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Title of Thesis  
PHOSPHATE ADSORPTION IN SOILS AND ITS AVAILABILITY TO PLANTS  
Author(s)  
Mushk-I-Alam  
Institute/University/Department Details  
GOMAL UNIVERSITY D. I. KHAN / AGRICULTURE  
Status (Published/ Not Published/ In Press etc)  
Published  
Date of Publishing  
1999  
Subject  
Agriculture Chemistry  
Number of Pages  
163  
   
Keywords (Extracted from title, table of contents and abstract of thesis)  
Soil phosphorus, Phosphate availability, D.I. Khan, P adsorption, P adsorbed,  

 

 
Abstract  

Some aspects of phosphate dynamics in soils varying in phyisco-chemical characteristics were studied in the present investigations. Chapter-I present a general introduction of various problems of soil phosphate and its availability to plants. Chapter 2 deals with short review of some aspects of phosphorus behaviour in the soils. Phosphate availability to Plants has been described in some details. Analytical techniques used in the present study, a short description of tile sites of sampling and some of physico-chemical properties of the soils have been dealt witl1 in chapter 3. Chapter 4 deals with phosphate status of 10 soil series of D. I. Khan district. Conventional Procedures were adopted to measure all types of extractable phosphate in the calcareous soils of D.I. Khan. The phosphate extracted by various extractants was assessed through their relationship with one another. 0.5 M acetic acid extracted the highest P followed by Na-bicarbonate. However, P extracted by Na-bicarbonate was consistent and significantly correlated with quantities of CaCO3 and clay contents present in tile soil and the variation were statistically significant. Chapter 5 represents phosphate adsorption in 10 soils. Adsorption isotherms of all these soils were measured with standard P concentrations O. 5, 1, 5, 1, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, and 100 ug P cm-3. All the soils indicated different behaviour towards P adsorption. The P adsorption data confirmed well to Freundlich equation in other some soils and to Langmuir equation in others soils. Langmuir P adsorption maxima were significantly correlated with CaCO3 and clay contents of the soils. Detailed Studies of P adsorption and desorption are given in chapter 6. The points of adsorption and desorption isotherms did not meet at the top as they are expected. The cause of the gap between the two points was studied through the effect time of shaking on adsorption and desorption. It was noted that P adsorption increased with time. There was little instantaneous P desorption with the passage of time. Chapter 7 describes phosphate availability to plants. The study was carried out in pot on rye grass (Lolium perene). The effect of plant growth on extractable and adsorbed P in 10 soils was studied. The results indicated that the dry matter yield and P content of leaves were the highest in Ramak soils. The variations recorded were statistically sigl1ificant .The NaHCO3 extractable P before planting was significantly correlated with dry matter yield (r=0.93). The P uptake in leaves was also significantly correlated with dry matter yield. The effect of plant growth was recorded on P adsorption isotherms. The regression analysis of the Langmuir equation obtained from P adsorbed before planting, non-grassed and grassed soils did not show significant differences. In chapter-8 the experimental results and their general conclusions along-with further suggested development of this work are described.

 
   
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Sr.No Chapter Table of Contents
 
i 180.kbs
96.KB
1 1

INTRODUCTION

1
45.KB
2 2 REVIEW OF LITERATURE 4
246.KB
3 3 GENERAL METHOD OF SOIL ANALYSIS 23
155.KB
4 4 ESTIMATION OF EXTRACTABLE SOIL PHOSPHATE 37
189.KB
5 5 PHOSPHATE ADSORPTION BY SOILS 57
385.KB
6 6 PHOSPHATE ADSORPTION AND DESORPTION IN SOME SOILS SERIES OF D.I.KHAN 98
183.KB
7 7 AVAILABILITY OF PHOSPHATE TO PLANTS 116
214.KB
8 8 CONCLUSIONS 142
60.KB
9 9 REFERENCES 146
60.KB