Atmospheric moisture, in addition to carrying water and heat, also carries out other, no less important functions, the essence and significance of which began to be studied only recently. It turns out that the water contained in the atmosphere actively participates in the transport of masses of solids. The wind raises particles of soil into the air, tears off foam from sea waves, carries away the smallest drops of salt water. In addition, the salts can enter the air and in a molecularly dispersed form, due to the so-called physical evaporation of them from the ocean surface. Therefore, the ocean can be considered the main supplier of chlorine, boron and iodine for the atmosphere, rain and river water.
Thus, rainwater, while in the cloud, already contains a certain amount of salts. In the course of powerful circulatory processes in the cloud masses, water and particles of salts, soil, dust, interacting, form solutions of diverse composition.
Dozens of chemical elements and various organic compounds are found in rain drops. Leaving the cloud, each drop contains an average of 9.3 · 10-12 mg salts. On the way to the Earth, in contact with atmospheric air, it absorbs new portions of salts and dust. An ordinary raindrop of 50 mg weighs 16 liters of air when it falls from a height of 1 km, and 1 liter of rainwater captures impurities contained in 300 thousand liters of air. As a result, with every liter of rain water, up to 100 mg of impurities enter the Earth. Of the total amount of dissolved substances carried away by rivers from the continents to the ocean, almost half comes back with atmospheric precipitation. At the same time, for each square kilometer of the earth's surface, up to 700 kg of nitrogen compounds alone (in terms of pure nitrogen) are accounted for, and this is a tangible fertilizing for plants.

Especially many salts contain sediments of coastal areas. For example, in England rain was recorded with a chlorine concentration of up to 200 mg / l, and in Holland - up to 300 mg / l.
It is interesting to note that the function of rain as a carrier of mineral compounds and nutrients can not be reduced to a simple calculation: the amount of fertilizers introduced is such an increase in yield. V.E. Kabaev for many years traced the direct relationship between the size of the cotton crop and the amount of water in the sediments. In 1970, he came to an interesting conclusion: the stimulating effect of rain on crops is apparently caused by the presence of hydrogen peroxide in it. The usual content of H2O2 in the sediments (7 ... 8 mg / l) is enough to ensure that atmospheric nitrogen is bound to compounds that enrich the nutrition of plants, the mobility of elements in the soil (primarily phosphorus) is improved, and the process of photosynthesis is activated. Having established this function of rain, the scientist considers it possible to artificially deliver plants hydrogen peroxide by adding it to water by spraying.