Effect of irrigation on awnless brome (Bromus inermis) yield on the agricultural landscape of reclaimed landfill

Abstract

Irrigation is an important type of land reclamation in the areas with insufficient moisture. Irrigation helps to increase yielding capacity and ensures yield stability. Irrigation water should comply with environmental safety requirements. The study to evaluate the impact of irrigation on the yielding capacity of perennial grasses was conducted on newly created constructozems (artificial soils) as a result of reclamation of a landfill located in the north-west of the City of Barnaul. The field experiment was carried out with 3 variants of potentially fertile soils: Variant 1 - soil (ordinary chernozem, thin, medium loamy); Variant 2 - mixture of soil and sewage sludge from sewage treatment plants; Variant 3 - sewage sludge. Each variant included areas without irrigation and with irrigation. In the areas with irrigation, the minimum moisture content recommended for perennial grasses in this type of agricultural landscape was maintained at 60% of the minimum field moisture capacity. The irrigation rates were as following: 2200, 2250, and 2350 m³ ha for variants 1, 2 and 3, respectively. The experimental plots were irrigated with natural water from the BR-247 water-supply well for awnless brome crops. In terms of agro-climatic zoning, the experiment area belongs to a warm, insufficiently humid sub-district. Insufficient moisture supply was observed during the study period: HTC = 0.7-1.0. The natural water used for irrigation, according to the results of laboratory tests, belonged to the 1st class of water (according to A.N. Kostyakov), i.e. fresh water; it was bicarbonate, calcium, low mineralized; the risk of constructozem salinization was minimal. The evaluation of the awnless brome yields showed the dependence of yields on irrigation. Awnless brome yield gains under the introduced irrigation regime compares to the variants without irrigation were as following: 3.3 t ha (Variant 1); 3.9 t ha (Variant 2); 4.6 t ha (Variant 3).