Tillage, cover crops (CC) and nutrient amendments are regenerative agricultural practices (RAPs) which enhance desirable ecosystem services (DESs), including the beneficial nematode community structure (BNCS), soil organic matter (SOM), pH, and available nitrogen, and the Ferris et al. soil food web (SFW) model relates changes in the BNCS to biophysicochemical conditions generating DESs. However, the SFW model’s power to identify soil health conditions influencing DESs’ outcomes has been limited. We tested how tillage, winter rye CC, and 0, 112, or 224 kg N/ha from inorganic and compost sources affected the DESs after four years of corn production. The SOM and NO₃ was much greater in the no-till than the tilled soil, and the SOM in the 224 kg organic source, compared with the rest of the N rates, was significantly increased. The N recovery was not proportional to what was applied. The variable effects of the RAPs on the DESs suggest either changing or continuing treatments until suitable outcomes are achieved, all without knowing the source(s) of variability. The SFW model revealed primarily resource-limited and structured (Quadrant C) conditions, suggesting that (1) nutrient cycling needs biological activities and (2) the presence of a process-limiting factor may have contributed to the variable results. The impacts of the SFW model as a diagnostic tool are outlined.

Summary: Conservation tillage, cover crops, and nutrient amendments are among the regenerative agricultural practices applied to suppress herbivore nematodes (Hvs) and improve soil health for which beneficial nematodes (BNs) are an indicator. Since Hvs and BNs exist in the same environment, quantifying Hvs in ways that parallel BNs could lead to improved ways of managing Hvs and soil health. This study advances concepts of accounting for all Hvs regardless of population density, mode of parasitism or host range and quantifying them on the 1-5 coloniser-persister (cp) ecophysiological scale grouped as cp 2 (Hvs2), cp 3-5 (Hvs35), and the sum of all (HvSum). We tested the effects of 4-year (Y) treatment of tillage (T), winter rye ‘Wheeler’ cover crop (C) and rates 0, 112 or 224 kg ha ⁻¹ nitrogen amendment (N) from inorganic and compost sources on all Hv groups under corn production. The total abundance of the Hv genera was very low, and C and N had no effect, potentially leading to little management concern and dropping the regenerative agricultural practices. When expressed on the ecophysiological scale, however, Hvs2 were only affected by the interaction of C*Y; whereas, conventional tillage, T*Y, N*Y, T*C*N and T*C*N*Y significantly decreased Hvs35, thus showing that the regenerative agricultural practices affect Hvs2 and Hvs35 differently. The cumulative accounting of Hvs grouped as Hvs2 and Hvs35 serves as a foundation for comparing Hvs and BNs on the same ecophysiolocal scale and improves the application of regenerative agricultural practices.