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

Effects of Liming on the Mineralization of Nitrogen as Influenced by Added Urea and Gypsum in Three Contrasting Soils

R. Mandal
Department of Soil, Water and Environment, University of Dhaka, Dhaka-1000, Bangladesh

P. C. Roy
Department of Soil Science, University of Dhaka, Dhaka-1000, Bangladesh

Z. Ahmnad
Department of Soil Science, University of Dhaka, Dhaka-1000, Bangladesh

Abstract/ Executive Summary:

The impact of liming on mineralization of nitrogen in three different soil series, namely Kajla, Tejgaon and Pritampasa incubated with each of 0 and 1 mg/g of N and S in all the possible combinations at 50% water holding capacity has been examined. Addition of N and S caused a significant initial sharp release of nitrogen at 15 days of incubation in all the soils irrespective of change in pH levels through 6.5 and 7 .0. This was followed by a significantly rapid decline at 30 days of incubation. Thereafter, a slow release in mineral N was observed. However, the initial accumulation and subsequent fall of mineral-N might possibly be due to easily decomposable and exhaustion of the N-substrate in the soils, respectively. Liming showed profoundly better positive impact on nitrogen mineralizing organisms in acidic tea soil (Tejgaon series) than other soils.

Keywords: Liming, Mineralization, Soils

Location: Department of Soil, Water and Environment, University of Dhaka, Dhaka-1000, Bangladesh

Start Date:

End Date:

Program Area: Crop-Soil-Water Management

Commodity: Soil fertility

Objectives:

To evaluate the impact of liming in mineralization of nitrogen as influenced by added urea and gypsum in three different soil series of Bangladesh.

Methodology:

Surface samples (0-15 cm) of forest, tea and alluvial soils were collected from Rajendrapur forest (Tejgaon series), Noapara Tea Garden of Habiganj (Pritampasa series) and Vatara area of Dhaka (Kajla series). The samples were air dried and ground to pass through a 2 mm sieve. Samples used for organic carbon and total nitrogen analysis were further ground to 100 mesh. Some physical and chemical characteristics of the soils were determined. pH was measured electrochemically by using a combined glass/calomel electrode. Particle size analysis was done by hydrometer method. Determinations were made of organic carbon by wet oxidation method, total and 2M KCl extractable available nitrogen by alkali distillation following Kjeldahl digestion and cation exchange capacity (CEC) by normal ammonium acetate (pH 7.0) method . Available phosphorus was extracted by using the technique of Bray and Kurtz0 2l and determined colorimetrically. Available sulphur was determined spectrophotometrically at 470 nm in 500 ppm P extract after developing turbidity with BaCl₂. Water holding capacity (WHC) was estimated following the method proposed by Keen and Raczkowski. A portion of air-dry alluvial soil (100g) was taken into a series of clean-dry 250 ml conical flasks. The weighed samples were mixed with 0 and 1 mg N/g and 0 and 1 mg S/g soil. N and S were added as urea and gypsum, respectively being suspended in water. CaO was added in the urea treated soil in such quantities to equalize the amount of calcium added as gypsum. Lime was added to raise the pH to 6.5 and 7.0. The amount of lime required to raise the pH to desired level was calculated from a pH titration buffer curve. The treatments used in factorial combinations were: Initial pH- NoSo, NISo, NoS1, N1S1; pH 6.5- NoSo, N1So, NoSI, NISI; pH 7.0- NoSo, N1So, NoS1, N1S1. Taking the quantities of added water as solvent into account, an extra calculated amount of water was added to bring the soil to 50% WHC. The contents in the flasks were mixed thoroughly and were covered with perforated parafilm. Twelve treatments, in triplicate, were arranged in a completely randomized block design and was placed in room temperature at 30 ± 0.5°C. Constant moisture content was maintained gravimetrically throughout the experimental period by making up the loss of moisture everyday. Similarly two sets of incubation experiments were also carried out with forest and tea soils separately. Samples of soil (5 g) from each treatment were collected at 0, 7, 15, 30 and 60 days of incubation to determine 2M KCl extractable mineral-N and moisture. pH of the treated samples was determined at the end of incubation.

Source of Information: Dhaka Universigy Journal, Bioilogical Science, 9(2) : 109-114, 2000 (July), ISSN 1021-2484

Article Link (Online Journal):

Funding Source:

Total Budget (Tk.) :

Achievement/Findings:

A significant change in release of nitrogen was observed in three different soils as influenced by added N (urea) and S (gypsum) under various pH conditions. Results revealed that combination of N and S could not show their superiority over the lone treatment of N significantly irrespective of the pH levels and soils. However, only marked difference in accumulation of mineral-N occurred at higher pH levels in tea soil and at highest pH value in forest soil only at 15 days of incubation. In tea soil, the nature of release in mineral-N was different irrespective of treatments at all pH levels. At pH 7.0, addition of gypsum promoted the release of mineral-N though not significantly different than that occurred at pH 6.5. The close proximity in acidity between pH 6.5 and 7.0 might possibly be the reason of such non apparent variation in nitrogen mineralization. However, the result postulates that a general trend in increase in mineralization of nitrogen was evident due to stimulation of the activity of nitrogen mineralizing organisms by liming. Liming in acid soils generally favours the efficiency and proliferation of the organisms involved in the process.07-21) The change in pH during incubation was measured at the end of incubation . Results showed no significant change in acidity of the soil.

Knowledge Management: Journal