Since 1968, in Romania was elaborated a long term field with fertilizers and lime in all the agricultural research stations that belong to National Agricultural Research and Development Institute of Fundulea. The experiments was set up using a unitary scheme for researching the evolution of soil fertility and the influence of fertilizers and lime rates and combinations on level and quality yield of different crops. The preluvosoil from Oradea, Romania, is a medium provide with the main nutritive elements, with a weak acid reaction in the ploughing horizon. The factors which have a negative influence on growing plants are: high level soil content in the H+ and Al3+, Fe+ and Mn+ and low level soil content in main nutrients, low activity of microorganisms, and stagnation of water because of unsatisfactory infiltration. In this paper are presented the results regarding the influence of potassium fertilizers applied on different NP background on main agrochemical indexes in long term field experiment set up in 1974 at Agricultural Research and Development Station Oradea. The main agrochemical indexes depends on the fertilizers’ type and on the rates fertilizers level applied. The mobile potassium content of the preluvosoil has average values between 85.4 – 161.1 if K rates is applied and are increasing from 0 to 120 K2O kg/ha in function with the NP background. The applications of potassium fertilizers on different NP backgrounds had a differentiated influence on humus level content, depending on K rates used and NP backgrounds. The mobile phosphorus content of preluvosoil has average values between 35.0 – 70.2 ppm if P rates applied are increasing from 0 to 80 P2O5 kg/ha in function with the nitrogen background. Potassium application in rates of K40 – K80 determine a increasing of phosphorus mobile content with 20 – 22 ppm. The results researches were carried out in the project PN-II-ID-PCE-2008-2 1047/2009 “Researches regarding the possibilities to improve the quality of the wheat yield in the conditions of NW Romania”.

potassium fertilizers; mobile potassium; mobile phosphorus; humus; preluvosoil

Presentation: oral