摘要:

Potassium nutrition of tobacco on a potassium fixing alluvial soilA field experiment was conducted to study the effects of K‐fertilization on potassium uptake by tobacco and the K‐dynamics in an alluvial soil rich in clay and carbonate content. It was observed that the amount of exchangeable potassium and the concentration of K in the soil solution increased on fertilization. There were only small changes in exchangeable potassium and significant reduction in the concentration of K in the soil solution during the growth period.Uptake of potassium by plants increased during first month due to its high concentration in soil solution. Decrease in the concentration of potassium after one month caused a rapid reduction in the uptake of potassium by plants (Figure 1).K Fertilization decreases the K‐Ca and K‐Mg potentials especially during the first month (Table 2) which increase again during the experimental period (because of the slow release of K from the solid phase and its rapid uptake by plants). Where as the concentration of potassium in the soil solution is closely related with K‐Ca and K‐Mg potentials on the one hand and with K‐uptake by plants on the other, no relationship was observed between exchangeable potassium content and K‐uptake (Figure 2).The potassium exchange curves of soils from K0and K5treatments show that the extent of K‐adsorption is greater in K0soil. A major part of K adsorbed during the shaking experiment can be easily removed by CaCl2solution in K5soil, where as in K0soil a part of adsorbed potassium exists in nonexchangeable form. Illite is the dominant clay mineral in this soil which show wedge type structures (exp

ISSN:0044-3263    

DOI:10.1002/jpln.19781410502

出版商:WILEY‐VCH Verlag    

年代:1978

数据来源: WILEY

摘要:

Tissue culture under conditions of boron deficiencyCambium tissue from sunflowers and carrots were cultured in nutrient solution according toMurashigeandSkoogwith graduated supplies of boron. A light‐coloured and well growing callus was formed only in the presence of boron. Explants on a boron‐deficient medium agglutinated at the edges, had only small areas of cell division and revealed appositions on the walls of some cells. Deficient tissues also became noticeably darker.Callus grown on normal medium and then transferred to boron‐deficient medium slowed down in growth rate – at the latest after 4 weeks – and also turned dark. In contrast to normal calli, the deficient cultures could not be easily separated in water into individual cells or small cell groups. Moreover, the cells were smaller on the average and often revealed grainy contents and (in the case of carrots) accumulation of plasma at the ends of the cells. A large number of deficient cells were plasmolyzed.An accumulation of undifferentiated cells in the cambium region is particularly striking in dicotyledons under conditions of boron deficiency. If this symptom should be the result of cell division activity, then isolated cambium should react to boron deficiency with intensive cell division. Contrary to expectation, isolated cambium of sunflowers and carrots in tissue culture did not reveal a promotion of cell division under conditions of boron deficiency.These results indicate that the symptom of “increased cambium growth” in intact dicotyledons is due to a secondary effect of bor

ISSN:0044-3263    

DOI:10.1002/jpln.19781410503

出版商:WILEY‐VCH Verlag    

年代:1978

数据来源: WILEY

摘要:

Dynamics and fixation of potassium in soils of North‐West‐IranThe following results were obtained from experiments conducted on two calcareous soils (A‐horizon) and on two soil samples from fertilizer experimental plots (K0= control plot, K5= 1000 kg K2O/ha) to study the dynamics and fixation of potassium in these soils:The K‐exchange curve of K5sample when compared with K0sample showed that, as a consequence of high fertilizer dose, most of the specific adsorption sites for cations (particularly on illites and weathering products of illites) were occupied by K which, thus, resulted into lower K‐adsorption as well as fixation.The shape of K‐exchange curves of other three samples (Alluvial soil, 16, Brown soil 26 and K0sample, Fig. 5 and 6) indicates a typical bend at definite activity ratios. This bend in the exchange curves exists apparently in soils containing high content of illitic clay mineral fraction. This behaviour has been interpreted as a consequence of contraction of layers of illitic minerals which were formerly expanded due to loss of potassium.The K‐desorption experiment, which then followed, showed that a major part of sorbed amounts of potassium could not be desorbed and remained fixed in the soil.Similar type bend as in the exchange curve was also observed in the potassium fixation curves (Fig. 6 and 7).Illite is the dominant clay mineral in all these soils which in Brown soil and K0‐sample is expanded at edges; the expansion goes back to 10 A on treatment with K which then does not expand again on sat

ISSN:0044-3263    

DOI:10.1002/jpln.19781410504

出版商:WILEY‐VCH Verlag    

年代:1978

数据来源: WILEY

摘要:

Influence of compost and Fe‐compunds on the uptake of Fe, Zn and Mn by sunflower and maize in pot experimentsThe 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 pla

ISSN:0044-3263    

DOI:10.1002/jpln.19781410505

出版商:WILEY‐VCH Verlag    

年代:1978

数据来源: WILEY

摘要:

Transformation and effect of urea – dicyandiamide and ammonium sulphate – dicyandiamide products with ryegrass and riceThe transformation of urea or ammonium sulphate fertilizers both in combination with dicyandiamide was tested in soil under aerobic conditions. Nitrification was determined after percolation and different incubation periods by measuring the amount of nitrate leached.The mineralisation of urea and ammonium sulphate in the fertile soil was relatively quick. However the addition of 5 to 10 % DCD of the total fertilizer‐N inhibited vigorously the nitrification for 6 weeks, 20 % DCD even for 10 weeks. In this way the danger of nitrate leaching was greatly diminished and a slow and constant release of available nitrogen rendered.After a preceding aerobic incubation (up to 4 weeks), flooding and rice‐seeding diminished the nitrogen losses by leaching and denitrification remarkably in the Ha/DCD – as well as AS/DCD‐pots if compared to urea or ammonium sulphate alone. This effect was particulary clear after a 4 weeks incubation period. Therefore these urea – and ammonium sulphate‐dicy‐andiamide products guarantee a proper and constant N‐nutrition of the rice plants and may decrease the N‐losses caused by leaching and denitrification.Nitrogen fertilizers with nitrification inhibitors are of special interest for rice culture, because they allow a better timing of N‐fertilizer application, rice seeding and water flooding and render a more economical utilization

ISSN:0044-3263    

DOI:10.1002/jpln.19781410506

出版商:WILEY‐VCH Verlag    

年代:1978

数据来源: WILEY

摘要:

Macro‐ and Microsymptoms of Zinc Deficiency in Higher PlantsThe development of zinc deficiency symptoms was studied in eight different plant species grown under controlled experimental conditions in soilless sulture. The following results were obtained.One symptom of zinc deficiency was found to be the development of a violet to red colouring matter which first appeared in the form of small dots or as spots of discolouration which later covered the entire leaf. This discolouration was found primarily in young but already completely developed leaves. Here, the symptoms started to devlop in single cells.Further symptoms of zinc deficiency were observed to be a retarded growth, short internodes, small leaves and a very poor formation of root

ISSN:0044-3263    

DOI:10.1002/jpln.19781410507

出版商:WILEY‐VCH Verlag    

年代:1978

数据来源: WILEY

摘要:

“Mobile fractions” of trace elements (Be, Cu, Cd, Co, Pb, V, Zn) in soils of the Bärhalde‐granite area0.01 n NH4OH is suitable for extracting the „mobile fraction”︁ of trace elements. Along with the exchangeable fraction, organically bound components are predominantly extracted from the top soil, while in the subsoil, the oxide fraction is mainly extracted. An average of 80–90% of the extract is composed of organic substances and Al and Fe hydroxides.Pb and Cd in the soil primarily stem from airborne immissions. Zn, V, Cd, Co and Cu are to a great extent incorporated into the organic cycle. All investigated trace elements are more or less subjected to podzolization, wet leaching, and slope gleying processes. Here the tendency for the re‐enrichment of Zn and Cd is much reduced, whereas that for Cu, Co, Pb and Be is manifest.In the mineral soil horizons the trace elements are more mobile than the macro‐elements, while in the organic layers they are less mobile than the macro‐nutrients K, P, Ca, and Mg. Be, Co, Cu, and Zn occur primarily in oxidic bonded forms; Pb is mainly organically bound. Co is most highly involved in redox processes.The mobility in the mineral soil increases in the following order: Zn>Cd = V>Pb>Cu>Co>Be; in the organic layers it is as follows: Zn>V>Cd>Cu>Co>Be>Pb.Therefore Zn, Cd, and V are primarily mobile elements; in contrast Co, Be, and Pb are predo

ISSN:0044-3263    

DOI:10.1002/jpln.19781410508

出版商:WILEY‐VCH Verlag    

年代:1978

数据来源: WILEY

摘要:

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.

ISSN:0044-3263    

DOI:10.1002/jpln.19781410509

出版商:WILEY‐VCH Verlag    

年代:1978

数据来源: WILEY

摘要:

The sorption of phosphate by underwater soils rich in carbonateThe phosphate sorption isotherms for carbonate rich under water soils (Unterwasserboden) can frequently be linearized by a modified Freundlich‐isotherm when one assumes that, because of previously sorbed phosphate, the concentration of the equilibrium soil solution, P1,0is greater than 0.However, in many cases, the character of the phosphate sorption can be adequately determined with only one phosphate addition (Ps,500). Both methods show that for dried samples from under water soils, the samples from reduced horizons have a higher P sorption than for the associated oxidized horizons. This can be explained by the presence of very sorption active ferrihydrite which has precipitated from previously biologically reduced materia

ISSN:0044-3263    

DOI:10.1002/jpln.19781410510

出版商:WILEY‐VCH Verlag    

年代:1978

数据来源: WILEY

摘要:

The resistance to penetration of model soils depending on water tensionThe device used for measuring resistance to penetration (Becher1978b) allows to measure varying resistances corresponding to differences in texture, bulk density and moisture. Model soils consisting of varying layers of sand (0,2–0,5 mm) and silt (∼ 10–60μm) were equilibrated with water tensions ranging from 20 to 600 cmH2O. The resistances to penetration measured after equilibrium were significantly influenced by water tension corresponding to second power regressions. The extrema of these regressions being found between 250 and 350 cmH2O water tension were always maxima for silt and in most of the cases minima for sand regardless of thickness and arrangement of the textural layers. Moreover, silt showed an overall higher resistance to penetration (30 kp/cm2) than sand (15 kp/cm2). The interaction between unwieldiness of soil particles, cohesive and adhesive forces, and rate of change of negative pore water pressure (= water tension) probably causes at the same tension the differences of friction and resistance to penetration as stated for sand an

ISSN:0044-3263    

DOI:10.1002/jpln.19781410511

出版商:WILEY‐VCH Verlag    

年代:1978

数据来源: WILEY