Adaan Sudário Dias

Physiological Indices and Growth of Castor Bean Irrigated With Waters of Different Cationic Nature

It was proposed, in the present study, to evaluate the gas exchange and the growth of the castor bean cv. BRS Energia due to the isolated or mixed cationic nature of irrigation water. The study was conducted in drainage lysimeters under greenhouse conditions, using an Eutrophic Greyish Argissolo with a sandy-loam texture in the municipality of Campina Grande, Brazil. A randomized block design was used with six cationic composition of irrigation water (S1-control, S2-Na+, S3-Ca2+, S4-Na++Ca2+, S5-K+ and S6-Na++Ca2++Mg2+ with four replicates, each composed of five plants. The plants under the control treatment were submitted to irrigation with low salinity water (ECw = 0.6 dS m-1) and the remaining treatments were irrigated with ECw of 4.5 dS m-1 prepared with salts of different cations in chloride form. The gas exchanges and the growth of the castor bean cv. BRS Energy were determined at 100 days after sowing. The gas exchanges and the growth of the castor cv. BRS Energy were more sensitive to the variation in the electrical conductivity of the water compared to the cationic nature of the water, being the least deleterious effect observed in the plants irrigated with potassic water. The plants irrigated with water of potassium composition obtained the highest values for stomatal conductance, transpiration and rate of assimilation of CO2; at 100 days after sowing; the castor bean cv. BRS Energia showed sensitivity to the presence of sodium and calcium salts in irrigation water.

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.

IRRIGAÇÃO COM ÁGUAS SALINAS E ADUBAÇÃO NITROGENADA NO CULTIVO DO ALGODOEIRO DE FIBRA COLORIDA

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 and fertilized with N doses (ND) of 65, 100, 135, 170 and 205 mg N kg soil, in a completely randomized block design, with three replicates. Irrigation using water with an ECw above 5.1 dS m, 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 and ND of 65 mg N kg of soil.