The nutrients necessary for optimum plant germination, growth, and seed fill are not the same. Over the course of a plant’s life, it needs different nutrients for different purposes.
Macronutrients such as nitrogen, phosphorus, and potassium are used by a plant throughout the growing season, with more need for certain ones in each growth stage.
Micronutrients are more specialized during the late stages of plant growth, especially at seed and fruit set. The micronutrients most commonly deficient are boron, copper, Iron, manganese, and molybdenum.
Boron Deficiency
Boron is essential for pollen tube growth and fruit development. This micronutrient supports membrane stability and cell integrity.
The health of your soil is a key contributor to boron deficiency. Boron deficiency is more likely in acidic soils. Both sandy and clay soils can be deficient but for different reasons. Sandy soils have low organic matter, which can lead to micronutrient deficiencies. Clay soil, on the other hand, may be high in iron or aluminum oxides which absorb boron and make the micronutrient unavailable for plant uptake.
Boron deficiency is visible first as slow or unhealthy growth. The leaf tips may be twisted or new leaves may appear curled or wrinkled. Plant stems may be hollow. There will also be reduced fruit set and hollow fruit.
Copper Deficiency
Copper kickstarts enzyme activity involved in a plant’s reproductive processes. Without copper, a plant sets little fruit and is unable to reproduce itself (provide good yield). Plant growth, male fertility, and seed production are all compromised. Copper deficiencies are particularly impactful on wheat.
Copper is also linked to protein accumulation in grains. Lower protein crop nutrient profiles result from copper deficiencies.
This deficiency shows up as the yellowing of younger leaves. Stunted plant growth and an examination of root structure will show abnormalities. If a deficiency is suspected a soil test is in order.
Iron Deficiency
Without sufficient iron there is poor chlorophyll synthesis. This shows up as interveinal chlorosis (yellowing between veins) in young leaves. Nitrogen fixation in soybeans and lignin formation in corn stalks are impacted by iron.
Iron deficiency significantly impacts both row and fruit crops. Stunted growth and diminished yield are the result of iron deficiency. In fruit crops a lack of optimum iron results in reduced yield, firmness, and a lower nutritional value.
Interveinal chlorosis in young leaves is an early indication of an iron deficiency.
Manganese Deficiency
Deficiency in manganese in early stages of plant growth show up at later stages as poor or malformed fruit and lower yields in row crops. Manganese aids in pollen germination so if it isn’t available at blossom it will show up at harvest.
Crops are morse susceptible to pathogens due to weakened structural resistance during the life of the plant with a deficiency of manganese. Reduced tolerance to drought and heat stress are additional effects.
Interveinal chlorosis, especially of young leaves, is a symptom of manganese deficiency. But chlorosis of young leaves is a symptom of many deficiencies. Be sure and get a soil test to be sure which micronutrient is deficient.
Molybdenum Deficiency
Molybdenum is crucial for nitrogen fixation in soybeans. Lower seed quality and decreased tasseling of corn are effects of less than optimal molybdenum in the soil.
In some soils, molybdenum is naturally low. In acid sandy soils molybdenum is held in forms that are unavailable for plant uptake. Soil pH affects molybdenum, and the form is takes in the soil.
Pale leaves with interveinal and marginal chlorosis are evidence of a deficiency of molybdenum. The first leaves to be affected with deficiency are older growth.
Besides individual deficiencies of micronutrients there are interactions and factors that may cause a deficiency. The four to keep in mind are:
- Imbalance soil pH: Whatever extreme the pH it will impact nutrient cycling. Plants prefer a pH between 6.5 and 7.1, except for acidic soil-loving plants such as blueberries.
- Poor soil fertility: Low SOM leads to soil with a lack of essential nutrients for strong plant growth and fruit set.
- Improper nutrient balance: Too many nutrients, including nitrogen, is detrimental to plant health.
- Abiotic factors: Climate extremes impact plant and microbial health. Unfavorable growing conditions impact nutrient absorption which leads to lower nutrient profiles in the crop.
Each micronutrient is dependent on all the of the nutrients, plant exudates, and microbial communities in the soil for optimal expression. Looking at your farm or ranch ecosystem is the first step to a balanced and productive soil – leading to healthy and productive plants. For more information on micronutrients and plant health, read this blog.
We are interested in learning how you’re assessing soil and plant health. Give us a call and our team will schedule a field visit to see what unique situation you’re dealing with. We know each farm or ranch is unique, and so are the solutions. Soil speaks, we listen.
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