Does increasing diversity of small grain cropping systems improve aggregate stability and soil hydraulic properties?

Authors: Klopp, Hans; Jabro, Jalal - Jay; Allen, Brett; Sainju, Upendra; Stevens, William - Bart; Rana Dangi, Sadikshya

Submitted to: Agronomy
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/6/2023
Publication Date: 6/8/2023
Citation: Klopp, H.W., Jabro, J.D., Allen, B.L., Sainju, U.M., Stevens, W.B., Rana Dangi, S. 2023. Does increasing diversity of small grain cropping systems improve aggregate stability and soil hydraulic properties? Agronomy. 13. Article 1567. https://doi.org/10.3390/agronomy13061567.
DOI: https://doi.org/10.3390/agronomy13061567

Interpretive Summary: Wheat and barley are two cereal crops that are grown in the northern Great Plains in the United States. Adding crops such as field pea, canola and camelina to wheat and barley cropping systems may improve soil quality and crop grain yields. Some of the important indicators of soil quality are soil physical properties. Few earlier studies have analyzed the effects of adding canola and camelina oilseeds to wheat or barley cropping systems on soil physical properties. We collected samples from a study in Sidney Montana, USA that had 10 different small grain cropping systems. We measured soil properties of dry aggregate stability, wet aggregate stability, water retention, bulk density, hydraulic conductivity, and soil carbon concentration. Our study found that most soil properties were not affected by cropping system diversity near the soil surface. The findings of our study show that adding alternative crops such as canola, camelina of field peas to wheat or barley cropping systems generally did not affect soil physical properties. This is important to agricultural producers in the Northern Great Plains because the results show that the ability of the soil to store water and the rate at which water infiltrates into the soil stays the same when wheat or barley cropping systems are diversified.

Technical Abstract: Wheat (Triticum aestivium L.) and barley (Hordeum vulgare L.) are two commonly grown cereal crops in the northern Great Plains. Adding other crops such as field pea (Piscum aestivium L.), canola (Brassica napus L.), or camelina (Camelina sativa L.) to wheat or barley cropping systems may improve soil quality. However, little is known about the effects of adding oilseeds to small grain cropping systems on soil physical properties. We sampled an 8-yr dryland study with 10 different cropping systems including continuous spring wheat, continuous winter wheat, continuous barley, pea-spring wheat, pea-barley, pea-winter wheat, pea-barley-camelina-spring wheat, pea-barley-canola-spring wheat, pea-winter wheat-camelina-spring wheat and pea-winter wheat-canola-spring wheat. We measured dry aggregate stability, wet aggregate stability, water retention, hydraulic conductivity, bulk density and total carbon. Continuous barley and winter wheat had a higher fraction of large dry soil aggregates, whereas pea-barley-canola-spring wheat and pea-spring wheat rotations had higher fraction of small aggregates in 0-15 cm depth. However, wet aggregate stability, water retention, bulk density, hydraulic conductivity and soil carbon concentration were not affected by cropping system in 0-15 cm depth. Diversifying small grain cropping systems by adding canola or camelina oil seeds and peas generally does not affect soil physical properties at this location.