Broadcasting and shallow dressing are the two conventional fertilizer application methods in the orchards in Taiwan. These methods are subject to the risk of fertilizer loss because of water or surface soil run-off during raining season, thus reducing the efficiency of fertilizer usage. Moreover, these methods often lead to shallow-rooted fruit trees that are susceptible to drought or chilling. In contrast, vertical drilling coupled with direct, deep fertilization improves physical features and aeration in the soil profile, prompts the development of deep root system, and enhances fertilization efficiency.

    At present, for deep fertilization in the orchard, the handheld core drilling machine is typically used first to drill small, deep holes around the trees. The holes are then filled with organic fertilizers. The whole process is a strenuous and exhausting physical activity for the farmers. There is also a safety concern for the drilling machine handler in case the drill head hits an unexpected hard soil layer, underground stones, or other obstacle. Moreover, hauling and applying of the fertilizer take up more than 50% of the time in the deep fertilization process.

    To prevail over the aforesaid drawbacks, TARI scientists have developed a prototype of self-propelled automatic machine with a design combining hole-drilling, deep fertilization mechanism, and vehicle body to carry fertilizers. The machine renders mobility and convenience, and improves deep fertilization efficiency in the orchard.

    It takes an average of 35 seconds for the said machine to complete deep fertilization at a specific spot, including 15 seconds for hole-drilling, 15 seconds for fertilization, and 5 seconds to move to the next spot. For a vineyard with a population density of 800 plants per hectare, this machine can accomplish 0.15 hectare of deep fertilization, including hauling of fertilizers, for an 8-hour working day. In comparison with the broadcasting method, the deep fertilization with this newly developed machine saves fertilizer costs, improves fertilization efficiency, and reduces fertilizer contamination in groundwater in addition to eliminating the drudgery of hand labor.