Glufosinate-Ammonium: A Broad-Spectrum Non-Selective Herbicide

Definition:
Glufosinate-ammonium is a non-selective, post-emergent herbicide widely used for controlling a broad spectrum of annual and perennial weeds in various crops and non-crop areas. It is a contact herbicide that inhibits plant growth by interfering with essential metabolic pathways.

Chemical Characteristics of Glufosinate-Ammonium:

• Chemical Name: (2S)-2-amino-4-(hydroxy(methyl)phosphinyl)butanoate ammonium salt

• Molecular Formula: C5H15N2O4P

• Molecular Weight: 181.15 g/mol (active ingredient basis)

• Appearance: Typically formulated as an aqueous solution or wettable powder.

• Solubility: Highly soluble in water.

• Stability: Stable under standard storage conditions.

Mode of Action:

Glufosinate-ammonium acts by inhibiting the enzyme glutamine synthetase (GS), essential for ammonia assimilation and nitrogen metabolism in plants. This inhibition leads to the accumulation of toxic levels of ammonia within plant cells, causing rapid leaf necrosis and plant death. It acts mainly through foliar contact and has limited translocation within the plant.

Uses and Applications:

1. Target Weeds:

   • Controls a broad range of grass and broadleaf weeds, including difficult-to-control species and glyphosate-resistant biotypes.

2. Crops:

   • Commonly used in glufosinate-tolerant genetically modified crops such as corn, soybean, cotton, canola, and other crops.

   • Also used in non-crop areas like industrial sites, orchards, and rights-of-way.

3. Application Timing:

   • Applied post-emergence on actively growing weeds for optimal efficacy.

Benefits of Glufosinate-Ammonium:

• Broad-Spectrum Activity: Effective on many grass and broadleaf weed species.

• Rapid Action: Visible effects appear within days, leading to quick plant desiccation.

• Resistance Management: Useful for controlling glyphosate-resistant weeds.

• Non-Residual: Breaks down quickly in soil, minimizing environmental persistence.

Limitations:

• Contact Herbicide: Requires thorough spray coverage for effective control.

• Non-Selective: Can harm crops if not used in tolerant varieties or applied carefully.

• Phytotoxicity Risk: Sensitive crops may suffer damage from drift or misapplication.

• Cost: Typically more expensive than some alternative herbicides.

Recommended Application:

• Dosage: Usually ranges between 0.3 to 1.5 kg active ingredient per hectare depending on weed species and growth stage.

• Method: Foliar spray with good coverage; use adjuvants as recommended to improve leaf penetration.

• Precautions:

  • Avoid application during periods of drought or crop stress.

  • Prevent spray drift to sensitive plants and non-target areas.

  • Follow local regulatory guidelines for use.

Storage and Handling:

• Storage: Store in original containers, tightly sealed, in a cool, dry place.

• Shelf Life: Generally stable for 2–3 years under recommended storage.

• Safety: Moderate toxicity; use personal protective equipment (PPE) during handling and application.

FAQ on Glufosinate-Ammonium:

Q1: What weeds can Glufosinate control?
A1: It controls a wide variety of annual and perennial grass and broadleaf weeds, including some glyphosate-resistant species.

Q2: How does Glufosinate kill weeds?
A2: By inhibiting glutamine synthetase, it causes toxic ammonia accumulation, leading to plant death.

Q3: Can Glufosinate be used on all crops?
A3: No, it is mainly used on glufosinate-tolerant crops or in non-crop areas; improper use can damage sensitive plants.

Q4: Is Glufosinate persistent in soil?
A4: No, it degrades rapidly and does not accumulate significantly in soil.