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Effect of fertilization on the potentially mineralize N forms of soil of long term field experiment was set in an acidic sandy soil
20-24

The aim of this paper was to provide further information about the nitrogen mineralization processes of soil. A modified incubation technique was applied to establish the amount of easily soluble mineral and organic N forms during the incubation period. An acidic sandy soil was used for incubation, which was sampled from the „Westsik” long-term field experiment. The incubation was carried out on fifteen selected soil samples which were received different treatments since the experiment was set up. 
From the obtained results, the amount of potentially mineralizable N and the mineralization rate constant were determined. Results of chemical analysis and biological interpretation of results are discussed.

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Fertilisation Effect on Quantity of 0.01 M CaCl2 Soluble N-Forms in a Long-Term-Small-Plot Experiment
166-170

long-term experiments have an opportunity to investigate the effects of fertilization and plant nutrition. The paper reports the results achieved in the 39th years of a long-term-small-plot fertilisation and liming experiment set up on acidic sandy brown forest soil in the Nyírség region. From the 32 treatment, four replications, altogether 128 plot experiments with 10 treatments are summarized. We took samples after harvest of triticale, in August.
We used a reliable method (segmented continuous flow analysis) to determine different (easily mobilized - 0.01 M CaCl2 soluble) N-forms of soil. The 0.01 M CaCl2 soluble inorganic and total N content and the UV digestable organic-N form of soil were determined by this method.
The results are summarized below:
– The mineralized-N (Nmin.) content of soil increased with dose of nitrogen treatment. Liming treatments increase the amount of Nmin.
– The maximum content of easily mobilize organic-N-fraction was found in the upper (0-20 cm) layer. This fact due to the large amount of crop and roots.
– Changing of content of 0.01 M CaCl2 soluble total-N-forms due to N doses.
– The ratios of these N forms are variable. It is very important that the content of organic N fraction is not negligible and this fraction plays a main role in the plant nutrition.

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The effect of long-term fertilization on the 0.01 M CaCl2 extractable nutrient content of a meadow soil
73-79

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.

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