The transformation of potassium and ammonium forms in the soil agrocenoses | Трансформация форм калия и аммония в почве агроценоза

English. The sustainability of the ratio of potassium forms as well as the variability of ammonium forms were shown in soils of agrocenosis under conditions of long-term field trial. The ratio between ammonium forms varies in soils of agrocenosis within wide limits; at the same time the change of content of various soil ammonium forms can occur in different directions. Ammonium fixation depends to a great extent on soil potassium state. In agrocenosis with exhausted soil potassium fund the soil does not fix practically the ammonium of applied fertilizers; its level in soil is reduced below that of virgin, even at selfsupporting nitrogen balance. As it was evidenced by laboratory trials, if there is no cation removal by plants the soil having low content of nonexchangeable potassium and ammonium fixes no more than 2–2,5% of applied ammonium itrogen. The fixing capacity of soil in respect of ammonium increases considerably (up to 8–10% of applied dose) when potassium level in soil is high, independently if this background was formed earlier or potassium is received simultaneously with nitrogenous fertilizers. Potassium fixation in the soil amounts to 70% of applied dose and practically does not depend on nitrogen balance in agrocenosis and ammonium content in the soil; joint application of potassic and ammonium fertilizers has a weak effect on nonexchangeable adsorption of potassium by soil.

Russian. Показаны устойчивость соотношения между формами калия в почве агроценоза и изменчивость соотношения для форм аммония. Трансформация форм аммония в почве во многом определяется ее калийным состоянием: почва с истощенным фондом калия практически не фиксирует аммоний, тогда как при высоком уровне калия в почве необменное поглощение аммония резко возрастает. Трансформация форм калия в почве агроценоза определяется уровнем поступления или выноса калия и не зависит от почвенного содержания аммония.