RIBEIRO, P. H. P.; http://lattes.cnpq.br/4033216443566560; RIBEIRO, Pedro Henrique Pinto.
Résumé:
Sunflower cultivation irrigated with saline water under nitrogen rates. The sunflower (Helianthus annuus L.) is one of the most potential oilseed specie for the
production of renewable fuel besides being an important alternative for the farmer in
rotation systems and crop sequence. Its wide adaptation to different climatic conditions
makes of the sunflower a highly promissory crop for the Brazilian Northeast. Soil
salinity is one of the main problems of irrigated agriculture and has reduced production
in growing areas worldwide. One way to mitigate the effects of salinity on plants is to
improve the nutritional quality of the soil. Due to the scarcity of information in this grad
in the semiarid region, a study was conducted, under greenhouse conditions, to evaluate
the growth and yield of Embrapa 122 / V-2000 sunflower variety under the influence of
different water salinities and nitrogen fertilization. The factors studied were 5 salt
salinity of irrigation water (0.5, 1.5, 2.5, 3.5 and 4.5 dS m-1) and five nitrogen doses (60,
80, 100, 120 and 140% of the recommended nitrogen for experiments in pots),
combined in a 5 x 5 split plot experimental design with three blocks, with one plant per
conducted. The plants were grown in 20 L pots, filled with a Entisol. The irrigations
were automatically daily leaving the soil at field capacity. Growth variables (plant
height, stem diameter, leaf area and phytomass), production variables (capitulum
diameter, productivity, number and percentage of viable achenes) velocity of
germination and water use by the sunflower were measured, and the results submitted to
analysis of variance and regression for those which were significant. Sunflower reduced
its growth and production at water salinity levels greater than 1.5 and 2.5 dS m-1,
respectively. Nitrogen levels influenced only the total phytomas of achenes and non
viable achenes and the percentage of viable achenes. Water consumption was affected
much by salinity as by nitrogen, observing that the N doses which mitigated the effect
of salt on the plant was equivalent to 100% of the recommended dose.