Historical Information

Boron (B) is one of the eight essential micronutrients, also called trace elements, required for the normal growth of most plants. It is the only nonmetal among the plant micronutrients. Boron was first recognized as an essential element for plants early in the twentieth century. The essentiality of boron as it affected the growth of maize or corn (Zea mays L.) plants was first mentioned by Maze (1) in France. However, it was the work of Warington (2) in England that secured strong evidence of the essentiality of boron for the broad bean (Vicia faba L.), and later Brenchley and Warington (3) extended the study of boron to include several other plant species. The essentiality of boron to higher plants was decisively accepted after the experimental work of Sommer and Lipman (4), Sommer (5), and other investigators who followed them.

Since its discovery as an essential trace element, the importance of boron as an agricultural chemical has grown very rapidly. Its requirement differs markedly within the plant kingdom. It is essential for the normal growth of monocots, dicots, conifers, and ferns, but not for fungi and most algae. Some members of Gramineae, for example, wheat (Triticum aestivum L.) and oats (Avena sativa L.) have a much lower requirement for boron than do dicots and other monocots, for example, corn.

Of the known micronutrient deficiencies, boron deficiency in crops is most widespread. In the last 80 years, hundreds of reports have dealt with the essentiality of boron for a variety of agricultural crops in countries from every continent of the world.