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What is the importance of control water logging and salinity in agriculture sector?

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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.
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