Effect of zinc fertilisation on yield and selected qualitative parameters of broccoli

Abstract

Three treatments were used in two-year (2014–2015) field experiments with broccoli cv. Bejo 2914 F1: (1) untreated control; (2) Zn<sub>0.75</sub> – Zinkuran SC as foliar fertiliser at the rate of 0.75 L/ha (375 g Zn/ha); (3) Zn<sub>1.50</sub> – Zinkuran SC as foliar fertiliser at the rate of 1.50 L/ha (750 g Zn/ha). The statistically significant differences of individual broccoli parameters were found after zinc applications. In both experimental years the yield of broccoli with additional zinc fertilisation was significantly higher by about 8.2–14.4% (Zn<sub>0.75</sub>) and 12.5–17.5% (Zn<sub>1.50</sub>), respectively, than in the control. Foliar zinc application significantly increased the sulforaphane content in broccoli florets by about 19.8–32.9% (Zn<sub>0.75</sub>) and 37.2–49.3% (Zn<sub>1.50</sub>), respectively, compared to the control. By contrast, the content of total polyphenolics (of about 9.0–12.5% (Zn<sub>0.75</sub>) and 33.9–35.2% (Zn<sub>1.50</sub>)) and antioxidant activity (Zn<sub>0.75</sub> (3.7–4.2%) and Zn<sub>1.50</sub> (5.3–7.0)) decreased as a result of zinc fertilisation. The investigations pointed to zinc as a very important micronutrient with strong influence on the yield and chosen qualitative, health promoting parameters of broccoli.

Effect of Irrigation with Acidified Water and Phosphorous, Iron and Zinc on Nutrients Concentration, Growth and Yield of Cabbage

“…As for the effect of zinc fertilization to the soil on the chlorophyll content in the leaves, the results of the same table showed a significant effect as the S 2 fertilization treatment excelled and gave a chlorophyll content of 65.88 SPAD, an increase of 13.31 % compared to treatment S 0 which gave a chlorophyll content of 58.14 SPAD. The reason for this may be attributed to the role that zinc plays in the synthesis of important compounds and enzymes for plant growth, as well as its direct influence on the formation of amino acids and carbohydrates, which increases the content of chlorophyll in the outer leaves , the results agree with [43]. The results of Table ( 5) also showed a significant effect as a result of adding sulfuric acid H 2 SO 4 with irrigation water to the soil on the chlorophyll content in the leaves, as treatment A 1 excelled and gave a chlorophyll content of 70.78 SPAD with an increase of 23.43 % compared to treatment A 0 which gave a chlorophyll content of 57.34 SPAD.…”

“…The effect of zinc fertilization to the soil on the concentration of zinc in the leaves, the results of the same table showed a significant effect, as the treatment of zinc fertilization S 2 excelled and gave a zinc concentration of 57.89 mg Zn kg -1 with an increase rate of 21.13 % compared to the treatment S 0 which gave a concentration of Zinc amounted to 47.79 mg Zn kg -1 . The reason attributed to the addition of zinc sulfate fertilizer and because the fertilizer contains zinc as well as root secretions that work to reduce soil pH and thus increase the readiness of zinc in the soil solution and thus its absorption by the plant as well on the positive role of zinc in increasing the total radical, which contributes to increasing the absorbed amount of nutrients, including zinc [37], the results agree with [27,43]. The results of table (4) also showed a significant effect on this characteristic as a result of adding commercial sulfuric acid H 2 SO 4 with irrigation water to the soil in the concentration of zinc in the leaves.…”

Influence of foliar spray and post-harvest treatments on head yield, shelf-life, and physicochemical qualities of broccoli

“…Glucosinolates are abundant phenolic compounds in broccoli. Foliar zinc application significantly increased the sulforaphane content in broccoli heads ( 81 ). Sulfur and boron application increased glucosinolate concentration in rapeseeds ( 82 ).…”

Limits to the Biofortification of Leafy Brassicas with Zinc

“…It is, therefore, unwise to extrapolate from the critical substrate fertiliser Zn concentrations obtained in the experiments reported here (Table 1) directly to farmers' fields. It is also noteworthy that in soils where the phytoavailability of Zn applied as fertiliser decreases rapidly, the Zn biofortification of crops is generally achieved by foliar application of Zn fertilisers [1,5,9,11,13,15,20,37].…”

“…This strategy is termed biofortification and can be achieved through the use of Zn fertilisers on plant genotypes that have greater ability to acquire and accumulate Zn in their edible tissues [1,[4][5][6][7][8][9]. Zinc might be applied to the soil as inorganic or organic fertilisers or to foliage as soluble salts [1,7,[9][10][11]. Inorganic fertilisers are often preferred because of their consistent composition; foliar applications are most effective where the phytoavailability of Zn decreases rapidly when applied to the soil [1,5].…”