Elucidating the Effects of Organic vs. Conventional Cropping Practice and Rhizobia Inoculation on Peanut Yield and Rhizosphere Microbial Diversity

Project Overview

Project Type: Graduate Student
Funds awarded in 2018: $16,496.00
Projected End Date: 02/28/2021
Grant Recipient: University of Florida
Region: Southern
State: Florida
Graduate Student:
Major Professor:
Dr. Jianping Wang
University of Florida


  • Agronomic: peanuts


  • Crop Production: nutrient management
  • Production Systems: organic agriculture
  • Soil Management: soil microbiology


    Nitrogen is an essential and often growth-limiting nutrient for plants. Legumes like peanut (Arachis hypogea) fulfill their nitrogen requirement by symbiotic association with nitrogen-fixing bacteria, rhizobia. This symbiotic interaction results in the formation of root nodules that fix atmospheric nitrogen to enhance the growth and yield of peanuts. In addition to this, peanut yield also depends on variety, farming practice, type of rhizobia inoculation, and nutrient availability. Nutrient availability is largely determined by microbial activity in the rhizosphere that influences plant health, nutrition, yield, soil structure, and soil fertility. However, our understanding of the complex response of peanut yield and microbial diversity to organic vs conventional farming systems and to rhizobia inoculations is extremely limited.

    In this research, we studied the impacts of conventional vs. organic cultivation practices and rhizobial inoculation with commercial vs. single strain inoculum on peanut yield and soil microbial diversity of five peanut cultivars.

    Our results showed that yields from organic cultivation were significantly lower than the yields from inorganic cultivation practices. Georgia06 and TUFRunner511 consistently showed higher yields in both organic and inorganic trials. Our results showed significant two-way interactions between cultivation type and genotype for most of the phenotypes tested.

    16S microbiome sequencing showed considerable variation between the cultivation types and inoculum showing that there is a preferential association of microbes to various inoculum and cropping systems. In a permutational multivariate analysis of variance, there was evidence for an effect of cultivation type and inoculum on bacterial communities. The cultivation type and inoculum explained a high percentage of the differences among bacterial communities. 

    Therefore, it is critical for the farmers to choose varieties properly based on their cultivation practices. Organic cultivation practice had higher diversity of bacteria than inorganic cultivation practice. This research guides farmers and scientists to improve peanut yield while promoting microbial diversity and increasing sustainability.

    Project objectives:

    Objective 1: To determine the effects of different farming practice, rhizobia inoculation, and peanut cultivars and their interactions on peanut yield.

    Objective 2: To elucidate the effects of different farming practice, rhizobia inoculation, and peanut cultivars and their interactions on soil microbial diversity.

    Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.