摘要:

Computersimulationsmodell des Phosphat‐ und Stickstofftransportes durch WassererosionAnhand der Ausarbeitungen vonMeyerundWischmeier(1969) undIshihara(1967) wurde mit einigen Abänderungen ein Computermodell entwickelt, das den Prozeß der Bodenerosion durch Regen und Wasserabfluß beschreibt. Das Modell berechnet die Pflanzennährstoffmengen, die während des Erosionsprozesses von der Oberfläche weggeschwemmt werden. In der ersten Phase berechnet das Modell die Wasserabflußrate auf der Bodenoberfläche und in der obersten Bodenschicht und danach den Anteil der verschiedenen Erosionsmechanismen am Verlust von Phosphor, Stickstoff und Bodenmaterial.Eine Anzahl von Computerdurchläufen mit verschiedenen Parametern zeigt die Empfindlichkeit des Modells für Änderungen der Bodeneigenschaften und Reg

ISSN:0044-3263    

DOI:10.1002/jpln.19781410402

出版商:WILEY‐VCH Verlag    

年代:1978

数据来源: WILEY

摘要:

Influence of the amount of sulfur supplied on the soluble leaf protein, the synthesis and the specific activity of some enzymes of young sunflower plantsThe influence of a sulfur supplement on the pattern of leaf proteins, soluble in 0.1 M phosphate buffer, pH 7.5, was studied in experiments with young sunflower plants. The leaves were harvested after growing periods of 14 and 21 days, respectively.In addition, the electrophoretic distribution of isoenzymes of some enzyme systems and their specific activities have been analyzed.1. Plant fresh weight was not affected by the level of sulfur supply, although symptoms of S‐deficiency were observed in the low S‐treatment.2. In contrast to this finding, a clear effect of S‐deficiency on the electrophoretic patterns of the leaf proteins was detected. This was specially the case in plants. grown for three weeks at a low sulfur level. Increased contents of low molecular protein fractions were found, whereas the relative amounts of high molecular proteins were reduced.3. In plants, which were kept S‐deficient, the number of isoenzyme components was lower in comparison to plants, which were adequately supplied with sulfur. The isoenzymes of malate dehydrogenase and acid phosphatase, however, were synthesized to about the same degree in both S‐treatments.4. The specific activities of most of the enzymes studied in these investigations were lower in the plants, grown at S‐deficiency in comparison with the control. These findings were particularly evident after a growth period of 3 weeks. The specific activities of glutaminate dehydrogenase, succinate dehydrogenase and a‐ketoglutarate dehydrogenase were not significantly influenced by the level of S‐supply. The specific activities of acid phosphatase and malate dehydrogenase were relatively high even in those plants, which were treated with low am

ISSN:0044-3263    

DOI:10.1002/jpln.19781410403

出版商:WILEY‐VCH Verlag    

年代:1978

数据来源: WILEY

摘要:

AbstractIncreasing salt concentration from 10−4N to 3 × 10−3N increased the uptake and percent of N and P in shoots and roots of barley and broad bean plants. This effect was higher the higher the cation valence and the lower the anion valence following the order CaCl2>KCl ⩾ K2SO4. The increase in N and P uptake was higher in broad bean plants having higher C.E.C. than in barley having lower

ISSN:0044-3263    

DOI:10.1002/jpln.19781410404

出版商:WILEY‐VCH Verlag    

年代:1978

数据来源: WILEY

摘要:

Forms of phosphates in underwater soils of Ca‐rich running watersUnderwater soils of small carbonaceous rivers in Upper Bavaria have phosphorus contents between 300 ppm in oligotrophic creeks and more than 0.2% in heavily polluted waters. The (Al,Fe)‐P and the Ca‐P occupied 20–35% and 28–38% of total phosphorus (Pt) resp., so that inorganic phosphates represent 53 to 64% of Pt. The correlation between Ptand carbonate is negative, but is positive between Ptand oxalate Fe or organic substance. Addition of P results in a relative increase of (Al,Fe)‐P compared with other forms. Approximately 7 to 15% of total P is subject to isotopic excha

ISSN:0044-3263    

DOI:10.1002/jpln.19781410405

出版商:WILEY‐VCH Verlag    

年代:1978

数据来源: WILEY

摘要:

Pore size distribution and soil fertility A contribution concerning the physical classifikation of soils at soil mapsTesting the physical classification of soils at soil maps pore size distribution of 17 well drained soils was measured. The results obtained for the 0–100 cm soil depth were correlated to land values as given in the „Reichsbodenschätzung”︁. Statistical evaluation of the data gave the following results: 1) Negative correlation (r = −0,11) between pore space pF 1,8–2, 9 and soil fertility. 2) Moderate correlation (r = 0,54) between pore space pF 1,8–4, 2. 3) Very close correlation (r = 0,95) between pore space pF 2,5–4, 2 and pF 2,9–4,2, respectively, and soil fertility. 4) Fair correlation (r = 0,76) between pore space pF>4,2 and soil fertility.Therefore soil fertility is strongly dependent on physical factors related to pore size distribution and concerning water and N‐economy of soils. In our humid climate the factor N‐economy obviously has a stronger bearing on soil fertility than the factor soil water.The results make it possible to classify the soils in relation to N‐economy and water supply using the same index of pore size distribution. With the pore space pF 2,5–4,2, fertility and filter properties of soils are comprehended in the best manner. The terminus „Kapillare Sorptionskapazität”︁ is proposed to define both the factors.Finally some consequences are mentioned concerning plant nutrition and N‐fertilizing in regard to the

ISSN:0044-3263    

DOI:10.1002/jpln.19781410406

出版商:WILEY‐VCH Verlag    

年代:1978

数据来源: WILEY

摘要:

AbstractGülle samples were unstable during both storage and experimentation. Phosphate concentrations in solution decreased quite sharply during the first month of storage at either 4°C or laboratory temperature, and thereafter continued to decrease at a slower rate until pseudoequilibrium was reached after 80–100 d

ISSN:0044-3263    

DOI:10.1002/jpln.19781410407

出版商:WILEY‐VCH Verlag    

年代:1978

数据来源: WILEY

摘要:

AbstractGrowth characteristics of the earthwormEudrilus eugeniaeand the impac of its activity on soil properties were studied in soil culture. The highest growth rate, fecundity and total weight increase were recorded in cassava mulch, compared with cocoyam mulch, grass and plantain pseudo trunk mulch treatments. With animal manure treatments, growth rate was highest in poultry manure compared with cow and goat manures although total weight increases were highest in poultry and goat manures and lowest in cow manure. The worm activity expressed as percentage reduction of soil bulk density was greatest in cassava mulch followed by grass mulch, cocoyam mulch and plantain pseudo trunk mulch in that order. Various animal manures did not differ in this aspect. Total soil N and soil organic matter increased significantly in cassava and grass mulch treatmens while in plantain pseudo trunk mulch these factors decreased. Soil pH increased in cocoyam and plantain mulch treatments and decreased in cassava and grass mulch treatments.

ISSN:0044-3263    

DOI:10.1002/jpln.19781410408

出版商:WILEY‐VCH Verlag    

年代:1978

数据来源: WILEY

摘要:

Determination of urease activity by two different methods in some soils and underwater soilsTwo methods differing in microbial activity during incubation with urea were used for the determination of urease activity. The results obtained showed a better relationship with natural conditions such as pH, organic substance‐, or clay content, if the microbial activity was not inhibited during incubation. This effect was found to be particularly pronounced in underwater soils, where addition of a bacteriostatic substance (toluene) resulted in practically uniform values that reflected neither bacterial nor nutrient statu

ISSN:0044-3263    

DOI:10.1002/jpln.19781410409

出版商:WILEY‐VCH Verlag    

年代:1978

数据来源: WILEY

摘要:

AbstractSorption of phosphate by hydrous oxides of aluminium was studied as a function of pH, presence of chelates of aluminium and of the specific surface areas of the oxides.Aluminon was most effective in reducing P sorption followed by oxalic acid and EDTA. Acetylacetone, 8‐hydroxyquinoline, salicylic acid and fluoride affected little P sorption. The sorption was found to be higher the higher the value of the specific surface area of the oxide, but the shape of the sorption curve was the same for all the oxides studied, exhibiting a maximum at about pH 5. This maximum was found to coincide with the point of zero charge as determined in the presence of acetate ions. The sorption data are explained in terms of a ligand exchange mechanism in which phosphate chemisorbs on surface aluminium atoms displacing uncharged surface hydroxyl

ISSN:0044-3263    

DOI:10.1002/jpln.19781410410

出版商:WILEY‐VCH Verlag    

年代:1978

数据来源: WILEY

摘要:

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 vivoless 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 manganesein vivo, which could partly explain the increase in manganese tolerance of the leaf tissue in presence of silicon.

ISSN:0044-3263    

DOI:10.1002/jpln.19781410411

出版商:WILEY‐VCH Verlag    

年代:1978

数据来源: WILEY