ABSTRACT
This study was conducted to investigate the impacts of water logging and salinity on crop production in village
Adina, District Swabi of Khyber Pakhtunkhwa. Questionnaire survey was used for data collection about underlying causes
of water logging and salinity in the area, comparative assessment of yield production in water logged and non-water logged
soil and vulnerability of different crops to water logging and salinity. Soil was also analyzed for pH and Electrical
Conductivity. Study findings indicated that yield of crops was comparatively low approximately (88%) in water logged and
saline areas. The major causes contributing to water logging and salinity were seepage from canals and Terbala Dam (48%)
and poor irrigation practices of farmers (28%). Rice crop was resistant to water logging while maize and wheat were most
effected crops. Results of analysis indicated that pH and electrical conductivity of water logged soil samples was high. It is
suggested on the basis of results that modern scientific methods should be used for irrigation and cultivation in the affected
area. Salinity Control and Reclamation Project (SCARP) was launched in the area that proved effective but still there is a
need to upgrade the existing project to reclaim important agricultural land.
Keywords: Water logging, Salinity, Village Adina, Rice, SCARP.
INTRODUCTION
Waterlogging and salinity reduce plant growth
and resultantly reduce crop production. Pakistan is mainly
dependent on agriculture sector and thus loss of
agricultural production poses serious threats to the
economy (Zaman and Ahmad, 2009). About 75% of the
total population is directly or indirectly dependent upon
the agricultural sector. The agricultural sector is mainly
dependent on the irrigation system of and almost 80% of
agricultural production comes from the lands which are
cultivated though irrigation channels and the remaining
20% are rain dependent lands (Chaudhry et al., 2002 and
Azhar et al., 2004a). Due to the poor drainage facilities in
the irrigation system not only the agricultural lands have
suffered but also agricultural production has suffered from
the twin menace of water logging and salinity. Thus water
logging and salinity act as severe constraints to the
agricultural production in Pakistan. It has been identified
as a biotic environmental factor which has been eroding
the agricultural production for more than three decades
and thus causing threat to our future survival. The lands
which are severely affected by water logging and salinity
have gone out of production while much decreased has
been caused to the agricultural production of lands which
are slightly or moderately affected (Federal bureau of
statistics, 1987). It has been estimated that water logging
and salinity affects 25% of irrigated land in Pakistan,
reducing crop yields (Chambers, 1988 and Yudelman,
1989). Moreover, 48% of the soils in Sindh, 18% in
Punjab are strongly affected by salinity and water logging
(Khan, 1991). Similarly in Khyber Pakhtunkhwa 0.472
Mha of land is affected by salinity (Qureshi and Lennard,
1998). Approximately 40,000 hectare of arable land in
Pakistan is lost annually to cultivation due to salinity, and
it is suggested that two tons of salt are added to each
irrigated hectare per year (Stoner, 1988). While
worldwide, Oldeman et al (1991) estimated that 10.5 Mha
are affected by waterlogging and 76.6 Mha are affected by
human-induced salinization, but they did not differentiate
salinity in the irrigated and non-irrigated rain- fed areas.
Similarly Ghassemi et al (1995) carried out a survey on
selected countries that represent about 70 percent of global
irrigated land, estimate the total world-wide salt-affected
lands in the irrigated area to be 45.4 Mha. The two major
environmental impacts of waterlogging and salt-affected
soils are the decline in crop productivity and loss of arable
land.
Water logging (hypoxia) and salinity have a
range of effects. Firstly, they rapidly decrease the initial
growth of roots and shoots (Barrett-Lennard, 1986a and
Drew et al., 1988). Secondly, affect the processes
associated with solute movement across membranes, such
as nutrients uptake e.g. nitrogen, and increase the
availability of nutrients, e.g. iron and manganese
(Ponnamperuma 1977; Trought and Drew, 1980 and
Buwalda et al., 1988a), the regulation of cytoplasmic pH
and membrane potentials (Greenway and Gibbs, 2003),
and thirdly, effect the stomatal conductance i.e. it causes
to decrease the stomatal conductance or leaf water
potential (Bradford and Hsiao, 1982; Huang et al., 1995a
and Else et al., 2001). Thus all these factors contribute to
the reduction of yields and loss of arable lands. The aim of
this study is to identify the causes of water logging and
salinity in the area, comparative assessment of yield
production and soil and vulnerability of different crops to
water logging and salinity. Although, the SCARP is
working effectively but still water logging and salinity are
major problems of the area, therefore, the emphasis would
be primarily on the technical aspects of reclamation.