Assessment of Plant Response and Data Record
Proper and unbiased assessment of plant responses to treatment is a pre-requisite for the success of a research Assessment should be done weekly, fort nightly of monthly or at most appropriate time after beginning the experiment. The initial assessment should be done at short interval even daily so that the development of the herbicide toxicity on a weed crop can be monitored. The method intercity and frequency of assessment for weed populations and growth as well as crop toxicity.
Except crop yield all other parameters can be assessed by qualitative or quantitative methods or both.
For simple observation test and primary screening trials qualitative assessment through visual observation is usually quite efficient. During visual scoring stand and vigour of weed and crop are taken into consideration.
Visual assessment to weed response is based on the effects like weed kill, weed growth, weed population, injury to weed etc. in a particular treatment.
Qualitative descriptions of treatment effects on weed and crops in the visual scoring scale of 0-10.
No Injury normal.
Very poor control
Slight stunting, injury or disorders
Some stand loss stunting or discolor
Poor to deficient
Injury more pronounced but not persistent.
Moderate injury recovery possible.
Deficient or moderate control
Persistent recovery doubtful
Near server injury to plants. No recovery possible.
Severe injury stand loss, almost destroying.
A new plants for stunting.
Good excellent control
Very few plants alive.
No advantage over qualitative assessment. However it is beneficial for advanced trials, it should be used in secondary screening trials, advanced trials, yield trials and special trials either alone or in combination with qualitative assessment.
It may be taken by placing quadrant in the field plot at random and counting the number of plants inside the quadrant. Quadrant size may be 20 X 20 m or 9 X 9 m. The area under quadrant should be 5 to 10 % of the plot size.
In this method weeds are either fresh or after drying once in a experiment. For experimental weeds, harvesting of weeds however is essential for studying the regeneration pattern under this crop response.
i) Crop Height:
Weed control affect crop with 80 to 90 % died are succeeded.
ii) Second Crop Weight:
One experimental row is used for reading observation.
iii) Crop Yield:
It is the important character for crop performance.
iv) Crop Stand:
Herbicide r frequency affects the survival of plants. All crop rows are used for crop stand count.