Soil microbial properties of durum growth after camelina, carinata, CC mix and fallow

Authors: Rana Dangi, Sadikshya; Allen, Brett; Jabro, Jalal - Jay; Rand, Tatyana; Campbell, Joshua; Calderon, Rosalie

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/5/2024
Publication Date: 9/7/2024
Citation: Rana Dangi, S., Allen, B.L., Jabro, J.D., Rand, T.A., Campbell, J.W., Calderon, R.B. 2024. Soil microbial properties of durum growth after camelina, carinata, CC mix and fallow. Agronomy Journal. 14(9). https://doi.org/10.3390/agronomy14092050.
DOI: https://doi.org/10.3390/agronomy14092050

Interpretive Summary: To enhance soil health in agroecosystems, adopting a novel rotation crop and diversification are important management tools. Rotation crops induce changes in the microbial community composition that can affect the performance of subsequent crops. Results from this field study showed a distinct variation in the microbial community structures of cover crops and oilseeds crops which were differentiated from the community associated with fallow. Changes in the abundance of specific microbial groups due to preceding crops may play a key role in the yield of subsequent crops, and overall soil health and quality. Our findings provide information to the scientific community and dryland farmers in making management decisions for their durum-based crop rotations as the land area planted to cover crops and oilseed crops are expected to increase in future years.

Technical Abstract: Crop rotation is an important factor influencing the composition of the rhizosphere microbiome. However, the effect of introducing oilseed and cover crops (CC) into monoculture durum rotations on soil microbial communities is not clear in the northern Great Plains. The objective of this study was to evaluate the effects of 2-year durum (Triticum durum D.) rotations with oilseed crops, Ethiopian mustard (Brassica carinata A.) or camelina (Camelina sativa L.), or a 10-species forage/CC mix planted in place of fallow on soil microorganisms. The study was designed as a randomized complete block with three replications in a no-tillage system. Results showed that total bacterial proportion was significantly higher in durum following fallow and camelina compared to durum following CC and carinata. Total fungal proportion was significantly higher in durum following CC and carinata compared to durum following camelina and fallow. Canonical variates analysis indicated important disparities in microbial community structure and the distinct variation increased over time among the rotation crops. The crop species, soil pH and a highly variable rainfall influenced the microbial community dynamics. The abundance of specific microbial groups due to crop-related changes might play a key role in the yield of subsequent crops and soil health. This study provides valuable insights into the use of a CC mix and oilseeds as alternative crops for fallow in a wheat-fallow system under dryland farming conditions. Future work is required to elucidate the biological mechanisms and functions of the soil microbial communities in the preceding and subsequent crop relative to soil health and crop productivity.