Estimation of Operating Costs When Using a Combined Irrigation System

Sprinkler irrigation currently plays a leading role in irrigated agriculture, while center-pivot irrigation machines are the most widely used type of irrigation equipment. Despite their widespread adoption, these systems are characterized by a relatively low land-use coefficient, which is approximately 0.78 for a typical square field and may decrease to 0.5 or lower for fields with complex configurations. Within the framework of a state-funded research project, a technical and technological solution was developed by the staff of the All-Russian Research Institute “Raduga” to increase the land-use coefficient to 0.98 through the combined operation of a center-pivot irrigation machine and a semi-stationary irrigation system equipped with long-range sprinklers controlled via a radio communication channel. A previous assessment of the investment efficiency of the proposed solution demonstrated an average annual economic benefit of approximately RUB 7.5 million with a payback period of about one year. The objective of this study was to evaluate the operating costs of the combined irrigation system. In accordance with GOST 34393–2018, a comparative assessment of the direct operating costs of conventional and combined irrigation systems was carried out for a typical 49-ha field. The cost structure included labor costs, fuel and lubricants, repair and maintenance costs, and depreciation charges. In addition, the influence of center-pivot machine length on the direct operating costs of the combined system was evaluated for machine lengths of 300, 400, 500, and 600 m. The results showed that the combined irrigation system reduces direct operating costs by approximately 9% compared with the conventional system. An approximation model describing the relationship between center-pivot machine length and operating costs was obtained. It was determined that the minimum direct operating costs are achieved with machine lengths of 400 - 500 m and amount to RUB 4,480 - 4,248 per hectare, respectively.