. A velocidade de crescimento e a fotossintese liquida da aceroleira decrescem com o aumento do estresse salino.

Production in the castor bean cultivated with saline water and dosages of nitrogen

The aim of this research was to evaluate production of the castor bean cv. BRS Energia, when subjected to irrigation with water at different levels of salinity and to fertilization with different levels of nitrogen, in an experiment carried out using lysimeters under field conditions at the experimental area of the Federal University of Campina Grande (UFCG), in Pombal, in the state of Paraiba, Brazil. A design of randomised blocks was used in a 5 x 4 factorial, with three replications, to test the combination of five levels of electrical conductivity of the irrigation water - CEa (0.3, 1.2, 2.1, 3.0 and 3.9 dS m -1 ) and four levels of nitrogen (70, 100, 130 and 160 mg N kg -1 soil). An increase in the salinity of the irrigation water caused a reduction in the number of fruits and seeds, and in the weight of seeds on the primary and secondary raceme. Irrigation with water of up to 3.9 dS m -1 prolonged the issue of primary and secondary racemes in the castor bean, and when subjected to irrigation with a CEa of 3.3 dS m -1 , the oil content of the seeds on the primary raceme was over 48%. The application of increasing levels of nitrogen increased the number of fruits on the primary raceme and the time needed for emission of the secondary raceme. The interaction between the level of salinity of the irrigation water and the level of nitrogen significantly affected the effective length of the primary and secondary raceme, and the oil content in the seeds of subsequent yields.

Physiology, growth and yield of castor bean under salt stress and nitrogen doses in phenophases

El alto crecimiento de la poblacion durante las ultimas decadas y la disminucion de los recursos hidricos, tanto en cantidad como en calidad, han hecho el uso necesario de agua salina en las actividades agricolas. Esta investigacion se realizo para evaluar la influencia del riego con agua salina en las diferentes fases fenologicas en ricino cv. Energia BRS. La investigacion se realizo bajo las condiciones de campo en Pombal-PB, Brasil, desde septiembre de 2011 a enero de 2012. El diseno experimental fue de bloques completos al azar, dispuestos en un diseno factorial 5x2x2 y fue adoptada con tres repeticiones. Se consideraron cinco niveles de conductividad electrica del agua de riego (ECw = 0,3; 1,2 ; 2,1; 3,0 y 3,9 dS m-1); dos estrategias de gestion de la salinidad del agua (riego con agua de baja salinidad durante la etapa vegetativa y la aplicacion de diferentes niveles de salinidad en la fase reproductiva y riego con diferentes niveles de ECw en todo el ciclo de cultivo) y dos dosis de nitrogeno (100 y 160 mg de N kg-1 suelo). Se evaluo materia seca de hojas (DML) y el tallo (DMS); numero de frutos (NFruPC) y numero de semillas (NSeePC) del racimo principal. El riego con ECw superior a 0,3 dS m-1 afecto negativamente a DML y DMS. La mayor acumulacion de materia seca se observo en las plantas que no fueron irrigados con aguas salinas en la fase inicial de desarrollo. El suministro de nitrogeno en dosis de 160 mg N kg -1 suelo aumento el DMS. No se observo efecto interactivo significativo entre los factores y las variables estudiadas.

EMERGÊNCIA, CRESCIMENTO E PRODUÇÃO DE GERGELIM SOB ESTRESSE SALINO E PROPORÇÕES DE NITRATO E AMÔNIO

In arid and semi-arid regions, the quality of irrigation water varies in geographic terms and during the year, and the occurrence of water with high concentrations of salts is common. In this context, this study aimed to evaluate the emergence, growth and production of sesame, cultivar CNPA G3, irrigated with saline water and fertilized with N of different carrier proportions by the ratio of nitrate and ammonium (NO3 -N and NH4 -N) in an experiment conducted in lysimeters arranged in a greenhouse in the municipality of Campina Grande-PB, Brazil. The treatments were distributed into randomized blocks using a 5 × 5 factorial scheme relative to levels of irrigation water salinity (ECw; 0.6, 1.2, 1.8, 2.4 and 3.0 dS m) and five proportions of NO3 -N/NH4 -N (200/0; 150/50; 100/100; 50/150 and 0/200 mg of N kg), with three replicates. The increase in ECw compromised the emergence, growth and production of sesame, cultivar CNPA G3, and the production components were the most sensitive variables. The highest growth in diameter was obtained with the proportion of 200/0 mg kg -1 of NO3 -N/NH4 -N. An ECw level of 3.0 dS m and fertilization with 0/200 mg kg of NO3 -N/NH4 -N promoted deleterious effects on the total mass of sesame fruits and mass of seeds. The interaction between water salinity levels and NO3 /NH4 + proportions significantly affected the number of leaves (at 50 and 70 days after sowing), the total mass of fruits and the mass of seeds.