Der Einfluß von Cadmium im Boden auf den Ertrag verschiedener Pflanzenarten und deren Cadmiumgehalt

Influence of Cadmium in Soil on the Yield of Various Plant Species and their Cadmium Content In pot experiments the influence of increasing quantities of cadmium in the soil (< 250 mg Cd/kg) on the growth of carrot, bushbean, tomato, ray grass and the cadmium content of various plant parts were studied. Considerable differences of the various plant species are observed. Sensitivity increases in the order: tomato (low) < broccoli < oat < lettuce < ray grass = carrot root < radish < bushbean = pea < spinach (very sensitive). Symptoms of toxicity are found in bush beans only. Fruit, seeds and roots accumulate less cadmium then leaves and straw.     

Der Einfluß unterschiedlicher Kalium- und Nitraternährung auf pH-Änderungen in der Rhizosphäre

The Influence of potassium and nitrate nutrition on pH changes in the rhizosphere Seedlings of winter wheat, barley, sunflower, peanut and field bean were grown in soils differing in K and nitrate content. pH changes of the rhizosphere soil were measured periodically with antimony electrodes. In soils relatively poor in K the lowest pH values were measured at the root surface of the dicots (maximum pH decrease from 5 to 4.2), while soil pH increases from 5 to 5.4 in contact with roots of the monocots. Increasing K addition caused decreasing pH near peanut and field bean roots. In soils fertilized with K, monocot roots also decreased soil pH. In a K-rich soil the roots of the dicots decreased pH even after addition of 6.6 mg NO₃-N/100 g soil, while the roots of the monocots did not change pH. The pH changes are explained by an imbalance between anion and cation uptake, causing release of protons or hydroxyl ions. The reason for the differences in behaviour between monocots and dicots may be due to the differing cation-exchange capacity of the plant roots, causing a higher cation uptake by dicots and therefore greater proton release.     

Einfluß von Müllkompost und Eisenverbindungen auf die Eisen-, Zink- und Manganaufnahme von Sonnenblumen und Mais im Gefäßversuch

Influence of compost and Fe-compunds on the uptake of Fe, Zn and Mn by sunflower and maize in pot experiments The influence of compost and different iron compounds on the uptake of Fe, Zn and Mn from calcareous soils was investigated in a pot experiment using sunflower and maize. Regardless of the iron compounds applied, the addition of compost resulted in an increase of the Zn content in both plant species. The compost treatment without Fe, resulted in a lower Fe content in sunflower and maize. This effect was partly or completely counteracted by the addition of Fe compounds. Very high Zn contents were observed in the Fe – EDTA treatments. The Zn content was further increased when compost was also added. In treatments in which compost was omitted none of the Fe compounds applied increased the Fe content of the plants.     

Einfluß von Natriumchlorid und Mycostatin auf den Mineralstoffgehalt im Blattgewebe und die Feinstruktur der Chloroplasten

Effect of Sodium Chloride and Mycostatin on the Mineral Content of Leaf Segments and on the Fine Structure of Chloroplasts Leaf segments of bean, barley and sugar beet were treated for several hours with 25 meq NaC1 or with the antibiotica mycostatin. The effect of these treatments on the content of potassium, sodium, calcium, magnesium and chloride in the leaf segments and on the fine structure of chloroplasts was studied. In bean sodium chloride treatment induced strong efflux of potassium and swelling of the chloroplasts. Sodium sulfate or mycostatin had the same effect. Despite of the strong efflux of potassium the content of calcium and magnesium in the segments was practically unaffected. Addition of 1 meq calcium to the external solution prevented the effect of sodium chloride on efflux of potassium as well as on the fine structure. In barley sodium chloride or mycostatin also induced efflux of potassium and swelling of the chloroplasts. These effects, however, were less pronounced than in bean. Again the content of calcium and magnesium in the segments was practically unaffected, and the addition of 1 meq calcium compensated the effect of sodium chloride. In sugar beet both mycostatin and sodium chloride did not induce efflux of potassium, despite of a strong influx of sodium in the sodium chloride treatment. In both treatments no change in the fine structure of the chloroplasts was observed. It was proved by isolation of chloroplasts that the typical sodium chloride induced differences in efflux of potassium from the leaf segments is also reflected in efflux of potassium from the chloroplasts. The results indicate the causative connection between efflux of potassium and change in the fine structure of the chloroplasts. Differences between the three plant species with respect to efflux of potassium induced by sodium chloride or mycostatin are reflections of different membrane properties. The presence of calcium in the external solution is much more important for the membrane stability of bean than it is for sugar beet e. g. The results obtained with leaf segments are a good reflection of the different tolerance of these three plant species to high sodium chloride concentrations under field conditions.     

Einfluß von N-Lignin auf Wachstum und N-Stoffwechsel von Weizen-Zellsuspensionskulturen

The effects of N-Lignin on growth and N-metabolism in wheat cells in suspension cultures N-Lignin is an organic N-fertilizer which is synthesized from waste liquors of the pulp industry by oxydative ammonisation. Nearly 40% of its N-content is available as ammonium, the rest is linked in organic compounds. Water-soluble fractions of N-Lignin were added to the nutrient solutions of wheat cells in suspension cultures in order to study the effects on growth and N-metabolism. The experiments show that N-Lignin is a suitable nitrogen source for growing wheat cells. The best growth was achieved when 50% of the total nitrogen content of the medium were added as N-Lignin nitrogen. This mixture of N-Lignin and nitrate was even superior to the standard B-5-medium with respect to the final dry weight. However, higher concentrations of N-Lignin inhibited cell growth. The effect of N-Lignin on cell growth is not only influenced by ammonia. If wheat cells were grown on media with ammonium-N as the sole nitrogen source acids of the citrate cycle had to be added to support growth. This was not necessary with N-Lignin. N-Lignin therefore seems to effect the energy metabolism. High amounts of ammonium-N or the reduced N-fractions of N-Lignin respectively resulted in an increase of certain amino acids and especially of the two amides glutamine and asparagine. Furthermore root formation was observed with cells grown in media containing N-Lignin or ammonium-N. The root formation seemed to be correlated with added amounts of reduced nitrogen. Root formation was not observed with cell cultures incubated with N-Lignin solutions which were made free of ammonium-ions with a cation exchanger (Amberlite IR-120) loadad with potassium. This indicates that the differentiation of roots in the normally embryonic cells is due to the ammonium-N content of N-Lignin. A possible correlation between the content of glutamine and asparagine and the formation of roots is discussed.     

Einfluß von Monoethanolamin auf Ertrag und Wasserausnutzung von Sommergerste

Effect of monoethanolamine on yield and water use efficiency of barley The effect of monoethanolamine (EA) on yield and water use efficiency (WUE) of spring barley plants was tested in pot experiments. The application of EA (8 to 12 mg/pot) increased the grain yield and WUE by about 4 to 15 per cent under stress conditions. In addition, EA improved the utilization of fertilizer nitrogen. The yield-increasing effect of EA was associated with an increase of the number of ear-bearing tillers and an improved root growth. The effects of EA were only significant at α = 0.05.     

Einfluß von Bewässerung und Plazierung von markierten Stickstoff-Düngern auf Ertrag und Stickstoffentzug bei Weizen unter semiariden Klimabedingungen im Iran

Effect of Irrigation and Fertilizer Placement on the N-Uptake by Wheat under Semiarid Conditions of Karadj/Iran Field and greenhouse experiments were conducted under semiarid conditions of Karadj/Iran on a sandy to silty loam of alluvial soils (pH% 8,2) to study the effects of soil moisture regimes and N-fertilizer placement on yield, N-uptake and recovery of fertilizer N from ¹⁵NH₄ ¹⁵NO₃, (¹⁵NH₂)₂CO and (¹⁵NH₄)₂SO₄. There were two moisture regimes as main plots (W₁ = Irrigation at 50% and W₂ = Irrigation at 25% available water in 0–30 cm depth of soil), and two methods of fertilizer placement (broadcast and band application). Irrigation at (W₁) increased the grain and straw yield 11 and 19% but not total N-uptake in the field experiment. (W₁)-irrigation combined with band application resulted in the highest yield and total N-uptake. Utilization of applied N, however, was higher with (W₂)-irrigation in both fertilizer placements. This result was confirmed by the data of the greenhouse experiment. Band application was superior to broadcast application for fertilizer N-uptake with both water managements. Ammonium sulfate showed the highest and urea the lowest difference between the two fertilizer placements.     

Einfluß der Cl-Ernährung auf Ertrag und Nitratgehalt von Spinat und Kopfsalat

Effect of Cl-supply on yield and nitrate content of spinach and lettuce The N-supply for maximum yield could be reduced for spring spinach from 250 to 200 kg N/ha, for autumn spinach from 200 to 150 kg N/ha without yield depressions by optimized Cl-supply. The optimal Cl-supply consisting of Cl-content in 0–60 cm soil depth and Cl-fertilization was about 350 kg Cl/ha. However, Cl-supply in top soil should not exceed 300 kg Cl/ha in order to avoid emergence decreases. Different amounts of Cl-fertilizer were necessary because soils of experimental sites contained chloride in the range of 66 to 435 kg Cl/ha. The nitrate content was reduced up to 50% by Cl-fertilization. This was caused by reducing the N-supply by 50 kg N/ha and to an increased nitrate reduction. The heighest head weight of lettuce could be achieved with N-supply of 90 kg N/ha and additional Cl-fertilization. Reducing the N-supply from 120 to 90 kg N/ha and improvement of Cl-nutrition decreased nitrate content considerably. Cl-supply should not exceed 150 kg Cl/ha in 0–30 cm, because lettuce reacts sensitive to saline conditions.     

Der Einfluß von Klärschlamm auf die mikrobielle Tätigkeit im Boden

The influence of sewage sludge on microbial activity in soil The effect of untreated, pasteurized and irradiated sewage sludge on soil biology was studied in model and field experiments. Sewage sludge from the sewage plant Geiselbullach in the west of Munich city was used for these experiments. The investigations were performed with 4 soil types according to the different locations. All the results demonstrate that there is an increase in biomass after application of sewage sludge while there were definite influences from the location. No significant relation could be observed according to sewage sludge treatment. Under favourable lab conditions the mineralization of the organic matter applied to the soil with higher amounts of sewage sludge induces in short time a definite decrease in pH. In accordance with these changes in pH there is a corresponding decrease in microbial biomass. Early results on the influence of microbial N-cycle demonstrated that amounts of sewage sludge applied under practical conditions brought an increase in denitrification capacity of the soil. In the experiment with soils nitrification rate was doubled after sewage sludge application.     

Einfluß der N-Düngung von Apfelkulturen auf Nitratgehalte im Boden,stickstoffhaltige Reservestoffe im Baum und Ertrag

Effect of N-fertilization in apple orchards on soil nitrate contents, nitrogenous reserves in the tree, and crop yield It should be investigated how nitrate supply affects crop yields and incorporation and mobilization of nitrogenous reserves with Golden Delicious' apple trees on M 7 and M 9, and whether N fertilizer needs are influenced by N reserves in the trees. Two trials were carried out in 1981–1983. In the first one on al loess soil increasing N levels (0, 40, 80, 120 kg N/ha) were applied. In the second one, on a podsolic sandy soil, N was applied either in spring and/or in August (0/0, 80/0, 40/40, 0/80 kg N/ha). N fertilizers were applied to the herbicide strips only. Both orchards were in their best cropping age. Soil nitrate contents were mainly influenced by N-fertilization. Precipitation and drip irrigation caused translocation of nitrate and leaching from the soil layer investigated (0–90 cm). Thus, on the sandy soil almost no nitrate was left in spring, whereas on the loess soil various amounts of nitrate were still available in the subsoil depending on N fertilization in the preciding year. In plots where N fertilization was at optimum, the soil nitrate contents varied between 65 and 130 kg N per hectare herbicide strip over the main growing season (May–August). In the bark N reserves were mainly proteins, but almost equal amounts of protein and soluble N were found in the wood. N reserves were incorporated into the bark mainly between October and December, but even earlier than September in the wood. They were mobilized from April through July. Arginine was stored in the wood in considerably higher amounts than in the bark. Asparagine contents showed a sharp increase immediately after blossom time, particularly in the bark. There was almost no significant influence of the different fertilizer patterns on incorporation and mobilization of nitrogenous compounds. The N-reserves had no effect on crop weight. Highest crop yields were obtained whenever at least 40 kg N/ha were applied in spring. Additional N supply in August did neither increase incorporation of N-reserves nor crop yields. The nitrogenous reserves in the trees can be ignored in estimating N-fertilizer needs. On the other hand, the soil nitrate contents at bud break in April should be taken into account.     

Einfluß von Ammonium- und Nitratstickstoff auf die Entwicklung von Buchenjungpflanzen

Influence of ammonium and nitrate nitrogen on the growth of young beech plants Young beech plants were grown in aerated nutrient solutions with NH₄ or NO₃ nitrogen for a period of 12 weeks. pH-changes caused by the source of nitrogen were corrected every second day. Absorption of NH₄-N was higher than of NO₃-N. NH₄-N was superior for shoot growth and development of lateral roots, NO₃-N for growth of the main root. Nutrient solution containing both sources of nitrogen was the most favorable.     

Der Einfluß von Fichtennadelwachs auf Nadelzersetzung und Erlenkeimung

The influence of spruce needle wax on the degradation of the needles and the germination of alder seeds 1- and 3-year old needles of Picea abies, each untreated or with the wax layer removed, were burried in a field. Dry-weight of needles without wax decreased faster during an exposition period of 1 to 5 months. Because the wax proved to be a highly selective substrate for microbial colonisation, it retarded the needle degradation. Wax on 1-year old needles slowed degradation down during 2 months, wax on 3-year old needles during 5 months. Degradation time varied for different wax components. The site of wax decomposition was determined by analysing the lipids eluted from different soil layers (depth 0–30 cm) in a natural spruce forest. Lipids forming the wax decreased in depth 1–5 cm and were missing in depth 7–14 cm. Microorganisms isolated from 3 soil layers (depth 1–7 cm) were able to use fatty acids and fatty alcohols out of the wax as a carbon source. But only microorganisms from depth 7–14 cm degraded all wax components. Wax of 1-year old needles delayed seed germination (Alnus glutinosa) for 6 days. Wax of 3-year old needles delayed and inhibited germination for at least 12 days. Pure stearic acid did not influence germination. The different effects show the importance of the chemical wax composition rather than of the water repellent property.     

Über die Wirkung von Pydanon auf Halmlänge und Ertrag von Winterweizen und Winterroggen

Influence of Pydanon upon Stalk Length and Grain Yield of Winter Rye and Winter Wheat. . In pot experiments with three varieties of winter rye a considerable reduction of stalk length was obtained by the growth regulator Pydanon without a significant reduction of grain yield. The necessary amount of active substance however was rather high and the period of time for optimal application was limited. Winter wheat did not respond to Pydanon.     

Einfluß von Stickstoffernährung und Wuchsstoffapplikation auf die Knolleninduktion bei Kartoffelpflanzen

Influence of nitrogen nutrition and application of growth regulators on tuber initiation in potato plants In water culture the effect of continuous and discontinuous N-nutrition on tuber initiation was investigated. Additional applications of growth regulators on growing stolon tips were carried out. Continuous supply of nitrate or ammonium inhibited completely the tuber initiation in S. tuberosum varieties ?Ostara”? and ?Clivia”?, The inhibition was compensated by application of CCC and ABA on the stolon tip. In contrast to this stolon application of kinetin and root application of CCC were ineffective. Temporarily damaging of the root system led to tuber initiation even when nitrogen was supplied continuously. In S. andigena grown under short day continuous N supply only delayed the tuber initiation but could not prevent it. Discontinuous N supply promotes tuber initiation in S. tuberosum. A sudden increase in N supply caused ?re-growth”? of the tuber, i.e. a stolon was formed on the tuber apex. GA₃ application on the growing tuber had the same effect. The effect of N nutrition on tuber initiation can be explained via changing the balance of endogenous growth regulators in general and the physiological aging of the leaves in particular. Discontinuous N supply seems to reduce cytokinin production in roots and therefore accelerates the aging of the leaves. This in turn favours the formation of inhibitors and/or presumably reduces the GA production in the shoot, which will change the balance of the growth regulators in the stolon tip in favour to tuber initiation.     

Redoxprozesse in der Rhizosphäre von Land- und Sumpfpflanzen

Redox processes in the rhizosphere of terrestrial and paludal plants In the rhizosphere of various dicotyledonous cultivated plants (Pisum sativum, Vicia sativa, Helianthus annuus) a decrease of the redox level could be measured close to the root tip using platinum and antimony microelectrodes. There were no changes of redox conditions in the rhizosphere of wheat (Triticum aestivum) and oat (Avena sativa). The reducing capacity of the roots of the dicotyledonous plants is probably due to the release of reducing exudates. The availability of iron to plants was improved by the decrease of the redox level. Roots of reed (Phragmites australis) showed an oxidizing power which was concentrated at the root tip. Close to the root tip aerobic redox conditions were reached even in a strongly reduced soil. This protects the plant against phytotoxic concentrations of reducing substances.     

Der Einfluß von P-Ernährung und pH auf die Phosphataseaktivität von Zuckerrübenwurzeln

The influence of phosphorus nutrition and pH on phosphatase activity of sugar beet roots For the determination of acid phosphatase activity (P_ase) of sugar beet roots (cultivar: Reka), plants were cultivated in nutrient solution with 1 or 100 μM P in a growth chamber for 12, 18, 24, 30, 36 and 42 days. The phosphatase activity of intact roots was measured in buffer solutions with pH 4 to 7.2 and 14 mM p-Nitrophenylphosphate (NPP) after 10 min of incubation at 20°C. The influence of P nutrition on P_ase activity was significant at all intervals. At P deficiency the activity was increased by a factor of 4 to 20. During the experimental period the pH optimum was 6. At pH 5 and 7.2 the P_ase activity reached only 63 and 64% respectively of the optimum value. At P deficiency (1 μmol P L^—1) the absolute rate of NPP-hydrolysis at pH 6 was 144 nmol min¹ m¹ root length (day 12 to 36). The plants which received optimum P supply showed only 10% of this value. Sugar beet roots with P deficiency have a high potential of P_ase activity from the acid to the neutral pH-range. Therefore, under this condition they may effectively use dissolved organic phosphorus compounds.     

Einfluß variierter Temperatur und Feuchte auf mikrobielle Aktivitäten im Boden unter Laborbedingungen

Influence of varied soil temperature and moisture on microbial activities under laboratory conditions Under laboratory conditions the influence of temperature (10°C, 20°C, fluctuation from 5° to 30°C within 12 h with additional freezing for 3 days) and soil moisture (30%, 60% w.h.c., remoistening to 60% for 1 week) on several microbial activities was investigated. The biomass-related, glucose-induced short-term respiration and the dehydrogenase activity (TTC reduction) were higher at 10°C in most cases as compared to 20°C. Independent of freezing fluctuating temperature caused the lowest activities. The nitrogen mineralization (including nitrification), however, was affected in the opposite way. No marked influences were observed with β-glucosidase, arylsulfatase, and alkaline phosphatase. In the sandy loam nearly no effects of the soil moisture occurred and in the loamy sand especially the dehydrogenase activity was higher at 30% w.h.c., whereas the nitrogen mineralization was lower. From the results it can be concluded, that ecological conditions favouring mineralization without substrate addition may even reduce microbial biomass by decomposition.     

Einfluß langjähriger Düngung mit verschiedenen Phosphatdüngerformen auf die Phosphatverfügbarkeit in der Rhizosphäre von Raps

Influence of long-term application of different P-fertilizers on phosphate availability in the rhizosphere of rape The residual P effect was investigated in soils from a 10 years' lasting field trial (North of Hessia, Alfisol-Udalf, pH 5.7) in which different P-fertilizer types had been applied with a rate of 111 kg P₂O₅ ha^?1 a^?1. Soil analysis showed that basic slag phosphate had increased the content of CAL-, H₂O- and EUF extractable P in the soil to a higher extent than Novaphos (partially acidulated phosphate rock) or Hyperphos (phosphate rock). In the latter treatment the highest content of DL soluble P was found as compared with the other P-fertilizer types. Pot experiments with rye-grass, rape and maize showed that P recovery was highest from the soil with the basic slag treatment and lowest in the treatment with Hyperphos, Novaphos taking an intermediate position. This finding demonstrates that the DL-method does not provide a reliable information on the P-availability of a soil, if treated with rock phosphate. The level of water soluble P in the rhizosphere of rape was investigated with a particular technique (Kuchenbuch and Jungk, 1982). It could be shown that the P level in the rhizosphere of the Hyperphos treatment was only slightly higher than the P level of the P₀ treatment (without P fertilizer) while in the Novaphos – and particularly in the basic slag treatment much higher levels of soluble P were found. It thus becomes evident that even in the rhizosphere the solubility of Hyperphos was poor. The levels of water soluble P in the rhizosphere followed a depletion curve. The steepest gradient was found for basic slag, followed by the Novaphos-, Hyperphos- and the P₀ treatment.