LIXIVIATION OF K AND MG OUT OF AN ALLUVIAL SILTY LOAM SOIL UNDER CONDITIONS OF INCREASED OR RESTRICTED WATER SUPPLY

When available soil K content was determined in a long-term potassium fertilizer trial carried out in a sour cherry orchard planted on a silty loam alluvial soil, it was found that, after four years, recovery of K (calculated in relation to the amount of this element applied in fertilizer) reached but 24% in case of plots treated once with 800 kg of K₂0 per ha and 32% on plots where 200 kg of K₂0 per ha were applied every year.
The question arose in that respect – what was the reason for losses of K – fixation or lixiviation?

In order to estimate a possible range of lixiviation under different conditions of water supply, in autumn 1985 an additional trial was established on the same soil, in a field close to the main fertilizer trial.

The results obtained indicate that in a loamy alluvial soil, rich with clay minerals, the range of K lixiviation is low even at very high K fertilizer doses and at increased water supply to the soil surface.
Hence it is concluded that probably not lixiviation but rather fixation has been responsible for a relatively quick decrease of K present in this soil in available forms.
On the other hand, heavy K fertilizer doses together with rainfall may promote lixiviation of Mg contained in that kind of soil.

International Symposium on Diagnosis of Nutritional Status of Deciduous Fruit Orchards

E. Jadczuk, J. Zmudzin

https://doi.org/10.17660/ActaHortic.1990.274.23