Effect of Magnesium and Boron Soil Fertilization and Their Interaction on Growth and Yield of Sunflower (Helianthus annuus L.) Grown in Gypsum Soil

• Ahmed, Ahmed Maath

  Author

A field experiment was conducted in gypsum soil at the College of Agriculture, Tikrit University, located at the geographical coordinates (34°41′03.9″N, 43°39′02.0″E), during the 2024 growing season. The aim was to determine the effect of soil fertilization with magnesium (magnesium oxide) at four levels (0, 7, 14, and 21 kg ha⁻¹) and boron (boric acid) at four levels (0, 5, 10, and 15 kg ha⁻¹), and the interaction between them, on some growth and yield characteristics of sunflower crops. The experiment was conducted using a randomized complete block design (RCBD) with a two-person operation and three replications, with a total of (48) experimental units. The results of the experiment showed a significant effect of both magnesium and boron fertilization, and their interaction, on most growth and yield characteristics of sunflower plants. The values ​​of the studied characteristics tended to increase gradually with increasing application levels. The interaction treatment of 21 kg Mg ha⁻¹ + 15 kg B ha⁻¹ achieved the highest values ​​for most characteristics, while the control treatment of 0 kg Mg ha⁻¹ + 0 kg B ha⁻¹ recorded the lowest values. The dry weight of the first cutting ranged between 26.1 and 49.9 g plant⁻¹, with average maximum and minimum values ​​of 49.9 and 26.1 g plant⁻¹, respectively. The dry weight of the second cutting ranged between 65.3 and 117.6 g plant⁻¹. The absolute growth rate ranged from 1.302 to 2.113 g plant⁻¹day⁻¹, while the grain yield ranged from 2.812 to 4.912 Mg ha⁻¹, and the biological yield ranged from 9.52 to 15.86 Mg ha⁻¹.

The results also showed a clear improvement in soil fertility after harvest as a result of integrated fertilization. The available magnesium concentration in the soil ranged from 8.318 to 20.911 mg kg⁻¹, while the available boron concentration ranged from 0.27 to 0.88 mg kg⁻¹. Overall, the highest average values ​​for the studied traits were observed with the treatment of 21 kg Mg ha⁻¹ + 15 kg B ha⁻¹, while the no-fertilization treatment recorded the lowest average values.

• pdf