How do nutrients get into my vegetables?
In agronomy, we pay attention to the nutrient 4R’s: right source, right rate, right time, and right place.
By Carlos Bonini Pires, Kansas State University
Sustainable, Secure Food Blog
Mar 22, 2022
Excerpt:
The three processes responsible for nutrients from the soil to reach the plant are diffusion, mass transport, and root interception. I know it seems to be complex to understand, but I promise it is not.
Diffusion
When the concentration of nutrients is higher in the soil than in the plant root, then the nutrients in the soil will move from a region of higher concentration (soil) to a region of lower concentration (vegetable). Potassium and phosphorus are examples of nutrients that get into the vegetables by diffusion.
Mass transport
Nutrients move to the roots via water. As plants transpire water, it draws water and nutrients from the soil up through the root system. Mass transport accounts for nutrient acquisition of mobile nutrients, such as nitrogen and sulfur.
Root interception
Vegetable roots grow through the soil to meet nutrients. As the root grows through the soil it generally only comes in contact with about 1% of soil volume. Good soil structure is essential in the process of root interception. Soil compaction can significantly limit root growth and interception with nutrients throughout the soil. Some important macro and micronutrients such as calcium, magnesium, iron, manganese, and zinc are absorbed by root interception.
Of course, some nutrients are absorbed in more than one way. For example, iron and zinc can be absorbed by three different methods. As you can see, there are a lot of variables that may impact how vegetable acquire their nutrients.
Moving within the plant
Once the nutrients get inside the plant, they can move upward to the leaves and developing vegetables. How? Like a human body, plants also have a vascular system. Rather than a bloodstream, they have xylem and phloem. The Xylem distributes water and dissolves nutrients upward to the plant, from the roots to the leaves. The phloem carries nutrients downward, from the leaves to the roots (photosynthesis). In simple words, the root is the mouth and xylem and phloem are the veins of a “plant body.”
