ISSN 1392-3196 / e-ISSN 2335-8947
Zemdirbyste-Agriculture, vol. 102, No. 3 (2015), p. 251–256
The distribution of phosphorus forms and fractions in Retisol under different soil liming management
Ieva JOKUBAUSKAITĖ, Danutė KARČAUSKIENĖ, Šarūnas ANTANAITIS, Jonas MAŽVILA, Alvyra ŠLEPETIENĖ, Donatas KONČIUS, Loreta PIAULOKAITĖ-MOTUZIENĖ
Investigations on phosphorus (P) distribution in a naturally acid and limed moraine loam, Bathypogleyic Dystric Glossic Retisol were conducted in a site of a long-term experiment at the Vėžaičiai Branch of Lithuanian Research Centre for Agriculture and Forestry in 2008 and 2011. The aim of the present study was to determine the distribution of different phosphorus forms and fractions in naturally acid soil limed for a long time (62 years). During this study different amounts (18.4 and 104.9 t ha-1) of lime materials were incorporated into the soil and affected the formation of two soil pHKCl levels – acidic (5.6) and near to neutral (6.7). Seven different organic and mineral phosphate fractions and plant-available phosphorus were determined in the soil.
The long-term soil liming was found to have no significant effect on the total P content and its distribution, but caused the changes in the proportions between the different phosphorus forms. Major part of mineral (74.02–83.68%) and organic (88.9–93.8%) P was composed of Al and Fe phosphates. Soil liming using ×2.0 liming rates every 3–4 years influenced a significant increase of the phosphates (AlPO4 and Al(Fe)PO4) little-available to plants obtained by the second cycle of extraction. It was determined that when soil pH becomes near to neutral, water soluble and plant-available P increases compared to its value measured at native pH. Increase of soil pHKCl till 6.7 had a significant effect on the amount of little plant-available Ca phosphates and less soluble organic phosphorus fraction amount in soil. The relatively optimal amounts of phosphorus fractions available for plants were determined in the soil with a pHKCl of 5.6, achieved by liming with a 0.5 rate every 7 years.
Key words: acid soil, liming, organic and mineral phosphorus, phosphorus fractions.
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