Influence of foliar fertilization with boron and zinc for maize grain crop in the hilly area of south-western Romania

Marius Nicolae Cioboată¹, Ramona Aida Păunescu¹, Denisa Florența Florea^1,2, 
Cătălin Aurelian Roșculete¹, Elena Roșculete ^1,2

¹ Faculty of Agronomy Craiova
²ARDS Caracal

Keywords: foliar fertilization, maize, foliar analysis, yield.

 Abstract: For 2 years (2020 and 2021) in the hilly area of south-western Romania a single-factor maize experiment (hybrid Kapitolis FAO 410 from KWS) was established with 4 foliar fertilization variants: V1 = untreated control ; V2 = Treatment 1 at BBCH 14-18 (maize with 4-6 leaves) using Lebosol products 1l/ha Zinc700 + 1,5l/ha Bor ; V3 = Treatment 2 BBCH 24-28 (maize with 8-10 leaves) using the same products ; V4 = Treatment 1 + Treatment 2.
Before the first treatment (T1) leaf and soil samples were collected and after the second treatment (T2) leaf samples from all 4 variants were collected for analysis. The foliar analysis before the first application showed normal values for nitrogen, phosphorus, calcium, magnesium, sulfur, iron, manganese, boron, iron, and molybdenum; low value for potassium; slightly low value for zinc and high value for calcium. After the application of the second treatment, zinc content values were much more improved within the leaves, boron remained constant but molybdenum content decreased a lot. Although at the borderline, the nitrogen content of leaf at T1 and T2 remained at normal value, after application of T1 + T2 it decreased from 4.6% (before application) to 2.96%. 
The lowest crop yield was obtained with the untreated control - 5210 kg/ha and the highest yield with the T2 variant - 6050 kg/ha. ANOVA yield analysis showed that the yield increase of 840 kg/ha at T2 is very significant compared to the untreated control and the one at T1 + T2 of 370 kg/ha is distinctly significant compared to the same control. Although the maize yield was high compared to the control after application of T1, it was not statistically assured. Of the yield and quality elements studied, the most stable were: test weight (values ranging from 69.9-71.8 kg/hl), protein content (values ranging from 5.79-6.55%) and fat content (values ranging from 3.13-3.26%). Large ranges of values were observed for the thousand kernels weight (values ranging from 300.3-352.4 g) and starch content (values ranging from 67.76-69.54%).
While boron is essential for pollination and thus for yield development, zinc plays an important role in optimal plant development.