K. Sardi

Potassium fixation of different soil types and nutrient levels

Abstract Potassium (K) fixation plays a significant role in the soil‐plant system influencing the effectiveness of fertilizaiton. Among the factors controlling fixation capacity of soils, clay mineralogy and soil moisture are of primary importance. The objective of this experiment was to study the K fixation capacity of different soil types and K levels as well as to develop quantitative relationships between amounts of exchangeable K and fixation under wet and dry conditions. Soil samples were collected from seven sites of national multi‐location long‐term fertilization trials representing different soil properties and K levels (i.e. clay content, clay minerals, and plant‐available K). At higher K fertilizer rates, exchangeable K was higher, and as a consequence, lower wet K fixation capacities were obtained. On the other band, higher values in dry fixation of K were observed with higher K fertilizer rates. A good correlation was obtained between dry K fixation capacity of the soils and ammomium acetate‐...

Effects of fertilizer salts on the germination of corn, winter wheat, and their common weed species

Abstract Laboratory and greenhouse experiments were carried out to study the effects of the fertilizer salts, NH4NO3, ammonium nitrate‐limestone, (NH4)2SO4, urea, KC1, K2SO4, superphospate, and triple superphosphate, on the germination of corn, winter wheat, and their common weed species (ABUTH and AMARE for corn and GALAP and MATIN for wheat). Increasing rates of fertilizer salts from 10, 100, and 1,000 ppm were applied in five replicates in both laboratory and greenhouse experiments on 0.5 kg of a loamy soil. In the laboratory experiments, seeds were germinated on top of paper at 22°C. Germination of winter wheat seeds was inhibited only by the highest dose of urea, while that of its weed species was highly affected by the applied fertilizers. Germination and emergence of corn was only slightly affected by the fertilizer salts. Significant changes in germination of AMARE could be observed with each fertilizer salt and each concentration; these changes tended to be positive even with the highest level of...

Correlation between soil K and winter wheat K contents in a network of Hungarian National Long-term Fertilization Trials.

Abstract Tillering stage winter wheat (Triticum aestivum L.) shoot weight, shoot K concentrations, acid ammonium‐acetate EDTA‐soluble (LE‐, Lakanen and Erviö, 1971) and neutral ammonium acetate ‐ exchangeable (Wanasuria et al., 1981) soil K were determined in a network of 28‐year‐old National Long‐term Fertilization Trials (NLFT) with different K fertilization rates at eight experimental sites representing various agro‐ecological and soil conditions of Hungary. Both wheat shoot weights and K concentrations were affected less by K levels than by the different agro‐ecological conditions. The effect of K fertilization, however, was also significant, especially on shoot K contents. The additional effect of a higher K rate, however, was not so substantial. There was no significant correlation between winter wheat shoot K. concentrations and shoot weight. Above 3.0 % shoot K concentrations, however, shoot weights did not increase significantly. Wheat shoot weight increased with increasing soil K values, up to about 150 mg/kg soil‐exchangeable K concentration. Correlation between exhangeable soil K and shoot weight was described by a saturation (Mitscherlich) curve (R=0.6***). Correlation between exchangeable soil K and shoot K contents was also described by a saturation (Mitscherlich) equation (R=0.5***). The lower limit of good K supply, indicated by shoot K concentration at tillering stage (3.0 % K) was usually reached when NH4OAc‐ K reached as high as 150 mg/kg. The closest, linear correlation was found between soil‐exchangeable and LE‐soluble K (r=0.8***). LE extractant dissolved 10% less K than NH4OAc‐ extractant at the average of sites and K levels. Both the LE‐ and the neutral ammonium acetate methods indicated the different soil K levels in a similar way. As a first attempt, new NH4OAc‐ extractable K supply categories were established for the Hungarian agro‐ecolgical conditions, for the non‐ K demanding crop group, including winter wheat. Soil and plant K analyses data proved to be useful tools in adapting the results of long‐term field trials for improved fertilizer recommendations.Tillering stage winter wheat (Triticum aestivum L.) shoot weight, shoot K concentrations, acid ammonium-acetate EDTA-soluble (LE-, Lakanen and Ervio, 1971) and neutral ammonium acetate - exchangeable (Wanasuria et al., 1981) soil K were determined in a network of 28-year-old National Long-term Fertilization Trials (NLFT) with different K fertilization rates at eight experimental sites representing various agro-ecological and soil conditions of Hungary. Both wheat shoot weights and K concentrations were affected less by K levels than by the different agro-ecological conditions. The effect of K fertilization, however, was also significant, especially on shoot K contents. The additional effect of a higher K rate, however, was not so substantial. There was no significant correlation between winter wheat shoot K concentrations and shoot weight. Above 3.0 % shoot K concentrations, however, shoot weights did not increase significantly. Wheat shoot weight increased with increasing soil K values, up to about 150 mg/kg soil-exchangeable K concentration. Correlation between exhangeable soil K and shoot weight was described by a saturation (Mitscherlich) curve (R=0.6 *** ). Correlation between exchangeable soil K and shoot K contents was also described by a saturation (Mitscherlich) equation (R=0.5 *** ). The lower limit of good K supply, indicated by shoot K concentration at tillering stage (3.0 % K) was usually reached when NH 4 OAc- K reached as high as 150 mg/kg. The closest, linear correlation was found between soil-exchangeable and LE-soluble K (r=0.8 *** ). LE extractant dissolved 10% less K than NH 4 OAc- extractant at the average of sites and K levels. Both the LE- and the neutral ammonium acetate methods indicated the different soil K levels in a similar way. As a first attempt, new NH 4 OAc- extractable K supply categories were established for the Hungarian agro-ecolgical conditions, for the non- K demanding crop group, including winter wheat. Soil and plant K analyses data proved to be useful tools in adapting the results of long-term field trials for improved fertilizer recommendations.

Relationship between soil potassium level and potassium uptake of corn affected by soil moisture

Abstract Several authors have observed that the availability of soil potassium (K) is affected by environmental and soil factors, e.g. moisture content although the extent of the effect is still uncertain. In a pot experiment carried out with corn (Zea mays L.) for five weeks, effects of two K dosses at two soil moisture levels were studied on the K uptake of young plants. Soils were collected from plots of long‐term fertilization trials representing different K levels. Results of the experiment show that amounts of K taken up by the plants were greatly dependent on soil moisture and available K levels. Soil moisture did not affect the very close linear relationship between dry matter production and K uptake of young corn plants.

Studies on the potassium fixation of soils at different temperatures

It is known that there are several factors affecting potassium fixation and release in soils. Wetting and drying as well as freezing and thawing are considered to be of primary importance among these. In our previous experiments, potassium fixation of different soil types and nutrient levels was evaluated as well as the significance of soil properties controlling fixation capacities of soils. The objective of this experiment was to study the influence of a relatively high and a low temperature (25 °C and 0 °C) on potassium fixation capacities of selected soils. Soil samples were taken from seven sites of multilocation long-term fertilization trials. Exchangeable K content (K ex ) in soils at both temperatures was significantly determined by soil characteristics, fertilizer rates and temperature. On the other hand, wet and dry K fixation (K wf and K df ) were dependent on soil characteristics. From the results of a stepwise regression analyses, it was established that soil parameters and mineralogy plays a significant role in the relationship between wet and dry K fixation. After evaluating the effect of temperature on exchangeable potassium content, it was concluded that at 25 °C, 40.7 percent of the value of K ex could be attributed to soil K 2 O content, total quantity of kaolinite plus chlorites in soils. At 0 °C, 63.5 percent of the value of exchangeable K was attributed to soil K 2 O, humus and illite content. Comparing the correlation coefficients obtained for the variables studied, it was concluded that the correlation between K ex and K wf was the closest.Abstract It is known that there are several factors affecting potassium fixation and release in soils. Wetting and drying as well as freezing and thawing are considered to be of primary importance among these. In our previous experiments, potassium fixation of different soil types and nutrient levels was evaluated as well as the significance of soil properties controlling fixation capacities of soils. The objective of this experiment was to study the influence of a relatively high and a low temperature (25°C and 0°C) on potassium fixation capacities of selected soils. Soil samples were taken from seven sites of multilocation long‐term fertilization trials. Exchangeable K content (Kex) in soils at both temperatures was significantly determined by soil characteristics, fertilizer rates and temperature. On the other hand, wet and dry K fixation (Kwf and Kdf) were dependent on soil characteristics. From the results of a stepwise regression analyses, it was established that soil parameters and mineralogy plays a significant role in the relationship between wet and dry K fixation. After evaluating the effect of temperature on exchangeable potassium content, it was concluded that at 25°C, 40.7 percent of the value of Kex could be attributed to soil K2O content, total quantity of kaolinite plus chlorites in soils. At 0°C, 63.5 percent of the value of exchangeable K was attributed to soil K2O, humus and illite content. Comparing the correlation coefficients obtained for the variables studied, it was concluded that the correlation between Kex and Kwf was the closest.

Applications in sustainable production

It is known that there are several factors affecting potassium fixation and release in soils. Wetting and drying as well as freezing and thawing are considered to be of primary importance among these. In our previous experiments, potassium fixation of different soil types and nutrient levels was evaluated as well as the significance of soil properties controlling fixation capacities of soils. The objective of this experiment was to study the influence of a relatively high and a low temperature (25 °C and 0 °C) on potassium fixation capacities of selected soils. Soil samples were taken from seven sites of multilocation long-term fertilization trials. Exchangeable K content (K ex ) in soils at both temperatures was significantly determined by soil characteristics, fertilizer rates and temperature. On the other hand, wet and dry K fixation (K wf and K df ) were dependent on soil characteristics. From the results of a stepwise regression analyses, it was established that soil parameters and mineralogy plays a significant role in the relationship between wet and dry K fixation. After evaluating the effect of temperature on exchangeable potassium content, it was concluded that at 25 °C, 40.7 percent of the value of K ex could be attributed to soil K 2 O content, total quantity of kaolinite plus chlorites in soils. At 0 °C, 63.5 percent of the value of exchangeable K was attributed to soil K 2 O, humus and illite content. Comparing the correlation coefficients obtained for the variables studied, it was concluded that the correlation between K ex and K wf was the closest.Abstract It is known that there are several factors affecting potassium fixation and release in soils. Wetting and drying as well as freezing and thawing are considered to be of primary importance among these. In our previous experiments, potassium fixation of different soil types and nutrient levels was evaluated as well as the significance of soil properties controlling fixation capacities of soils. The objective of this experiment was to study the influence of a relatively high and a low temperature (25°C and 0°C) on potassium fixation capacities of selected soils. Soil samples were taken from seven sites of multilocation long‐term fertilization trials. Exchangeable K content (Kex) in soils at both temperatures was significantly determined by soil characteristics, fertilizer rates and temperature. On the other hand, wet and dry K fixation (Kwf and Kdf) were dependent on soil characteristics. From the results of a stepwise regression analyses, it was established that soil parameters and mineralogy plays a significant role in the relationship between wet and dry K fixation. After evaluating the effect of temperature on exchangeable potassium content, it was concluded that at 25°C, 40.7 percent of the value of Kex could be attributed to soil K2O content, total quantity of kaolinite plus chlorites in soils. At 0°C, 63.5 percent of the value of exchangeable K was attributed to soil K2O, humus and illite content. Comparing the correlation coefficients obtained for the variables studied, it was concluded that the correlation between Kex and Kwf was the closest.

Evaluation of Agronomic and Environmental Soil P Test Methods in a Network of Hungarian Long‐Term Field Trials

Abstract Winter wheat shoot weight and phosphorus (P) concentrations, corn leaf weight and P concentrations, and soil AL, Olsen, H2O, Bray 1, Pi (Fe-oxide impregnated paper strip) and AERM (anion exchange resin membrane) contents were determined in a network of uniform Hungarian national long‐term field trials. P application had a significant effect on soil P test values at different P levels and sites. The relationship between the different soil P test methods was studied separately for different soil groups (all, acid, and calcareous soils). Corn leaf weight was influenced by the sites much more than by soil P supply level, whereas corn leaf P percentage was influenced by both sites and P levels. For winter wheat, both sites and soil P levels had a positive effect on wheat shoot weight. Wheat shoot P percentage was influenced by the soil P supply much more than by the sites. Correlation between corn leaf P percentage and the Pi or AERM extractable P and between wheat shoot P percentage and the Pi and AERM P values was logarithmic.

Long-term fertilization trials in Hungary

In 1967, according to the proposal of specialists in Hungary, the National Long-Term Fertilization Trials (NLFT) were initiated to establish a uniform network of fertilizer trials representing different agro-ecological regions of the country. The aim of conducting these trials was to study the effects of increasing fertilizer rates on soil nutrients, as well as to predict fertilizer consumption in Hungary. In recent decades environmental pollution in water, soils and the atmosphere has increased; thus investigations on the environmental impact of fertilization (e.g. on soil acidification, nutrient leaching etc.) has become of primary importance. Results obtained in the long-term fertilization trials provide, a) essential information on these processes and b) a reliable database for interpretation of the possible causes of these changes.

Comparison of methods evaluating the plant available potassium content in soils of different types and potassium levels

Abstract The amount and quality of clay minerals in Hungarian soils show considerable differences. In relation to this, in long‐term multi‐location field experiments, different levels of K supply have developed even when fertilized at the same K fertilizer rate. In an incubation experiment (4 weeks at constant temperature and moisture), carried out with the soil samples taken from several sites at these fertilization field trials which were different in their clay content and K levels, changes in the plant available K content in these soils were studied. A high constant dose of K fertilizer was applied on every soil type. Two extraction procedures were used for estimating plant available K content of soils, AL‐soluble (NH4‐lactate, pH 3.7) and NH4‐acetate (pH 7.0), were compared based on the obtained exchangeable amounts of K. As a consequence of the high K dose applied at the beginning of the incubation experiment, plant available K levels measured by the two extraction procedures were significantly diff...

Data presentation, interpretation, and communication

K, Ca and Mg concentrations in tillering stage winter wheat (Triticum aestivum L.) shoot, as well as acidic (pH 4.65) ammonium-acetate + EDTA - soluble (LE-, Lakanen and Ervio, 1971) and neutral ammonium acetate- exchangeable (Wanasuria et al., 1981) soil K, Ca and Mg contents were determined for a network of 28-year-old National Long-term Fertilization Trials (NLFT) with different K fertilization rates at eight experimental sites representing various agro-ecological and soil conditions of Hungary. All the sites had the same fertilization pattern. Correlation between the two soil Ca and the two soil Mg methods, between soil and shoot Ca, and Mg, as well as between shoot K and shoot Ca+Mg contents were evaluated. Close, linear correlations were found between NH 4 OAc-Ca and LE-Ca and between NH 4 OAc-Mg and LE-Mg on non-calcareous soils (r = 0.95). Acidic LE-extractant dissolved significant amounts of Ca and Mg from the Ca- and Mg-carbonates in the calcareous soils. Neutral NH 4 OAc-Ca values increased with increasing soil calcium carbonate contents. Neutral NH 4 OAc-Mg values, however, were the lowest in the calcareous soils, probably due to the large quantities of Ca 2+ more strongly adsorbed to the cation exchange sites of the colloids compared to Mg 2+ . Exchangeable K + values were also small in the calcareous soils, although all of the soils were loams with medium clay contents. There was a positive logarithmic correlation between soil LE-Ca and shoot Ca (R = 0.55), and a quadratic polynomial one between soil LE-Mg and shoot Mg contents, resp. (R = 0.45). The positive logarithmic correlation between NH 4 OAc-Ca and shoot Ca was even closer (R = 0.60). However, there was no correlation between NH 4 OAc-Mg and shoot Mg values. A close negative, logarithmic correlation was found between wheat shoot K contents and Ca + Mg contents (R = 0.78).Abstract K, Ca and Mg concentrations in tillering stage winter wheat (Triticum aestivum L.) shoot, as well as acidic (pH 4.65) ammonium‐acetate + EDTA ‐ soluble (LE‐, Lakanen and Erviö, 1971) and neutral ammonium acetate‐ exchangeable (Wanasuria et al., 1981) soil K, Ca and Mg contents were determined for a network of 28‐year‐old National Long‐term Fertilization Trials (NLFT) with different K fertilization rates at eight experimental sites representing various agro‐ecological and soil conditions of Hungary. All the sites had the same fertilization pattern. Correlation between the two soil Ca and the two soil Mg methods, between soil and shoot Ca, and Mg, as well as between shoot K and shoot Ca+Mg contents were evaluated. Close, linear correlations were found between NH4OAc‐Ca and LE‐Ca and between NH4OAc‐Mg and LE‐Mg on non‐calcareous soils (r = 0.95). Acidic LE‐extractant dissolved significant amounts of Ca and Mg from the Ca‐ and Mg‐carbonates in the calcareous soils. Neutral NH4OAc‐Ca values increased with increasing soil calcium carbonate contents. Neutral NH4OAc‐Mg values, however, were the lowest in the calcareous soils, probably due to the large quantities of Ca2+ more strongly adsorbed to the cation exchange sites of the colloids compared to Mg2+. Exchangeable K+ values were also small in the calcareous soils, although all of the soils were loams with medium clay contents. There was a positive logarithmic correlation between soil LE‐Ca and shoot Ca (R = 0.55), and a quadratic polynomial one between soil LE‐Mg and shoot Mg contents, resp. (R = 0.45). The positive logarithmic correlation between NH4OAc‐Ca and shoot Ca was even closer (R = 0.60). However, there was no correlation between NH4OAc‐Mg and shoot Mg values. A close negative, logarithmic correlation was found between wheat shoot K contents and Ca + Mg contents (R = 0.78).