Enhancing zinc uptake and grain yield of Ciherang and Inpari IR Nutri Zinc rice varieties using Zn-solubilizing bacteria

Abstract

In elevated atmospheric CO2 conditions, a prominent greenhouse gas contributing to climate change, there is a notable reduction in zinc (Zn) concentration within lowland rice crops. Zn deficiency diminishes rice productivity and lowers Zn content in grains, impacting human health, particularly stunting. This study aims to assess the effects of applying isolated Zn-solubilizing bacteria (ZnSB) strains and ZnSO4 on Zn uptake and yield in two rice varieties: Inpari IR Nutri Zinc (high Zn content) in the first trial and Ciherang (medium Zn content) in the second trial, conducted in an Inceptisol soil. The treatments were organized in a Randomized Block Design with three replications. The first factor involved ZnSO4 fertilizer (Z0 = without ZnSO4; and Z1 = with ZnSO4). The second factor was ZnSB strains (B0 = without ZnSB; B1 = Klebsiella pneumoniae Zn2; B2 = Enterobacter cloacae CmA12; B3 = E. bugandensis CmD2; B4 = S. marcescens CmT13; and B5 = B. thuringiensis PuT1). The results indicated that applying ZnSB strains without ZnSO4 significantly increased grain yields for both Ciherang and Inpari IR Nutri Zinc varieties (7.67% and 4.12%, respectively) and enhanced Zn uptake (28.05% and 13.58%, respectively). Moreover, combined ZnSB and ZnSO4 application also significantly increased yields for both varieties (12.14% and 25.03%, respectively) and Zn uptake (33.29% and 13.99%, respectively), demonstrating the potential of ZnSB for enhancing Zn uptake and rice yield. These findings suggest promising strategies for addressing Zn deficiency in rice cultivation under elevated CO2 conditions.