CONDITIONS FOR THE FORMATION OF MELIORATIVE REGIMES OF SOILS IN RICE IRRIGATION SYSTEMS

This study systematizes and quantitatively evaluates the main factors determining soil reclamation conditions and rice productivity in the Krasnodar Krai–Russia’s leading region for rice grain production. Based on a synthesis of literature materials, regulatory data and observational results from rice irrigation systems in the Lower Kuban, an analysis was conducted of three groups of factors: natural (temperature regime, photosynthetically active radiation), land reclamation-related (particle size distribution, soil salinity, irrigation water quality, drainage), and technological (crop rotation, drainage and discharge network operation, field layout). Empirical relationships between rice yield and soil salinity, the Stebler irrigation coefficient, the specific length of the collector-drainage network, and the layout defect criterion have been summarized. Using digital models of two real fields (Robur software, 20×20 m grid), it is shown that increasing the planning error from ±5 to ±15 cm reduces the predicted yield from 6,47 to 4,04 t/ha (by 37,6%). It has been established that the limiting factor for rice productivity in the region is not heat availability, but rather a combination of managed land reclamation and technological conditions.