Reduced N Application Rate in Sunflower Production Through Supplying P and K Need and Dense-Planting: a Modeling and Optimization Approach by RSM

Abstract

Optimizing agricultural resources such as fertilizer level and plant density is important to reconcile economic and environmental goals in sustainable agriculture. Therefore, the aim of this study was to optimize the levels of nitrogen (N), phosphorus (P), potassium (K), and plant spacing (PS) in order to maximize yield traits and N use efficiency (NUE) of sunflower. The experiment was conducted through response surface methodology (RSM) in a Box-Behnken design with four factors of N (0, 80, and 160 kg ha −1 ), P (0, 15.4, and 30.8 kg ha −1 ), K (0, 20.75, and 41.5 kg ha −1 ), and PS (15, 25, and 35 cm). The seed yield was improved with increasing N and P levels and decreasing PS. The response of seed oil content to each of the N and P factors depended on the rate of the other factors. PS had a quadratic effect on oil content. The NUE decreased by increasing N rate and PS, while P application positively affected NUE. The K fertilization had no effect on seed oil production and NUE. The optimized levels of factors to obtain desirable values of responses were 62.3, 30.8, and 41.5 kg ha −1 of N, P, and K respectively and PS of 15 cm, resulting in 3797 kg ha −1 of seed yield and 24.8 kg kg −1 of NUE. Optimization indicated that through denseplanting and meeting the sunflower need for P and K, the application rate of N can be remarkably reduced along with obtaining an acceptable seed yield.

Two-way NxP fertilisation experiment on barley (Hordeum vulgare) reveals shift from additive to synergistic N-P interactions at critical phosphorus fertilisation level

“…Duncan et al (2018b) showed that NUE in wheat increased with addition of P, and also K, compared to just N alone and attributed this to increases in root mass and architecture. Similarly, Mehrparvar et al (2021) showed that when sunflower plant's P and K requirements were met, the required N fertilisation rate decreased whilst NUE increased. Our NUE data fit with these findings but there is little literature on the effect of N on PUE for comparison with our results.…”

RSM and ANN Modeling of Camelina (Camelina sativa L. Crantz) Seed Yield as Affected by Nitrogen, Sulfur, Cow Manure, and Row Spacing

“…showed that modifications to the common fertilization rates are needed so that the optimum levels of N, P, and K fertilizers were found to be 35, 40, and 30 kg ha −1 , respectively [12]. The RSM modeling of sunflower yield responses to N, P, K, and planting density indicated that with denseplanting and applying high rates of P and K, it is possible to reduce the application rate of N and obtain an acceptable yield [13]. An optimization study on the effects of plant density (5-10 plants m −2 ), N (0-200 kg ha −1 ), and micronutrients (M) (0-4 g L −1 ) on sage (Salvia officinalis L.) showed that by using a dense-planting method (10 plants m −2 ) and applying 71 kg ha −1 of N fertilizer, along with 4 g L −1 of M, it is achievable to produce biomass and essential oil at a satisfactory level, while enhancing N use efficiency [14].…”

Impact of Reducing Fertilizers and Pesticides on Sunflower Production in Romania versus EU Countries

“…All the aspects presented determine directly and indirectly the ideal germination of the field by sunflower [35]. The optimization of fertilizers and also the density of plants lead to the achievement of economic and environmental objectives in sustainable agriculture [36]. At present, in order to increase crop yields, effective management is needed [37].…”