摘要:

Langmulr phosphate sorption isotherms for several representative Nigerian soils derived from different parent materials were studied. Two straight‐line portions of the isotherm were obtained for each soil studied after 24‐hour equilibration. The number of straight‐line portions or “breaks”; of the isotherm for a soil was found to depend not only on the P concentration range but on the time of equilibration as well.

ISSN:0010-3624    

DOI:10.1080/00103627409366527

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

Lead is being added to the environment in automotive exhausts and as an industrial pollutant. To understand its fate in the environment, it is necessary that factors affecting the capacity of soils to sorb Fb be determined.

ISSN:0010-3624    

DOI:10.1080/00103627409366528

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

A method is described for the extraction of acid oxalate‐soluble Al and Fe from soil, by leaching with oxalate reagent following the leachings for cation exchange properties. The method is faster and more convenient than the shaking method of Tamm, and gives comparable results.

ISSN:0010-3624    

DOI:10.1080/00103627409366529

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

An established stand of alfalfa was fertilized with different combinations of N, P and K. The rate used per nutrient was constant for all combinations. The study was conducted to evaluate the effect of fertilizer application, diurnal change and period to period fluctuation on the mineral composition of alfalfa. Two experiments were conducted at different stages of morphological maturity. Experiment one (E‐1) was initiated when regrowth after an initial hay harvest was in the late‐vegetative to early‐bud stage. The second experiment (E‐2) was initiated when regrowth from E‐1 was approximately 20 cm tall.

ISSN:0010-3624    

DOI:10.1080/00103627409366530

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

Kinetics of phosphate desorption from twenty soils by anion‐exchange resin were not satisfactorily explained by either film diffusion (or ion exchange mechanism) mechanism or particle diffusion mechanism. Eut the phosphate desorption process was adequately explained by a two‐constant rate equation. The two constants, the coefficient term (i.e., rate factor) and the constant term (i.e., solution P initially) were significantly correlated with amorphous Al; rate factor increased and solution P decreased with the increase in amorphous Al among the soils. Thus, influence of amorphous Al in P availability from soils must be considered.

ISSN:0010-3624    

DOI:10.1080/00103627409366531

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

The design and use of a modified heating block that is adaptable to routine plant tissue digestion is presented. The block was constructed from two aluminum plates: the heat‐transfer plate (50.8 cm × 30.5 cm × 5.08 cm) and the test tube support plate (50.8 cm × 30.5 cm × 0.953 cm). The block can digest 50 samples simultaneously, requires limited laboratory space, and is very economical to construct and operate.

ISSN:0010-3624    

DOI:10.1080/00103627409366532

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

No‐tillage corn (Zea maysL.) culture normally entails the placement of N fertilizer on the soil surface without mechanical incorporation. This field investigation was conducted to compare the N fertilizers that are most widely used in Virginia, when applied in this manner, for their effectiveness in producing notillage corn. Comparisons of the time of applying NH4NO3were also made. Grain and stover yields, in addition to N removed in the crop, were used to draw conclusions. The experiments were conducted on both fertile and infertile soils in 1972 and 1973, both of which were relatively wet years. The fertilizers tested, urea, NH4NO3, and N solutions, were equally effective, per unit of N applied. Split applications of NH4NO3showed no statistically significant advantage over all applied at planting but slightly trended to do so. N deficiency reduced grain yields relatively more than stover yields.

ISSN:0010-3624    

DOI:10.1080/00103627409366533

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

Three greenhouse experiments were conducted to compare the response of five tobacco (Nicotiana tabacumL.) cultivars to different levels of NaH2PO4and ammonium polyphosphate (APP) in nutrient media by measuring tissue content of selected nutrient elements (P, Na, K, Ca and Mg). Plants were grown in sand cultures fertilized with nutrient solutions in two experiments and a soil‐sand mix fertilized with solid materials in a third experiment. Plant P and Na content increased as the concentrations of these elements increased in nutrient solution. Plant K content was not generally affected by treatments. Magnesium was reduced in flue‐cured and cigar‐filler tobaccos but was not changed in cigar‐wrapper and Turkish types by increasing amounts of NaH2PO4. All of the cultivars responded similarly to NaH2PO4with respect to plant Ca. High levels of P in the nutrient media were consistently related to low levels of Ca in plant tissue.

ISSN:0010-3624    

DOI:10.1080/00103627409366534

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

A serum bottle method for counting anaerobic bacteria in soil is described.

ISSN:0010-3624    

DOI:10.1080/00103627409366535

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

Work to evaluate the Orion nitrogen oxide electrode indicated that this electrode can be used satisfactorily for determination of nitrite in soil extracts and water samples. The electrode method of analysis described is simple, rapid, and precise, and its results agree closely with those obtained by the colorimetric method of Griess‐Ilosvay. The electrode method has the advantage that its results are not affected by color or turbidity or by Cu2+and Hg2+present in samples under analysis

ISSN:0010-3624    

DOI:10.1080/00103627409366536

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor