Weed Management in Horticultural Crops

Exercise 6

Exercise 6: How to Calculate Herbicide Dose

Weed count: A permanent one square meter quadrant is randomly fixed in each plot before the emergence of weeds. Monocot and dicot weeds are then counted 30, 60 and 90 days after the herbicidal spray and weed population is expressed per square meter.

Advantages: Useful method in assessing changes caused by treatments.

Disadvantages: Tedious and consumes time and resources, accuracy depends on the size and number of Quadrants

Suppose , a grower wants to spray weed infested field at 5 kg a.i. per hectare with a herbicide containing 50% active gradient. Then the herbicides required will be calculated as under :

 

Weight of herbicide required = Dose of a.i. required/% a.i. in commercial product x 100

= 5/50 × 100
= 10 kg