Soil health indicators and crop yield in response to long-term cropping sequence and nitrogen fertilization

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

Submitted to: Geoderma
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/26/2021
Publication Date: 8/12/2021
Citation: Sainju, U.M., Liptzin, D., Rana Dangi, S., Ghimire, R. 2021. Soil health indicators and crop yield in response to long-term cropping sequence and nitrogen fertilization. Geoderma. 168. Article 104182. https://doi.org/10.1016/j.apsoil.2021.104182.
DOI: https://doi.org/10.1016/j.apsoil.2021.104182

Interpretive Summary: Improving soil health in croplands is purported to provide numerous ecological and agronomic benefits. It is important to identify soil health indicators that correlate with dryland crop yield so that crop producers in these semi-arid climates will be able to monitor the effects of cultural practices on soil physical, chemical and biological properties that affect productivity. ARS researchers at Sidney, MT collaborated with researchers at the Soil Health Institute to evaluate 56 soil health indicators from a 14-year-old tillage, cropping sequence, and nitrogen fertilization experiment. They found that no-till continuous cropping increased soil aggregation and stability, phosphorus concentration, labile carbon and nitrogen concentrations, and microbial and enzyme activities, but reduced soil bulk density and sulfur and nitrate-nitrogen concentration compared to crop-fallow. Nitrogen fertilization increased soil available N, but reduced soil aggregation, water content, and magnesium and sodium concentrations compared to no nitrogen fertilization. While the most promising soil health indicators related to crop yield were soil organic matter, bulk density, and silt concentration, several biological parameters were also well-correlated with crop yield. Producers can enhance soil health and crop yield by including soil biological properties in addition to physical and chemical properties in the routine soil test.

Technical Abstract: There is a need for including soil physical and biological properties along with chemical properties to accurately measure soil health and relate to crop yields. The objective of this study was to measure 56 soil health indicators that included physical, chemical, and biological properties and relate them to crop yield in a 14-yr-old cropping sequence and N fertilization study in eastern Montana, USA. Main-plot (cropping sequence) treatments were conventional till barley/spring wheat (Triticum aestivum L.)-fallow (CTWF), no-till continuous barley (Hordeum vulgaris L.)/spring wheat (NTCW), no-till barley/spring wheat-fallow (NTWF), and no-till barley/spring wheat-pea (Pisum sativum L.) (NTWP) and split-plot (N fertilization) treatments were 0 and 80/100 kg N ha-1 applied to barley and spring wheat. The NTCW increased aggregate stability, wet soil stability index, average slake aggregate, P concentration, KMNO4-extractable C, CO2 evolution (1 d incubation), potentially mineralizable N, and N-acetyl ß-glucosaminidase (NABG), but reduced fine earth fraction bulk density and S and NO3-N concentrations compared to other treatments. Water-stable aggregate, macro-porosity, volumetric water content at water saturation, and Mg and Na concentrations were greater with 0 kg N ha-1, but water-extractable total N and NO3-N concentration were greater with 80/100 kg N ha-1. Mean crop yield from 2006 to 2019 were greater in NTCW with 80/100 kg N ha-1 than other treatments. Crop yield positively correlated to silt and Cd concentrations, soil organic matter, autoclaved citrate extractable protein index (ACEPI) and N-acetyl ß-glucosaminidase (NABG), but negatively to bulk density and B, S, and NO3-N concentrations. No-till continuous cropping without N fertilization enhanced soil physical and biological properties, but conventional till crop-fallow with N fertilization increased N availability. Because of increased sensitivity of soil biological properties to management practices and crop yield, biological properties can be used as important soil health indicators for the routine soil test in addition to physical and chemical properties.