**3. Amelioration and management approaches for improving WP in the saline areas of lower KRB**

There is no doubt that one of the most important requirements for the reclamation of lands in the L-KRB is installation of adequate drainage network for the entire irrigated area. Installation of drainage network is a fundamental solution to improve the quality of salt-affected soils in the L-KRB. Drainage system will reduce the adverse effects of shallow water table and waterlogging issues in the agricultural lands. Hence it will contribute to the improvement of crop production and crop WP. Promising efforts have been initiated by the government in this regard, but still the progress is low and very costly.

To avoid further salinization of agricultural lands and to ameliorate the current situation, the communities and agricultural agencies are called to apply sound management practices until adequate drainage systems are installed.

One of the most important prerequisites to enable sustainable crop production in the area is the development of a monitoring network for observing the effect of different management practices on the salt content of groundwater as well as the salt and water balance of the crop's root zone. The regular monitoring and data acquisition will provide the database required for providing the best measures to prevent restoration of soil and water salinity and secondary salinization of the crop root zone. Moreover, water and salt balance studies at the watershed level will increase the capability to predict the role of any hydrological impacts on the fate and behavior of catchments' salinity.

Salinity and depth to shallow water table in DA were monitored in observation wells during November 2003 to April 2004 [18, 19]. There was a large variation in salinity of groundwater ranging between 4 and 100 dS/m. No trend of salinity changes throughout the study area was found. However, trend of groundwater salinity changes may partly be explained in regard to the soil texture variation in a manner that was lower in light-textured soils than that of heavier textured ones.

**183**

ince (**Figure 3**).

yield and WP were suggested.

selected fields is demonstrated.

during growth season; and finally crop yield.

*Water Productivity Improvement Under Salinity Conditions: Case Study of the Saline Areas…*

projects for improving WP in the area, and the results were promising.

obtained results are given and elaborated in the next sections.

**4. Determination and evaluation of water productivity**

Appropriate irrigation schedules based on soil moisture depletion or climatic data, and improvement of irrigation efficiency, would prevent excess losses of irrigation water into the subsoil or groundwater. Land leveling could improve water distribution in the field and prevent waterlogging problems. More attention should be paid to the irrigation systems. Efficiency of irrigation water application should be increased, and water should be applied more uniformly along the field [18, 19]. Some of these measures are tested in the field as part of the CPWF project, and the

Another important issue limiting crop production in the area is the accumulation of salt in the top soil. This phenomenon mainly occurs during the fallow period, when the soil is uncultivated and the farm is left for the next cropping season. Conducting soil leaching activities prior to the sowing and land preparation activities could reduce the soil surface salinity. Therefore, it will ameliorate the adverse effects of salt stress on crop establishment especially in the early stages of crop growth. Other suitable practices are mulching with crop residues, adding organic matters to the soil, selection of suitable crop rotations, and implementation of proper cropping patterns [18, 19].

As improvement of WP and identification of its sources of inefficiencies are set as one of the top priorities in Iran, especially in KRB, some studies were conducted in the downstream areas of L-KRB located in the DA plain in the Khuzestan prov-

The main objectives of these studies were to determine and evaluate WP of irrigated wheat, as a major cultivated crop in DA. Moreover some recommendations and simply applicable management approaches for the better management of irrigation practices and the amelioration of salinity-waterlogging hazards on crop

The researches were conducted in seven farmers' fields, typical of the farms in the region and during cropping season of 2006–2007. In **Figure 3** location of the

The measured parameters were irrigation water inflows and runoffs; soil texture; soil and water salinity; soil and water pHs; soil organic matter; the P, K, Fe, Mn, Zn, and Cu elements of the soil profile; depth and quality (EC) of groundwater

Also salinity was lower in the vicinity of the river tributary than those further away from the river. The depth to water table was lowest in April as a result of deep percolation from winter rains, excess irrigation of fields, river floods, and seepage from earthen channels. The depth to water table reaches its maximum in September due to high evaporation during the hot dry summer. This pattern seems to repeat itself throughout the years resulting in accumulation of salt in the top surface soil layer. Generally saying, the agricultural cropping systems and practices in the area are suboptimal. But there are great scopes and opportunities for their improvement. At present, the crop varieties used by the farmers are not adapted to the prevailing soil conditions, and significant improvements in crop production could be realized by introducing or applying of salt-tolerant crop varieties and species. As already noted the majority of the cultivated areas (almost 90%) are allocated to the winter wheat. The average yields of its two cultivated varieties grown, i.e., Chamran and Verinak, are low and about 2 tons/ha. Introducing and testing of high-yielding varieties to the area available in the country may respond well and be promising. Some salttolerant varieties such as Kavir, Bam, and Sistan were tested as part of the CPWF

*DOI: http://dx.doi.org/10.5772/intechopen.86891*

#### *Water Productivity Improvement Under Salinity Conditions: Case Study of the Saline Areas… DOI: http://dx.doi.org/10.5772/intechopen.86891*

Also salinity was lower in the vicinity of the river tributary than those further away from the river. The depth to water table was lowest in April as a result of deep percolation from winter rains, excess irrigation of fields, river floods, and seepage from earthen channels. The depth to water table reaches its maximum in September due to high evaporation during the hot dry summer. This pattern seems to repeat itself throughout the years resulting in accumulation of salt in the top surface soil layer.

Generally saying, the agricultural cropping systems and practices in the area are suboptimal. But there are great scopes and opportunities for their improvement. At present, the crop varieties used by the farmers are not adapted to the prevailing soil conditions, and significant improvements in crop production could be realized by introducing or applying of salt-tolerant crop varieties and species. As already noted the majority of the cultivated areas (almost 90%) are allocated to the winter wheat. The average yields of its two cultivated varieties grown, i.e., Chamran and Verinak, are low and about 2 tons/ha. Introducing and testing of high-yielding varieties to the area available in the country may respond well and be promising. Some salttolerant varieties such as Kavir, Bam, and Sistan were tested as part of the CPWF projects for improving WP in the area, and the results were promising.

Appropriate irrigation schedules based on soil moisture depletion or climatic data, and improvement of irrigation efficiency, would prevent excess losses of irrigation water into the subsoil or groundwater. Land leveling could improve water distribution in the field and prevent waterlogging problems. More attention should be paid to the irrigation systems. Efficiency of irrigation water application should be increased, and water should be applied more uniformly along the field [18, 19]. Some of these measures are tested in the field as part of the CPWF project, and the obtained results are given and elaborated in the next sections.

Another important issue limiting crop production in the area is the accumulation of salt in the top soil. This phenomenon mainly occurs during the fallow period, when the soil is uncultivated and the farm is left for the next cropping season. Conducting soil leaching activities prior to the sowing and land preparation activities could reduce the soil surface salinity. Therefore, it will ameliorate the adverse effects of salt stress on crop establishment especially in the early stages of crop growth. Other suitable practices are mulching with crop residues, adding organic matters to the soil, selection of suitable crop rotations, and implementation of proper cropping patterns [18, 19].
