Agricultural Research Management Information System

Home
Research Summary
Search
About Us
- ARMIS
- Brochure
Contact Us
Report
User Request
Data Input
Help
- Operation Manual
  - PDF
  - Video
- Program Area & Commodity
We have reached 37600 number of research entries at this moment.

- Logout

Research Detail

Home
Research
Detail

Phosphorus Fixation Capacity of Some Acid Soils of East Pakistan

A. Islam
Department of Soil Science, Dhaka University, Dhaka, Bangladesh

I. Rashid Chowdhury
Department of Soil Science, Dhaka University, Dhaka, Bangladesh

Abstract/ Executive Summary:

Most tropical soils are well marked for their high capacity for phosphate fixation. When a soluble phosphatic fertilizer is applied to these soils, it undergoes various chemicals and physicochemical reactions and become intricately locked up in the soil and thus become unavailable to the plant. An attempt, therefore, has been made to study the phosphate fixation capacity of some acid soils of East Pakistan. Phosphorus availability of the soils increased significantly with the increased level of phosphorus application from 30 to 240 Ibs of phosphorus per acre, while 15 Ibs of phosphorus per acre could not substantially increase the availability except Brahmaputra soil where fixation seemed to be minimum. Highest phosphorus fixation had taken place in Cox's Bazar soil. This is true with all the methods. When Acetic Acid method was considered as an index of measurement, lowest fixation had taken place in Brahmaputra soil, Dhaka soils ranked between the two.

Keywords: Soil, Fertilize, Organic carbon, Phosphorus, Acid soil

Location: Cox's Bazar and Dhaka, Bangladesh

Start Date: 00-00-1963

End Date:

Program Area: Crop-Soil-Water Management

Commodity: Soil fertility

Objectives:

To determine the Phosphorus fixation capacity of some Acid soils of East Pakistan

Methodology:

Soil samples representing 0-6" depth and differing in texture and pH were collected from Cox's Bazar, Dhaka University Experiment station (Tejgaon), Govt. Agricultural Farm (Tejgaon), and Demra (Dhaka). The purpose of the experiment was to determine the phosphorus fixation capacity of these four soils. An experiment was set in the Soil Science green House of Dhaka University in 1963. Eight pounds of air dried soil, which was screened through two millimeter sieve was taken in each pot (excepting Cox's Bazar, where 3 Ibs of soil were used due to shortage of soil). The treatment one received no fertilizer with phosphoric acid (H₃P0₄) at the rate of 15 Ibs., 30 lbs., 60 Ibs., 120 lbs., of elemental phosphorus per acre basis, respectively. The soil samples, obtained from each pot, were air-dried, ground and then screened through a two millimeter sieve. Three laboratory procedures were tested for the estimation of available phosphorus of all the soil samples. In all cases, the determinations were made by using Junior Coleman spectrophotometer after the development of blue color with ammonium molybdate and stannous chloride. The intensity measurement was made at 660 mu. The extractant used in Bray No.1 method was 0.03 N NH₄F in HCI. The soil extractant ratio of I:0 was used and extraction time was five minutes. Troug's method (1930) as modified by Peech (1947) was used. 0.002 N H₂S0₄ solution buffered to pH 3.0 with (NH₄)₂S0₄ was the extracting solution used. The soil solution ratio was 1:100 and the extraction period was 30 minutes. 0.5 N acetic acid which was originally proposed by Hibbard (1931) was the extractant used. The soil extractant ratio was 1:100 and the extraction period was two hours. Before fertilization and seeding, the soils were also mechanically and chemically analyzed. The methods adopted follow: (a) The soil was mechanically processed and screened through 2 millimeter sieve. The mechanical analysis was done by hydrometer method according to Piper (1951) and textural classes were determined from the triamgular coordinates as devised by U. S. Department of Agriculture (1951). (b) Organic carbon was determined volumetrically by wet-oxidation with K₂Cr₂0₇ and H₂S0₄ and rapid titration with normal FeS0₄ solution. (c) Available nitrogen (NH₄-N and NO₃-N) was determined on the N-KCI leachate of soil.Ammonical nitrogen was distilled over by magnesia and NO₃-N by Devarda's alloy according to Piper (1951). (d) Available potassium was determined by precipitating potassium in Dyer's (1894) citric acid extract with sodium cobaltinitrite and oxidising the sodium-potassium cobaltinitrite with KMN0₄ following, Piper(l95I). (e) Exchangeable calcium was determined on the N-KClleachate of the soil by precipitating the Ca as calcium oxalate and finally titrating with KMN0₄ following, Piper (1951). (f) Exchangeable magnesium was determined on the KCI leachate. Mg precipitated, as magnesium pyrophosphate (Mg₂P₂0₇) was determined gravimetrically following, Piper (1951). pH was determined colorimetrically using Lovibond comparator. The soil: water ratio was 1: 10.

Source of Information: Pak. J. Soil Sci. 5 (1): 10-22, 1966

Article Link (Online Journal):

Funding Source:

1.

Budget:

Total Budget (Tk.) :

Achievement/Findings:

Highest phosphorus fixation had taken place in Cox's Bazar soil. This is true with all the methods. When Acetic Acid method was considered as an index of measurement, lowest fixation had taken place in Brahmaputra soil, Dhaka soils ranked between the two. This high rate of fixation by the three red soils may be due to reaction of phosphate with soluble iron, aluminium and manganese at very low pH, interaction with sesquioxide and hydrated oxides of these elements, adsorption on soil colloids and secondary adsorption by precipitated or adsorbed particles of phosphates. Fixation in Brahmaputra soil could be attributed to retention by calcium clay on the acid side of neutrality precipitation with divalent cations around pH 6, physico-chemical sorption ad secondary adsorption by precipitated or adsorbed particles of phosphates.

Knowledge Management: Journal