Relationship between soil carbon and nitrogen, soil properties, and dryland crop yields

Authors: Sainju, Upendra; LIPTZIN, DANIEL - Soil Health Institute; GHIMIRE, RAJAN - New Mexico State University; Rana Dangi, Sadikshya

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/5/2021
Publication Date: 12/15/2021
Citation: Sainju, U.M., Liptzin, D., Ghimire, R., Rana Dangi, S. 2021. Relationship between soil carbon and nitrogen, soil properties, and dryland crop yields. Agronomy Journal. 114(1):395-414. https://doi.org/10.1002/agj2.20938.
DOI: https://doi.org/10.1002/agj2.20938

Interpretive Summary: Measurement of soil organic matter requires a two-step process of determining soil total carbon and inorganic carbon in arid and semiarid regions because these regions are usually rich in soil inorganic carbon. Researchers in ARS, Sidney, MT in collaboration with Soil Health Institute and New Mexico State University evaluated soil total carbon or nitrogen, which requires only one step-process to determine, as an alternative to soil organic matter as a potential soil health indicator in two long-term dryland cropping systems in the northern Great Plains. They found that soil organic matter was more strongly correlated to a greater number of soil physical, chemical, and biological properties and mean crop yield across years than soil total carbon and nitrogen. They concluded that soil organic matter can be a potential soil health indicator in predicting crop yields compared to soil total carbon or nitrogen in dryland cropping systems in the northern Great Plains, although its determination requires a two-step process.

Technical Abstract: As dryland farms in arid and semiarid regions are enriched in soil inorganic C (SIC), soil total C (STC) or total N (STN) may be used as an inexpensive potential soil health indicator alternative to soil organic matter (SOM) for enhancing soil functioning and predicting crop yields. We related STC, STN, and SOM to 62 soil properties and mean crop yields across years in two long-term (14-36 yr old) experiments in the northern Great Plains, USA. Treatments were rotations of till- and no-till spring wheat (Triticum aestiveum L.)/barley (Hordeum vulgaris L.), pea (Pisum sativum L.), and fallow with and without N fertilization. No-till continuous cropping increased STC, STN, and SOM compared to crop-fallow, with limited effect of N fertilization. The STC correlated to 3-9 soil physical, 2-8 chemical, and 3-10 biological and biochemical properties and STN to 0-7 physical, 0-8 chemical, and 0-9 biological and biochemical properties. Similarly, SOM correlated to 3-11 physical, 5-9 chemical, and 7-12 biological and biochemical properties. Combination of data from both experiments enhanced the relationship among STC, STN, and SOM and selected soil properties. The SOM was better related to mean crop yield than STC and STN. Although additional step is required to analyze soil samples for SOM by determining SIC and STC, SOM can be used as a promising soil health indicator that relates to most soil properties and predicts crop yields in dryland cropping systems in the semiarid northern Great Plains.