Soil Studies Project of the 46,000-hectare Sistan

Í Soil Studies Project of the 46,000-hectare Sistan Plain Î

The Complementary soil studies, land suitability, leaching management, land reclamation and soil fertility enhancement in 46000 ha Project of Sistan plain, Iran.

Sistan plain having area of 203 thousand hectares of cultivable land is located in the lower part of Hirmand catchment area. The area of Hirmand catchment is 150,000 km2 and 18,200 km2 of this area consists of Hirmand River Delta which is located in Iran. The most important source of water supply in this basin is the Hirmand River with a length of 1050 km, which is very variable in terms of water supply, and 84% of its water irrigates the forms in months of February to May.

Due to its location at the end of the Sistan plain basin, it is highly dependent on Hirmand water and Chahnimeh in which the river's water is stored for agriculture, environmental protection and drinkable water. However, with the construction of several reservoir and diversion dams by Afghanistan have severely reduced the area of Lake Hamoon, the volume of water in the Chahnimeh, and the level of agricultural land over the past 100 years.

The Digital Elevation Model of the Hirmand River and Chahnimeh area

These phenomena have led to the following challenges in the region:

[ Limited water resources and untimely surface inflows of Hirmand River and non-compliance with the water requirements of plants in the cultivation of the region, has caused a serious challenge in the possibility of planning agricultural development projects in the region and reduce the yield of these crops.

[ Occurrence of drought in recent years.

[ Soil fertility decline, severe deficiency of soil organic carbon and nutrients for sustainable production.

[ Poor irrigation efficiency (especially water use efficiency).

[ The lack of proper access to water for the farmer and lack of appropriate cultivation pattern.

[ Non-uniformity and continuity of water distribution in irrigation networks (due to high sediment load of river inflows, lack of appropriate irrigation crop calendar).

[ The lack of proper access or improper use of inputs and seeds or mismatch of fertilizer application time with plant demand due to water is unavailable.

[ High risk of agricultural production due to unexpected events such as storms, dust and strong winds and rapid depletion of soil moisture, especially in critical growth stages of plants and lack of convenient and fast access to the farmer.

[ Low agricultural knowledge, high age of farmers in the region, lack of transfer of indigenous knowledge to the new generation.

[ Inappropriate soil structure, low permeability of soil, high evaporation, high water table, the presence of soil limiting layer at a depth of 2 to 5 meters.

[ Water losses and flooding caused by the type of irrigation and poor soil quality in the fields at different stages of irrigation.

[ Dispersal across farmland and increase in production costs and management of inputs and irrigation and transportation and sales problems.

Based on this, by order of the Deputy Minister of Water and Soil Affairs, in the contract for consulting services, the project entitled "Carrying out complementary soil studies and land suitability, leaching management, land improvement and soil fertility improvement in 46,000-hectare Sistan plain project" was defined and researches with the aim of determining land suitability for crops and orchards for cultivation pattern, land suitability for various irrigation systems, determining soil fertility and improving nutrition management for crops and orchards, and evaluating water quality, soil salinity and preparation of leaching management package and soil improvement has conducted since April 2019.

The Status of Soil Surface Salinity in All Lands of Sistan plain