Evaluation of the economic impact of adopting precision crop load management for sustainable apple production
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Crop Load Management in Apple Production is one of the main factors determining the annual profitability of Apple orchards. Under or over-thinning the number of fruits on a tree can have serious economic consequences for growers. Finding the specific fruit load per tree is imperative to increase or achieve maximum profit per tree. Prior research uncovers a theoretical tradeoff between the fruit number left on a tree that makes it to harvest and gross economic value. The literature suggests a possible optimum range, but no specific optimum crop load target is given for Gala and Honeycrisp apple varieties in New York, Washington, Michigan, and North Carolina. Based on secondary experimental data, in this research, we studied the precise optimum point of the relationship at which maximum profit is achieved. We used independent regressions per state and variety to create a quadratic profit function that relates the dependent variable (profit) and the independent explanatory variable (fruit # per tree or crop load). The function enabled me to calculate the maximum point of the relationship where maximum profit is achieved. As expected, the relationship between fruit load and profit per tree is curvilinear bell-shaped-type. The results show different optimal treatment points for maximum profit among the states and cultivars studied. A summary of the maximum point per state and variety can be found in the results section. As expected, due to its geographical advantage, Washington state presents the highest magnitude in profit for both cultivars (Gala & Honey crisp) than all other states that are part of this experiment. Further on, a Box-Cox transformation was also performed to compare the standard quadratic regression vs. a more flexible one. The standard and Box-Cox quadratic profit functions present different corresponding maximum treatment points for profitability. Only the NY transformation gave a significant lambda value, but we failed to reject a Chi-square test for the lambda value, rendering the transformation statistically indifferent from the standard quadratic function. As expected, managing crop load does have a significant influence on apple orchard profitability. The findings of this research are intended to serve as tools for agricultural extension teams to address grower profitability with precise recommendations per state.