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. Effect of groundwater use on groundwater salinity, piezometric level and boro rice yield in the Sundarbans of West Bengal

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Title . Effect of groundwater use on groundwater salinity, piezometric level and boro rice yield in the Sundarbans of West Bengal
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Creator Burman, D., Mahanta, K.K., Sarangi, S.K., Mandal, S., Maji, B., Mandal, U. K., Bandyopadhyay, B.K., Humphreys, E. and Sharma, D. K.
 
Subject ground water
 
Description Not Available
Agriculture in the Sundarbans of India is mainly mono-cropped with kharif rice (aman) grown in the monsoon
season. Scarcity of fresh surface water for irriga􀆟on during the post-monsoon period is the main constraint on
growing boro (post monsoon/dry season) rice and other crops. Therefore, there is increasing exploita􀆟on of
groundwater through shallow tube wells (STWs). At present, STWs are used to irrigate about 32% of the total
irrigated area of approximately 55,300 ha in the Sundarbans. However, there is concern about the
sustainability of current rates of groundwater use and its con􀆟nued expansion. Therefore a series of surveys
was conducted on the status of STWs in South 24 Parganas and North 24 Parganas districts from 2000 to 2014.
The depth of STWs varied from 67 to 128 m below ground level (bgl). A study throughout 2003 showed that
the piezometric pressure level was highest and salinity was least a􀅌er the monsoon (November-December)
and that piezometric level was least and salinity highest before the onset of the monsoon (May-June). The
piezometric level and water quality recovered during the 2003 monsoon. Detailed study of STWs used for
irriga􀆟ng boro rice in 2003, 2009 and 2014 showed that the piezometric level decreased significantly from an
average of 2.1 m bgl in January to 3.9 m bgl in May while the discharge rate decreased significantly from 10.8
to 7.2 ls-1. Over the same period, groundwater salinity increased significantly from an average of 2.0 to 3.7 dS
m-1. Salinity (ECe) of the topsoil (0-15cm) in boro rice fields irrigated from STWs increased significantly from
an average of 3.0 dS m-1 at sowing to 5.8 dS m-1 at harvest. The grain yield of boro rice increased significantly
with increasing installa􀆟on depth of STWs. STW depth accounted for 70% varia􀆟on in grain yield and this was
at least partly due to a significant decrease in water salinity with increasing STW depth. While the piezometric
level and water quality recovered during the 2003 monsoon, whether this would be the case in more
intensively irrigated areas is not known. The sustainable level of groundwater use needs to be determined
across the region. Measures for more judicious use of groundwater are also needed to increase produc􀆟vity of
this precious resource.
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Date 2018-11-13T07:01:39Z
2018-11-13T07:01:39Z
2014-12-01
 
Type Proceedings
 
Identifier Not Available
Not Available
http://krishi.icar.gov.in/jspui/handle/123456789/10725
 
Language English
 
Relation Not Available;
 
Publisher Not Available