100(2)_str15

 

ISSN 1392-3196 / e-ISSN 2335-8947
Zemdirbyste-Agriculture, vol. 100, No. 2 (2013), p. 119–126
DOI  10.13080/z-a.2013.100.015

Leaching of base cations as affected by a forty-year use of mineral fertilisation

Tomas ADOMAITIS, Gediminas STAUGAITIS, Jonas MAŽVILA, Zigmas VAIŠVILA, Jonas ARBAČIAUSKAS, Jadvyga LUBYTĖ, Donatas ŠUMSKIS, Antanas ŠVĖGŽDA

Abstract

A long-term crop rotation experiment was established in Central Lithuania (Skėmiai, Radviliškis region) in 1971 (lysimeters were installed in 1976) on a sandy loamy Endocalcari-Endohypogleyic Cambisol (CMg-n-w-can). The effect of regular fertilisation with different rates and combinations of NPK fertilisers in a crop rotation (winter wheat → sugar beet → spring barley → spring rape → annual grasses and perennial grasses) on the concentrations of cations (Ca2+, Mg2+, K+ and Na+) in lysimeter water, sampled at 40 and 80 cm depths during winter and summer periods, was investigated.

During the period 1976–2011, leaching of calcium was the most intensive one, followed by that of magnesium; leaching of sodium and potassium was significantly less. As a result of application of the N111P96K96 fertilisation rates the sum of average concentrations of the base cations Ca2+, Mg2+, Na+ and K+ in lysimeter water at 40 cm depth was 179.58 mg l-1 in winter and 218.99 mg l-1 in summer (calcium – 145 and 180 mg l-1, magnesium – 29 and 33 mg l-1, sodium – 3.92 and 4.20 mg l-1, potassium – 1.66 and 1.79 mg l-1, respectively). Average fertilisation rates (N111P96K96) increased the concentration of Ca2+ in lysimeter water by 1.4 times in winter and by 1.5 times in summer, while high rates (N222P192K192) – by 1.9 and 2.2 times, respectively. Mineral fertilisation resulted in 232–360 kg ha-1 Ca2+ leached each year into the deeper layers of soil. Phosphorus fertilisation makes the calcium balance in the soil less negative, while nitrogen and potassium fertilisation encourages the process of calcium leaching. The extent of magnesium leaching from the soils treated with mineral fertilisers was within the range of 31–56 kg ha-1 Mg2+ in winter and 17–30 kg ha-1 Mg2+ in summer. Average and high fertilisation rates increase the level of magnesium leaching by 1.5 and 2.5 times, respectively. Small amounts of potassium were leached into the 40 cm depth of light loamy soil: in not fertilised plots 0.93 kg ha-1 K+ in winter and 0.60 kg ha-1 K+ in summer, in plots treated with N111P96K96 and N222P192K192 – 1.80 and 0.95, and 4.54 and 2.42 kg ha-1 K+, respectively. Low levels of potassium leaching had little effect on potassium balance in the soil. Sodium leaching level did not exceed 7.67 kg ha-1 Na+ in winter and 3.39 kg ha-1 Na+ in summer. Application of mineral fertilisers resulted in sodium leaching increase by 5.77 kg ha-1 Na+ on an average; potassium fertilisation encouraged the process of sodium leaching.

As a result of intensive fertilisation the concentrations of calcium and magnesium ions in lysimeter water sampled at 80 cm depth were slightly higher than in the lysimeter water at 40 cm depth, the concentration of potassium ions – lower, and the concentration of sodium ions – about the same.

 Key words: concentrations of Ca2+, Mg2+, K+, Na+, lysimeters, NPK fertilisers, soil.

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