Exploring the Relationships between Greenhouse Gas Emissions, Yields, and Soil Properties in Cropping Systems

Gevan Behnke,María Villamil,Emerson Nafziger,Cameron Pittelkow

doi:10.3390/agriculture8050062

Gevan Behnke, María Villamil + Show 2 more

Open Access

https://doi.org/10.3390/agriculture8050062

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Abstract

Relationships between greenhouse gas emissions, yields, and soil properties are not well known. Utilizing two datasets from long-term cropping systems in Illinois, USA, our we aim to address these knowledge gaps. The objective of this study was to explore the relationships between the physical and chemical properties and greenhouse gas (GHG) emissions of soil, and cash crop yields over a four-year time-period and following 15 years of treatment implementation in Illinois, USA. The experimental layout was a split-plot arrangement involving rotation and tillage treatments in a randomized complete block design with four replications. The studied crop rotations were continuous corn [Zea mays L.] (CCC), corn-soybean [Glycine max (L.) Merr.] (CS), continuous soybean (SSS), and corn-soybean-wheat [Triticum aestivum L.] (CSW), with each phase being present for every year. The tillage options were chisel tillage (T) and no-tillage (NT). We used an array of multivariate approaches to analyze both of our datasets that included 31 soil properties, GHG emissions (N2O, CO2, and CH4) and cash crop yields. The results from our analyses indicate that N2O emissions are associated with a low soil pH, an increased Al concentration, the presence of soil nitrate throughout the growing season, an increase in plant available water (PAW) and an increased soil C concentration. Likewise, soil CO2 respiration was correlated with low pH, elevated Al concentrations, low Ca, increased PAW, higher levels of microbial biomass carbon (MBC), and lower water aggregate stability (WAS). Emissions of CH4 were associated with increased levels of MBC. Lastly, the yield index (YdI) was correlated with lower levels of soil Ca and available P and lower values of WAS. The association between high YdI and lower WAS can be attributed to tillage, as tillage lowers WAS, but increases yields in highly productive cropping systems in the Midwest.

Highlights

The Midwestern United States (US) is regarded as having some of the most productive lands in the world; deep and dark Mollisols cover over half of the state of Illinois [1]
The principal component analysis (PCA) of the 32 variable dataset for greenhouse gas (GHG) emissions rendered a set of eight uncorrelated variables or principal components (PCs) (PC1 to PC8, Table 1) with eigenvalues larger than 1, which, when added together explained about 83% of the total variability contained in the GHG database
Our analysis showed the complex relationships among GHG emissions, yield and soil properties

Summary

Introduction

The Midwestern United States (US) is regarded as having some of the most productive lands in the world; deep and dark Mollisols cover over half of the state of Illinois [1]. Illinois places in the top two states for corn (Zea mays L.) and soybean [Glycine max (L). Merr.] production, with nearly 5 million ha of corn planted and 4 million ha of soybean planted each year [2]. In 2016, 954,400 tons of N and 446,350 tons of P were applied to 98% and 86% of the planted corn area, respectively [2]. This demand for high yield does not come without consequences; agriculture contributes around 9%

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