When agricultural land gradually decreases, assessing the efficiency of arable land use has scientific and practical significance. It provides information and data for regional planning. The land fund of Binh Son district, Quang Ngai province, is almost thoroughly exploited.  Unused land occupies just 0.6% of the total area (46,685.24 ha). Research on thirteen major crops in Binh Son district indicates that chilli, squash, and watermelon have the highest economic efficiency with a profit (VA) of 126.7, 90.1, and 87 million VND/ha/crop, respectively. Their profit is 9.0, 6.5, and 6.3 times that of rice. Also, their capital efficiency is relatively high at 1.35–1.45. However, watermelon is subjected to more risks than chilli and squash because of market instability. Cucumbers, melon, red pumpkin, corn, peanuts, green beans, sugarcane, and cassava have medium to low economic efficiency (18.2 to 41.1 million VND/ha/crop). The lowest economic efficiency is found with rice (11.6 million VND/ha/crop). Generally, farmers apply fertilizers unreasonably and out of balance. Applying a low quantity of organic fertilizers and a high amount of inorganic fertilizers (especially nitrogen fertilizer) causes soil degradation. Therefore, local authorities should encourage farmers to adjust their fertilizer application to prevent soil degradation and health risks.