How Glufosinate-Ammonium Offers Targeted Weed Control Without Soil Residues

Introduction to Glufosinate-Ammonium
Glufosinate-ammonium is a non-selective, post-emergent herbicide widely used to control a broad range of annual and perennial weeds. It is valued for its rapid action and minimal residual activity in soil, making it a preferred choice in orchard crops, non-crop areas, and herbicide-tolerant genetically modified (GM) crops.

Chemical Profile and Mode of Action
Glufosinate-ammonium is the ammonium salt of glufosinate, a naturally derived amino acid analog. It inhibits the enzyme glutamine synthetase, leading to the accumulation of ammonia within plant tissues. This disrupts photosynthesis and causes cell death. Classified under Group 10 by HRAC (Herbicide Resistance Action Committee), it provides an alternative mode of action compared to glyphosate and other herbicide groups.

Application Areas in Agriculture
Glufosinate-ammonium is used in a variety of agricultural systems, particularly in vineyards, orchards, plantations, and for weed control in GM crops such as glufosinate-resistant corn, cotton, and canola. It effectively manages hard-to-kill species such as Amaranthus, Conyza, and Echinochloa while providing a useful rotation or tank-mix partner in resistance management programs.

Advantages of Glufosinate-Ammonium

• Fast knockdown: Visible effects in 2–4 days after application.

• Broad-spectrum control: Targets grasses, sedges, and broadleaf weeds.

• Non-residual: Decomposes quickly in soil, reducing environmental persistence.

• Resistance management: Offers an alternative mechanism in herbicide programs.

• Minimal translocation: Remains in treated areas, reducing damage to nearby plants.

Limitations and Considerations
Glufosinate-ammonium works best on small, actively growing weeds. Its limited translocation makes it less effective against deep-rooted perennials unless applied thoroughly. It can be inactivated by soil particles and must be applied directly to foliage. Care is required to avoid spray drift, especially near sensitive crops.

Toxicity and Environmental Impact
Glufosinate-ammonium is considered moderately toxic to mammals and aquatic organisms. It is not highly persistent in the environment and binds tightly to soil, minimizing leaching risks. However, exposure through inhalation or ingestion should be avoided. Proper protective clothing and equipment are recommended during handling and application.

Formulations and Usage Guidelines
Available primarily in soluble liquid (SL) or suspension concentrate (SC) forms, glufosinate-ammonium should be applied in accordance with weather conditions—avoiding high temperatures or rain forecasts. Dose rates vary from 200–750 g a.i./ha depending on weed type and growth stage. It should not be applied more than twice a season in most cases.

FAQ About Glufosinate-Ammonium

Q1: Is Glufosinate the same as Glyphosate?
No. While both are non-selective herbicides, they have different modes of action. Glufosinate inhibits glutamine synthetase, while glyphosate inhibits EPSP synthase.

Q2: How soon can I plant after using Glufosinate-ammonium?
Because it has low soil persistence, replanting is usually allowed within a few days, but this depends on local label guidance and crop sensitivity.

Q3: Is it safe to use near water bodies?
Glufosinate has moderate aquatic toxicity. Buffer zones and application precautions should be observed to prevent runoff into water sources.

Q4: Can Glufosinate be mixed with other herbicides?
Yes, it is often tank-mixed with other herbicides for broader control and resistance management, but compatibility testing is recommended.

Q5: Are there resistant weeds to Glufosinate?
Resistance is still relatively limited but has been reported in some species. Rotating herbicides and integrating non-chemical control methods are crucial.