Small-plot field trials, developed by SGS, are spearheading herbicide research on prominent weed communities in India.

Weeds compete with cultivated crop species for space, sunlight and nutrients. They also host plant-pathogens and insect-pests. Herbicides are the most popular form of weed control and are used in various crops across different geographies.

Traditional herbicide field trials are conducted in large field plots, and researchers often find themselves limited by the absence or non-uniform density of the weed species to be tested in the trial plots.

Small-Plot Field Trials

In India, SGS has developed an alternative approach that uses small-plot field trials, where typical weed communities of the major crops are planted at the desired, uniform, density across randomise plots. SGS initially covers the important complex-weed-flora of paddy (direct seeded and transplanted), cotton, soy bean, groundnut and maize for the ensuing kharif (rainy) season. The planting of weed seeds can be planned in line or as broadcast, or as mixture of line and broadcast. Herbicide trials can be tailored for different herbicide management regimes:

  1. Pre-plant incorporation (PPI)
  2. Pre-emergence (PRE)
  3. Post-emergence (POST)

All management regimes can be tested in simple Randomised Complete Block Design (RCBD) or factorial design, depending on the number of factors of investigation. The trial results will be analysed by statistical means and results submitted as the percentage control of weeds,along with significance of various treatments at a level of 5 %.

Various purposes can be fulfilled alongside efficacy testing of herbicides, including:

  1. Phyto-toxicity evaluation
  2. Effects of herbicides on germination (with or without safener)
  3. Effect of herbicide application on follow-up crops
  4. Effects on soil micro-flora
  5. Examination of weed-resurgence

Trials can also be conducted under small poly-tunnels, or in a green-house, depending on the requirement and size of treatments, to avoid the risk of additional weeds through dispersal and to eliminate the uncontrolled effects of rain.

Increased Benefits

This new field trial method will benefit formulators and manufacturers. They will be able to use it as a research tool to complete efficacy evaluations of new formulations, the inclusion of mixing partners to the formulation, or for tank mix formulations. Small-plot trials will help to fix the dosage and test efficacy before going through the expensive process of registration. In the future, this method will be extended for other crops like wheat, vegetable crops and other complex weed flora.

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For further information, please contact:

Dr. Ranjeet K Poddar
Agricultural Services
Manager - Field Trials
SGS India Private Limited
Ecospace, Block – 3A, 2nd Floor,
Kolkata – 700 156, West Bengal, India
t: + 91 33 665 06 188
m: + 91 86977 30059