Einfluß der Löslichkeit verschiedener Phosphatdüngemittel auf die Phosphataufnahme und den Ertrag von Sommerweizen

Solubility of various phosphate fertilizers in a brown podzolic soil and their effect on phosphate uptake and yield of spring wheat. The solubility of various phosphate fertilizers (Superphosphate, Rhenaniaphosphate, Novaphos, Carolonphosphate and Hyperphosphate) was studied in an incubation experiment, and P uptake and yield effect of these fertilizers were investigated in a pot experiment. The soil used was a carbonate free brown podzolic earth (C horizon) with a neutral pH and low in available phosphate and humus. The quantities of P extracted from the soil by the EUF technique were the lower, the higher the amount of non processed phosphate of the incubated P fertilizers. This clear differentiation in the solubility of the various P-fertilizers was not obtained by the DL extraction. The P uptake of plants was highly correlated with the P quantities extracted by EUF (r = 0,95***), while the correlation between P uptake and the P of the DL extract was less narrow (r = 0,64*). The yield, particularly the grain yield, decreased with an increase of the non processed P in the fertilizers tested. Grain yield and EUF extractable P were highly correlated (r = 0,86***); while the relationship between grain yield and the DL extractable P was poorer (r = 0.62*). The experiments have shown that mainly the easily soluble phosphate is of decisive importance for the yield formation.     

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 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.     

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.     

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 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.     

Einfluß des Bodengefüges auf Wurzelwachstum und Phosphataufnahme von Sommerweizen

Influence of Soil Structure on Root Growth and P Uptake of Spring Wheat The effect of soil structure (fine aggregat, coarse aggregate and compacted structure) on root growth, root morphology, and P availability of spring wheat (Triticum aestivum L.) was studied in pot and split root experiments using three soils (2 × Alfisol-Udalf, Alluvium). CAL-soluble P was 63–90 mg P · kg^?1 soil, indicating a sufficient P supply. Root length, root surface, root fresh weight, shoot weight, and seed yield were decreased due to coarse aggregate and compacted structure. Roots were significantly thickened and roots hairs were longer in the fine aggregate structure than in the compacted and coarse aggregate structures. P concentration in the shoot and P uptake of spring wheat growing in the coarse aggregate and compacted structure were lower because root growth was decreased. In the split root experiment, in contrast to pot experiment, P uptake was lower in the compacted than in the fine aggregate treatment. The results demonstrate that P availability was influenced by soil structure via the influence on root growth and thus access of roots to P.     

Entwicklung und Ertrag von Sommerweizen in Hydrokultur unter dem Einfluß verschiedener Ernährungsbedingungen

Development and yield of spring wheat in water culture as influenced by nutrient concentration. The development of spring wheat cv. Solo grown until maturity in nutrient solutions of normal concentration changed weekly, differs from similar plants growing in soil. In experiments in which nutrient supply was reduced at different growth stages, an attempt was made to minimize the differences. These consist mainly of permanent tillering, retarded senescing of leaves and in dry matter accumulation in the grain. 1) Reducing the total nutrient supply during the grain filling period decreases the chlorophyll-con-tent of the flag-leaf at an earlier stage and hence also its ability to assimilate CO₂. This reduction in nutrient supply has thus a beneficial effect on the development of the grain by allowing a better coordination with leaf senescence and an increase in nitrogen and dry matter transfer from the flag leaf to the grain. 2) The retarded response to a reduction of the nutrient concentration points to a “luxury consumption” in the vegetative phase. This might be the reason why it was not really possible to achieve optimal timing of vegetative and generative development. 3) After examination of the effect of lowering the nutrient supply in the vegetative phase, a nutritional design for growingspring wheat in water culture was proposed. This consists of lowering the concentration to meet the needs of plants and comprises a rise and fall of the concentration (0.25,0.5, 0.75,0.5 and 0.25 of the normal conc., see fig. 4). 4) Comparing 0.4 and 0 mMol/l N during the grain filling(other nutrients supplied according to the concept outlined above), the relevance of nitrogen for the CO₂,-assimilation capacity and more obviously for the senescence of the flag leaf was shown. Nitrogen deficiency decreases the assimilation ability within a short time and depresses grain development. These findings confirm the validity of the nutritional concept proposed.     

Untersuchungen über den Einfluß von Gibberellinsäurespritzungen auf den Ertrag,die Anatomie der Wurzel und die Karotinverteilung bei Karotten

Investigations on the Influence of Gibberellic Acid Treatments on Yield, Root Anatomy and Carotene Distribution of Carrot Plants . Application of GA₃ onto the shoots of carrot plants increases shoot growth whereas root growth was reduced. Furthermore, due to the GA₃-application carotene content (Table 2) in the shoots was increased and decreased in the roots. Anatomical investigations of the roots revealed that apparently the reduction of root growth after GA₃-application was due to a decrease of phloem oriented cambial activity (Table 3).     

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 von NaCI-Salinität auf die CO2-Assimilation und auf den Einbau von 14C in verschiedene Inhaltsstoffe bei jungem Sommerweizen

Effect of NaCI salinity on CO₂ assimilation and incorporation of ¹⁴C in various chemical fractions of young wheat plants The effect of an increasing NaCI salinity on CO₂ assimilation and on the distribution of ¹⁴C in various chemical fractions of young wheat plants was studied. Increasing salinity restricted growth and in particular ¹⁴CO₂ assimilation being measured at the end of the experimental period. Correspondingly the amounts of ¹⁴C found in the various chemical fractions (amino acids, organic anions, carbohydrates, proteins, lipids, insoluble residue) were decreased with an increase in salinity. The relative distribution of ¹⁴C in the chemical fractions also was affected by salinity. At low salinity level a relatively low ¹⁴C concentration was found in the low molecular fractions, while the high molecular fractions showed a relatively high ¹⁴C concentration. At high salinity level this tendency was only weakly evident. Increasing salinity had no major impact on the nutrient concentrations (N, P, K, Ca, Mg) in the shoots, whereas the concentration of Na and especially of CI was remarkably raised. It is assumed that this excessive Na and CI concentrations in the shoots are resulting in the yield depression.     

Einfluß der VA-Mykorrhiza auf P-Aufnahme und Regenerationsfähigkeit von Mais (Zea Mais L.) unter Wasserstreß

Influence of the VA-Mycorrhiza on P uptake and recovery potential of corn (Zea mays L.) under water stress conditions In a seven week pot experiment the influence of the VA-Mycorrhiza on P uptake and water stress tolerance of corn was investigated. During the eight day water stress period the VAM-plants took up less phosphorus than the control plants. However, during the successive five day recovery period under a normal water regime the VAM-plants showed an increased root growth and an enhanced phosphorus uptake compared with the control plants. The free prolin concentration was lower in leaves of VAM-plants than in those of nonmycorrhizal plants at the end of the water stress period, pointing to a different water stress tolerance.     

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 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.