Georg Müller

Beiträge zum Problem der mikrobiell induzierten Harnstoffumwandlung im Boden: II. Mitt.: Der Einfluß von Bewässerung auf Verlagerung und Wirkung von Ureaseinhibitoren

Inhibition of ureolysis by specific inhibitors presume at first efficiency of the chemical compound itself and at second the joint distribution of both the compounds in the soil. In model experiments it could be confirmed that some inhibitors were carried along with percolating water up to four centimeters, being efficacious in this range. Also for several formulations of urea with inhibitors a tendency of urea protection by the applied inhibitors from the surface up to a depth of 6 cm was established.

Über den mehrjährigen komplexen Einfluß von Bearbeitungs-, Düngungs- und Fruchtfolgemaßnahmen auf den Humuszustand des Bodens und die Ertragsbildung: A long-term Experiment on the Complex Influence of Cultivating, Fertilizing, and Crop Rotation Measures on Humic Substances in Soil and Development of Yield

Summary In a 10-year field experiment, the influence of fertilizing, cultivating, and crop rotation measures on the C-content of the soil, humus quality of the organic soil substance, and the yield was investigated. With cultivation of fodder plants only, the C-content of the soil can be improved by increased mineral and increased organo-mineral fertilization at any depth of cultivation. When in the same location there was a turn between cereals and green crops, a decrease of C-rate can only be prevented by increased organo-mineral fertilization. Continuous cultivation of root crops resulted in a decrease of the C-content. Deeper tillage of the soil generally decreased C-content. Within the years, a variability of the pure humin substances could be detected, depending on the rotation of crops and C-content. The composition of the fulvic acids is differentiated in dependence on the factors “time” and “cultivation”. The effect of fertilization variants on the yield was different. Fertilization in that location with manure only, compared with mineral fertilization, caused in most cases depression in yield. Decrease on yield by deeper ploughing had the least influence with root crops.

Prüfung von Beziehungen zwischen mineralischer Düngung und Huminstoffen: Examination of relations between fertilizing and humic matters

Summary The influence of N, P, K, and Ca single or in combination on the humification was examined in a pot-fertilizing experiment. In characterization the achieved end-situations in the soil probes, the “Farbtiefen” and “Farbtypen” were used as indicators for concentrations and for the degrees of polymerisation, respectively, in the conventional extracted and isolated fulvic and humic fractions. These two humic fractions are regarded as mixed polymerisates resp. as analytic given pools with limited spans of polymerization of the coupling humic matters in each case. — The interaction between the fertilizer elements and the plant vegetation on the vessels leads to different degrees of humification in the soils, indicated not only by the alterations of the color-criterions within the humic fractions but also in the changes over from the fulvic to humic fraction. — It could be shown, that it is possible to characterize experimentaly induced humification processes by the aid of applied humic analytic without great expense on the conventional way.

Der Einfluß von Mineralisationsvorgängen auf die Nährstoffdynamik von Böden: I. Mitt.: Die Umsetzung der organischen Substanz sowie Säurebildung

Summary In order to ascertain the changes in the availability of nutrients, induced by the biological activity of the soil, soil samples from the A-horizon of rendzina, brown earth, and staugley were supplied with dextrose, fructose, clover meal and straw meal, as well as with ammonium nitrate. After sterilization they were treated with different inoculations: a re-inoculation with the natural population or an inoculation with Penicillium nigricans . After 11 days of incubation, above all the transformations of the added organic matter, the formation of organic acids, and the resultant changes in the concentration of the hydrogen ions were examined. The carbon losses ranged, in general, between 20 and 30%, except with fructose addition, where the losses were less than 20%, and with brown earth and staugley in the dextrose variant with ammonium nitrate addition, where the losses are higher than 30%. In all the substrates that received additional carbon or nitrogen compounds, there occurred an enrichment of metabolic products, among others of organic acids. In rendzina the acid formation was only just slight after 11 days, while with straw meal addition the acid formation is completely lacking. Here the matter was decomposed up to the final products in most cases. In brown earth and staugley organic acids could be proved in all variants. This seems to indicate a certain tendency for maintaining the organic acids, but also for the presence of easily decomposable material even after 11 days. The resultant changes in the concentration of hydrogen ions are considerable in some cases. In rendzina the concentration of hydrogen ions decreased during the incubation, and with addition of clover meal it differed almost by one pH unit, compared with the initial value. In brown earth and staugley the concentration of hydrogen ions increased, except when clover meal was added. Both these soils had no chance for neutralizing the hydrogen ions, originating from microbial metabolic processes. The demonstrable increase of the pH value in all the soils with clover addition might have its origin in the ammonification of the organic N compounds abundantly present.

Einfluß von Witterung und Kulturpflanzenbestand auf bodenbiologische Leistungen. 4. Mitt.: Nitrifikationsfähigkeit des Bodens

Summary Nitrification capability of a soil in general is determined by climatic and soil-specific conditions. There is a connection with its biological activity. Moreover, nitrification in arable soils is decisively determined by the cultivated crop. The capability of nitrification was least in fallow, increased, however, under cultivated plants in the order of wheat

Einfluß von Witterung und Kulturpflanzenbestand auf bodenbiologische Leistungen: 4. Mitt.: Rangfolgevergleich bei 16 Prüffaktoren im zweiten Anbaujahr der Kulturpflanzen

Summary In a comparison of the orders of precedence, with 16 pedological test parameters (climate, root mass, humus condition, enzyme activity, soil respiration, micropopulation, stock of animals, and others), eight cultivated plants (sugar beet, potato, maize, oats, barley, wheat, rape-seed, and broad bean) grown on a loess habitat in their second year are assessed. It appeared that the cereals have a mid-position within the order and that the broad bean with its high soil biological activity has made more use of the store of humus in the soil than potato and sugar beet. A comparison of these annual cultures with annual and perennial forage plants grown on a sandy soil habitat revealed that here, too, the annual leguminosae showed the lowest level of root mass formation, but they rank among the first as regards the promotion of soil biological activities during their most active phase of growth. With respect to the preservation of the store of humus in the soil the present assessment of the annual leguminosae in pure seed may perhaps require a correction to be made.

Beiträge zum Problem der mikrobiell induzierten Harnstoffumwandlung im Boden: I. Mitt.: Über das Harnstoffverwertungsvermögen von BodenmikroorganismenContribution to the Problem of Microbially Induced Urea Transformation in Soil: I. On the Ability of Urea Utilization by Soil Micro-Organismsba

Summary The present publication is the first of a series on the enzymatic urea transformation in soil. With about 2,000 pure cultures of micro-organisms it was possible to prove the very good urea utilization by the soil micro-organisms (bacteria, actinomycetes, and fungi). Above all the fungi showed an excellent utilization of urea, while bacteria and actinomycetes were somewhat poorer. Contrary to this is the urease activity of these organisms, and that is the reason why fungi in soil may be regarded as short-time accumulators for urea nitrogen and must not be suppressed by inhibitors.

Beiträge zum Problem der mikrobiell induzierten Harnstoffumwandlung im Boden: I. Mitt.: Über das Harnstoffverwertungsvermögen von Bodenmikroorganismen

Summary The present publication is the first of a series on the enzymatic urea transformation in soil. With about 2,000 pure cultures of micro-organisms it was possible to prove the very good urea utilization by the soil micro-organisms (bacteria, actinomycetes, and fungi). Above all the fungi showed an excellent utilization of urea, while bacteria and actinomycetes were somewhat poorer. Contrary to this is the urease activity of these organisms, and that is the reason why fungi in soil may be regarded as short-time accumulators for urea nitrogen and must not be suppressed by inhibitors.

Der Einfluß von Mineralisationsvorgängen auf die Nährstoffdynamik von Böden: II. Mitt.: Veränderung der Nährstoffbindungsformen und Löslichkeits-verhältnisse von Kalium und Phosphor

Summary After 11 days of incubation under the conditions described in the first information, i.e., addition of organic matter in the form of dextrose, fructose, clover dust, and straw dust; re-in-oculation of the soils with their natural population or with Penicillium nigricans , with addition of nitrogen (ammonium nitrate) or without such addition, the following changes occurred in the availability of nutrients. The content of water-soluble calcium increased in the examined soil types rendzina, brown earth, and staugley by about the double amount. It depends, however, also on the carbon sources applied, since the nutrient release is especially high with dextrose and fructose addition, respectively. The same applies to the addition of ammonium nitrate. The correlation co-efficients show with brown earth and staugley a significant negative correlation between the p H values, ascertained after incubation, and the content of water-soluble calcium from: brown earth r = -0,66, staugley r = -0,59, rendzina r = ±0. The reason for this may probably be found in the shifting of the carbonate: bicarbonate ration in both the first-mentioned soil types. The content of water-soluble potassium increased by desorption processes, above all in staugley, a soil type with a higher part of anorganic colloids. With rendzina and brown earth and in the control as well, immobilizations are indicated by the addition of dextrose and fructose, respectively. Contrary to this, addition of straw, but above all of clover resulted in essential increases; the same applies to the addition of nitrogen. Again the correlation coefficients show a significant relation between p H value and water soluble potassium: brown earth r = 0.71, staugley r = 0.62, rendzina r = 0.40. The content of lictate-soluble potassium increased with staugley during incubation again, but also rendzina showed an essential increase beyond the initial value. The addition of nitrogen improves the solubility. With both the soil types poorer in humus, a relation between the p H value after incubation and the lactate-soluble content of potassium is found: brown earth r = 0.81, staugley r = 0.71. The detected content of exchangeable potassium differs only slightly from that of the lactate-soluble, except in rendzina. This soil type shows distinctly that it possesses greater reserves of potassium in more difficultly available forms that were easier accessible to the ammonium acetate solution than to the calcium lactate. The exchangeable potassium as well as the non-exchangeable potassium are, however, exceptions excluded (dextrose and fructose addition), forms of K-linkage which by relatively short-timed changes of the biological activity can be less influenced. The content of lactate-soluble phosphate is subject to small increases only; a certain part of the dissolved phosphate, however, was evidently immobilized, especially by addition of nitrogen and by inoculation. With calcium, aluminuim, and iron phosphates, re-arrangements into other forms of linkage take place during incubation. In rendzina and brown soil the content of calcium phosphate increases at the expence of aluminium and iron phosphates. For the increase of calcium phosphate above all the addition of dextrose and clover is responsible. The highest degree of convertion during incubation takes place with aluminium phosphates. Evidently a greater part of them is also immobilized. The iron phosphates are distinctly altered in their content only in brown earth.

Determinations of parameters on soil biological activities: V. Complex interactions between test factors and experimental variants

Summary In this 5th and last information on a series for determination of soil micro-biological activity parameters, complex studies — in dependence of the results reported in the former publications — on the interaction between the test factors: oats yield, Aspergillus niger growth, bacterial, actinomycetes, and fungal population, soil respiration, fermenting activity, and crumble stability were carried through with three steps each in the following test variants: soil, water level, temperature level, rate of fertilizing, degree of humus, pH stage, and seasons. With the first discussed reaction standards of the test factors with regard to the steps of the trial variants it could be demonstrated that the differentiating influence of water level, soil, and temperature level is especially high in all the test factors. Less distinct was the differentiating influence of the trial variants seasons, pH, degree of humus, and rates of fertilizing. Attention is called to some peculiarities. This discussion was followed by the investigation of the parallel or opposite, positive or negative deviations from the experimental mean value in the order of the results according to the three steps of the trial variants; here the probable edaphic cause is considered. Several ways of behaviour, up to now considered isolated only, could now be explained in a complex manner. Further, the repeatedly raised question of a possible interrelation between the plant yield of the soil (soil fertility) and its micro-biological activity was investigated by comparing the obtained oats yield on each step of the respective trial variant with the micro-biological results achieved in this study. Here it is evidenced that all the examined soil micro-biological characteristics — as well as the oats yield — were improved by the intensity of fertilizing. Also the relation with the humus content steps is analogous to a high degree. All the other environmental influences give evidence of specific interactions, partly in the same direction, partly opposite, between oats yield and activity for the soil micro-organisms. Of the micro-biological test factors shows the growth of Aspergillus niger the greatest similarity to the oats yield (Aspergillus test according to NIKLAS). Finally, the complex interactions between the characteristics of ecological site and biological activity of a soil are grouped in a simplified manner in a tabulated arrangement for practical purposes as “activity expectation”.