AS WE MOVE through July and our yard and gardens are flourishing, let us dive into a “Nutrients 101 short course.”
For those who might not know, there is a principle in agriculture science called “Liebig’s Law of Minimum.” In essence, it states that growth on plants is not controlled by the total amount of nutrient available, but rather by those in scarcest amounts according to need of that plant.
The best way I had it explained to me is “a chain is as strong as its weakest link, so increasing the strength of the weakest link best strengthens the entire chain.”
This is why a soil test is not only advisable but critical to elevating your soil’s health and fertility. This is also why, in addition to the macronutrients (NKP, or nitrogen, phosphorus and potassium), we have two additional subjects of fertilizer: the secondary and micronutrients.
The secondary nutrients consist of calcium, magnesium and sulfur (Ca, Mg, S), and are basically given second-class status — not due to their importance, but rather the quantity available in the soil needed for robust plant development.
Secondary nutrients
• Calcium: Aids in root structure and creates strong leaves better able to resist wind, hail, bugs, diseases and stress. It improves overall plant structure and tends to be sufficient in most soils; however, our friend lime is an excellent choice of products to increase calcium in the soil.
• Magnesium: This is an important atom in chlorophyll, the molecule that performs photosynthesis. It is almost entirely found in the chlorophyll of plants, and its absence is defined by brownish, yellowish or reddish old leaves with green veins. Again, lime is a good source along with magnesium sulfate and/or chloride.
• Sulfur: This element must be present for amino acid production, the cornerstone of proteins found in all living organisms. Sulfur also gives onions, chives, mustard, garlic and leeks their pungent smell. It is abundant in organic material, so again, mulches, compost, manure, leaf mold, worm casings and peat moss are excellent sources, as is ammonium sulfate and magnesium sulfate (2 for 1).
The micros
• Molybdenum: Along with sulfur, this element is a co-factor in various enzymes in building life-sustaining amino acids. It is also beneficial in metabolizing nitrogen and lack of the element stuffs growth.
• Boron: Obligatory in the forming and strengthening of the cellular wall. Boron also affects cell division, flowering and fruiting, and facilitates food and sugar transportation within the plant. It is a highly soluble mineral. Dry soil conditions greatly enhance related deficiency problems, such as stunted growth and new growth “die-off.” Organic material and borates are common additives.
• Sodium: Improper stomatal functions, which is how the plant gives off waste gases and takes in beneficial atmosphere as well as photosynthesis, enzyme activity, water balance, leaf sizes and regeneration. It is pretty important stuff, and too much causes just as severe problems as lack thereof. Sources of sodium are found in most all other additives, and the soil test is critical for finding your total amount of sodium present.
• Zinc: Plays a key role in genetic transcription (reproducing), plus zinc is required in many enzymes. A lack of zinc causes “little leaf syndrome,” or severely stunted growth and leaf production. Getting zinc into the soil is as easy as adding zinc oxide, zinc sulfate or zinc chelate.
• Chlorine: Is necessary for osmosis, which is how moisture and especially nutrients are transferred from the soil to the root system. It also helps the ionic balance, which is to regulate the countering effects of pH and nutrient uptake (oversimplification). Most chloride is found sufficiently in soil.
So there you go, more than enough info on soil nutrients.
See how a soil test is crucial? Because, without analysis, how do you know what you have? And finally, the test reveals pH for micronutrients tends to be less available in soils with low pH (acidic) and micronutrients less available in high pH soils (alkaline). And if needed, lime added to the soil also increases air and water movement within the soil.
So concludes Nutrients 101!
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Andrew May is a freelance writer and ornamental horticulturist who dreams of having Clallam and Jefferson counties nationally recognized as “Flower Peninsula USA.” Send him questions c/o Peninsula Daily News, P.O. Box 1330, Port Angeles, WA 98362, or email news@peninsuladailynews.com (subject line: Andrew May).
