Does Turbulent-flow Conditioning of Irrigation Water Influence Soil Chemical Processes: II. Long-term Soil and Crop Study

ABSTRACT

Recent laboratory evidence suggests that the intrinsic behavior of molecular water in soil is altered by turbulent-flow conditioning (CTap) of mineralized irrigation water (Tap). This 9-yr (2009 to 2017), irrigated, outdoor, cropped pot study evaluated the effect of Tap and CTap irrigation water on soil leachate chemistry, nutrient availability, and aboveground crop biomass yield and nutrient uptake. CTap increased cumulative mass losses of: nitrate nitrogen 2.5-fold; manganese 2-fold; potassium (K) 1.6-fold; magnesium (Mg), dissolved organic carbon, and ammonium nitrogen (NH₄-N) an average 1.2-fold; and increased the mean electrical conductivity of leachate 1.2-fold. In both the current and a previous laboratory study (see Part 1), K, NH₄-N, and Mg were leachate components most consistently selected by multivariate analysis as best discriminating between water treatments. The evidence also suggests that CTap increased mean available soil zinc (Zn) 2.4-fold, copper, K, and soil phosphorus an average 1.4-fold, sodium and iron (Fe) 1.2-fold, and decreased soil total carbon, TC (4%), total inorganic carbon (8%) and Mg (9%) relative to the Tap. In addition, CTap increased average crop biomass element concentrations: Zn, Fe, and aluminum an average 1.3-fold; total nitrogen, calcium, K, and sulfur 1.1-fold; and decreased TC (2%) relative to Tap. If the capacity of this simple device to increase soil cation leaching can be confirmed in broader applications, it could potentially provide an economical means of increasing the availability of nutrients in soils irrigated with conditioned water and managing or remediating degraded, salt-affected soils.

KEYWORDS:

• Calcareous soils
• cations
• anions
• geochemistry
• leaching
• leachate
• salts

Acknowledgments

We thank several anonymous reviewers for insightful comments on an initial draft of the manuscript; Larry Freeborn, Katie Shewmaker, Jim Foerster, and Susan Glaze for their technical support, and Evan Albright, Kandis Bordi Diaz, Kevin Robison, and Quinn Inwards for their able assistance in the laboratory and field.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Supplementary material

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Additional information

Funding

This research was supported in-house by the USDA-Agricultural Research Service.