Die Wirkung von Branntkalk auf den Wasserhaushalt eines vulkanischen Aschenbodens aus Südchile (Trumao) im Gefäßversuch

Effect of burnt lime on water regime of a soil formed on volcanic ashes in Southern Chile (Trumao) A dystrandept of the south of Chile was mixed with 5% in weight CaO. The variation in water balance of limed and unlimed samples of this soil was studied. The liming provokes a disminution in the evaporation. The surface of the limed soil drys very rapidly, in relation to its unlimed equivalent, in such a way that it serves as a transpiration barrier. The decrease in the water loss favourably influenced growth of lettuce plants.     

Der Einfluß variierter Düngergaben von Stickstoff,Kupfer und Magnesium auf den Ertrag von Hafer

The Influence of varying Amounts of Nitrogen, Copper and Magnesium on the Yield of Oat 1. In pot experiments with oat high amounts of copper (500 mg) copper sulfate/pot, comparable to 50 kg (Cu/ha) together with a high nitrogen supply as calcium nitrate led to a remarkable increase in yield of grain in comparison to a normal copper fertilization (50 mg copper sulfate/pot, comparable to 5 kg Cu/ha). When using high amounts of ammonium sulfate the observed effect of high amounts of copper was only small. 2. According to the results and to the copper content and copper uptake of the plant it was concluded, that nitrogen fertilization given as ammonium sulfate increased the availability of soil copper and/or fertilizer copper presumably by affecting the soil reaction. Nitrogen fertilization given as calcium nitrate therefore needs a higher copper level in the root medium either from soil or fertilizers in order to obtain the maximum yield. 3. It was assumed that the form of nitrogen fertilizers was responsible for the different availability of copper in these experiments, as the amount of available copper in the soil increased with the lowering of soil pH due to ammonium sulfate addition. 4. The high copper supply to the soil remarkably reduced the harmful effect of high amounts of nitrogen given as calcium nitrate but not as ammonium sulfate. 5. The nitrogen fertilization with calcium nitrate, especially in combination with a high copper supply, resulted in the reducing effect of a magnesium deficiency. 6. The harmful effect of high amounts of nitrogen, especially in the ammonium sulfate form, upon yield was reduced by an optimal magnesium supply. 7. The results presented suggest that for evaluating the copper status of the soil and for estimating the demands of copper fertilization, soil reaction and its change by the form of nitrogen fertilizers should more be taken in consideration.     

Die N-Mineralisierung von Böden im Laborbrutversuch

N mineralization in soils under laboratory incubation conditions The potential rate of release of nitrogen by the organic matter in agriculturally used soils was determined under laboratory conditions by means of incubation. Mineralization of the more resistant soil organic matter proceeded linearly with time during an incubation period of 2–3 weeks, when field-moist and air-dried samples were used and at the beginning of the incubation experiment sufficient water was added to bring them to saturation. Mineralization was taking an exponential course in soils with additions of easily decomposable organic matter or in soils with a higher proportion of organic residues from crops. For the 14 investigated arable and grassland soils great variations in the average daily rate of mineralization were found ranging from 5–60 μg N_min/10 g DM. The data correlated very well with the biomass (r = 0.96) and the cell-free protease activity (r = 0.98) of the soils. Different measures of soil management (preceding crops, application of sewage sludge, addition of heavy metals) had a more or less pronounced influence on the rate of mineralization. The optimum temperature was 50°C for N mineralization and 26°C for nitrification. Contrary to nitrification, the soil reaction had only little influence on mineralization and proved also independent of the N_min content of soils. The results indicate that ammonification of organic N compounds may largely proceed via the microbial biomass.     

Die Bedeutung der Umsetzung von Weizenstroh im Hinblick auf den C- und N-Haushalt von Löß-Ackerböden

The significance of wheat straw decomposition with regard to the C- and N-cycle of a cultivated loess soil In 1984/85, a microplot experiment with ¹⁵N-enriched fertilizer was carried out on a field of the Calenberg loess area near Hannover (surface area of the plots: 1 ± 2 m; experimental soil: stagnigleyic cambisol from loess). On the one hand, the extent of immobilization as well as remobilization of native soil- and fertilizer-N associated with straw incorporation (± 8 t/ha) was quantified. On the other hand, the turnover as well as the alteration of C- and N-masses in the decomposing straw material was studied. About 70% of the initial dry organic matter of straw was mineralized within one year. An enrichment of fertilizer-N as well as native soil-N in the residues of up to 20 kg/ha was observed as compared to the initial N-mass. On a microplot cropped with winter-wheat, microbial N-immobilization of about 30–40 kg/ha (native soil-N and fertilizer-N) occured in the soil after straw incorporation. The immobilization extended to march 1985. Subsequent, associated with a C/N-ratio in the straw of 43, N-remineralization as well as -extramineralization was observed with 40 kg/ha at maximum in december 1985.     

Die Wirkung von ausgefaultem Klärschlamm auf den Stoffwechsel 3jähriger Fichten und Kiefern

Effect of digested sewage sludge on the metabolism of three year old spruce and pine trees. Three year old Norway spruce and Scots pine trees were grown in mixtures of sand and sewage sludge. The mixtures used were composed of 5 litres of sand and 1.25 or 1.67 litres of digested sewage sludges from municipal waste water treatment plants. A mixture of 5 litres of sand and 1.67 litres of peat was used as a control. In all cases sewage sludge depressed growth as measured by height and the yields of fresh material. The contents of N, Ca, Mg, Zn in the needle dry matter were higher than in control. The P content was only increased in the newly formed needles in the high sewage sludge treatments. However, the corresponding Mn contents were depressed, also the K contents in spruce. The higher rate of nitrogen assimilation, in the sewage sludge treatments especially in spruce, lead to a greater accumulation of the amino acid arginine and also to a reduction in the content of organic acids and polyphenols. These effects do not explain why some plants died. For spruce a lethal factor appears to be the depression of water uptake combined with high transpiration. The ratio of K/Ca in the needles was extremly low, which indicated a possibility of both potassium deficiency and calcium toxicity. The observed enrichment of proline is also associated with water stress. Scot pine was more sensitive than spruce to treatment with sewage sludge. In all treatments with sludge some Scot pine trees died, especially when municipal wastewater sewage sludge was used.     

Wirkung von Gummimehl auf Phaseolus vulgaris

Effects of ground rubber on Phaseolus vulgaris Phaseolus vulgaris was grown in sand culture containing ground rubber. The rubber caused red-brown and black spots and stripes to appear on the veins. The leaves developed widespread chlorosis. The vascular bundle tissues and the mesophyll differentiated incorrectly. Brown deposits were found in all tissues, some being manganese enriched. Plants were analysed for Boron, Cadmium, Manganese and Zinc after a vegetation period of 49 days. Zinc toxicity was considered ground rubber's primary effect. It also caused Boron starvation and excess of Manganese.     

Evapotranspirationsbestimmungen an Hafer im Gefäßbestand zur Beurteilung von Fruchtfolgewirkungen

In den Jahren 1982 bis 1988 wurde auf zwei Flußauenstandorten im Gebiet der mittleren Elbe die Einsaat von verschiedenen wertvollen Gräsern in Dauergrünlandnarben geprüft. Die eingesäten Zuchtgräser vermochten minderwertige Dauergrünlandbestände mit hohen Anteilen von Agropyron repens über einen Zeitraum von vier und mehr Jahren zu guten und sehr guten Pflanzenbeständen aufzuwerten. Eine chemische Behandlung der Grünlandnarbe mit einem graswuchshemmenden Mittel vor der Einsaat förderte das Etablieren der eingesäten Gräser.     

Versuche mit Bor an Lemnaceen Die Wirkung des Bors auf den Kohlenhydratgehalt vonLemna minor L

Zusammenfassung Bormangel führt beiLemna minor zu extremer Stärkeakkumulation. Da Translokationsschwierigkeiten kaum eine Rolle spielen können, muß eine Beeinflussung des Kohlenhydratstoffwechsels durch Bor angenommen werden. Bormangel bewirkt eine erhebliche Herabsetzung des Eiweißgehaltes zugunsten löslicher Verbindungen. Der relative Trockengewichtsanteil am Frischgewicht ist stark erhöht, vermutlich infolge Vermehrung von Zellwandmaterial.

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Summary Boron deficiency exerts an extreme accumulation of starch inLemna minor. This seems to be mainly due to an influence of boron on carbohydrate metabolism rather than to any effect on translocation owing to the small size of the organism. The protein content is remarkably reduced in favour of soluble nitrogen. The elevated relative dry weight is considered to be mainly a consequence of an increased level of cell wall material.

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Lemna minor - . , . . — , .

     

Die Wirkung verschiedener im Frühjahr und Herbst durchgeführter Bodenbearbeitungsmethoden auf lehmigem Sand

Es werden die Kaliumbilanzen von 6 unterschiedlichen hydromorphen Mineralböden mitgeteilt. Die Untersuchungszeit betrug 13 bis 19 Jahre. Die Lysimeterböden wurden im intensiven Futterbau genutzt. Obwohl die jährliche K‐Düngung im Mittel 18...19 g.m‐²(180...190 kg.ha^?1) betrug, ist bei allen Böden die Bilanz negativ. Der mittlere jährliche K‐Verlust aus dem System Boden schwankt zwischen 5,5 und 21,6 g.m^?2(55...216 kg.ha^?1)· Den höchsten Verlust erlitt ein Sand‐Humusgley, den geringsten ein Tieflehm‐Humusamphigley. Der engste Zusammenhang ergab sich zwischen absolutem K‐Vorrat und dem K‐Verlust.     

Einfluß von Silizium auf den Bindungszustand von Mangan im Blattgewebe von Bohnen (Phaseolus vulgaris)

Effect of silicon on the chemical state of manganese in bean leaf tissue (Phaseolus vulgaris L.) In water culture experiments with bean plants the effect of different manganese supply and of silicon on the chemical state of manganese in the leaf tissue has been studied. Water, KCl, EDTA and methanol have been used for extraction. Water extracted up to 80% of the total manganese from previously frozen or freeze dried leaf tissue. This water soluble fraction of manganese showed a positive correlation with manganese supply and leaf age. Silicon had no effect on the manganese extractable by water, KCl or EDTA. The high proportion of manganese in the water extract is probably the result of manganese oxides (MnO₂?) being dissolved during extraction by organic cell constituents e.g. organic acids. Therefore, in vivo less manganese is water soluble than the amount extractable with water. In contrast to water, methanol extrated less than 10% of the total manganese. Silicon supplied in the culture solution doubled the amount of manganese extracted from the leaves by methanol. This result suggest that by affecting the compartmentation of manganese silicon increases the soluble manganese in vivo, which could partly explain the increase in manganese tolerance of the leaf tissue in presence of silicon.     

Einfluß von Stroh und Nitrapyrin auf den verfügbaren Stickstoff im Boden,den Ertrag und den Stickstoffentzug von Lolium multiflorum

Effect of straw and nitrapyrin application on the nitrogen availability in the soil and the yield and nitrogen uptake of Lolium multiflorum. In pot experiments the effect of straw and nitrapyrin application on the turn-over of fertilizer NH and on the nitrogen availability in the soil was investigated. The investigation comprised two sections: an incubation experiment in which straw and nitrapyrin together with NH-N were incorporated into a brown podsolic soil and a subsequent pot experiment with ryegrass. Nitrapyrin inhibited the nitrification and reduced the nitrogen loss of the soil. Compared with the treatments without nitrapyrin application, nitrapyrin resulted in a lower dry matter yield and in a lower nitrogen uptake of the ryegrass. Straw application reduced the nitrate content in the soil significantly. This effect was particulary evident in the treatments which did not receive nitrapyrin. Accordingly, nitrogen uptake and yield of ryegrass were significantly lower in the ‘straw treatments’ as compared with the treatments without straw. It is suggested that the impared nitrogen availability in the ‘straw treatments’ was mainly due to nitrogen losses caused by denitrification.