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• Effects of long-term K fertilization and liming on the extractable and exchangeable K contents of a Haplic Phaeosem soil

  141-145

  Emese Berta-Szabó

  György Zsigrai

  Anita Szabó

  Jakab Loch

  Views:

  30

  Effects of regular K fertilization and liming on the easily extractable K content of a Haplic phaeosem soil determined in 0.01 M CaCl2
  and AL (traditional method in Hungary) were examined in the B1740 type of the National Uniformed Long-Term Fertilization Experiments
  at Karcag.
  Close correlation (r=0.95) was found between the 0.01 M CaCl2 and ammonium lactate - acetic acid (AL) extractable K contents of
  soils.
  K fertilization increased the amount of 0.01 M CaCl2 and AL extractable K significantly. Liming had different effects on the amounts of
  K extracted by these two methods. Liming increased the amount of AL-K and decreased the amount of CaCl2-K. CaCl2 extractable K was in
  close correlation with the relative amount of exchangeable K content of the soil (K%) and the agronomic K balance. The results of regression
  analysis confirmed that the CaCl2-K characterized K% and the AL-K related to the absolute amount of exchangeable K.
  On the basis of the presented results it can be stated that the 0.01 M CaCl2 is able to detect not just the increase of easily extractable K
  caused by fertilization and liming but the changing of the rate of the relative amount of exchangeable K.

• The effect of long-term fertilization on the 0.01 M CaCl2 extractable nutrient content of a meadow soil

  73-79

  Emese Bertáné Szabó

  Views:

  93

  During my research, I studied the 0.01 M CaCl₂ extractable NO₃^--N, NH₄⁺-N, Norg, P and K contents of the soil samples originated from a long term fertilisation trial in the experimental site Hajdúböszörmény. Relationships among the soil nutrient contents, the agronomic nutrient balances of the 2009 year, and fertilization were studied. 
  From the results of the study it was concluded as follows:
  – Fertilization significantly increased the CaCl₂ extractable NO₃^--N, NH₄⁺-N, and K contents of soil.
  – Norg fraction increased as a function of the increasing yield. Hence, it can be assumed that the greater the produced yield, the more the stubble and root residues remain on the arable land. These organic residues can result significant increase in the Norg content of soils.
  – The CaCl₂ extractable P and K contents were compared with the calculated P and K limit values. According to these, the experimental soil has a good phosphorus and lower potassium supply capacity. These results are in accordance with the results of the conventional Hungarian fertilization recommendation system.
  – It can be stated that the 0.01 M CaCl₂ is able to determine not just inorganic N forms but Norg fraction as well that characterize the easily mineralizable nitrogen reserves. The results proved that AL-P and -K (ammonium lactate acetic acid, traditional Hungarian extractant) are in good agreement with the P and K reserves, but it is important from the aspect of environmental protection and plant nutrition to measure the easily soluble and exchangeable K-, and P-contents of soil. 0.01 M CaCl₂ method is recommended for this.

• Study of factors controlling the amount of 0.01 M CaCl2 extractable Norg fraction

  437-449

  Emese Szabó

  Jakab Loch

  Views:

  181

  The use of new methods describing the “readily available” nutrient content of the soil is spreading on a global scale. The 0.01 M CaCl2 extractant is a dilute salt solution in which the easily soluble inorganic (nitrate-N and ammonium-N) and organic N fractions, P, K and micronutrients are also measurable. The 0.01 M CaCl2 has been tested in the University of Debrecen, Institute of Agricultural Chemistry and Soil Sciences since the 90’s. The results of the researches related to organic N fraction, performed in the last decades, and the results of the present study (originating from the long-term experiment of Karcag, 2007–2009) can be concluded as follows:

  The measurement of easily soluble and oxidizable organic nitrogen (Norg), besides inorganic fractions, could improve the nutrient management.

  The amount of the Norg fraction is determined by the soil conditions, therefore it is considered to be a site-specific parameter.

  Management practices and cropyear affect the amount of Norg as well. The present research confirmed that, the effect of fertilization on the amount of Norg can be explained by the changing of the yield (related to total biomass production), while the effect of cropyear is related to the differences in mineralization circumstances and yield as well.

  The measurement of the Norg fraction is increases the accuracy of N-supply, therefore it could prevent the environmentally harmful excess N application as well.