The Effect of Earthworm (Lumbricus terrestris L.) Population Density and Soil Water Content Interactions on Nitrous Oxide Emissions from Agricultural Soils

Figure 3

A response surface regression showing the relationship between N₂O flux (kg ha⁻¹ day⁻¹), gravimetric soil water content (%), and earthworm density (number of earthworms 0.033 m⁻²). Equation of the line is 36.7186−(0.36143∗𝐷)+(3.1095∗𝑀)+(0.0174∗𝐷∗𝐷)+(0.00810∗𝑀∗𝐷)−(0.0518∗𝑀∗𝑀) (𝑅²=0.17, 𝑃≤.0001), where 𝐷 is earthworm density and 𝑀 is gravimetric soil water content.