The changes of soil mineral nitrogen observed on farms between autumn and spring and modelled with a simple leaching equation
2009
Haberle, J.,Vyzkumny Ustav Rostlinne Vyroby, Prague (Czech Republic) | Kusa, H.,Vyzkumny Ustav Rostlinne Vyroby, Prague (Czech Republic) | Svoboda, P.,Vyzkumny Ustav Rostlinne Vyroby, Prague (Czech Republic) | Klir, J.,Vyzkumny Ustav Rostlinne Vyroby, Prague (Czech Republic)
The content of nitrate or mineral nitrogen (Nmin = N-NO3- + N-NH4+) in soil in autumn is recognized as the indicator of potential risk of N leaching during winter. The apparent changes of Nmin in the 0-60 cm soil layer on farm fields in the Czech Republic during winter were calculated. A significant positive relationship between Nmin in autumn and the change during winter was observed in eight out of the nine farms studied. Nitrate N data produced similar relationships as Nmin. The regression analysis suggested that 40-90% of Nmin above a specific amount (14-35 kg N/ha) on farms were apparently lost from the soil zone. The corresponding results for pooled data (n = 187) were 74% and 25 kg N/ha (r = 0.90, P less than 0.001). The proportion of N leached from the 0-60 cm layer calculated with a simple leaching equation was significantly correlated (n = 187, r = 0.92, P less than 0.001) with observed Nmin change during winter. The results of the study support the use of autumn Nmin within the leaching equation as a robust indicator of the risk of N leaching.
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