Cotton irrigation regime under the mole irrigation method in the south of Russia

Volgograd State Agrarian University, Volgograd, Russia

^* Corresponding author: e419829@yandex.ru

Abstract

Studies on developing optimal soil water regimes under mole irrigation of cotton compared with sprinkling and drip irrigation were conducted in 2023 on light-chestnut soils of southern Russia. As a result, it was found that under mole irrigation, with increasing the pre-watering threshold of soil moisture from 70-70-65 to 80-80-75 % of the lowest water holding capacity (LWC) irrigation rates decreased from 250...290 to 170...210 m³/ha and the number of irrigations and irrigation rate increased from 4 to 7 units and from 1040 to 1270 m³/ha. A comparison of irrigation methods showed that under mole irrigation, in comparison with drip irrigation, irrigation rates increased by 7.4. 13.3 %, and the number of irrigations per season and irrigation rate decreased by 1...2 units and 11.2...12.6 %, respectively. Compared to sprinkling, irrigation rates and total amount of water decreased by 45.2...46.3 and 28.8...34.5 %, respectively, and the number of irrigations increased by 1 unit. It was also found that maintaining a moisture availability level of 75-75-70 % LWC created optimal conditions in cotton crops, which, combined with mineral fertilizer application with doses N140P60K45, allowed the highest cotton yield under mole irrigation of 3.18 t/ha. When sprinkling on a similar option, it decreased by 0.21 t/ha, and at drip irrigation, it increased by 0.13 t/ha.