Influence of Flooding On Soil Properties and the Agrobiological Indicators of Natural Herbage in the Farmlands of West Kazakhstan

Flooded agricultural lands in the arid areas of the West Kazakhstan Region serve as a reliable source of high-grade fodder, the shortage of which impedes the development of livestock breeding.The use of the region's permanent water sources to flood agricultural lands secures the production of grass fodder regardless of weather conditions.Therefore, the study aims to identify the optimal flood regime to enhance the productive parameters of the soil.The methods of chemical analysis and quadrant sampling were applied to establish changes in soil pH, humus content, NO3, P2O5, and K2O, and the species composition of plots under different flood regimes.Results showed that greater flooding volumes were significantly associated with higher agrochemical indicators in the uppermost soil layer, with humus ranging from 2.8-3.7%(P<0.05),nitrate nitrogen 6.3-6.78mg/kg(0.2), and mobile phosphorus 53.2-74.3mg/kg(1.5).The only exception was mobile potassium, which increased only with the flooding volume of 4,000-4,500m/ha, reaching 680.65.3mg/kg.Exchangeable sodium content was more favorable for soil fertility at irrigation rates of 3,500-4,000 and 4,000-4,500m/ha.Flooding volumes over 3,000m/ha supported optimal soil salinity.Plant density per m also increased with higher flood volumes.The natural herbage was dominated by couch grass, which reached a density of 269.5 to 374.2units/m 2 and a share of 93.2-97.8%(of the total number of plants) in flooded areas and 101.8units/m 2 and 43.3% in the non-flooded area (control).The highest average yield across the study years was achieved at flooding volumes of 4,000-4,500 m/ha (27.2 cwt/ha) and 3,500-4,000 m/ha (25.0 cwt/ha), exceeding the control by 253.2% and 224.7%, respectively (P<0.05).As a result, the study establishes 3,500-4,500 m/ha as the optimal flooding regime for improving soil fertility and forage yield in semi-arid West Kazakhstan.These findings can inform irrigation management strategies in other arid and semi-arid regions, where similar flood-based practices could be adapted to enhance soil quality and fodder production.