Assessment of physicochemical properties of a loamy sand treated with biochar and dairy manure under silage corn production in western Newfoundland

Vermooten, Marli (2017) Assessment of physicochemical properties of a loamy sand treated with biochar and dairy manure under silage corn production in western Newfoundland. Memorial University of Newfoundland. (Unpublished)

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Abstract

Soil physicochemical properties play an important role in crop growth and final harvest. Different agronomic practices can improve soil health through modulating these physicochemical properties. Dairy manure (DM) is a good and abundant source of nutrients in Newfoundland, and both biochar (BC) and DM are considered good soil amendments. A field experiment was conducted at Pynn’s Brook Research Station, Pasadena NL, to evaluate the effect BC and DM has on various soil physicochemical properties, as well as to establish a relationship between soil electrical conductivity (EC) and these selected physicochemical properties. Experimental treatments with four replicates included control, inorganic nitrogen (IN), IN+BC, DM, and DM+BC. Dairy manure was applied at the rate of 30,000 L ha-1, whereas BC was applied at 20 t ha-1 (both were applied on May 23, 2016) and mixed within the top 10 cm of the loamy sand soil (82% sand + 6% silt + 12% clay). Disturbed soil samples were collected from treatment plots on four different days. Results showed no significant (p > 0.05) treatment effects on gravimetric and volumetric moisture contents, pH, ammonium nitrogen (NH4+-N), cation exchange capacity (CEC), or EC of tested soils, within each field day. Soil organic carbon (SOC) had a significant (P=0.042) difference between DM and DM+BC treatments only on August 4. However, significant temporal effects were recorded for pH, NH4+-N, and EC – both apparent electrical conductivity (ECa) and electrical conductivity of soil solution (ECw) – across four field days. The decrease of NH4+-N could possibly be accounted to volatilization, uptake by plants, immobilization by microbes, or conversion to nitrate-nitrogen, while the decrease in EC may be due to a decrease in ion concentration from uptake by plants and leaching. No significant differences were observed between the 0-10 cm and 10-20 cm soil depths within each treatment for the tested soil properties. Positive correlations were recorded for EC with SOC, NH4+-N, and CEC (ECa, ECw 0-10 cm, & ECw 10-20 cm, p=0.000). Once correlation data has been validated, the electromagnetic induction method can be used to map the ECa and respective spatio-temporal variability of important soil properties for similar soils in Newfoundland.

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