Abiotic Disorders in Plants and Soil Management

Abiotic Disorders in Plants

• Abiotic disorders are plant problems caused by non-infectious factors
• These factors can include unfavorable soil properties, fertility imbalances, moisture extremes, temperature extremes, chemical toxicity, physical injuries, and other issues
• Abiotic disorders can weaken plants, reduce health, and even kill them
• Many abiotic disorders can make plants more vulnerable to infectious diseases

Soil Structure

• Soil structure affects the soil's ability to hold water, nutrients, and oxygen, making them available for plants
• Compaction is a common soil structure issue, reducing pore space for root growth

Soil pH

• Soil pH measures the H+ ion activity in the soil solution
• High H+ activity creates an acidic soil condition
• Low H+ activity creates an alkaline soil condition
• A slightly acidic pH range of 6-7 is generally optimal for most plant growth

Nutrient Toxicities

• Excessive levels of macronutrients (fertilizers or manures) can harm plants
• Micronutrient toxicities are also common
• Symptoms might include leaf chlorosis or necrosis on leaf margins or tips, leaf spotting, flecking, and other symptoms

Nutrient Deficiencies

• Nutrient deficiencies often result from a lack of plant nutrients in the soil
• Nitrogen deficiency causes pale yellowing (chlorosis) in non-leguminous plants
• Phosphorus deficiency can cause weaker stems, lodging in grain crops, and unusual leaf colors
• Iron deficiency leads to interveinal chlorosis on leaves, often with a striped appearance
• Calcium deficiency is associated with blossom end rot on fruits, plant stunting, localized tissue necrosis, and leaf marginal chlorosis.

Moisture Extremes

• Low water status can cause short-term or chronic conditions, leading to wilted leaves or shoots
• Excessive soil moisture reduces oxygen to roots, leading to wilt, similar to drought
• Excess soil moisture can be acute or chronic

Temperature Extremes

• High temperatures coupled with low soil moisture can scorch leaf margins, premature leaf drop, and even kill the plant
• Damage from low temperatures comes from ice crystal formation in cells, harming membranes and organelles

Chemical Injuries/Toxicities

• Herbicides can cause root issues, such as stunting or swelling, that might be mistaken for nematode damage
• Some herbicides cause necrotic/chlorotic spots, a problem that can be confused with a foliar disease
• Herbicide damage can sometimes show up as colors, distortion, or vein banding, similar to a viral disease

Air Pollution and Damaging Gases

• Ozone and sulfur dioxide can damage plants, possibly causing flecking, bronzing, chlorosis, and necrosis (issues that may be confused with other disorders),

Storm Damage

• High winds, heavy snow, or ice loads can lead to significant limb breakage, tree damage due to root and butt rot or wood decay, and even tree death

Explore the impact of abiotic disorders on plant health, including how soil structure, pH, and nutrient levels contribute to these issues. Understand the factors that lead to plant vulnerabilities and how to address them for better growth outcomes.