The Silent War Beneath

How Herbicides Are Saving India's "King of Fodders"

The Green Crown Under Siege

Berseem (Trifolium alexandrinum L.), known as the "King of Fodders," is a nutritional powerhouse for livestock across India, Pakistan, and the Mediterranean. This leguminous winter crop provides protein-rich fodder through multiple cuttings from November to May. Yet, beneath its lush canopy, a silent battle rages.

Weed infestations slash berseem yields by 25–50%, threatening the livelihoods of millions of farmers 2 5 . Manual weeding is labor-intensive and costly, making chemical weed control a critical, albeit controversial, ally.

This article explores how scientists are deploying herbicides to safeguard berseem—balancing efficacy, economics, and environmental stewardship.

Berseem Benefits
  • Protein-rich fodder for livestock
  • Multiple cuttings per season
  • Improves soil nitrogen content
Weed Threats
  • 30-40% yield reduction
  • 50% seed yield loss
  • 38 weed species identified

The Weed Menace: Uninvited Guests in the Fodder Kingdom

Berseem's slow growth during the first 60–70 days after sowing allows weeds to dominate. Over 38 weed species from 16 plant families thrive in its fields. Dominant invaders include:

Cichorium intybus
Cichorium intybus

(wild chicory): Present in nearly all Indian berseem fields 2 .

Anagallis arvensis
Anagallis arvensis

(scarlet pimpernel): Flourishes in northern states 2 .

Phalaris minor
Phalaris minor

(canary grass): A competitive grassy weed 5 .

These weeds steal nutrients, light, and moisture, reducing green fodder yields by 30–40% and seed yields by up to 50% 2 6 .

Breakthrough Science: The Hisar Experiment

A landmark study at CCS Haryana Agricultural University, Hisar, tested 15 herbicide combinations during the 2013–14 Rabi season. The goal: Identify sustainable chemical controls without compromising fodder quality or soil health 1 .

Methodology: Precision in Practice

  1. Herbicide Selection: Tested pre-emergence (PRE), pre-plant incorporation (PPI), and post-emergence (3 WAS) applications.
  2. Key Treatments: Included butachlor (1,000–1,500 g/ha), pendimethalin (750–1,000 g/ha), imazethapyr (50–100 g/ha), and oxadiargyl (75–100 g/ha).
  3. Design: Randomized Block Design with three replications, comparing treated plots against unweeded controls.
  4. Metrics Tracked: Weed density, dry matter accumulation, weed control efficiency (WCE%), phytotoxicity, and fodder yield 1 4 .

Results: A Clear Victor Emerges

  • Imazethapyr (100 g/ha at 3 WAS): Achieved 77.3% WCE and boosted green fodder yield to 86 t/ha—the highest recorded.
  • Butachlor (1,500 g/ha PRE): Delivered 75.8% WCE and 82.1 t/ha yield.
  • Pendimethalin (0.4 kg/ha): Reduced weed density by 65% and increased seed yield by 119% in multi-location trials 1 3 6 .
Table 1: Top Herbicide Performers in Berseem Trials
Herbicide Rate (g/ha) Application Timing Weed Control Efficiency (%) Fodder Yield (t/ha)
Imazethapyr 100 3 WAS* 77.3 86.0
Butachlor 1,500 PRE** 75.8 82.1
Oxyfluorfen fb*** Imazethapyr 100 + 100 PRE then Post-I cut 83.9 81.0
Pendimethalin 400 PRE 66.9 47.9
*WAS: Weeks After Sowing; **PRE: Pre-Emergence; ***fb: Followed By 1 3

Economics & Ecology: The Delicate Balance

Profitability for Farmers

  • Pendimethalin (0.4 kg/ha): Generated net returns of ₹1,69,191/ha with a benefit-cost ratio of 7.12—47% higher than other treatments 6 .
  • Oxyfluorfen + Imazethapyr: Boosted net income to ₹54,810/ha in Maharashtra trials .
Table 2: Economic Returns from Herbicide Use (3-Year Average)
Treatment Net Returns (₹/ha) Benefit-Cost Ratio
Pendimethalin (0.4 kg/ha) 169,191 7.12
Oxyfluorfen fb Imazethapyr 54,810 1.96
Weedy Check (Control) - 1.00

Environmental Trade-Offs

Herbicides leave residues that persist in soil:

  • Imazethapyr: Half-life of 57–71 days; persists up to 240 days 2 .
  • Pendimethalin: Half-life of 55–77 days; detectable for 60–200 days 5 .

These residues can suppress soil microbial activity and root nodulation—critical for berseem's nitrogen fixation. Studies show imazethapyr reduces rhizobium nodules by 18%, though chlorophyll content remains unaffected 5 .

The Scientist's Toolkit: Essential Herbicide Solutions

Table 3: Herbicide Arsenal for Berseem Weed Management
Herbicide Application Type Function Key Target Weeds
Imazethapyr PRE/POST Inhibits branched-chain amino acid synthesis Broadleaves (e.g., Cichorium)
Butachlor PRE Disrupts cell division Grasses & broadleaves
Pendimethalin PRE Inhibits root growth Annual grasses
Oxyfluorfen PRE/POST Generates oxidative free radicals Broadleaves & sedges
Quizalofop-ethyl POST ACCase inhibitor for grasses Phalaris minor

Beyond Chemicals: Integrated Solutions for the Future

While herbicides like imazethapyr are game-changers, researchers advocate integration with non-chemical tactics:

Staggered Applications

PRE oxyfluorfen followed by POST imazethapyr cuts weed biomass by 84% 3 .

Soil Health Monitoring

Regular tests for microbial activity (e.g., dehydrogenase assays) to detect herbicide residue impacts 5 .

Biological Detoxification

Microbial consortia that degrade pendimethalin residues within 60 days 5 .

Key Insight

The future of berseem cultivation lies in integrated weed management—combining the precision of herbicides with ecological monitoring and biological solutions to maintain both productivity and soil health.

Conclusion: Winning the War, Sustainably

Chemical weed control in berseem has evolved from blanket spraying to precision science. The Hisar experiments prove that herbicides like imazethapyr and butachlor can secure fodder yields above 80 t/ha—enough to feed millions of livestock. Yet, the path forward demands balancing productivity with ecological care.

As research advances, "smart" herbicide combinations, residue-monitoring tech, and microbial detoxifiers promise a future where berseem's green crown remains unchallenged.

For farmers, the message is clear: The right herbicide, at the right time, can save the king.

References