Study of variations in sugarcane [Saccharum officinarum] management by farmland size: A case study of Kitadaito, Okinawa [Japan]

Kitadaito Village, the focus of this study, despite having made the transition to an integrated operational system of large-scale mechanization, has a low grade and unstable crop unit, resulting in low revenue. The objective of this study in focusing on Kitadaito Village, where the financial health of farms is severe, is to clarify the tasks necessary for increasing future revenue by analyzing management patterns and fertilization practices. The analysis done in this study showed that, although actual fertilization operations in Kitadaito Village, which are for the most part conducted in accordance with the "the sugar cane cultivation guidelines", are implemented using large-scale machinery, they have not necessarily increased unit crop nor lead to an increase in revenue. Mechanization of fertilization made it possible for farms to operate on a large-scale with few workers. However, fertilizing work on farms has only been a pursuit of efficiency. Although fertilization in Kitadaito Village should be conducted at the appropriate time, it is not. Accordingly, the precision with which farms are undertaking this work is surmised to be low. This reduces output, and evolves into a factor reducing revenue. The application of fertilizer determines sugar content. All management types undertook a certain level of fertilization, and there was no difference among those management patterns. The task remaining is to grasp in detail sugar content and the timing of fertilization, which farms undertake, and to elucidate how those variations affect revenue. On small scale isolated islands such as Kitadaito Village, the impact of droughts and typhoons is extremely pronounced, so meteorological factors have a great impact on unit crop and sugar content. Because this results in variations in farm revenue, it is necessary to examine the way in which fertilization practices are implemented per unit of cultivated field and conduct an analysis aimed at improving revenue. Due to large variations in unit crop and sugar content per unit of cultivated field, an important task is to understand how fertilization practice is actually performed per agricultural field unit.