Change in climatic conditions of the Black Sea Steppe and productivity of winter wheat

Abstract

The purpose of the publication is to summarizeand practically assess changes in the agroclimatic conditionsof the Black Sea steppe and their impact on the productivityof winter wheat. Research methods – the use of an arrayof data from observations of a weather Post and a fieldlong-term experiment with fertilizers, statistical methodsof information processing.Results. Systematization and analysis of climateindicators of the Black Sea steppe on the exampleof the Odessa region in the period from 1970 to 2021 allowedus to obtain the following results:– every year, since the beginning of the XXI century,the average air temperature in the territory of the Odessaregion was consistently higher than the climatic norm,its deviations range from 0.8 ° C to 2.7 ° C; the largestdeviations were noted in January and July: that the averageJanuary temperature for a 51-year period increased by1.3°C, and July – by 2.2°C;– during the observation period, the average annualprecipitation (O) was 456.8 mm, and the average forthe growing season of winter wheat was 450.8 mm witha probability of 70.6%;– in the last 20 years, there are no significant changesin precipitation relative to the climatic norm, but thereis a redistribution of precipitation in individual monthsand seasons; the number of days with precipitationdecreases to an average of 61.5 days, and in the last10 years – to 53 days against 85 days for the growingseason of winter crops in 1971-1980, or against an averageof 86.2 days for calendar years 1970-1992;– during the growing season of winter wheat,thecharacteristics of precipitation by their gradationssignificantly changed: on average,in 2011-2021, the shareof days with precipitation less than 1 mm decreased from25.3% (1971-1980) to 7.8% ; the share of precipitation from1 to 5 mm remained almost at the same level (39.4-38.2%);the percentage of days with precipitation of 5-9.9 mm and 10-19. 9 mm increased by 1.6 and 1.4 timesand the share of days, when, when more than 20 mmfell out at a time, it increased 1.6 times, and more than50 mm – twice;– the productivity of winter wheat when it is grownwithout fertilizers had a high degree of dependenceon the number of days with precipitation (R2=0.98),and against the background of fertilizers – the average levelof dependence at R2=0.68, while the value of the increase ingrain yield when using fertilizers had an inverse dependenceof the average degree (r=-0.56): the more rainy days duringthe growing season, the smaller the increase relative tothe control without fertilizers.Conclusions. Over the past decades, the Odessaregion has significantly changed the thermal regime,the humidification regime, and the characteristicsof precipitation by their gradations both by calendar yearand by the growing season of winter crops. The averageannual air temperature increased by 2.0 ° C compared to1970-1980, and precipitation during this period decreasedby 56.7 mm with a tendency to stabilize in the last 10 years.The number of rainy days has almost halved.The contribution of natural fertility to the formationof winter wheat crop increments in the Black Seasteppe is 13.7%, fertilizers – 52.1, and the shareof the complex impact of weather conditions rangesfrom 25.1 to 30.9%.