Soil Water Availabilities in the Content and Accumulation of Nitrogen and Chlorophyll Index in the Safflower

Abstract

The safflower (Carthamus tinctorius L.) is adapted to grow in adverse conditions, is tolerant to salinity and water deficit, however, its productivity increases when grown in areas with greater availability of water and in fertilized conditions, showing that the knowledge of crop management can bring income gains for producers. It is known that extreme conditions of soil moisture damage the crop development. Given this context, the objective was to evaluate the influence of water availability on the nutritional characteristics of the safflower. The experiment was conducted in a greenhouse in a completely randomized design with five water availabilities (25%, 50%, 75%, 100% and 125% of the maximum water holding capacity of the soil) in four replications. Maintaining soil moisture was performed by gravimetric method with daily weighing of experimental units. The variables analyzed were SPAD reading (chlorophyll content), concentration and accumulation of nitrogen in the shoot and in the sections. The results were submitted to analysis of variance and regression test at 5% probability by Sisvar program. There was adjusting of variables to linear and quadratic regression models. Water availabilities between 65% and 75% have greater potential to promote better nutrition for safflower plants. Both deficit and excess of water in the soil are detrimental to the absorption of nitrogen and reduce the chlorophyll content. Safflower is less tolerant to excess than to deficit of water.