ИСТИНА

Phosphorous is one of the most essential macroelements in plant’s life. For this reason, the reduction of phosphorus content in soils under the influence of water erosion is considered as a worldwide catastrophe [1]. Mobile forms of phosphorous and forms adsorbed on the surface of fine soil particles (especially clay particles) wash out and moves down the slope in the lakes and rivers, and eventually accumulate in the ocean. The return of phosphorus to land takes thousands of years [8,9]. Moreover, phosphorus increases the eutrophication of water bodies [2,5]. The use of fertilizers can provide plants with phosphorus, but will not solve the problem, since, firstly, fertilizers increase the mineralization of stable organic compounds, and secondly, for the most part, they remain untouched in the surface soil layer and are easily washed out by surface runoff. [3,4]. Finally, phosphorus sources are exhaustible, and farmers may face a shortage of phosphorus for plant growth and development already in the 21st century [1,6]. So, it is very important to investigate phosphorous transportation and accumulation and find ways to reduce phosphorous loss. Thus, Vermic Chernozems with different land use were studied: mowed grassland, soil under the wood line, soil of perennial fallow, tillage and no-till farming and then arable Sod-Podzol with different location on the slope: on the top, in the middle, and at the bottom of the slop. All soil sample was divided into four groups of different-sized aggregates (> 5 mm, 5-2 mm, 2-1 mm and < 1 mm) by Savvinov dry sieving method. The content of organic carbon, mobile phosphorous, organic phosphorous, mineral phosphorous and total ratio of phosphorous was also determined. Soil cultivation methods influence the transformation of phosphorous. In undisturbed soils, available (mobile) phosphorus content is low, and vegetation protects soil organic matter (particularly from mineralization). Tillage increases mineralization processes and availability of phosphorous and in addition induce phosphorous loss with water and small soil particles. Phosphorus is easily washed out from the slope and from the soil at the foot of the slope, especially from the slopes of southern [7] and eastern exposure (according to our observations), despite the fact that fine soil particles accumulated there. Mineral phosphorous of sod-podzolic soil was stable only in aggregates from 2 to 5 mm diameter. It is obvious that tillage reduces amount of stable phosphorus compounds in soil and induces its loss with erosion. The distribution of soil particles and phosphorous on the slop leads us to conclusion, that it is easier to prevent erosion then to deal with the consequences. 1. Alewell C., Ringeval B., Ballabio C., Robinson D. A., Panagos P., Borrelli P., 2020/ Global phosphorus shortage will be aggravated by soil erosion// Nature Communications, V. 11 2. Evans N. M., Stewart W. P., Davis M. A., 2020. Phosphorous, farms, and families: Institutional narratives about agricultural intensification and water quality in northeastern Wisconsin. Journal of Rural Studies, V. 80. P. 418–426 3. Grando D.L., Gatiboni L. C., Mumbach G. L., Dall’Orsoletta D. J., Anacleto de Souza Junior A., Schmitt D. E., 2021/ Phosphorus in the runoff of soils with contrasting textures influenced by soil slope and pig slurry application// Agricultural Water Management, V. 258 4. Haygarth, P.M., Bardgett, R.D., Condron, L.M., 2013. Nitrogen and phosphorus cycles and their management. Soil Conditions and Plant Growth. P. 132–159. 5. Roohi M., Arif M. S., Yasmeen T., Riaz M., Rizwan M., Shahzad S. M., Ali S., Bragazza L., 2020. Effects of cropping system and fertilization regime on soil phosphorous are mediated by rhizosphere-microbial processes in a semi-arid agroecosystem// Journal of Environmental Management. V.271. 6. Yang X., Chen X., Yang X., 2019. Effect of organic mater on phosphorus adsorption and desorption in a black soil from Northeast// Soil & Tillage. № 187. P. 85 –91. 7. Губарев Д.И. Вайгант А.А. Ларькин М.А., 2019. Неоднородность почвенно-агрохимических показателей чернозёма обыкновенного в условиях выраженного рельефа// Сайт Федерального аграрного научного центра Юго-Востока - https://www.arisersar.ru/conference/soil_science-19/Gubarev.pdf. 8. Иванов А.Л., 2012. Агробиогеохимический цикл фосфора / Ред. Иванов А. Л. / Сычев В.Г., Державин Л.М., Адрианов С.Н., Бражникова Н.В., Карпова Д.В., Карпухин А.И., Кирпичников Н.А., Конончук В.Д., Саймолов Л.Н. // М.: Россельхозакадемия. 512 с. 9. Макаров М.И. 2009 Фосфор органического вещества почв. М.: ГЕОС, МГУ. 397 с.