The Amazon rainforest accounts for over half of the world's rainforests. The Amazon basin covers an estimated 7 million km²,of which approximately 5.5 million km²is forests. This unique habitat is home to tens of thousands of species from the plant and animal kingdoms, and with all insect species added, the number reaches over 2.5 million. Several factors contribute to this region's remarkable biodiversity, the main being optimal climatic conditions[1]. The average annual temperature hovers around 26°C. The minimum average is around 24°C, and the maximum does not exceed 32°C. Stable sunlight lasts 12 months, with an average of 7 to 9 hours of sunshine. Humidity in the rainforest rarely drops below 85%. Annual rainfall exceeds 2000 mm/m²,and the number of rainy days in the rainforest exceeds 200 per year[1,2].
The significant rainfall that falls annually on the Amazon basin carries enormous amounts of nutrients, including phosphorus-rich dust carried by winds from western sub-Saharan Africa, volcanic ash, sea salt, and ash from forest and savannah fires. The mass of this life-giving dust falling on the Amazon is estimated at nearly 28 million tons. This allows the rain to provide all the essential macro- and micronutrients for Amazonian plants, while also replacing nutrients washed from the ground by heavy rainfall.[3,4] The composition of rainwater falling in the heart of the Amazon varies throughout the year. During the wet season, the nutrients are lower, but the mass of water falling per unit area of the jungle is two to three times greater than during the dry season. However, during the dry season, the mineral content of rainwater is 1.2 to three times higher. The conclusion is that the mass of nutrients supplied to the Amazonian biotope is more or less evenly distributed throughout the year, providing very good conditions for vegetation throughout all months. The main components of rainwater are the following ions: Na+, K+, Ca2+, Mg2+, Cl–, SO42-, NO3–, silica (SiO2), P, and trace elements such as Al, Zn, Fe, Sr, Cu, Mn, Ba, Ni, Rb, V, Co, and Pb. Conductivity is in the range of 4-8 µS, while pH is 4-5.8. The main components reach concentrations ranging from several to several dozen µM, while trace elements are quantities measured in nM (nanomoles) ranging from several to several hundred [5]. Because the humus layer is thin and Amazonian soils are among the least fertile in the world, rain is practically the only source of nutrients essential for all vegetation. Nutrient uptake occurs largely through the leaf blade, and rainforest plants grown in our homes also prefer this method of fertilization.
1. Wikipedia.org,
2. Climate-data.org,
3. Anne E. Barkley, Joseph M. Prospero, Natalie Mahowald, Douglas S. Hamilton, Kimberly J. Popendorf, Amanda M. Oehlert, Ali Pourmand, Alexandre Gatineau, Kathy Panechou-Pulcherie, Patricia Blackwelder, and Cassandra J. Gastona, “African biomass burning is a substantial source of phosphorus deposition to the Amazon, Tropical Atlantic Ocean, and Southern Ocean”, Proc Natl Acad Sci US A. 2019 Aug 13; 116(33): 16216–16221,
4. Hongbin Yu, Mian Chin, Tianle Yuan, Huisheng Bian, Lorraine A. Remer, Joseph M. Prospero, Ali Omar, David Winker, Yuekui Yang, Yan Zhang, Zhibo Zhang, Chun Zhao. “The Fertilizing Role of African Dust in the Amazon Rainforest: A First Multiyear Assessment Based on CALIPSO Lidar Observations.” Geophysical Research Letters, 2015,