THE EFFECTIVENESS OF INNOVATIVE SOIL MANAGEMENT TECHNIQUES FOR PADDY RICE ON SALT-AFFECTED ALLUVIAL SOILS IN HON DAT AND AN BIEN DISTRICTS, KIEN GIANG PROVINCE

Abstract

The Vietnamese Mekong delta is one of the largest food granaries in the Southeast Asia and is of utmost importance to Vietnam. In recent years, rice yields in the Vietnamese Mekong delta have been declining due to excessive land exploitation combined with adverse environmental changes. To maintain productivity, the amount of chemical fertilizers used for rice is currently 20 - 30% higher than recommended, while the use of organic fertilizers remains neglected, leading to soil degradation and reducing the competitiveness of Vietnamese rice on the international market. Two experimental sites, each with 7 demonstration models covering 600 m² per model were established in Hon Dat and An Bien districts of Kien Giang province, where rice was cultivated on alluvial soils with shallow acid sulfate and salinity issues during the dry season. This study aimed to apply innovative soil management practices that integrate the use of organic fertilizers, biochar, efficient fertilizer application and deep placement of inorganic fertilizers to improve soil quality, enhance fertilizer use efficiency and sustain rice yields. Rice yields was recored and soil chemical properties at harvest were measured to evaluate soil fertility and health. The results indicated that for salt-affected and low pH soils, the application of organic fertilizers and biochar, solely or in combination, is essential. Implementing innovative soil management practices, such as incorporating organic fertilizers and biochar, has helped maintain or increase rice yields while improving soil fertility indicators like available phosphorus and soil respiration and reducing inorganic fertilizer use by 25% compared to recommendations..