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Performance of a procedure for fruit yield estimation

Published by the American Society of Agricultural and Biological Engineers, St. Joseph, Michigan

Citation:  2010 Pittsburgh, Pennsylvania, June 20 - June 23, 2010  1009638.(doi:10.13031/2013.29974)
Authors:   Felipe Aravena Zamora, Camila Potin Téllez, Ines Zamora Lagos, Dvoralai Wulfsohn Associate Prof., ASABE Member, Marta García-Fiñana Senior Lecturer
Keywords:   Apples, Grapes, Kiwi, Sampling, Trees, Uncertainty, Variance, Yield estimation

Early estimation of expected fruit tree yield is important for the market planning and for growers and exporters to plan for labour and boxes. Large variations in tree yield may be found, posing a challenge for accurate yield estimation. We evaluated a multilevel systematic sampling procedure for fruit yield estimation. In the Spring of 2009 we estimated the total number of fruit in several rows in each of 14 commercial fruit orchards growing apple, kiwi, and table grapes in central Chile. Survey times were 10-100 minutes for apples, 85 minutes for table grapes, and up to 150 minutes for kiwis. At harvest in the Fall, the fruit were counted to obtain the true yield. Yields ranged from lows of several thousand (grape bunches), to highs of more than 40 thousand fruit (apples, kiwis). In 11 orchards, true errors less than 10% were obtained. In two highly variable orchards we obtained absolute true errors of about 20%. An analysis based on systematic sub-sampling of sample data across each sampling stage was used to determine how to distribute sampling effort to acheive the desired precision.

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