Xie, H. T., Yang, X. M., Drury, C. F., Yang, J. Y. and Zhang, X. D. 2011. Predicting soil organic carbon and total nitrogen using mid- and near-infrared spectra for Brookston clay loam soil in Southwestern Ontario, Canada. Can. J. Soil Sci. 91: 53–63. Mid-infrared (MIR) and near-infrared (NIR) spectroscopy of soils have been tested to estimate soil organic carbon (SOC) and total N (TN) concentrations at local, regional and national scales. However, these methods have rarely been used to assess SOC and TN concentrations of the same soil under different management practices. The objective of this study was to determine if models developed from infrared spectra of Brookston clay loam soils under different management practices could be used to estimate SOC, and TN concentrations and the C:N ratio. Soils used for model calibration included 217 samples from a long-term fertilization and crop rotation study and a long-term compost study, whereas 78 soil samples from a long-term tillage study on the same soil type were used for model validation. Soil organic carbon and TN concentrations of all samples were also analyzed using dry combustion techniques. Soil samples were scanned from 4000 to 400 cm−1 (2500–25 000 nm) for MIR spectra and from 8000 to 4000 cm−1 (1250–2500 nm) for NIR spectra. Partial least squares regression (PLSR) analysis was used for the calibration dataset to build prediction models for SOC, TN and C:N ratio. The SOC and TN concentrations determined using dry combustion techniques were compared with the prediction from the models using the calibration datasets. The predictions of SOC and TN concentrations by the PLSR method using infrared spectra were statistically sound, with high coefficient of determination with the calibration dataset (R2cal, SOCMIR=0.99 and SOCNIR=0.97, TNMIR=0.98 and TNNIR=0.97) and the validation dataset (R2val, SOCMIR=0.96 and SOCNIR=0.95, TNMIR=0.96 and TNNIR=0.95) and low root mean square error (RMSEPcal, SOCMIR=0.93 and SOCNIR=1.60, TNMIR=0.08 and TNNIR=0.12; RMSEPval, SOCMIR=1.40 and SOCNIR=1.75, TNMIR=0.11 and TNNIR=0.12). The predictions of SOC and TN concentrations in the 5 to 30 cm depth were better than the predictions for either the surface (0 to 5 cm) soils or for soils from lower depths (>30 cm). The models could be used as an alternative method for determining SOC and TN concentrations of Brookston clay loam soils; however, larger sample populations and improved model algorithms could further improve predictions.

X. M. 2015. Temporal effects of food waste compost on soil physical quality and productivity. Can. J. Soil Sci. 95: 251Á268. The benefits of compost additions on soil organic carbon content and crop productivity are extant in the literature, but detailed studies of compost effects on soil physical quality (SPQ) are limited. The objective of this study was therefore to describe how one-time additions of compost impact the immediate, mid-term and long-term SPQ and crop yields of an agricultural soil. Food waste compost (FWC) was incorporated once into the top 10 cm of a humid-temperate Brookston clay loam soil at rates of 0 (Control), 75 dry t ha(1 (FWC-75), 150 dry t ha(1 (FWCÁ150) and 300 dry t ha (1 (FWC-300); measurements of SPQ parameters and corn yield were then made annually over the next 11 yr. The SPQ parameters included bulk density (BD), organic carbon content (OC), air capacity (AC), plant-available water capacity (PAWC), relative field capacity (RFC), and saturated hydraulic conductivity (K S ), which were obtained from intact (undisturbed) soil core samples. Prior to compost addition, BD, OC, AC, PAWC, RFC and K S were substantially non-optimal, and BD had increased relative to virgin soil by 46%, while OC, AC and PAWC had decreased relative to virgin soil by 60, 56 and 43%, respectively. Improvements in SPQ 1 yr after compost addition were negligible or small for FWC-75 and FWC-150, but FWC-300 generated optimal values for BD, OC, AC, PAWC and RFC. The SPQ parameters degraded with time, but 11 yr after compost addition, OC and AC under FWC-300 were still within their optimal ranges, as well as significantly (PB0.05) greater than the Control values by 65 and 26%, respectively. Soil cracks and biopores apparently induced substantial annual variation in K S , but average K S nevertheless increased with increasing compost addition rate. Corn grain yield varied substantially among years, which was likely due to weather and compost effects; however, 11-yr cumulative yields from the compost treatments were greater than the Control by 2200Á6500 kg ha (1 .

Miller, J. J., Beasley, B. W., Drury, C. F., Hao, X. and Larney, F. J. 2014. Soil properties following long-term application of stockpiled feedlot manure containing straw or wood-chip bedding under barley silage production. Can. J. Soil Sci. 94: 389–402. The influence of long-term land application of stockpiled feedlot manure (SM) containing either wood-chip (SM-WD) or straw (SM-ST) bedding on soil properties during the barley (Hordeum vulgare L.) silage growing season is unknown. The main objective of our study was determine the effect of bedding material in stockpiled manure (i.e., SM-WD vs. SM-ST) on certain soil properties. A secondary objective was to determine if organic amendments affected certain soil properties compared with unamended soil. Stockpiled feedlot manure with SM-WD or SM-ST bedding at 77 Mg (dry wt) ha−1 yr−1 was annually applied for 13 to 14 yr to a clay loam soil in a replicated field experiment in southern Alberta. There was also an unamended control. Soil properties were measured every 2 wk during the 2011 and 2012 growing season. Properties included water-filled pore space (WFPS), total organic C and total N, NH4-N and NO3-N, water-soluble non-purgeable organic C (NPOC), water-soluble total N (WSTN), denitrification (acetylene inhibition method), and CO2 flux. The most consistent and significant (P≤0.05) bedding effects on soil properties in both years occurred for total organic C, C:N ratio, and WSTN. Total organic C and C:N ratio were generally greater for SM-WD than SM-ST, and the reverse trend occurred for WSTN. Bedding effects on other soil properties (WFPS, NH4-N, NO3-N, NPOC) occurred in 2012, but not in 2011. Total N, daily denitrification, and daily CO2 flux were generally unaffected by bedding material. Mean daily denitrification fluxes ranged from 0.9 to 1078 g N2O-N ha−1 d−1 for SM-ST, 0.8 to 326 g N2O-N ha−1 d−1 for SM-WD, and 0.6 to 250 g N2O-N ha−1 d−1 for the CON. Mean daily CO2 fluxes ranged from 5.3 to 43.4 kg CO2-C ha−1 d−1 for SM-WD, 5.5 to 26.0 kg CO2-C ha−1 d−1 for SM-ST, and from 0.5 to 6.8 kg CO2-C ha−1 d−1 for the CON. The findings from our study suggest that bedding material in feedlot manure may be a possible method to manage certain soil properties.

Miller, J. J., Beasley, B. W., Drury, C. F. and Zebarth, B. J. 2011. Accumulation and redistribution of residual chloride, nitrate, and soil test phosphorus in soil profiles amended with fresh and composted cattle manure containing straw or wood-chip bedding. Can. J. Soil Sci. 91: 969–984. Limited research has compared the effect of fresh versus composted beef (Bos taurus) cattle feedlot manure containing straw or wood chips on accumulation and redistribution of residual chloride (Cl), NO3-N, and soil test P (STP) in soil profiles of the Great Plains region of North America. Barley (Hordeum vulgare L.) was grown (1999–2007) on an irrigated clay loam soil in southern Alberta where organic amendments and fertilizer were annually applied for 9 yr from 1998 to 2006. The field experiment was a factorial arrangement of two manure types (fresh versus composted feedlot manure), two bedding materials (straw versus wood-chips), and three application rates (13, 39, 77 Mg ha−1dry wt). There was also one inorganic (IN) fertilizer treatment and an unamended control. The soil profile (0–1.5 m) was sampled in the fall of 1999 to 2002, 2004, 2006, and 2007 and analyzed for residual soil NO3-N, Cl, and STP. Manure type had a significant (P≤0.05) effect on the accumulation of these chemicals, but there was an interaction with application rate (NO3-N), or with bedding and year (STP). The maximum accumulation of Cl after 9 yr was at the 0.6 to 0.9 m depth, but mean values at this depth were similar for the four organic amendments. The maximum accumulation of NO3-N after 9 yr (2007) was at the 0.3 to 0.6 m depth, and mean values at this depth were significantly greater by four- to sixfold for FM and CM with straw than wood-chips, which suggested greater N immobilization in soils with wood. Redistribution of Cl and NO3-N downward into the soil profile suggested a potential for leaching of these chemicals below the root zone. In contrast, soil test P did not accumulate below the 0.3 m depth, suggesting little potential for leaching. However, accumulation of soil test P at this depth was generally greater for the amendment treatments compared with inorganic fertilizer and was likely related to greater P applied in the amendments.

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