USA
The natural conditions of the main part of the United States are very diverse and, to a certain extent, are unique. Located between 49 and 25 ° north latitude, this territory is located at the junction of the moderately warm and subtropical climatic zones, and in the extreme south (Florida) it also enters the tropics. At the same time, according to the nature of the relief, the territory of the country is clearly divided into a flat east and a mountainous (Cordillera) west. The uniqueness of the territory of the United States lies in the fact that nowhere in the world there are such vast flat areas with a very warm climate, very favorable for human life and economic activity. Thus, in well-moistened areas in the northeast (New England) and in the Lake District, grass-sowing and dairy farming are most widely developed. The most fertile soils of the prairies (with the center in the state of Iowa) are used for corn crops, and cotton and tobacco growing are developed in the highly humid subtropical regions in the southeast. The steppe regions of the foothill plains are the main area for grain farming, and the vast arid interior plateaus of the Cordillera are used as natural pastures. The narrow river valleys within the Cordillera are home to irrigated agriculture, and the vast California Valley, which has a favorable subtropical climate, has developed a citrus cultivation area.
In general, about 70% of the main territory of the United States is used for agriculture (20% — arable land and 50% — meadows and pastures). Irrigated lands occupy more than 20 million hectares.
In the eastern plains of the United States, winter is not so much cold as it is a cool season. Frost and snow fall here, but in most of the southern part of the plains, temperatures stay above freezing throughout the day. The duration of the frost-free period, which characterizes the general heat supply of the territory, on the plains ranges from 150 days near the border with Canada to
