Does nitrogen fertilization rate, timing, and splitting affect sunflower yield and grain quality?

Abstract

Nitrogen (N) deficiency could have a negative effect on sunflower (Helianthus annuus L.) yield and grain quality. Therefore, it is necessary to adjust the optimum rate, timing, and frequency of N fertilization to improve sunflower crop nutrition. Our objective was to evaluate the effect of N fertilization rate, timing, and splitting on grain yield, and grain and oil quality. Twelve field experiments were carried out between 2016 and 2020. Treatments consisted of at least three N rates ranging from 0 to 200 kg N ha−1 applied at V2. Moreover, the 80 kg N ha−1 rate was applied at V14 (80NV14) or split between V2 and V14 (80Nsplit). Treatments were evaluated in two sunflower genotypes, high oleic (HO) and conventional (CONV). A significant grain yield response to N fertilization was observed in six out of twelve experiments, generally at rates greater than 80 kg ha−1. The mean response to fertilization was 369 kg ha−1. Fertilization increased grain protein concentration (PG) (+1.5%) at experiments E1–E3 and E9–E12 and decreased oil concentration (OG) (−2%) at experiments E1, E4, E9, E11, and E12. The maximum N rate, increased oleic and stearic acid concentration (+3%–4%), depending on the genotype (AO and CONV). Neither fertilizer timing nor splitting affected grain yield or OG. Late N fertilization (V14) increased oleic acid (+2.4%), whereas it decreased linoleic acid (+2.2%). Based on our results, N fertilization can increase yield without negatively affecting commercial grain quality (OG and fatty acids concentration), regardless of fertilization timing and frequency.

Yield of sweet corn and sunflower as affected by different cultivation methods and fertilisation schemes

“…The harvested area of sunflower increased from 502 000 hectares in 2010 to 655 000 hectares in 2021 (Hungarian Central Statistical Office 2022). Availability of nutrients is a major factor affecting the achene yield (Aryafar et al 2023, Tovar Hernández et al 2023. Sunflower generally has high demands for essential nutrients (Nuccio et al 2018).…”