Peningkatan Pertumbuhan Tanaman Bayam Merah (Amaranthus tricolor L.) pada Beberapa Cekaman Salinitas dengan Aplikasi Bakteri Penghasil ACC Deaminase dan Amandemen Organik

Abstract

Salinity is a major abiotic stress that induces the accumulation of aminocyclopropane carboxylic acid (ACC) which can inhibit plant growth. This study aimed to investigate the effect of applying ACC deaminase producing bacteria and organic amendments on the growth of red spinach (Amaranthus tricolor L.) under different salinity stress conditions. The research was conducted in a greenhouse and analyzed at the Soil Chemistry and Biology Laboratory, Faculty of Agriculture, Universitas Sumatera Utara and the Agricultural Instrument Standardization Agency (BSIP) Laboratory in Medan, from August to December 2024. This study employed a Randomized Block Design (RBD) with three treatment factors and two replications. The first factor involved four treatments of ACC-deaminase-producing bacterial isolates: no bacterial application (A0), Bacillus cereus (A1), Priestia flexa (A2), and Achromobacter xylosoxidans (A3). The second factor involved three organic amendment treatments: no organic amendment application (M0), rice straw compost at 30 tons/ha (M1), and rice straw biochar at 30 tons/ha (M2). The third factor was soil salinity level, consisting of two treatments: moderate salinity (S1) and high salinity (S2). The results showed that the application of ACC-deaminase-producing bacteria significantly influenced plant height, leaf number, stem diameter, microbial population, and soil respiration, with Achromobacter xylosoxidans exhibiting the best treatment. The application of organic amendments significantly affected plant height, leaf number, stem diameter, shoot fresh weight, shoot dry weight, soil electrical conductivity, soil pH, and microbial population, with rice straw biochar providing the best treatment. The combination of bacterial application and organic amendments resulted in the best growth of red spinach plants when Bacillus cereus and rice straw biochar were combined.