Experiments on the Mechanical Harvesting of Litchi and its Effects on Litchi Storage

Abstract

Abstract. This article presents a fruiting branch shaker designed for litchi ( Sonn.) harvesting and field testing results of the mechanical shaker with abscission chemical treatment. During the mature litchi season, mechanical harvesting experiments were conducted on Feizixiao litchi trees with and without applying the abscission chemical (Ethrel, 2-chloroethyl phosphoric acid). Fruit detachment force (FDF) and fruit weight (W) were measured to determine the effect of chemical treatment on the FDF/W ratio. Fruits harvested by different methods were transported to the laboratory in Guangzhou city and stored at 6°C. Testing results showed that more than 88% of litchi fruits untreated with the chemical were removed at a frequency of 26 or 32 Hz and that the harvesting rate was roughly 3.5 times greater than that of hand harvesting. Application of the abscission chemical increased the removal percentage and harvesting rate of litchi fruits by about 10% while showing a decreased damage rate. Storage tests also indicated no significantly different characteristics between untreated fruits harvested by the shaker and by hand. However, there were significant differences between treated fruits and untreated fruit in browning index and total soluble solids content. Keywords: Abscission chemical, Detachment force, Litchi (Litchi chinensis Sonn.), Mechanical harvest, Multi-finger branch shaking.