Stacking Agricultural Management Tactics to Promote Improvements in Soil Structure and Microbial Activities

Abstract

Linking agricultural management tactics to quantifiable changes in soil health-related properties is a key objective for increasing adoption of the most favorable management practices. We used two long-term, no-till cropping studies to illustrate the variable patterns of response of soil structure indices and microbial activity to additional management tactics, including crop rotational diversity, residue management and cover cropping. We found that observable effects of management tactics on soil properties were often dependent on the current crop phase sampled, even though the treatments were well-established. In some cases, a single additional management tactic produced a response, two tactics each produced a response and sometimes there were interactions between tactics. However, importantly, we never observed a negative effect for any of the response variables when stacking soil health building practices in no-till cropping systems. The collective results from the two field studies illustrate that soil health improvements with stacking management tactics are not always simply additive and are affected by temporal relationships inherent to the treatments. We conclude that the implementation of multiple positive management tactics increases the likelihood that improvements in soil properties can be documented with one or more of the proxy measures for soil health.

Root length density of cereal and grain legume crops grown in diverse rotations

“…We speculate that improved soil physical (mean weight diameter and erodible fraction) and biological (short‐term C mineralization) properties, including those measured by Lehman et al. (2019) in rotations with winter wheat, provided greater soil quality benefits, resulting in higher yield with smaller root systems. Such differences were not observed in corn, as there were no significant differences in corn root length density in response to crop rotation (Table 4).…”

“…In these same long‐term research plots, Lehman et al. (2019) found that the COWwS and CPWwS rotations had improved soil structure (as measured by mean weight diameter and erodible fraction) and increased biological activity (as measured by short‐term C mineralization) compared with the 2‐yr crop rotation. Additionally, past research done in this region found that diversified rotation decreased soil erosion as measured by the erodible fraction (Pikul, Osborne, Ellsbury, & Riedell, 2007), Specific research on root growth by McNickle and Cahill (2009) found that plant roots will travel shorter distances in search of resources when grown in a nutrient‐rich environment compared with low‐nutrient environments, which could explain the root length density differences in soybeans.…”

“…All crops were managed using conventional no‐till production techniques practiced by farmers in the region. More information regarding the fertilization for each crop during the growing season was reported in Lehman, Osborne, and McGraw (2019). During the growing season, weeds were controlled by 2,4‐dichlorophenozyacetic acid and glyphosate across the plots.…”

The Potential Roles of Arbuscular Mycorrhizal Fungi in Soil Health and Conservation

“…The aggregates are bound by agents, such as fine roots, soil microbes, and fungal hyphae (Tisdall and Oades, 1982;Six et al, 2004). Soil aggregates and the pores of diverse shapes and sizes within the aggregates are crucial in defining soil structure; and they primarily affect the fertility, quality, and sustainability of soil (Lehman et al, 2019). For instance, soil pores maintain habitats of soil microbes, facilitate water infiltration, and promote gas exchange that altogether aid in nutrient biogeochemical cycling.…”

“…In addition, a pore matrix facilitates penetration and growth of plant roots in soil. Soil erosion mediated by wind and water is reduced in well-aggregated soils (Lehman et al, 2019). Thus, soil structure plays an important role in soil conservation and ecosystem functioning.…”