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Soil degradation under the influence of long-term nitrogen fertilization and possibility of counteracting by liming

100%

Harapiak J. T., Malhi S. S., Nyborg M., Wisniowska-Kielian B.

Zeszyty Problemowe Postępów Nauk Rolniczych

1999

tom 467

nr 2

Effects of 27 years of fertilization with ammonium nitrate (in rates: 0, 56, 112, 168, 224 and 336 kg N·ha⁻¹·yr⁻¹) to bromegrass (Bromus inermis Leyss.) on the soil acidification, and on Al, Fe and Mn content in the soil studied in field experiment set up in 1968 on a Thin Black Chernozem soil in Alberta. A part of each N plot was treated with surface-applied lime in calcium carbonate form in 1991 at rates to bring soil pH (in H₂O) to near 7.0. Both the limed and non- limed portions were sampled for soil in the autumn 1994. Under the influence of N fertilizer the soil was acidified. In the 0 - 5 cm layer soil pH was 6.85 when no N was applied, and drastically decreased along with N dose (pH≤4.10) when the N rate was ≥168 kg N·ha⁻¹. There was also distinct depression in soil pH from the three higher N doses in the 5 - 10 cm layer, and in the next layer only at the highest N rate (336 kg N·ha⁻¹). Liming increased markedly soil pH only in the 0 - 5 cm layer, particularly at higher N doses. The content of extractable Al and Fe visibly increased along with the N dose in the upper two layers and was closely correlated with the decrease in soil pH from N fertilization. The Mn content also raised in the upper three layers but the scheme of changes was different. In the 0 - 5 cm soil layer the lower three N doses caused regular increase of DTPA-extractable Mn, and beyond 112 kg N·ha⁻¹ dose decreased the Mn content. In the next layer increase of extractable Mn was induced by 168 and 224 kg N·ha⁻¹ rates, while in the 10 - 15 cm layer the same effect appeared only at the highest N dose. Liming drastically decreased extractable Al in soil in the two upper layers, while increasing extractable Fe in the 0 - 5 cm and decreasing it in the lower layers. Visible changes caused by liming in extractable Mn in the 0 - 5 cm soil layer after statistical estimation appeared no significant, but lime decreased Mn content in the next two layers.

Ograniczanie wyników

1 Zeszyty Problemowe Postępów Nauk Rolniczych

1 Harapiak J. T.

1 Malhi S. S.

1 Nyborg M.

1 Wisniowska-Kielian B.

1 1999

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Soil degradation under the influence of long-term nitrogen fertilization and possibility of counteracting by liming