Okra Growth, Yield and Rhizosphere Microbiome Responses to the Encapsulated Bioinoculant Application under Reduced Fertilization Regime

Abstract

There is limited evidence that Enterobacter hormaechei can improve plant physiology and yield through soil phosphate (P) and potassium (K) amelioration. This study unraveled the effect of different soil inoculation methods i.e., free-cell and encapsulated (alginate bead containing sugar-protein hydrolysate and molasses) E. hormaechei 40a with different rates of PK-fertilization on okra P and K uptake, and soil rhizosphere bacterial community. The results revealed that 3HB (half-dose PK-fertilizer + encapsulated strain 40a) had the highest soil available P (SAP) and K (SAK), as well as P and K uptake for all plant organs, followed by 3F (full-dose PK-fertilizer), 3HI (half-dose PK-fertilizer + free-cell strain 40a), and 3H (half-dose PK-fertilizer), and improved yield by up to 75.6%. Both inoculated and full-dose fertilizer treatments produced larger pods (>15 cm) compared to 3H. We discovered increased bacterial richness and diversity in both 3HB and 3HI samples compared to uninoculated treatments. Both 3HB and 3F treatments were positively correlated with the increasing abundance of Acidobacteriales, Burkholderia caballeronia paraburkholderia, Gemmataceae, and Sphingomonas along with the SAP and SAK. The plant-beneficial effect of one-time 3HB treatment on okra growth and yield was comparable to biweekly inoculation in 3HI, suggesting a new cost-effective farming approach in precision agriculture.

A review: Revealing the important of bio stimulant coated microbeads biofertilizers for improving the effectiveness of inoculant for enhancing the agronomic traits and productivity of crops

“…The use of Pseudomonas fluorescens coated with biostimulant can enhance the availability of nitrogen, phosphorus, and potassium for tomato plants, leading to increased shoot length and root length, fruit weight, and the number of branches and fruits per plant, thus improving crop yields [27]. The experiment conducted on okra plants by Roslan et al, (2022) showed that the use of Enterobacter hormaechei encapsulated with biostimulant resulted in an increased yield of up to 75.6% by altering soil characteristics, which indirectly enhanced okra phosphorus (P) and potassium (K) uptake. This was achieved by elevating soil available phosphorus and soil available potassium, along with acid excretion, even under low P and K fertilizer inputs.…”