A large amount of water is needed for normal plant development.The primary source of soil moisture is atmospheric precipitation.
Along with rain, solid precipitation in the form of snow that falls in the winter season exercises a significant influence on the agricultural cycle. Snow creates a snow cover that protects winter crops, perennial grasses and the root systems of fruit trees and small fruit plants against injury from frost. Furthermore, the snow cover provides a moisture reserve used by the plants in the spring and the first half of summer.
These moisture reserves accumulated in the soil before sowing contribute significantly to the development of all plants. Agricultural practice worldwide attests to the fact that the moisture accumulated during autumn and winter is a major factor limiting possibilities for un-irrigated agriculture. For example, deciding which areas to seed for wheat in arid districts often depends on the soil moisture content in the spring. If insufficient, fields designated for sowing wheat are used for crops that require less depth of moisture, or else are left fallow.
The role played by soil moisture in successful sowing varies considerably depending on the meteorological conditions during the growing season.
Very little dissipates in rainy seasons with lower air temperatures. On the other hand, plants survive largely at the expense of water in the soil during arid years, which normally dries up along the entire length of root development. In these situations, the autumn and winter water reserve from frozen precipitation is a primary source for providing plants with moisture, and field crops use up all these reserves completely in producing the harvest.
Given this situation, it’s difficult to overestimate a factor like precipitation accumulated over the winter. It’s possible to plan for field use for the upcoming season, decide which crops to plant and plan for the size of the harvest when you have data available on accumulated precipitation.
Accumulated precipitation data is calculated as the total precipitation for a given period, based on historical data.