ABSTRACT
This study examined the role of microbes in plant health and soil fertility in Nigeria, with specific focus on the Ministry of Agriculture, Imo State. The study was motivated by the declining soil fertility, increasing land degradation, and unsustainable farming practices that have characterized Nigerian agriculture, leading to over-reliance on chemical fertilizers which degrade soil health and reduce microbial diversity over time. The study was guided by three objectives: to investigate the diversity and abundance of beneficial soil microbes in different agricultural regions of Nigeria; to evaluate the impact of different agricultural practices on microbial community structure and function in Nigerian soils; and to assess the relationship between soil microbial communities and key indicators of plant health and soil fertility. A descriptive survey research design was adopted, with a population of 1,200 agricultural officers, extension workers, and farmers registered with the Ministry of Agriculture, Imo State. A sample size of 300 respondents was determined using the Taro Yamane formula, and stratified random sampling technique was employed for selection. Data were collected using a structured questionnaire with a four-point Likert scale. The validity and reliability of the instrument were established through content and face validity and the test-retest method, yielding a reliability coefficient of 0.82. A total of 280 questionnaires were properly filled and returned, representing a response rate of 93.3%. Data were analyzed using descriptive statistics (frequencies, percentages, means, and standard deviations) and inferential statistics (Chi-square test) with the aid of SPSS version 25.0. The findings revealed that nitrogen-fixing bacteria (Rhizobium) were the most diverse and abundant beneficial soil microbes, followed by mycorrhizal fungi and phosphate-solubilizing bacteria. The level of awareness of beneficial soil microbes was moderate, with 55.0% of respondents indicating they were aware or very aware. Agricultural practices such as the application of organic manure and crop rotation were found to enhance microbial activity, while chemical fertilizers and monocropping were perceived to reduce microbial diversity. The study established a strong positive relationship between soil microbes and indicators of plant health and soil fertility, including crop yield enhancement, nutrient uptake improvement, and nitrogen and phosphorus availability. Barriers to the adoption of microbial technologies included limited availability of biofertilizers, high cost, inadequate awareness, and limited extension support. The Chi-square test of hypothesis provided statistically significant evidence to reject the null hypothesis, confirming that microbes have a significant role in influencing plant health and soil fertility in Nigeria (χ² = 30.89 - 48.23; p = 0.000). The study concluded that soil microbes play a significant role in enhancing plant health and soil fertility in Nigeria, and their potential remains underutilized due to various barriers. Recommendations were made including the development and implementation of policies promoting biofertilizer production and distribution, strengthening of agricultural extension services to enhance awareness and adoption of microbial technologies, increased investment in research on indigenous microbial strains, and promotion of sustainable agricultural practices that protect and enhance soil microbial communities. The study contributes to the growing body of evidence supporting microbial-based solutions as a strategy for sustainable agricultural intensification in Nigeria.
