Cultivation of CNPA G3 sesame irrigated with saline water and fertilized with nitrate-N and ammonium-N

Cultivo do gergelim ‘CNPA G3’ irrigado com águas salinas e adubação com N-nitrato e N-amônio

ABSTRACT

The study aimed to evaluate the effects of irrigation with saline water and fertilization with nitrate (NO₃^--N) and ammonium (NH₄⁺-N) ratios on growth, flowering, water consumption and water use efficiency of the sesame cv. CNPA G3. The treatments were distributed in randomized blocks in a 5 x 5 factorial with three replicates, referring to five levels of electrical conductivity of the irrigation water - ECw (0.6, 1.2, 1.8, 2.4 and 3.0 dS m^-1) and nitrate (NO₃^--N) and ammonium (NH₄⁺-N) (200/0, 150/50, 100/100, 50/150, 0/200 mg kg^-1) ratios. Irrigation with saline water above 0.6 dS m^-1 inhibited the growth, delayed flowering and promoted early maturation of capsules of sesame, cv. CNPA G3. The proportion of 0/200 mg kg^-1 of NO₃^--N/NH₄⁺-N promoted the greatest increase relative to stem diameter and height of sesame plants. Water consumption decreases with increasing ECw and was significantly lower in plants fertilized with the proportion of 0/200 of NO₃^--N/NH₄⁺-N. The interaction between ECw levels and ammonium/nitrate proportions significantly affect water use efficiency, and the highest value was obtained with ECw of 0.6 dS m^-1 and fertilization with 150:50 mg kg^-1 of NO₃^--N and NH₄⁺-N.

Key words:
Sesamum indicum L.; salt stress; NO₃^--N and NH₄⁺-N ratios