Achinsk forest steppe agrolandscapes water supply

The aim of research is to study the moisture supply of the agro landscapes of the Achinsk forest-steppe and the conditions for the formation of the annual runoff. The Achinsk forest-steppe includes three agricultural landscapes: Achinsko-Bolsheuluisky, Bogotolsky, Chulymsky. The Achinsko-Bolsheuluisky agrolandscape is ridged flat, drained and occupies the eastern part of the forest-steppe with absolute heights of 300 m with a deep erosional incision - 100-150 m. The predominant soils are leached and podzolized chernozems, while gray forest and marsh soils occupy a subordinate position. The area of the agricultural landscape is 177112 hectares. The Bogotol agrolandscape is composed of Middle Cretaceous sediments overlapped from the surface by mantle loams, hypsometric heights reach 260 m, the dominant soils are gray forest and chernozems, the area is 201829 hectares. The Chulym agrolandscape is a valley with a complex of erosion-accumulative and accumulative terraces with a predominance of Meso-Cenozoic deposits. It revealed eight terraces above the floodplain, composed of gravel-pebble deposits. In general, the natural conditions of agricultural landscapes are quite suitable for the cultivation of zoned varieties of agricultural crops, but in dry years they experience a lack of moisture. The distribution of runoff in the annual cycle is very uneven. In fact, the entire annual volume of runoff in small open catchments and agricultural landscape areas is formed in two spring months - March and April. In this regard, the following typical runoff distribution was adopted: high-water years (p ≤ 33 %): March - 15, April - 85 %; years with average water content (p ≤ 33 ≤ 67 %): March - 40, April - 60 %; dry years (p ≥ 67 %): March - 0, April - 100 %. In small catchments with forest stands ≥ 10 % of the catchment area, the formation of runoff is completely shifted to April. Determination of the calculated values of the characteristics of the annual runoff for agricultural landscape areas is carried out by the interpolation method.