The regularities of mineral nitrogen distribution in Lithuania’s soils in spring

Abstract

The monitoring of mineral nitrogen (N min ) concentration in Lithuanian soils was conducted during the period 2005– 2014 in 206 test sites of 20 × 20 m size located in 15 different soil regions considering the appropriate geographical units. The soil regions are distinguished from one another by relief, soil type, soil texture, climatic conditions as well as the specialisation and intensity of agricultural activities. It was found that soil N min concentration in spring differed not only between years, but also between the geographic climatic zones of Lithuania. The most important factors and their interactions affecting the soil N min concentration in spring were crops and pre-crops, soil texture, winter air temperatures and precipitation levels. The lowest N min concentration in 0–60 cm soil layer in spring was recorded in perennial grass fields and pastures, in fields where pre-crops were spring cereals and spring rape, in sandy loam and particularly sand soils, when precipitation levels during the November–March period were high and especially when this level exceeded 250 mm, when predominant winter air temperature was above 0°C. The soil N min concentration tests taking into account the territorial division of Lithuania into 15 soil regions enabled us to assess the long-term fluctuation of this indicator as affected by the local conditions. The accumulated and processed multiannual data can be used as a reference for the assessment of the results of the future tests.