APPARATUS REQUIRED
i) Quadrat of definite size
ii) Pencil
iii) Graph sheet
iv) Cellotape
THEORY
The structure and composition of plant communities Can be studied qualitatively by observing each and every individual of plant species growing in a particular habitat. As counting of plant species of the whole area is not possible, random sample areas are identified at different places within the study area of a particular habitat for the rough estimate of species content. This sampling is done by using a geometric system of nested plots of different sizes. When a graph of the number of species is found in plots against the sample plot size, a small quadrat plot will be determined by locating the point on the curve where horizontal life starts and joining it to the horizontal axis.
PROCEDURE
First of all the study area to be studied was chosen. Then the quadrat was thrown randomly in the study area and the name of the species was noted. Similarly, the quadrat was thrown for a second time and the species was noted moreover. This process was repeated until there was no further increase in plant species. The accumulating total number of species in each quadrant was taken. Then a graph paper was taken and the number of quadrats was plotted against the accumulating total number of species on Y-axis. On plotting the data o curve was obtained. The point at which the curve started flattening up was noted. A horizontal live to x-axis and vertical line to y-axis was drawn that give rise to the minimum number of quadrats to be laid down in the field.
OBSERVATION TABLE
| S.N. | Name of Species | No. of quadrats Q1 | No. of quadratsQ2 | No. of quadrats Q3 | No. of quadrats Q4 | No. of quadrats Q5 | No. of quadrats Q6 | No. of quadrats Q7 | No. of quadrats Q8 | No. of quadrats Q9 | No. of quadrats Q10 | Inference |
| 1. | Alternanthera | + | + | + | + | + | ||||||
| 2. | Bidens Pilosa | + | + | + | Minimum | |||||||
| 3. | Cyanogen | + | + | + | number | |||||||
| 4. | Tagetes erecta | + | + | + | + | + | Of | |||||
| 5. | Chenopodium album | + | + | quadrat | ||||||||
| 6. | Polygonum | + | + | + | + | + | is 5 | |||||
| 7. | Monocot grass | + | + | + | + | + | ||||||
| 8. | Equisetum | + | + | |||||||||
| 9. | Artemisia Princeps | + | ||||||||||
| 10. | Oxalis | + | ||||||||||
| 11. | Drymaria | + | + | |||||||||
| 12. | Ipomoea Aquatica | + | + | |||||||||
| Accumulating total no.of species | 3 | 1+34 | 4+15 | 5+16 | 6+28 | 8 | 8 | 8 | 8 | 8 |
RESULT
Thus, from the graph the minimum number of quadrats in the study area was found.
CONCLUSION
The minimum number of quadrats to be sampled in the study area can be found.