The effect of wheat straw ash as a fertlizizer was studied in a pot experiment with an acidic sandy loam soil (pH_KCl=4.9) with weak K and P supply. The test plant was ryegrass (Lolium perenne). The treatments were the following: 1. control untreated soil, 2. NPK fertilizer, 3. small dose of ash (1.4 g kg^-1), 4 large dose o...f ash (2.8 g kg^-1), 5. small dose ash completed with NP fertilizers. Soil parameters (pH_H2O, pH_KCl, ammoinum-lactate soluble P, K, 0.01 M CaCl₂ soluble PO₄^3--P, K, Mn, Cu, Zn ) and plant parameters (yield, P, K, Ca, Mg, Zn, Mn uptake) were investigated. Based on the analysis of the straw ash sample and the results of pot experiment it can be stated that the wheat straw ash is suitable for the fertilization of the studied soil. The small dose ash completed with NP resulted in the largest yield increment (43%). In order of the treatments the pH_KCl changes to: 4.9, 4.8, 5.2, 5.8, 5.1. As the N : P₂O₅ : K₂O ratio is 0 : 1: 3.5 in the wheat straw ash sample, to reach optimal yield ash should be completed with N and P.

The best known and most remarkable example of continuous production in Hungary is the Westsik’s crop rotation experiment, which was established in 1929, and is still in use to study the effects of organic manure treatment, to develop models, and predict the likely effects of different cropping systems on soil properties and crop yields. In th...is respect, Westsik’s crop rotation experiment provides data of immediate value to farmers concerning the applications of green, straw and farmyard manure, as well as data sets for scientific research.
Although commonly ignored, the release of nitrogen by root and green manure crops has a significant impact on soil organic matter turnover. The design of sustainable nitrogen management strategies requires a better understanding of the processes influencing nitrogen supplying capacity, as the effects of soil organic matter on soil productivity and crop yield are still very uncertain and require further research. In the treatments of Westsik’s crop rotation experiment, nutrients removed from soil through plant growth and harvesting are replaced either by fertilisers and/or organic manure. Data can be used to study the nitrogen supplying capacity of soil under different cropping systems and its effect on the 0.01 M CaCl₂ soluble organic nitrogen content of soil.
The aim of this paper is to present data on the nitrogen supplying capacity of brown forest soil from Westsik’s crop rotation experiment and to study its correlation with hundredth molar calcium-chloride soluble organic nitrogen. The main objective is to determine the effects of root and green manure crops on the nitrogen supplying capacity of soil under different cropping systems. The nitrogen supplying capacity was calculated as a difference of plant uptake, organic manure and fertiliser supply.
The 0.01 M CaCl₂ soluble organic nitrogen test has proved reliable for determining the nitrogen supplying capacity of soils. Brown forest soils are low in organic matter and in the F-1 fallow-rye-potato rotation, the nitrogen supplying capacity was 15.6 kg/ha/year. 0.01 M CaCl₂ soluble organic nitrogen content was as low as 1.73 mg/kg soil. Roots and green manure increased the nitrogen supplying capacity of soil by more than 100%. This increase is caused by lupine, a legumes crop, which is very well adapted to the acidic soil conditions of the Nyírség region, and cultivated as a green or root manure crop to increase soil fertility.

Hungary has a rich history of soil analyses and soil mapping. Our main tasks today are the preservation of soil fertility as well as balancing the goals of production and environmental protection. The main requirement of agricultural production is to adapt to ecological and economic conditions.
In a series of consultative meetings in the pas...t seven years, representatives from Central and Eastern Europe have analyzed nutrient management practices in their respective countries. According to a joint memorandum agreed upon in 2000, in the countries awaiting accession, the quantity of nutrients used per hectare is considerably smaller than the Western-European usage targeted through special subsidies. The current low nutrient usage contradicts the principles of sustainability and that of the efficient use of resources, jeopardizing soil fertility.
In Hungary, the use of inorganic fertilizers underwent a dynamic development, which manifested itself in an almost tenfold usage growth between 1960 and 1985. This growth slowed down somewhat between 1985 and 1990 and then reduced dramatically after 1990, reaching record lows at the usage levels of the 60s. The nutrient supply has had a negative balance for the last 15 years.
The increasing and then decreasing usage trends can equally be detected in the domestic yield averages of wheat and corn as well as in the nutrient supply of soils. Yields were the largest when usage levels were the highest, and decreased thereafter. Draughts have also contributed to smaller yields. The dramatic decrease in the use of inorganic fertilizers when adequate organic fertilizers are lacking endangers our soils’ fertility.
About 50% of soils in Hungary are acidic. Acidity is mostly determined by soil formation, but especially on soils with a low buffering capacity, this acidity may intensify due to inorganic fertilizers. Sustainable agriculture requires the chemical improvement of acidic soils. According to their y1 values, the majority of our acidic soils need to be improved. This chemical soil remediation is required in 15% of the acidic soils, while it’s recommended for another 20% of these soils.
Results of the analyses conducted in the framework of the soil-monitoring system set up in Hungary in 1992 show that in 95% of the analyzed samples, the toxic element content is below the allowable limit. Cultivated areas are not contaminated; toxicity above the legal level was found only in specific high-risk sampling areas: in the vicinity of industry, due to local overload. The basic principle of sustainable agriculture is to preserve soil fertility without undue strain on the environment. The intensity of the production needs to be considered according to the conditions of the site; i.e.; nutrient management needs to be site-specific. It is recommended to differentiate three types of cultivated land in terms of environmental sensitivity: areas with favorable conditions, endangered areas, and protected areas, and then to adopt nutrient management practices accordingly. To meet all the above-mentioned goals is impossible without systematic soil analysis. Tests conducted by the national monitoring system cannot replace regular field measurements.

In the last decade, the 0.01 M CaCl₂ extraction procedure was tested as a multi-nutrient extractant. In 1995-97, international joint research activities were carried out within the COPERNICUS project. Detailed calibration of conventional and the 0.01 M CaCl₂ extraction procedures for pH, Mg and K were published.
The amo...unt of phosphorus extracted using a 0.01 M CaCl₂ solution is very low and reflects the intensity parameter of phosphorus bio-availability. As a readily desorbed P fraction of soils can reflect the soil P-supply and the CaCl₂-P values are in close correlation with P-fertiliser rates and P balance. However, the effects of various soil characteristics on CaCl₂-P values are different and their interpretation is difficult.
Relatively poor correlations were found between amounts of P extracted by conventional and CaCl₂ soil test methods and, therefore, P limit values could not be calculated directly. To characterise the soil P supply at different sites, the CaCl₂ desorbed P and the adsorbed P in a modified Baker Soil Test were also applied.
Soil test results of Hungarian long-term fertiliser experiments and recommended CaCl₂-P limit values, calculated on yield effects and soil characteristics, are discussed.

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.

Ceramic suction cups were used for the measurement of N-concentration in soil solutions under different soil and climate conditions in both field experiments of Rostock University and Agricultural University of Debrecen (Hungary). Depending on the soil utilisation the change in the N concentration of the soil solution can be proved on both site...s.
The experimental field of Rostock University can be characterised by its high groundwater table. The nitrogen concentration of soil solutions in the different soil layers were determined by the trend downward of water. In the dactylis (Dactilis glomerata) experiment, the quadruple treatments involved the following: with and without N-fertiliser, with and without harvesting, respectively. In the lower soil layers, the least rising N concentrations were established in case of the treatment without N-fertiliser combined with harvesting. The nitrogen leaching calculated from the infiltrated water quantity and the nitrate N concentration increased in the following order: without N-fertiliser, with harvesting < without N-fertiliser, without harvesting < with N-fertiliser, with harvesting << with N-fertiliser, without harvesting.
The field experiment site of Debrecen can be characterised by a low groundwater table. The effect of N-fertilisation on the nitrate-N concentration of soil solution in the soil layers can be stated unanimously. Permanent nitrate-N leaching cannot be established due to the water upward movement under semiarid climate conditions. Intermittently transfer of nitrate-N between the soil layers is probable in cases of remarkable precipitation.

The Hungarian fertilizing recommendation systems use AL soil test for the evaluation of potassium supply. The 0.01 M CaCl₂ is a definitely milder extractant, it extracts the easily soluble and exchangeable potassium amount. Its European introduction was already taken into consideration in 1994. The research project on this topic is s...tarted in several european countries, also in Hungary at the Department of Agricultural Chemisty of Agricultural University of Debrecen. Another advantage this multielement method is that the different element-ratios can also be calculated.
The Baker-Amacher extractant’s principle is that it contains a known amount of K, P, Mg in the CaCl₂ solution. During the soil extraction adsorption and desorption process take place, so the adsorption or desorption can be calculated from the original and the final concentrations.
In this paper we introduce the results of comparing analysis of the samples (n=630) from Soil Information and Monitoring System. Our aim was to measure the use of new extractants beside conventional extractant (AL) for the evaluation of K-supply would be reasonable.
It can be stated that there is a medium close relationship (r=0.75) between AL-K and 0.01 M CaCl₂-K. My calculations confirmed the results of  former examinations, and proved that the two extractants don’t extract and change the same rate of K-fractions. We found that regression  between 0.01 M CaCl₂ and AL depend on texture classes, pH classes, amount of lime, and organic matter content of soils.
Comparing the relations between AL and Baker-Amacher we find relatively loose correlation (r=0.45). We stated that there are K-fixing soils among soils considered to be well supplied with potassium by AL. This might be caused by the high amount of mineral clay and the quality of mineral clay. We stated that the dK averages show that the Hungarian nutrient-supply categories characterize generally well K-supplement of soil.
It can be stated that it would be necessary to use new extractants to specify evaluation of plant available K. We found that the 0.01 M CaCl₂ and Baker-Amacher extractants could complete usefully the AL procedure and could help effective potassium fertilization.

The effect of NPK-fertilization on the dynamics of nutrient uptake of maize (Zea mays L., cv. Clarica) was examined on chernozem soil under irrigated and non-irrigated conditions in a field experiment.
The following results were made:
• the element concentrations in the plant decreased over time,
• there is no difference between th...e dynamics of nutrients on irrigated and non-irrigated sites because rainfall was satisfactory for plants in vegetation period,
• the N doses not only significantly increase the nitrogen content in maize, but also have a noticable effect on Ca and Mg concentrations,
• because of the acidifying effect of N-fertilizers, increasing the amount of N-fertilizer increased the Mn, Zn, Cu content of the plants,
• the P doses have a significant effect on the maize P and N content and the Zn concentration of the plant via P-Zn antagonism in the soil,
• as the high K doses treatments alter the ion ratios in the soil, the Ca, Mg content of the plant decreased.