Download or read book Characterization Desorption and Mining of Phosphorus in Noncalcareous Sandy Soils written by Gerwin Ferdinand Koopmans and published by . This book was released on 2004 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Characterizing Phosphate Desorption Kinetics from Soil written by Abi Taddesse Mengesha and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Many agricultural fields that have received long-term applications of P often contain levels of P exceeding those required for optimal crop production. Knowledge of the effect of the P remaining in the soil (residual effect) is of great importance for fertilization management. In order to characterize P forms in soils, a wide variety of methods have been proposed. The use of dialysis membrane tubes filled with hydrous ferric oxide (DMT-HFO) has recently been reported as an effective way to characterize P desorption over a long-term in laboratoty studies. However, there is little information on the relationship between kinetics of P release using this new method and plant P uptake. This method consist of a procedure of shaking a sample for a long period of time there by exploiting the whole volume of the soil which is in contrast to the actual plant mode of uptake. This method has also practical limitations in employing it for a routine soil analysis, as it is very expensive and time consuming. The objectives of this study were (i) to study the changes in labile, non-labile and residual P using successive P desorption by DMT-HFO followed by a subsequent fractionation method (combined method) (ii) to assess how the information gained from P desorption kinetic data relates to plant growth at green house and field trials (iii) to investigate the effect of varying shaking time on DMT-HFO extractable P and (iv) to propose a short cut approach to the combined method. The release kinetics of the plots from long term fertilizer trials at the University of Pretoria and Ermelo were studied. P desorption kinetics were described relatively well by a two-component first-order model (R2 = 0.947, 0.918, & 0.993 for NPK, MNK, & MNPK treatments respectively). The relative contributions of both the labile pool (SPA) and the less labile pool (SPB) to the total P extracted increased with increased P supply levels. Significant correlations were observed between the rate coefficients and maize grain yield for both soil types. The correlation between the cumulative P extracted and maize yield (r = 0.997**) however was highly significant for Ermelo soils. This method was also used to determine the changes in the different P pools and to relate these P fractions with maize yield. Highly significant correlations were observed between maize grain yield and the different P fractions including total P. In both soil types the contribution of both the labile and non-labile inorganic P fractions in replenishing the solution Pi was significant where as the contributions from the organic fractions were limited. The C/HCl-Pi is the fraction that decreased most in both cases as well. Investigation was carried out to evaluate the effect of varying shaking periods on the extractable DMT-HFO-Pi for UP soils of varying P levels. Four shaking options were applied. Significant difference was observed for the treatment of high P application. Shaking option 2 seemed relatively better than the others since it showed the strongest correlation. Thus for soils with high releasing kinetics and high total P content, provided that the P release from the soil is a rate limiting step, reducing the length of shaking time could shorten the duration one needs to complete the experiment with out influencing the predicting capacity of the methodology. The other objective of this thesis was also to present a short cut method alternative to the combined fractionation method. Comparison of the sum of DMT-HFO-Pi, NaHCO3-Pi, NaOH-Pi, D/HCl-Pi and C/HCl-Pi extracted by a conventional step-by-step method with the sum of DMT-HFO-Pi and a single C/HCl-Pi extraction as a short cut approach for all extraction periods resulted in strong and significant correlations. The C/HCl-Pi fraction extracted by both methods was correlated with maize grain yield and it was found to be highly significant. This study revealed that this short cut approach could be a simplified and economically viable option to study the P dynamics of soils especially for soils where the P pool acting as a source in replenishing the labile portion of P is already identified. The method employed here therefore could act as an analytical tool to approximate successive cropping experiments carried out under green house or field condition. However, data from a wider range of soils is needed to evaluate the universality of this method. More work is also required in relating desorption indices of this method with yield parameters especially at field level.

Download or read book Characterization of the Phosphorus Supplying Capacity of Soils by Desorption Q I Relationships and Kinetics written by Klaus Peter Raven and published by . This book was released on 1992 with total page 388 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Studies in the Characterization of Phosphorus Movement on Sandy Soils written by Lawrence Edward Johannes and published by . This book was released on 1976 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Phosphate Sorption and Desorption Characteristics in Soil Systems Determined with a Polynuclear Al saturated Cation Exchange Resin written by Yingming Liang and published by . This book was released on 1988 with total page 414 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Losses and Adsorption desorption Characteristics of Phosphorus from Agricultural Soils in the Maumee River Basin of Ohio written by Dennis Lee McCallister and published by . This book was released on 1977 with total page 268 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Transformation of Inorganic Phosphorus Under Continuous Flooded Conditions and Wet dry Cycles and the Phosphorus Sorption desorption Characteristics of Two Acid Sulfate Soils written by Daud Bin Chinta and published by . This book was released on 1981 with total page 276 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Characterization and Availability of Phosphorus in Calcareous Soils written by Johan A. Asleson and published by . This book was released on 1957 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Phosphorus Sorption and Desorption Characteristics by a Soil Column Technique written by Michel A. Beck and published by . This book was released on 1996 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Phosphorus Sorption and Desorption Characteristics of Selected Oklahoma Soils written by Jonathan Karl Fuhrman and published by . This book was released on 2000 with total page 96 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Phosphate Desorption Characteristics of Some Tropical Soils written by S. J. McKean and published by . This book was released on 1989 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Apparent Phosphorus Fixation and Phosphorus Sorption desorption Characteristics of Selected Soils of Louisiana written by Mohd. Lukamanur Rahman Bhuiyan and published by . This book was released on 1985 with total page 384 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract.

Download or read book Phosphate Sorption and Desorption Characteristics of Irish Soils and Their Relationship with Other Soil Properties written by Thomas D. Branigan and published by . This book was released on 1977 with total page 97 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Characterizing Phosphate Desorption Kinetics from Soil an Approach to Predicting Plant Available Phosphorous written by Abi Taddesse Mengesha and published by . This book was released on 2008 with total page 334 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Phosphorus Desorption and Leaching During Water Infiltration in a Sandy Agricultural Soil written by Ben-Ali Burgoa and published by . This book was released on 1984 with total page 154 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Turkish Journal of Agriculture Forestry written by and published by . This book was released on 1994 with total page 640 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Estimation of Available Phosphorus in Soils by Extraction with Sodium Bicarbonate written by Sterling Robertson Olsen and published by . This book was released on 1954 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: