Physical quality indices of acid sulfate soils and their improvements as induced by vertical mulching for oil palm production

Name: Prapaipit Srimawong

LCSH: Kasetsart University -- Dissertations. Ph.D. (Soil Science) 2023.

Classification :.LCCS: S597.O35

LCSH: Kasetsart University. -- Department of Soil Science -- Dissertations.

LCSH: Oil palm -- Soils

LCSH: Acid sulfate soils.

LCSH: Soil amendments.

LCSH: Deficit irrigation.

Abstract: The rising global demand for oil palm has prompted its cultivation in Thailand's acid sulfate soils, which are plagued by severe acidity, nutrient imbalance, and poor soil quality. This study employed a two-part experimental approach: the first part aimed to identify key physical limitations of these soils for oil palm production, and the second part focused on improving the identified limitations using vertical mulching (VM). Conducted on a 29,700 m² site in Nakhonnayok province, the selected soil physical quality parameters—including penetration resistance, hydraulic conductivity, bulk density, moisture characteristics, available water capacity (AWCA), available water content (AWCO), and the S-index (derived from the van Genuchten equation)— were measured at 32 points. VM was installed under the canopy of three selected oil palm trees exhibiting soil physical limitations, while another set of three trees served as the control. The VM involved drilling 14-16 holes (60 cm deep) and filling them with coarse sand. Soil water content and oil palm water deficit were monitored for 18 months, with fresh fruit bunch (FFB) yields collected at 12, 18, 24, and 30 months post-VM installation. Results identified critical physical limitations: low S-index values and significant water shortages, especially in the Ap horizon, where the S-index was 0.024 compared to 0.033 in the subsoil, and AWCA was lower (0.21) than in the subsoils (0.30). During the wet season, 78% of the site showed negative AWCO in the subsoils, indicating severe water deficits. VM significantly improved water distribution from topsoil to subsoil layers. Compared to the control, VM-treated plots demonstrated greater soil moisture stability and higher overall water content, resulting in increased FFB yields—639 kg per tree at 30 months post-treatment versus 511 kg in the control. This study highlights that VM can alleviate soil physical limitations in acid sulfate soils, enhancing oil palm production. Further research is recommended to assess the applicability of VM to other tree species where under-canopy soil physical quality is typically neglected.

Kasetsart University. Office of the University Library

Address: Bangkok

Email: tdckulib@ku.ac.th

Name: Surachet Aramrak

Role: Thesis Advisor

Name: Natthapol Chittamart

Role: Thesis Co-Advisor

Name: Apiniti Jotisankasa

Role: Thesis Co-Advisor

Created: 2023

Modified: 2025-06-26

Issued: 2025-06-26

วิทยานิพนธ์/Thesis

วิทยานิพนธ์/Thesis

application/pdf

URL: http://www.lib.ku.ac.th/KUthesis/2566/prapaipit-sri-all.pdf

CallNumber: S597.O35.P73

eng

DegreeName: Doctor of Philosophy

Level: Doctoral Degree

Descipline: Soil Science

Grantor: Kasetsart University

©copyrights Kasetsart University

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