Download or read book Labile and Anion Extractable Phosphate in Calcareous Soils and Their Suitability for Characterizing the Phosphate Availability written by R. S. Abd El Aal and published by . This book was released on 1978 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Availability of Phosphates in Calcareous Or Alkaline Soils written by James Frank Breazeale and published by . This book was released on 1926 with total page 740 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Relation of Phosphate Availability Soil Permeability and Carbon Dioxide to the Fertility of Calcareous Soils written by William Thomas McGeorge and published by . This book was released on 1931 with total page 68 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 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:
Download or read book Phosphorus and Iron Availability in Calcareous Soils as Measured by Chemical and Plant Culture Methods written by Arthur Herman Post and published by . This book was released on 1948 with total page 250 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Phosphate Solubility Studies on Some Unproductive Calcareous Soils written by William Thomas McGeorge and published by . This book was released on 1931 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Factors Influencing the Availability of Native Soil Phosphate and Phosphate Fertilizers in Arizona Soils written by William Thomas McGeorge and published by . This book was released on 1939 with total page 52 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 Availability of Phosphates in Calcareous Or Alkaline Soils written by University of Arizona. Agricultural Experiment Station and published by . This book was released on 1926 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Electrodialysis as a Measure of Phosphate Availability in Soils and the Relation of Soil Reaction and Ionization of Phosphates to Phosphate Assimilation written by William Thomas McGeorge and published by . This book was released on 1932 with total page 54 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Characterization of Mobile Forms of Phosphorus in a Calcareous Soil written by Mostafa Hassan Mohamed Hilal and published by . This book was released on 1966 with total page 172 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Availability of Phosphates in Calcareous Or Alkaline Soils written by University of Arizona. Agricultural Experiment Station and published by . This book was released on 1926 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Use of Electrodialysis for Estimating Phosphate Availability in Calcareous Soils written by James Bennett Goodwin and published by . This book was released on 1935 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Soils and Fertilizers written by and published by . This book was released on 1998-07 with total page 1294 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Legacy Phosphorus in Agriculture Role of Past Management and Perspectives for the Future written by Luke Gatiboni and published by Frontiers Media SA. This book was released on 2021-01-07 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Bibliography of Agriculture written by and published by . This book was released on 1979 with total page 1394 pages. Available in PDF, EPUB and Kindle. Book excerpt:
