Soil health within transitions from irrigation to limited irrigation and dryland management

Authors: BHANDARI, KRISHNA - Texas Tech University; Acosta-Martinez, Veronica; Perez-Guzman, Lumarie; WEST, CHARLES - Texas Tech University

Submitted to: Agricultural & Environmental Letters
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/14/2022
Publication Date: 5/16/2022
Citation: Bhandari, K., Acosta Martinez, V., Perez-Guzman, L., West, C.P. 2022. Soil health within transitions from irrigation to limited irrigation and dryland management. Agricultural & Environmental Letters. 7(1). https://doi.org/10.1002/ael2.20077.
DOI: https://doi.org/10.1002/ael2.20077

Interpretive Summary: Reductions in water available for irrigation in the Texas High Plains are forcing some growers to convert irrigated cropland to dryland production. Research on the impacts of this transition will facilitate the selection of appropriate dryland management practices to maintain the soil productivity and health. Researchers from Texas Tech University and USDA-ARS in Lubbock, Texas took soil samples since the first year producers changed some of their land from high to low irrigation (center pivot to subsurface drip) or irrigation to dryland. The soil water content decreased in all sites over a 3 year period due to decreased irrigation. Soil nitrate was higher by the third year. The most consistent changes were declines in soil microbes including fungi while bacteria populations were unaffected. Transitioning to low water-input management in a semi-arid environment challenges effort to maintain microbial components of soil health. Longer-term comparisons are needed to detect slow changes in soil health indicators under low-water conditions.

Technical Abstract: The decline in groundwater supply in the Texas High Plains is forcing some growers to convert center-pivot irrigated cropland to dryland production. Transitioning toward reduced water input can lead to declines in soil health. We assessed short-term changes in soil health indicators in two transition scenarios, (i) from high irrigation method to low irrigation method (center pivot to subsurface drip) and (ii) from high irrigation method to dryland (center pivot to dryland), in comparison with continuous center-pivot management. We monitored changes in chemical and biological indicators in four fields for each transition scenario and in three pivot-irrigated fields. There were declines in soil water content, K, Na, and organic C with transition from irrigation to reduced irrigation and dryland. Severe drought in the final year revealed reduced amounts of multi-enzyme activities, total EL-FAME, and total fungi. Transitioning to low water-input management in this environment complicates efforts to maintain microbial components of soil health. Longer-term comparisons are needed to detect slow changes in soil health indicators on producers’ fields.