The current state of reclaimed lands in the Arctic zone of Yakutia in a changing climate
On the example of the estuary irrigation system «Bolshaya Polyana» of the Verkhoyansk region, the current state of reclaimed lands in the Arctic zone of Yakutia in a changing climate is considered. Research methods included reconnaissance and topographic surveys of the study area, analysis and processing of research materials previously obtained by the author. An analysis of natural and climatic conditions showed that due to climate change, there is a reduction in the cold winter period, catastrophic amounts of winter precipitation, abnormal heat in summer periods and an increase in the average annual temperature over the past 15 years by 1.2°C, which affected the shift in the start date of irrigation of estuary meadows for early periods up to 9 days. The heterogeneity of the relief of estuary meadows and the overgrowth (cluttering) of irrigation canals were revealed, in connection with which the irrigation period reaches 25-30 days, as a result of which waterlogging of the soil occurs. Agrochemical studies determined the type of soils, frozen peat-gley soil in the hay area of estuary irrigation and frozen humus-gley soil in the natural area. Measurements of the seasonal thaw layer in the natural area show deeper thawing of soils than in the hay fields of the estuary irrigation system. Also, measurements at different flood depths show that the greater the flood depth, the smaller the thawing layer. These phenomena, in our opinion, are due to the type of soils and may be associated with the influence of the layer of irrigated waters on the thawing of soils. The results of the studies carried out require further measures and studies to create an optimal irrigation regime, improve the water-physical properties of soils, for which it is proposed to improve irrigation methods by building a double-regulation reclamation network and subsequent study of its effect on the thermal and moisture conditions of irrigated haylands and agrochemical indicators of soils.