Compared to conventional, ecological intensive management promotes beneficial proteolytic soil microbial communities for agro-ecosystem functioning under climate change-induced rain regimes

Abstract

Projected climate change and rainfall variability will affect soil microbial communities, biogeochemical cycling and agriculture. Nitrogen (N) is the most limiting nutrient in agroecosystems and its cycling and availability is highly dependent on microbial driven processes. In agroecosystems, hydrolysis of organic nitrogen (N) is an important step in controlling soil N availability. We analyzed the effect of management (ecological intensive vs. conventional intensive) on N-cycling processes and involved microbial communities under climate change-induced rain regimes. Terrestrial model ecosystems originating from agroecosystems across Europe were subjected to four different rain regimes for 263 days. Using structural equation modelling we identified direct impacts of rain regimes on N-cycling processes, whereas N-related microbial communities were more resistant. In addition to rain regimes, management indirectly affected N-cycling processes via modifications of N-related microbial community composition. Ecological intensive management promoted a beneficial N-related microbial community composition involved in N-cycling processes under climate change-induced rain regimes. Exploratory analyses identified phosphorus-associated litter properties as possible drivers for the observed management effects on N-related microbial community composition. This work provides novel insights into mechanisms controlling agro-ecosystem functioning under climate change. As in many terrestrial ecosystems, nitrogen (N) is the most limiting nutrient for plant growth in agroecosystems 1-3. The last century has been characterized by a considerable increase of N inputs in agricultural soils 4-7 , mostly in mineral form (NH 4 +), making plant growth less dependent on microbial N provisioning. However, the increased amount of reactive N in the environment has severe environmental and human health consequences 7 .

Resistance–recovery trade‐off of soil microbial communities under altered rain regimes: An experimental test across European agroecosystems

“…Our results show distinct microbial community compositions between soils under conventional and ecological management types (Hypothesis 1, Table 2), although this variation of community composition (detected using relative abundance of PLFAs) was small compared to the difference between countries or rain regimes. This result is consistent with previous studies from the same experiment or from the same study sites, also reporting management effect on microbial community composition using different methods (amplicon sequencing), with plant community composition, litter‐P traits and fertilization types as important drivers of differences in soil microbial properties between the two management types (Hartmann et al., 2015; Lori et al, 2018, 2020). These findings add to the growing body of evidence that distinct soil microbial community compositions might play a fundamental role in the functional differences between different agroecosystems (Bender et al., 2016).…”

“…Nevertheless, the combined management practices of ecological management appear to limit long‐term effect on microbial community biomass and functioning in response to both dry, wet and intermittent altered rain regimes, by increasing recovery capacity of these fundamental properties for soil fertility. Such functional attributes of microbial communities under ecological management can have positive cascading effect on forage growth and nutrients uptakes under altered rain regimes as demonstrated in previous studies (Lori et al, 2018, 2020; Piton, Legay, et al., 2020). To sum up, management based on ecologically sound principles, typically comprising lower fertilization load, the use of organic fertilizer and more diversified plant communities from the local species pool (Bender et al., 2016; Bommarco et al., 2013; Lori et al., 2020) should be encouraged to maintain long‐term soil fertility.…”

“…Soil structure (not assessed in this study) can also influence microbial community resistance and recovery, independently of community composition differences (Griffiths et al, 2008). For instance, distinct crop residues between ecological and conventional management (Lori et al, 2018(Lori et al, , 2020.…”

Diazotrophs for Lowering Nitrogen Pollution Crises: Looking Deep Into the Roots

“…Beneficial soil microorganisms cycle and/or supply nutrients to plants, while the invertebrates decompose organic matter and aerate soils and prey on crop pests ( Kremen, 2020 ). Analysis of the effect of management (ecological intensive vs. conventional intensive) and comparison of the diazotrophic communities in both systems show that ecological intensive management promoted a beneficial N-related microbial community composition involved in N-cycling processes ( Lori et al, 2020 ).…”

Factors Affecting the Number of Pollen Grains per Male Strobilus in Japanese Cedar (Cryptomeria japonica)

“…We counted pollen numbers from 26 clones of Japanese cedar and used piecewise Structural Equation Modeling (pSEM) to identify factors that affect pollen number. pSEM, which has gained attention in recent years in the fields of ecology and evolution, can reveal complex relationships among various factors by constructing a path diagram [ 27 , 28 , 29 , 30 , 31 ]. Because trees grow densely in breeding stands, it can be difficult to sample male strobili from branches of the same height and facing the same direction.…”