Einfluß einer variierten Stickstoffdüngung auf Assimilationsleistung und Ertragsbildung von Sommerweizen

Effect of varied N-fertilization on assimilation rate and yield of spring wheat In pot experiments with spring wheat the effect of a variied N-fertilization on yield and assimilation rate was studied by the use of ¹⁴CO₂. The assimilation rate per pot increases during the vegetative period in both years till the time short before flowering, followed by a decrease towards the end of experiment. Increased N-supply results only in a small increase of total assimilation per pot, but in the young leaves of high nitrogen plants the assimilation was enhanced. N-fertilization has a pronounced effect on the loss of assimilated ¹⁴C due to respiration. Plants with high N-supply lost 20%, those with low N-supply 50% of the ¹⁴C assimilated during the period of emergence of ears. The different yields of plants with variied N-supply are not primarely the result of an altered assimilation rate, but of the different loss due to respiration.     

Einfluß langjähriger Düngung mit verschiedenen N-Formen auf die Phosphat-Dynamik einer Ackerbraunerde

Influence of long-term application of different nitrogen sources on the dynamics of phosphate in an arable brown earth In a long-term field experiment parameters of the soil phosphate status were determined after 53 years. Soil characteristics of the arable brown earth are: sandy silt loam; pH 5,9–6,6; total carbon 0,9%; CEC 13–15 meq/100 g soil; effective field capacity 160 mm unto 150 cm. The following results were obtained: Total P content was slightly higher in the plots without mineral N and with farm manure (90 and 93 mg P/100 g soil resp.) than in the plots with mineral N supply (Ø 85 mg P/100 g soil). Application of farm yard manure and ammonium sulfate caused higher proportions of ?Fe and Al phosphates”? (56–57% of inorganic phosphate) whereas calcium cyanamide, calcium nitrate and ammonium sulfate with annual liming led to higher a content of Ca-phosphate (52–56% of inorganic phosphate). When pH was brought to 6,5 by liming, P uptake of rye grass and green oats/green rape-seed in a pot experiment depended on the soil content of ?Fe- and Al-phosphates”?. Without liming, P uptake was lower in the plot with ammonium sulfate, however, in the calcium cyanamide plot P uptake was higher than expected from the content of ?Fe- and Al-phosphate”?.     

Die Wirkung von Stroh- und Klärschlammdüngung auf das Huminstoffsystem einer Braun- und einer Schwarzerde

The influence of fertilization with straw and sewage sludge on the humic system of a brunizem and a chernozem The influence of fertilization with straw, sludge and mineral nitrogen on the humic system of a black and a brown soil was determined. Soil samples from a polyfactoriel pot experiment lasting two years were analyzed using a photometric analysis of the humic system. Sewage sludge increased extractable humic substances in both soils; straw increased chernozem humic substances but not brunizem humic substances. The other factors tested had no influence. Fertilization with straw, sludge and mineral-N each caused a degradation of the humic system of both soils, as was the case with the combined treatmetns on the brown soil. On the black soil, however, the combined treatment with straw and sludge caused a pronounced aggregation of the humic system. Additional fertilization with mineral-N resulted in an aggregation already with the lower sludge-treatment.     

Einfluß einer Düngung auf den Diffusionsfluß nicht gedüngter Kationen

Effect of Mineral Fertilizer Application on the Diffusion of Cations that have not been Added with the Fertilizer . Mineral fertilizer application increases the concentration of all cations in the soil solution, because the cations added displace partly those cations occupying exchange positions into the soil solution. In pot experiments, therefore, the K concentration could be raised by Mg-fertilization and vice versa. In the first experiment the response of alfalfa to Mg fertilization was to be studied. 1.2 g Mg/pot (12 kg soil/pot) was applied before sowing and 0.5 g/pot after each cut. 1.0 g P/pot as CaHPO₄ was added, but no K was added in the first year (except soil No. 6 K). In the 2^nd year 1 g K/pot was added after each cut. At 3 sampling dates soil samples were taken for diffusion measurements. In a second experiment K availability was tested at different K and soil water contents. 4 K treatments were included (0, 9, 29 and 49 mg K/100 g). K and Mg diffusion were measured. In the first experiment an increase of K concentration in the soil solution was recorded (Tab. 1) and in the second one an increase of Mg concentration (Fig. 1). This increase of concentration took place without altering the amounts present in the soil, but it led to an increase of the diffusive flux of the cations in question (Tab. 1 Fig. 2). This is taken as further evidence that cation diffusion takes place in the soil solution and depends mainly on the cation concentration in the soil solution. In those cases in which the cation availability depends mainly on cation diffusion to the roots mineral fertilizer application may affect the supply of cations that have not been added to the soil. This effect will be important in pot experiments to which large amounts of fertilizer are applied and which are not subject to leaching. It cannot be detected by most of the conventional soil testing methods because the amounts of cations - except, of course, those that have been added - have not changed. Only an analysis of the soil solution will reveal whether this ?salt effect”? is significant or not in a specific case.     

Einfluß langjähriger Düngung mit verschiedenen N-Formen auf pH-Wert,Humusfraktionen, biologische Aktivität und Stickstoffdynamik einer Acker-Braunerde

Influence of long-term fertilizing with different forms of nitrogen fertilizer on pH, humic fractions, biological activity and dynamics of nitrogen of an arable brown earth The evaluation of soil characteristics in a 53 years field trial (arable brown earth, sandy silty loam, eff. field cap. 160mm, pH 5,9, total C 0,9 %, total N 0,1 %, CEC 15 meq/100 g soil) gave the following results: Fertilizing with ammonium sulfate decreased pH in topsoil down to 4.9. The acidification reached a depth of 50cm. Liming in addition to ammonium sulfate could not keep pH on the same level as calcium cyanamide did. The other treatments showed pH-values between 5.8 and 6.0. Total carbon and nitrogen in treatments with farm manure, calcium cyanamide and ammonium sulfate were 0.91 to 0.98 % C, in the treatments without N and with nitrate 0.81 resp. 0.87 % C. Farm manure and calcium cyanamide produced a higher content of humic acids in organic matter than ammonium and nitrate fertilization did. Ammonium fertilization increased the content of fulvic acids. Biological activity of soils, measured as activity of 5 enzymes and 02-consumption depends mainly on pH. Highest activity is found in the soil of treatment calcium cyanamide (except catalase). The proportion of hydrolysable and non-hydrolysable nitrogen (12 % non-hydrolysable N) was not changed by fertilizing (except in the plot with farm manure which increased non-hydrolysable N to 14%). Nitrogen mineralisation in laboratory incubation trials were closely correlated with total N (r = 0.94). Lower correlation was found in plant experiments (r = 0.72 to 0.79). Other factors influencing nitrogen mineralisation are discussed.     

Einfluß unterschiedlicher Düngungsarten auf das potentielle Stickstoff-Fixierungsvermögen (Acetylen-Reduktionstest) einer Sandparabraunerde

Effect of different fertilizers on the potential N₂-fixing capacity (acetylene-reduction assay) of a sandy orthic luvisol The N₂-fixation capacity of 36 different soil samples, taken from a field trial with 4 fields crops, was tested by the acetylene-reduction-method. Each of the 4 plots was divided into strips. I = mineral fertilizer (NPK), II = stable manure compost, III = stable manure compost with bio-dynamic preparations. These different kinds of fertilizer were given in three amounts of N: 1 = 0,5 × A kg N/ha, 2 = 1 × A kg N/ha, 3 = 1,5 × A kg N/ha. Like the 3 years before in 1984 rye ?Halo”? A = 100, potatoes ?Nicola”? A = 120, red beets ?Rote Kugel”? A = 160, carrots ?Luwal”? A = 120 were cultivated. The soil samples were taken after harvest, dried and sieved. 50 g soil were moistened with a glucose-solution, hatched at 25°C for 24 h and then incubated for another 24 h at the same temperature and an acetylene concentration of 9,23%. The amount of ethylene which had developed after 8 h, 15 h and 24 h was analysed by GC. The acetylene-reduction (AR) of the soils was significantly higher after the cultivation of rye and potatoes compared with carrots and red beets; but always the crops formed the main influence. On an average the organic manured soils showed a higher AR than the mineral fertilized ones. The encouraging effect of the different organic manures was depending on the type of crop.     

Der Einfluß von Gibberellinsäurespritzungen auf das Blühverhalten von Karotten

The influence of Gibberellic Acid Treatments on Flowering of Carrots . The influence of GA₃-treatments on flower formation of carrot plants at different light conditions was investigated. No flower formation occurent during natural long day conditions at all GA₃-concentrations (6, 30, 60 ppm). (Fig. 1). Nevertheless under artificial long day conditions flower formation was observed after application of 30 and 60 ppm GA₃. Apparently a positive interaction between GA₃-application and illumination on shooting exists. Conditions leading to the formation of vegetatives apices from generative are described. (Formation of ‘Hochrosetten’, Fig. 2).     

Einfluß der Schwefeldüngung auf Ertrag und Qualitätsmerkmale bei einem Gefäßversuch mit Winterweizen

Influence of sulphor fertilizing on yield and baking quality of wheat Sulphur fertilizer was added to virtually sulphur-free substrate in pot experiments to study the effect on yield and quality of winter wheat (Type: Breustedts Werla). The N/S ratio in the plant was reduced, and there was a significant increase in the yield of grain and straw and in the thousend kernel weight of the wheat. Control treatment showed that the plants were not able to meet their sulphur requirement from air when no sulphur fertilizer was added. The analysis of “free amino acids”, albumin, gliadin and glutenin showed that the protein pattern was not affected by the sulphur fertilizer. In contrast, baking quality of the wheat grain, measured from the sedimentation value (Micro-Zeleny-Test) was considerably improved when sulphur was added.     

Der Einfluß künstlicher vertikaler Grobporen in einer verdichteten Bodenmatrix auf das Wachstum von Winterweizen II. Wachstum von Winterweizen auf einem primären Pseudogley

The influence of artificial vertical macropores in a compacted soil on the growth of winterwheat. II. Growth of winterwheat on a pseudogley In a pseudogley the effect of artificial vertical macropores in a compacted structure was compared to a compacted structure without artificial vertical macropores and to a loosened structure. Only in a very wet year (830 mm precipitation), water extraction and yield were positively influenced by the artificial vertical macropores in the compacted structure. Compared to the compacted structure without artificial macropores, where most of the water was extracted from the upper 25 cm of the soil, with vertical macropores most water was extracted from the depth 25–50 cm. In a dry year (700 mm precipitation), the difference in water extraction between the compacted structures with and without vertical macropores was only small. Most water was extracted from the loosened structure, but yield was reduced compared to both compacted structures. However, in the dry year, water extraction from the compacted structure without artificial macropores was uniform for the depth 0–50 cm, whereas for the structure with artificial macropores and for the loosened structure most water was extracted from the depth 0-25 cm. Neither in the wet nor in the dry year, vertical root extension was increased by the vertical macropores, but in the wet year root mass was positively influenced by the vertical macropores.     

Der Einfluß künstlicher vertikaler Grobporen in einer verdichteten Bodenmatrix auf das Wachstum von Winterweizen I. Wachstum von Winterweizen auf einer Parabraunerde aus Löß

The influence of artificial vertical macropores in a compacted soil on the growth of winterwheat. I. Growth of winterwheat on an alfisol derived from loess In field experiments on a compacted alfisol it was investigated, how artificially made vertical macropores in the compacted structure influence water extraction and growth of winterwheat compared to the compacted structure without vertical macropores and to the loosened structure. The experiments were carried out in two subsequent years with different precipitation (308, 0 and 440, 1 mm in the period of November until August of both growth periods). The influence of the different soil structure was most pronounced during periods of increasing water tension. Compared to the compacted structure, water extraction as well as yield was improved by the vertical artificial macropores to a similar extend as by the loosened structure. Both structures increased water extraction from deeper parts of the soil (25-50 cm). The beneficial effects of the vertical macropores were more pronounced in the dry compared to the wet year. Despite of the unequal distribution of roots in the compacted structure with vertical macropores, water extraction from the soil between the macropores was not negatively affected.