摘要:

The relative effectiveness of two African rock phosphate (Morocco rock, MR and Togo rock, TR) was compared with the more reactive North Carolina rock phosphate (NCR) and with Triple superphosphate (TSP) in greenhouse using two strongly acidic Ultisols from southern Nigeria with and without application of lime.

ISSN:0010-3624    

DOI:10.1080/00103627909366956

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

Seven rice soils varying in texture, pH, organic matter and total nitrogen content were extracted with 1Nand 2NKCl, 1Nand 2NNacl, 10% Nacl at pH 2.5,NCH3CooNa at pH 3.0, and Morgan's reagent using a soil: solution ratio of 1:10. The ammonium in the extracts was determined by steam distillation with MgO.

ISSN:0010-3624    

DOI:10.1080/00103627909366957

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

The NH4+fixing capacity of 12 tropical rice soils was studied by treating 10 g soil samples with 50 mg NH4+as (NH4)2SO4dissolved in 20 ml of water, equilibrating for 2 h by continuous shaking and then extracting NH4+with 2 M KCl. The portion of NH4+added which was not extracted by KCl was termed fixed.

ISSN:0010-3624    

DOI:10.1080/00103627909366958

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

Twenty‐eight agriculturally important Delaware soils were cropped intensively in a greenhouse experiment. There was no consistent positive correlation between K uptake and percent sand, silt, clay, clay minerals of the clay fraction, K‐feld‐spars of the sand fraction or K‐feldspar weathering of the soils from the A horizon. Only potassium feldspar from the sand fraction and K‐feldspar weathering correlated with K uptake in the soils of the B horizon. This correlation was only significant at the latter part of the experiment when nonexchangeable K was probably the source of plant available K.

ISSN:0010-3624    

DOI:10.1080/00103627909366959

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

The A and B horizons of 29 Delaware soils were extensively cropped to sudan grass (Sorghum vulgarePers. Piper) and corn (Zea mays L. Pioneer Brand Hybrid No. 3958) to evaluate the K release characteristics of these soils.

ISSN:0010-3624    

DOI:10.1080/00103627909366960

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

Results of field trials with sunflowers grown on an Ultisol over three seasons indicated that applications of lime and gypsum had little effect on the boron concentration in plant tissues. Only when 30 kg borax/ha/annum had been applied did soil amelioration slightly but significantly decrease the B concentration in 1‐month‐old sunflower seedlings. Liming for three seasons significantly decreased the B concentration in the topmost mature leaf at flowering only when 30 kg borax/ha/annum had been applied and the pH (NKCl) was 4.4 and above. A pot experiment with the same soil was designed to test whether high pH levels affected B uptake. The reduction of toxic aluminum markedly increased top and root growth but higher rates of line had no further benefit. Liming significantly decreased the B concentration in seedling tope but the total B content of the tops was increased by liming. It appeared that liming to pH (NKCl) 7.0 did not adversely affect the uptake and translocation of B by sunflower roots, and that the decreased B concentration in seedling tops resulted from a dilution effect due to the benefit from liming.

ISSN:0010-3624    

DOI:10.1080/00103627909366961

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

Ca, Mg, Na, K and P contents of 3 plant tissues obtained by H2SO4‐H2O2‐Li2SO4‐Se peroxidation digestion were compared with those determined by mixed acid (HNO3‐H2S04‐HC104) and dry ashing procedures. Differences between methods were not consistent between elements or tissue types but the mixed acid digestion generally yielded higher Ca, Mg and P values than did dry ashing and peroxidation. Tissue K contents estimated by both wet digestion techniques were not significantly (P ≤0.05) different. Differences in Na values between digestion methods were highly inconsistent between tissue types and the precision of the Ma data was poor. N contents determined by peroxidation digestion and a conventional Kjeldahl method agreed closely.

ISSN:0010-3624    

DOI:10.1080/00103627909366962

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

ISSN:0010-3624    

DOI:10.1080/00103627909366955

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor