Localized Reclamation of the Saline-Sodic Soil in Pistachio Orchards under Subsurface Irrigation System

Hosseininia, M. (2016) Localized Reclamation of the Saline-Sodic Soil in Pistachio Orchards under Subsurface Irrigation System. Doctoral thesis, University of Zabol.

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Soil salinity is one of the most important environmental hazards which causing a considerable decrease in agricultural productivity and production especially in Kerman pistachio orchards. In recent decades, several solutions have been developed and recommended to ameliorate and to leach saline-sodic soil in different countries. However, the application of existing recommendations is due to the specific conditions of pistachio orchards in Kerman area not possible. High cost of amendments and water requirement are major factors which determine the need for developing new techniques and approaches in leaching. Therefor in this study, localized reclamation and leaching of main active root zone under subsurface drip irrigation system was evaluated. First, in order to obtain preliminary information, the laboratory experiment in 100 cm of soil columns with treatments 1) irrigation water, 2) gypsum powder, 3) dissolved gypsum and 4) diluted sulfuric acid was conducted. Leaching was done intermittently with 2 pore volumes of soil column. The results indicate that there was no significant difference in the concentration of cations as well as EC among different treatments. Application of 1 PVs of irrigation water, removed 60% of the total sodium, 70% of magnesium and 70% of soluble salts from the soil column. Application of chemical amendments was not significant on infiltration rate as compared to irrigation water. In the second stage, the effect of three treatments: 1) irrigation water, 2) gypsum powder and 3) sulfuric acid were investigated in a pistachio orchard under clay subsurface irrigation system. According to the soil column results, localized leaching with 1 pore volume of irrigation water and using tape which located in 40 cm of the tree (the location of subsurface clay pipes) was carried out. Before and after leaching, soil samples were taken on an 80 x 120 cm grid at 20 cm intervals to measure the EC and cations. The trend changes showed that leaching led to further salts and cations leaching at distances of 20, 40 and 60 cm from tree to 120 cm depth (effective leaching area). Among treatments, irrigation water and gypsum had similar effect on salts, sodium and magnesium removal from effective leaching area. Compared with other treatments, sulfuric acid removed the least amount of harmful salts, sodium and magnesium cations from the soil. However, due to the difference in the initial amount of salts in the soil treated with three treatments, the salt removal percentage to 100 cm depth from effective leaching area for all three treatments was similar and about 50%. Thus, according to effectively reduced soil sodium, magnesium, EC, leaching and reclamation costs, applying 1 pore volume of irrigation water without no amendments under localized leaching can be recommended as the appropriate strategies for reclamation of the studied soil.

Item Type: Thesis (Doctoral)
Uncontrolled Keywords: Saline soil, Localized leaching, Soil amendments, Pistachio orchard, Kerman
Subjects: S Agriculture > S Agriculture (General)
Depositing User: admin admin1 admin2
Date Deposited: 19 Dec 2016 07:46
Last Modified: 19 Dec 2016 07:46
URI: http://eprints.uoz.ac.ir/id/eprint/1135

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