Earthworms are essential on all farms - Leaving Cert Agricultural Science - Question 17 - 2022

The activities of earthworms significantly enhance soil productivity in several ways:

1. Increased Drainage and Aeration: Earthworms create channels in the soil that enhance drainage, preventing waterlogging and improving aeration, which is crucial for root respiration.

2. Enhanced Fertility: Through decomposition of organic matter in their digestive tracts, earthworms enhance nutrient availability. Their castings are rich in nutrients such as nitrogen, phosphorus, and potassium, which are vital for plant growth.

3. Soil Structure Improvement: Their burrowing activities aid in forming soil aggregates, which improves the soil's ability to retain moisture and nutrients, thus fostering a more productive environment for crops.

To estimate the total number of earthworms:

1. Area of Pasture: 98m x 178m = 17444m²
2. Number of Earthworms per Quadrat: The mean number of earthworms detected in the 4 quadrats:
   • Average number of earthworms per 0.25m² quadrat is:
   egin{align*} ext{Average} &= rac{28 + 45 + 23 + 19}{4} \ &= rac{115}{4} \ &= 28.75 ext{(for 0.25m²)} \ ext{Total number of earthworms} &= rac{115 imes 17444}{0.25} = 2,006,060 ext{earthworms for the total area.} ext{Thus, the estimated total is approximately } 2,006,060 ext{ earthworms.} \ ext{(If the candidate just gives } 2,006,060 ext{ earthworms then award 6 marks.)} \ ext{Area of pasture is } 69.76 ext{ x } 78.75 = 2,006,060.

A high concentration of earthworms in quadrat 2 may be attributed to the presence of rich organic matter, which provides ample food resources and suitable habitat for their survival and reproduction.