engleski

Micro-analysis of soil total and mineral nitrogen under different nitrogen fertilization levels

Agricultural contamination by reactive nitrogen from nitrogenous fertilizers is a worldwide concern. In order to determine micro-spatial analysis of mineral (N-NO3- and N-NH4+) and total nitrogen (TN), surface soil samples (0-0.25 m) were collected during maize vegetation (June 2007) from a long-term experimental field in central Croatia (Popovaca). This study was carried out on drained Stagnosols in an area characterized by a continental climate where mean annual temperature is 10.7 °C and annual average rainfall is 865 mm. A 1 x 1 m sampling grid was established at treatments with four different nitrogen fertilization levels (0, 100, 200, 300 kg N ha-1) and 16 samples were taken at every 0.25 m along a 1 m grid length. Mineral nitrogen was determined by ion chromatography and total nitrogen by the dry combustion method. The coefficients of variation (CV) for nitrate-nitrogen were 31.1- 58.9%, for ammonium-nitrogen 27.7-53.8%, and for total nitrogen 6.9-10.0%. Variability described by variance indicate that variance increased with applied fertilization levels and average values for all treatments were 492 mg kg-1, 77.5 mg kg-1 and 27, 400 mg kg-1 for N-NO3-, N-NH4+, and TN, respectively.

soil; nitrogen fertilization; spatial distribution

nije evidentirano