Impact of the farming systems on the content of biologically active substances and the forms of nitrogen in the soils
¹Research Center for Agricultural and Forest Environment, Polish Academy of Sciences,Bukowska 19, 60-809 Poznań, Poland; e-mail: szajlech@man.poznan.pl
²Institute of Soil Science and Plant Cultivation, Czartoryskich 8, 24-100 Puławy, Poland;e-mail: jankus@iung.pulawy.pl
Abstract:
Investigations were carried out in 2000 and 2001 to assess the impact of four farming systems on the content of biologically active substances and different forms of nitrogen in the soils. The transformation of bound amino acids and the total amount of free phenolic acids, urease activity as well as the total nitrogen, concentration of ammonium, nitrate, organic carbon, and humus in the soils were related to the choice of the farming systems. The highest concentration of bound amino acids, lysine and β–alanine, the total nitrogen, organic carbon, and humus in soils was found in ecological and conventional systems. It was confirmed that the increase of free phenolic acids in the soils of continuous cropping of winter wheat was followed by the decrease of the yearly mean concentrations of urease activity, the total amount of bound amino acids, the total nitrogen and grain yields, weight of 1000 grains, and number of ears m-2. The conventional system affects the increase of the yearly mean concentrations of the total amount of bound amino acids, the ammonium ions, and the grain yield, weight of 1000 grains, number of ears m-2 and the decrease of the total amount of free phenolic acids in the soils.
Key words:
amino acids, ammonium and nitrate, farming system, organic carbon, phenolic acids, total nitrogen, urease activity