Variations on the inorganic constituents in groundwater in tobacco agrosystem

M.L. Sharma, . and Aminuddin Yusoff, . and M.Zulkefli, . and M. Mohd Zain, . and Abdul Rashid Ahmad, . (1996) Variations on the inorganic constituents in groundwater in tobacco agrosystem. [Proceedings Paper]

Tobacco is grown mainly on sandy soils. In this soil vertical transport of nutrients through soil profile is much greater than that of clay soils. Under such condition excess nutrients particularly N can be leached into the groundwater resulting in groundwater contamination. Study are carried out to quantify and evaluate the short-term variation in inorganic constituents of the groundwater in a typical tobacco farm and identified the factors and processes that influence the levels of inorganic pollutants in the groundwater. Eighteen piezometers sixteen on grid basis and another two near the household well were installed to a depth of 2 m. Water samples including those from drinking wells were collected on weekly basis during the tobacco growing period and once a month during off-season periods. At each sampling accession in situ measurement of pH Eh EC TDS temperature and depth of water table were recorded. The water samples were analysed in the laboratory for NH4-N NO3-N PO4-P K Fe and CI. Spatial distribution of NO3-N and NH4-N concentrations shows that high NO3-N concentrations are associated with the organic souce toilet and poultry shed. Overall higher PO4-P concentration was closely related with NH4-N which occurred during low water table conditions. The was large variation among sampling points. Redox potential Eh values were closely related to water table depth and it varied spatially as well as temporally. Correlation analyses showed that there were close relationship between water depth and the variables that were affected by redox potential such as NH4-N NO3-N PO4-P and Fe. In general the Eh values decreased with increasing in watertable. Under low EH condition high water table NH4-N would remain un-oxidised and NO3-N would be denitrified to N2O and N2. The ferric iron Fe3 would reduced to ferrous Fe2 releasing adsorbed PO4-P into the solution. Under high Eh condition low water table aerobic environment would occur resulting in nitrification of NH4-N to NO3-N. At the same time ferrous iron would be re-oxidised to Fe3 and PO-P readsorbed.

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Abstract

Tobacco is grown mainly on sandy soils. In this soil vertical transport of nutrients through soil profile is much greater than that of clay soils. Under such condition excess nutrients particularly N can be leached into the groundwater resulting in groundwater contamination. Study are carried out to quantify and evaluate the short-term variation in inorganic constituents of the groundwater in a typical tobacco farm and identified the factors and processes that influence the levels of inorganic pollutants in the groundwater. Eighteen piezometers sixteen on grid basis and another two near the household well were installed to a depth of 2 m. Water samples including those from drinking wells were collected on weekly basis during the tobacco growing period and once a month during off-season periods. At each sampling accession in situ measurement of pH Eh EC TDS temperature and depth of water table were recorded. The water samples were analysed in the laboratory for NH4-N NO3-N PO4-P K Fe and CI. Spatial distribution of NO3-N and NH4-N concentrations shows that high NO3-N concentrations are associated with the organic souce toilet and poultry shed. Overall higher PO4-P concentration was closely related with NH4-N which occurred during low water table conditions. The was large variation among sampling points. Redox potential Eh values were closely related to water table depth and it varied spatially as well as temporally. Correlation analyses showed that there were close relationship between water depth and the variables that were affected by redox potential such as NH4-N NO3-N PO4-P and Fe. In general the Eh values decreased with increasing in watertable. Under low EH condition high water table NH4-N would remain un-oxidised and NO3-N would be denitrified to N2O and N2. The ferric iron Fe3 would reduced to ferrous Fe2 releasing adsorbed PO4-P into the solution. Under high Eh condition low water table aerobic environment would occur resulting in nitrification of NH4-N to NO3-N. At the same time ferrous iron would be re-oxidised to Fe3 and PO-P readsorbed.

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Item Type:	Proceedings Paper
Additional Information:	Available at Perpustakaan Sultan Abdul Samad Universiti Putra Malaysia 43400 UPM Serdang Selangor Malaysia. mal S590.2 S683 1995 Call Number
AGROVOC Term:	NICOTIANA TABACUM
AGROVOC Term:	TOBACCO
AGROVOC Term:	GROUNDWATER
AGROVOC Term:	GROUNDWATER FLOW
AGROVOC Term:	GROUNDWATER TABLE
AGROVOC Term:	INORGANIC COMPOUNDS
AGROVOC Term:	SOIL SCIENCES
AGROVOC Term:	MALAYSIA
Geographical Term:	MALAYSIA
Depositing User:	Ms. Norfaezah Khomsan
Last Modified:	24 Apr 2025 05:27
URI:	http://webagris.upm.edu.my/id/eprint/16290

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