Optimum stature-bush height ratio for predicting working efficiency of tea pluckers
An optimum stature-bush height ratio (SBHr) and its interrelationship with different physiological variables and on-field productivity of tea pluckers were determined. The regression equation derived from studies with 202 pluckers indicated that the optimum SBHr varies between 1.5 to 1.7 and pluckers within this range of optimum SBHr showed maximum plucking efficiency. Any change of this optimum ratio, high or low was found to affect the total yield (TY) of a plucker. The regression equation derived between optimum SBHr (1.34 - 2.26) and other physiological variables (n = 17) indicated that there exists a negative relationship between optimum SBHr and heart rate (85.00 - 112.00 bt.min-1). Similarly, a negative relationship was also found between SBHr and body part discomfort frequency severity (BPDFS) (44.00 - 58.00) (n=17). Regression analyses further indicated that there exists a positive relationship between BPDFS and heart rate (n=17). Prediction analyses suggest that there were good associations between the predicted and observed values of all the different variables (r = 0.77 to r = 0.98). It is envisaged that determination of optimum SBHr of pluckers is critical to improve their performance (TY) by reducing both physical discomfort and physiological demands.
Keywords: Tea plucking, optimum stature-bush height ratio, posture, productivity, heart rate.