Effectiveness of Bacillus paramycoides for Improving Zinc Nutrition of Rice Irrigated with Alkali Water

Worldwide zinc deficiency in the soil under cereal production is a common problem affecting the yield and nutritional value of several crops. Bioaugmentation of soil zinc with zinc-solubilizing bacteria can be a promising option for increasing the zinc nutrition to crops. The objectives of the study were to evaluate Bacillus paramycoides for improving yield, zinc nutrition, and zinc availability in rice grown under sodicity stress caused by alkali water irrigation. Treatments included T1: control, T2: substrate, T3: Bacillus paramycoides, T4: control (T1) + zinc sulphate, T5: substrate (T2) + zinc sulphate, and T6: Bacillus paramycoides (T3) + zinc sulphate. Rice yield, zinc content, and uptake, and apparent zinc recovery were not altered by Bacillus paramycoides. The different fractions of zinc measured after 30 and 60 days after transplanting of the rice remain unaffected by the inoculation of Bacillus paramycoides. Further, an equal number of zinc-solubilizing bacteria present in the rice rhizosphere of control plots after 30 days of transplanting suggests the importance of the native rhizospheric microbiome in zinc nutrition. It is concluded that the application of Bacillus paramycoides in sodicity-stressed rice did not provided additional benefits in terms of zinc nutrition and yield. Further investigation will be required to improve the apparent zinc recovery of crops in those areas, where alkali water is continuously utilized for irrigation.