Abstract

The manual method of wet sieving of soil is tedious and time-consuming, though it is used to measure soils’ aggregate stability. To overcome this challenge, basic anthropometric data from 20 soil laboratory attendants were collected. A plunger machine, a rotary machine, and the conventional manual methods were used by each of the subjects to carry out wet sieving of 200g of agricultural soil sample. The heartbeat rate was converted into oxygen consumption and energy expended, and the time taken to carry out the task using the 3 methods for each of the subjects was measured and compared for the performance of the methods. There is no significant difference in the oxygen consumption of the subjects for the 3 methods. The plunger machine expended, on average, the least energy of 4.65 kJ min-1 but took the longest time (0.94 minutes) to carry out the sieving. Wet sieving using the rotary machine took the least time of 0.55 minutes but required the largest energy of 5.32 kJ min-1. Male subjects expended more energy consumed more oxygen and took more time to wet sieve the same type and quantity of soil as the female subjects.

Key words: Energy expended, heartbeat rate, oxygen consumption, wet sieving