ISSN 1392-3196 / e-ISSN 2335-8947
Zemdirbyste-Agriculture, vol. 101, No. 1 (2014), p. 3–10
Potassium leaching from Endocalcari-Endohypogleyic Cambisol as influenced by precipitation rate and crop management
Angelija BUČIENĖ, Šarūnas ANTANAITIS, Alvyra ŠLEPETIENĖ, Dana ŠIMANSKAITĖ, Vytas MAŠAUSKAS, Martynas BUČAS
The aim of this research was to compare a few crop management systems in respect of potassium leaching in order to reduce the leaching losses. Research was carried out on an Endocalcari-Endohypogleyic Cambisol (CMg-n-w-can) at the experimental site of Lithuanian Institute of Agriculture (currently – Institute of Agriculture, Lithuanian Research Centre for Agriculture and Forestry). The focus was on the search for factors responsible for leaching, including precipitation amount and rate, and selected soil properties.
The highest potassium cation (K+) leaching with drainage runoff 3.8 kg ha-1 year-1 was determined in the conventional system with high K inorganic fertilization level as compared with 1.9 kg ha-1 year-1 in the treatment with zero fertilization (reference) during the first research period in 1995–1999. However, later, after a few changes in experimental design and under the drier conditions, leaching of K+ was low and similar in all crop management treatments on the arable plots (approx. 1.6 kg ha-1 year-1). The rate of K and N fertilizers positively influenced the leaching of K+ only during the normal and wet years with precipitation rate >450–600 mm. The content of soil aggregates <0.25 mm in topsoil positively correlated with K+ leaching losses during the first research period (P < 0.01). During the whole research period the precipitation rate was the factor from the main effects, which explained 64% of the K+ leaching variance. The final model explained 76% of K+ leaching variance for all data and 65 ± 16% on cross-validation data, showing relatively high and stable accuracy of predictions. Among the variables, the interaction of precipitation rate and content of humus, the interaction between the precipitation rate and content of soil aggregates <0.25 mm were the most important, each explaining more than 60% of the variance of K+ leaching losses.
Key words: crop management systems, humus content, leaching, potassium cation (K+), precipitation.
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