Approximately 7750 soil samples were collected and analyzed in a study conducted between the Ministry of Agriculture, Soil Fertilizer and Water Resources Central Research Institute and BOREN in order to determine and map the boron status of Turkish Soils, covering 81 cities. In the light of these analyses, the boron distribution map of the Turkish soil was drawn. This map is given below. According to the results obtained, it has been determined that 46.2% of the country soil is deficient in boron, 31% have sufficient boron, 19.4% have excess boron, and 3.3% have toxic levels of boron.
Among the micronutrient deficiencies, after zinc deficiency, boron deficiency is shown as the micronutrient deficiency that most affects plant production in the world (Shorrocks, 1977, Plant and Soil, 193:121-148; Alloway, 2007, Zinc in Soils and Crop Nutrition, 2nd Edition, IZA Publications). Boron deficiency is more common in areas where soil acidity and precipitation are high. If acidic soils are also low in organic matter and rich in sand content, the risk for occurrence of boron deficiency in plants increases further. In such soils, the risk of boron being washed out of the soil profile is high. In addition, liming, which is frequently used in acidic soils, reduces the solubility of soluble boron in the soil and causes boron deficiency in plants. Acidic soils are known as the soils with the highest risk of boron deficiency in plants. The fact that approximately 1/3 of the soils under vegetative production in the world have low pH indicates that the risk of boron deficiency in plants is potentially very high.
Boron deficiency in plants also occurs in clay soils with high pH. In such soils, there is a strong adsorption of boron, which reduces the boron uptake of the roots.
A map showing the prevalence of boron deficiency in soils in the world has not been developed yet. Developing such a map with a further study may be useful, at least, to show the regions where boron deficiency may occur potentially. Dr B. Rerkasem from Chiang Mai University showed the countries where boron deficiency occurred in wheat plant and the results were published in a map as side (CMUPNlab FARM NOTE). In fact, in general, the boron requirement of wheat is low. However, during the generative growth period, wheat shows a high boron requirement as in other plants. The map given below shows the countries that are mostly seen in plants during the generative period and the results are published.