Cover Crop and Fertility Effects on Escherichia coli Abundance in a Composted Poultry Litter-Amended Silt Loam Soil

Sait Sarr,Avinash Topè,Maheteme Gebremedhin,Mark Coyne,Shreya Patel

doi:10.1155/2020/4564289

Abstract

Soil conservation practices such as cover crops can improve crop production, soil quality, and water quality. Cover crops can also influence soil microbial growth and activity. Cover cropped and manured soils can potentially store and transmit fecal bacteria (e.g., E. coli) to surface water if runoff and subsurface seepage occur. While many studies have shown the soil health benefits of cover crops, fewer studies have evaluated the extent to which cover crops influence the abundance of potential waste-borne pathogens. A two-year study (2015–2017) was conducted on a limited-resource farm in Logan County, Kentucky, USA, to quantify the abundance of the fecal indicator Escherichia coli (E. coli) bacteria (as a proxy for fecal coliforms) in treatments with and without cover crops or composted poultry litter. The cover crop consisted of a cereal rye (Secale cereale L.), Austrian winter pea (Pisum sativum L.), and crimson clover (Trifolium incarnatum L.) mix. Summer crops consisted of a no-till maize (Zea mays L.)—soybean (Glycine max L.) rotation. Soil samples were taken before and after each summer crop season and assessed to detect and enumerate E. coli. At the end of the study period, no significant treatment differences in the E. coli abundance in soil were detected (ca. 104 CFU·g−1) (p>0.05). However, season/time was a significant factor (p<0.05). We conclude that the background E. coli already present in soil was sufficiently high, inhibiting the detection of the influence of added composted litter. These indigenous E. coli were unaffected by cover crop and nutrient management but did fluctuate on a seasonal basis.

Highlights

Conservation management practices can improve crop production and soil quality [1, 2]. ere are numerous benefits derived from using cover crops, including protecting the soil from erosion [3, 4], enhancing soil mineralization [2, 5], suppressing weeds and soilborne diseases [6], more efficient nutrient cycling [7], and improving soil quality and yield [8, 9]
Schutter et al [13] observed that season was the key determinant of microbial community structure, rather than winter or summer cover crop use; E. coli numbers declined as temperatures fell
Results and Discussion e site had a baseline mean E. coli count of 6.3 × 104 CFU·g− 1 soil in Fall 2015 prior to planting cover crops. is was attributed to the site having been fertilized with poultry litter for the past five years

Summary

Introduction

Conservation management practices can improve crop production and soil quality [1, 2]. ere are numerous benefits derived from using cover crops, including protecting the soil from erosion [3, 4], enhancing soil mineralization [2, 5], suppressing weeds and soilborne diseases [6], more efficient nutrient cycling [7], and improving soil quality and yield [8, 9]. Conservation management practices can improve crop production and soil quality [1, 2]. Soil can be a reservoir for transmitting fecal pathogens if use of manure is one of the conservation practices [11], and soil-borne pathogens can contaminate farm produce, vegetables, at the crop production level. Schutter et al [13] observed that season was the key determinant of microbial community structure, rather than winter or summer cover crop use; E. coli numbers declined as temperatures fell. Other factors influencing the presence and survival of fecal bacteria include soil type, pH, manure application rate, nutrient availability, and competition [15].

Methods

Results

Conclusion