Boron: The Basics

The basics of boron deficiency

Marcel Barbier Development Specialist

What happens to your soil and crops without adequate boron? Hear why boron matters and how deficiency affects various plants. Watch video

What Is Boron?

Boron is a micronutrient that is essential to plant growth. Adequate boron is necessary for proper absorption of macronutrients.

Although Boron is a naturally occurring element, boron deficiencies are common. Overfarming, extremely hot or cold conditions, drought, an overabundance of rainfall or irrigation, sandy soils—all these factors can reduce the amount of boron available to crops.

Healthy crop growth depends on the right nutrients in soil. Soil needs macronutrients—elements such as nitrogen, phosphorus, potassium, calcium, and magnesium—but they are only one piece of the puzzle. Just as important are micronutrients, such as iron, copper, zinc—and boron.

How Plants Use Boron

Borons role in flower production
Boron plays an important role in regulating plants’ hormone levels and promoting proper growth. Boron increases flower production and retention, pollen tube elongation and germination, and seed and fruit development. Deficiencies that might not seem to affect vegetative growth might show up in poor fruit, nut, and seed production, bud and flower drop, and poor quality crops. For example, boron deficiency can cause incomplete pollination of corn or prevent maximum pod set in soybeans.
Boron is important for plant energy
Sugar movement is an important part of photosynthesis, the process by which plants transform sunlight energy into plant energy. Boron increases the transport rate of sugars from the leaves in which they are created to actively growing regions, such as roots and developing fruits. Boron is essential for normal development of root nodules in legumes such as alfalfa, soybeans, and peanuts.
Boron and Cell Wall Structure
Boron and calcium are involved in cell wall structure, and boron facilitates the movement of calcium into and within plants. For example a peanut ailment called hollow-heart can occur when a boron shortage limits calcium movement, normal cell wall development, and cell division. 
The role of boron in nutrient transportation
 Root tips, new leaves and buds, and other active parts of the plant rely heavily on adequate boron. Boron also ensures the healthy transport of water, nutrients, and organic compounds to these growing portions. A shortage of boron will show up first in these areas. For example, rosetting or stunting of plants is a common symptom of boron deficiency in alfalfa, clovers, and legumes.

How do plants use boron?

Damien Slowik Technical Development Specialist

Learn the role that boron plays in plant health and which factors affect boron availability. Watch video

Different regions have unique challenges—and opportunities—involving boron. To learn more, choose your region on the map below.
Throughout Africa, soils can benefit from application of refined boron. Of course, this vast region comprises a multitude of climates, soil types, and crops. Yet frequent droughts and pervasive sandy soils mean that most growers here can see higher yields and greater ROI through the use of refined boron. Learn More
Australia / New Zealand
Australia / New Zealand
Australia and New Zealand are well known for their wide expanses and thriving agricultural industry. With numerous areas of volcanic or sandy soil and fairly high rainfall, refined boron can be beneficial when applied correctly. Learn More
Like many areas of the world, much of China features boron-deficient soils. The issue is of particular concern in Guangxi, Guangzhou, Yunnan, Xinjiang, Liaoning, Heilongjiang, Jilin, Henan, Guizhou, and Shandong provinces. China’s growers and fertilizer producers also face challenges related to fertilizer use and identification of high-quality products. Fortunately, U.S. Borax can help. Learn More
European growers face boron-depleted soils, especially given the demands of widespread crops such as rapeseed. Refined boron can help, and offers a variety of application methods to meet growers’ needs. Learn More
India and Bangladesh
India and Bangladesh
Growers in this region have a high agricultural demand for boron, which is especially deficient throughout Bangladesh and eastern India. Monsoon patterns and depletion from the variety of high-yield crops in the area mean that refined boron supplementation is vital to help prevent fruit and flower drop and protect growers’ livelihoods. Both family growers and larger land holdings can benefit from the application of high-quality, highly available refined boron. Learn More
Latin America
Latin America
Latin America—comprising Mexico as well as countries throughout Central America, South America, and the Caribbean—is a vital contributor to the world’s food and agricultural resources. With a great deal of farmable land and a wide range of available crops, this region relies on boron for optimal yields. Learn More
North America
North America
Canada and the United States comprise vast swaths of renowned farmland. From the corn fields of Iowa to the apple orchards of Ontario, boron plays an important role in the health of North American agriculture. Learn More
Southeast Asia
Southeast Asia
Many growers in Southeast Asia can benefit from improved soil nutrition supported by boron supplementation. The region’s fluctuations between drought and heavy rains, as well as sandy soils in many areas, increase the leaching of boron and can harm valuable crops such as rice, tropical fruits, and oil palm. Learn More

Boron deficiency: It starts in the soil

Low concentrations of boron are found in soils that
  • Have a low concentration of organic matter
  • Are acidic and sandy
  • Are in areas with high humidity
What factors make boron more available to plants?
  • Finely textured subsoils with a higher clay content tend to show the highest levels of boron, even when overlaid with a sandy top surface.
  • Too much or too little pH, especially pH above 6.5 or below 5.0, tends to reduce boron availability.
  • Microorganisms are crucial to the release of boron from organic compounds. Warm, moist, well-tilled soils with adequate aeration improve microbial activity and likely have better boron availability.

Boron and Plant Health

Adequate boron is a crucial factor in high crop yields and quality. Existing research indicates that boron plays a significant role in
  • The strength of plant cell walls
  • Membrane function and cell division
  • Stimulation/inhibition of metabolic pathways
  • Development of flowers and fruit
  • Both new and reproductive growth

Susceptibility of crop species

Certain crops are more susceptible to boron deficiency than others. For example, apples and broccoli tend to fare worse than bananas or barley. In general, cereals and grasses are less sensitive to low boron than are legumes and certain vegetables. These differences might be related to cell-wall composition and likely involve boron mobility.

Boron: The Micronutrient That Maximizes Crop Yield

A boron deficiency prevents absorption of essential macronutrients.

Refined borate fertilizer allows plants to get maximum benefits from the nutrients farmers add.
Understanding the interplay of macro- and micronutrients is important when choosing products and agricultural practices. By understanding boron’s role in soil and plant health, you increase your ability to give soil the nutrition it needs to produce high yields of high-quality crops. Liebig’s Law of the Minimum says that yield is proportional to the amount of the most limiting nutrient. That means a boron deficiency can limit yield, even when sufficient macronutrients are applied to the soil. Proper application of supplemental boron can have a direct and significant impact on soil and crop nutrition. Learn More

Boosting crop health: U.S. Midwest

Success Story Corn & Soybeans

Growers in the U.S. Midwest are seeing higher yields and greater profits thanks to an understanding of the importance of micronutrients, including boron. Hear... Watch video

U.S. Borax, part of Rio Tinto, is a global leader in the supply and science of borates—naturally-occurring minerals containing boron and other elements. We are 1,000 people serving 500 customers with more than 1,700 delivery locations globally. We supply 30% of the world’s need for refined borates from our world-class mine in Boron, California, about 100 miles east of Los Angeles.  Learn more about Rio Tinto

Copyright © 2018 Rio Tinto. All Rights Reserved.