Assessment of Irrigation Erosion Rates for Soil Protection on Slopes at the Foothill Zone of the Chui Valley, Kyrgyzstan

A multifactorial stationary field experiment on water infiltration and the rates of irrigation erosion of mountainous chernozems on slopes of 0.02 to 0.06 at the foothills of the Kyrgyz Range was conducted. The studied chernozems contained 6–8% of humus, 0.25–3.0% of nitrogen, 0.22–0.3% of phosphorus, and 2.6–3% of potassium. The parent material was loess-like, non-solonetzic loam with a slightly alkaline reaction and varied particle size distribution. Geographic information systems and remote sensing technologies were used to collect, process, analyze, and map spatial data. The experiment included various slopes of agricultural plots with varying configurations and furrow irrigation of row crops (sugar beets, grain corn, and perennial grasses). Soil erosion losses were assessed by collecting irrigation water samples in various experimental setups and subsequently determining the soil solids content of the water. The data obtained indicate that protective measures such as seeded furrows and reinforced pipes increase infiltration and reduce soil erosion. During precipitation without slope tillage, the maximum water absorption rate averaged 7.3 cm/h, while with transverse autumn plowing, the absorption rate increased to 18.2 cm/h. This made it possible to increase (due to atmospheric precipitation) the moisture capacity of the 0–80 cm soil layer by 560 m3/ha, creating the necessary reserves of soil moisture.