摘要:

General agreement does not exist as to the most appropriate method to estimate plant available Mn in soils. In the current investigation soil and soil solution Mn were measured in limed and unlimed treatments of 11 acidic subsoil horizons and related to plant Mn concentrations, Mn uptake and growth of subterranean clover (Trifolium subterraneumL. cv. Mt. Barker) and switchgrass (Panicum virgatumcv. Cave‐in‐Rock). Manganese measurements were taken at planting and harvest and included: Mn extracted by 1MNH4OAc (pH 7), 0.01MCaCl2, 0.05MCaCl2, 0.033MH3PO4, 0.005MDTPA, 0.2% hydroquinone in 1MNH4OAc (pH 7), 0.01MNH2OH.HCl 4 2 in 0.01MHNO3, total soil solution Mn and concentrations and 2+ activities of Mn2+calculated from the GEOCHEM program. Measured and calculated values of soil solution Mn generally gave the best correlations with subterranean clover and switchgrass Mn concentrations and Mn uptake. Root Mn concentrations were highly correlated with soil solution Mn measurements taken at harvest with r=0.97 and r=0.95 (p<0.01) for subterranean clover and switchgrass respectively. The Mn extracted by 0.01M CaCl was also significantly correlated (p<0.01) with plant Mn concentrations and Mn uptake and proved to be better than the other extractants in estimating plant available Mn. Although Mn concentrations as high as 1769 mg/kg (shoots) and 8489 rag/kg (roots) were found in subterranean clover, Mn did not appear to be the major factor limiting growth. Measures of soil and soil solution Mn were not strongly correlated with yield. Both Al toxicities and Ca deficiencies seemed to be more important than Mn toxicities in limiting growth of subterranean clover and switchgrass in these horizons.

ISSN:0010-3624    

DOI:10.1080/00103628809367965

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Hot 0.01M CaCl2extraction followed by inductively coupled plasma atomic‐emission spectrometric (ICP‐AES) analysis of soil boron was carried out on a number of soils and compared with hot water extraction and curcumin colorimetric analysis. There were only minor differences between extractable boron determined by the two methods. Some factors affecting the amount of boron extracted by CaCl2we're investigated.

ISSN:0010-3624    

DOI:10.1080/00103628809367966

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Phosphorus was extracted from 30 alkaline soils from western Minnesota using the Olsen NaHCO3, the Soltanpour AB‐DTPA, Mehlich 2, Mehlich 3, Bray‐1, and resin methods. Values from the first six methods were compared to resin extractable phosphorus.

ISSN:0010-3624    

DOI:10.1080/00103628809367967

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Cowpea nodules(Vigna unguiculata[L.] Walp. cv. CB5) were pierced with two opposing optical fibers (280 μm diameter), and absorbance spectra of 0.1 mm of nodule tissue were recorded from 415 to 600 nm using a modified spectrophotometer with a nodule sampling stage.

ISSN:0010-3624    

DOI:10.1080/00103628809367968

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

The determination of carbon in soils using the Leco CR‐12 resistance furnace has been investigated. The microprocessor‐ controlled furnace, and aspects of its use and performance, are described with particular attention to the routine analysis of soil materials. Some of the effects of furnace temperature, sample weight, fine grinding, ‘comparator’ setting and nature of the carbon on carbon determination and analysis time have been investigated on a range of soils. The furnace method has been compared with a wet oxidation technique and the possibility of characterization of soil carbon ‐ organic and inorganic ‐ was briefly investigated.

ISSN:0010-3624    

DOI:10.1080/00103628809367969

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

An improved sodium salicylate‐hypochlorite, automated method for ammonium in soil extracting solutions using nitroprusslde as catalyst has been investigated. This method is 2 to 3 times more sensitive than previously published procedures and also is less subject to interferences, has less noise in the signal, and has two alternative ranges. The range with maximum sensitivity is linear to about 2.5 ppm; the second range is linear to 9 ppm. The procedures and instrumentation are simple for both ranges.

ISSN:0010-3624    

DOI:10.1080/00103628809367970

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

The relationship between water soluble and exchangeable cations (Ca, Mg, Na, and K) was investigated for surface horizons of 195 soils including many taxonomic categories and a wide range in physical and chemical properties from around the world. This will provide information on exchangeable soil cation solubility for use in estimating plant uptake and leaching potential. Amounts of water soluble and exchangeable cations were not consistently related (r2of 0.50, 0.08, 0.77, and 0.49 for Ca, Mg, Na, and K). High correlations were biased by high water soluble and exchangeable cation levels of a few soils that had 3.8‐ and 2.5‐fold greater mean than median values. The ratio of exchangeable to water soluble cations was closely related to cation saturation (r2of 0.87, 0.95, 0.95, and 0.93 for Ca, Mg, Na, and K, respectively). As the degree of saturation of the exchange complex by a certain cation increased, solubility Increased. A change in saturation had less effect on K than on Na, Mg, and Ca solubility. Only exchangeable soil cations (NH4OAc extractable) are routinely measured and reported in soil survey reports, thus, water soluble levels may be determined from cation saturation. This will allow estimation of the amounts of cation that can potentially move in solution through the soil or be taken up by plants. Use of cation saturation, in addition to exchangeable content, will better characterize soil cation availability by representing quantity, intensity, and buffer factors.

ISSN:0010-3624    

DOI:10.1080/00103628809367971

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

A study relating N uptake by wheat to several N soil tests was conducted throughout North and South Dakota. Sixty nine sites were utilized over a period of 5 years.

ISSN:0010-3624    

DOI:10.1080/00103628809367972

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

ISSN:0010-3624    

DOI:10.1080/00103628809367964

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor