limitations of, near infrared reflectance spectroscopy applications in soil analysis: A review. Can. J. Soil Sci. 89: 531Á541. Near infrared reflectance spectroscopy (NIRS) is a cost-and time-effective and environmentally friendly technique that could be an alternative to conventional soil analysis methods. In this review, we focussed on factors that hamper the potential application of NIRS in soil analysis. The reported studies differed in many aspects, including sample preparation, reference methods, spectrum acquisition and pre-treatments, and regression methods. The most significant opportunities provided by NIRS in soil analysis include its potential use in situ, the determination of various biological, chemical, and physical properties using a single spectrum per sample, and an estimated reduction of analytical cost of at least 50%. Contradictory results among studies on NIRS utilisation in soil analysis are partly related to variations in sample preparation and reference methods. The following calibration statistics appear to be most appropriate for comparing NIRS performance across soil attributes: (i) coefficient of determination (r 2 ), (ii) ratio of performance deviation (RPD), (iii) coefficient of regression (b), and (iv) ratio of the standard error of prediction (SEP) to the standard error of the reference method (SER), i.e., the ratio of standard errors (RSE). Further investigations on issues such as (i) RSE guidelines, (ii) correlation between NIRS spectrophotometers, (iii) correlation of different reference methods for a given attribute to soil spectra, (iv) identification of key factors affecting the accuracy of NIRS predictions, and (v) efficient use of spectral libraries are required to enhance the acceptability of NIRS as a soil analysis technique and to make it more user-friendly. Standardized guidelines are proposed for the assessment of the accuracy of NIRS predictions of soil attributes.

Most methods for soil analysis are based on wet chemistry. Near infrared reflectance spectroscopy (NIRS) is a cost‐effective and environmentally sound alternative technique. This study evaluated the effect of sample fineness (0.2, 0.5, 1, and 2 mm) and sample cups (transport versus spinning) on the accuracy of NIRS predictions of soil texture, cation‐exchange capacity, pH, total C and N, organic C, and potentially mineralizable N (Nmin) using 150 air‐dried samples collected from a 15‐ha site dominated by Humaquept, Endoaquept, and Dystrochrept soils. The best spectral pretreatment was determined for each property. Principal component analysis (PCA) was used to select samples in calibration and validation sets. Calibration equations were developed using the modified partial least square regression. The accuracy of NIRS prediction was evaluated using three statistics for the prediction set: coefficient of determination (R2), ratio of performance deviation (RPD), and ratio error range (RER). Across the factorial designed treatments, successful calibrations were observed for clay, sand, and Nmin (R2 ≥ 0.90, RPD ≥ 3, RER ≥ 15). Prediction accuracy of pH was poor (0.51 ≤ R2 ≤ 0.74, 1.39 ≤ RPD ≤ 1.92, 6.13 ≤ RER ≤ 8.33), while it was intermediate for remaining properties. Sample fineness of 2 mm appeared to be sufficient since finenesses of 0.2, 0.5, or 1.0 mm did not improve calibration accuracy. These findings at small scale should not be extrapolated and further investigations are required to validate them at a larger scale.

extractable nutrients as determined by near-infrared reflectance spectroscopy. Can. J. Soil Sci. 89: 579Á587. Near-infrared reflectance spectroscopy (NIRS) is a cost-effective and environmentally friendly technique of soil analysis that is particularly advantageous in intensive soil sampling and soil nutrient management as well. This study evaluated the potential of NIRS for predicting P, K, Ca, Mg, Cu, Zn, Mn, Fe, and Al extracted by Mehlich 3. We used 150 air-dried samples collected from a 15-ha site dominated by Orthic Humic Gleysol and Gleyed Dystric Brunisol soils. Calibration equations were developed using modified partial least squares regression. The accuracy of NIRS prediction was evaluated using the coefficient of determination (R 2 ), the ratio of performance deviation (RPD), and the ratio of error range (RER). Reliable calibrations were found for Ca, Cu, and Mg (R 2 ]0.7, RPD ]1.75, and RER ]8). Less-reliable calibrations were found for Al, Fe, K, Mn, P, and Zn (R 2 B 0.7, RPDB1.75, and RER B8). In the validation with independent samples, acceptable regression coefficients (i.e., 0.8 5 slope 51.2) were only found for Ca, Mg, and Mn. We presumed that the pH of the Mehlich 3 extractant (2.590.1) may affect the solubility of most of these nutrients, regardless the soil texture and, consequently, the potential of NIRS to predict them. The more a nutrient was correlated to clay content, the more it was likely predictable by NIRS. The prediction models obtained for Al, Ca, Cu, Fe, K, Mg, and Mn could still be used for screening purposes in cases where high accuracy is not required. These NIRS prediction models should be validated across larger geographic areas of geological homogeneity.

2008. Evaluation of fresh and aged clam processing wastes as potential agricultural liming materials for coastal area vegetable production soils. Can. J. Soil Sci. 88: 559Á569. Clam canning in New Brunswick generates 1800 t of clam processing wastes (CPW) annually. Thirty-year-old stockpiles of CPW must now be remediated to satisfy environmental regulations. This study examined fresh and aged CPW as potential agricultural liming materials for acid coastal vegetable production soils. Clam processing wastes were ground to three size fractions (B0.250 mm, 0.250 to B1.00 mm, 1.00 to B2.00 mm) and analyzed for calcium carbonate equivalent (CCE). They were then mixed with two soils of contrasting textures at three rates, in duplicate, and then placed in a control-plusfactorial pot experiment, with commercial agricultural lime of fine texture (B0.250 mm) as reference. During an 8-wk incubation, soil water pH and electrical conductivity (EC) were monitored biweekly. At 4 and 8 wk, a soil extract germination test was conducted using cress (Lepidium sativum L.) as an indicator plant. CPW of B1 mm raised soil pH with effectiveness increasing as particle size decreased. Application rates in function of the fineness to induce a given pH change (DpH) could be obtained using prediction graphs with high coefficients of determination (r 2 : 0.84 to 0.97). The average EC in all treatments to the end of the incubation period was B2 dS m(1 , indicating that salt stress is not a risk following CPW application to soil, since even sensitive crops are capable of withstanding such an EC. Seeding could take place between 4 and 8 wk after the CPW application to loamy sand with no adverse effect on germination index. In the loam soil, this period could safely be shortened.Key words: Clam, liming, soil pH, soil EC, cress, germination index Owen, J., LeBlanc, S., Toner, P., Nduwamungu, C. et Fava, E. 2008. É valuation des re´sidus de transformation des myes, frais et vieux, comme mate´riel de chaulage pour des sols coˆtiers utilise´s pour la production de cultures maraıˆche`res. Can. J. Soil Sci. 88: 559Á569. La mise en conserve des myes au Nouveau-Brunswick ge´ne`re chaque anne´e 1 800 tonnes me´triques de re´sidus de transformation des myes (RTM). On doit aujourd'hui assainir des piles de RTM datant d'il y a une trentaine d'anne´es pour satisfaire a`la re´glementation sur l'environnement. La pre´sente e´tude examine la possibilite´d'utiliser des RTM, frais et vieux, comme mate´riel de chaulage des sols coˆtiers acides servant a`la production maraıˆche`re. Des RTM ont e´te´broye´s en trois fractions granulome´triques (B0,250 mm, 0,250 a`B1,00 mm, 1,00 a`B2,00 mm), puis ont fait l'objet d'analyses visant la de´termination d'e´quivalents de carbonate de calcium (CCE). On les a ensuite me´lange´s, en duplicats, ad eux sols de texture diffe´rente, a`trois doses, dans un plan expe´rimental factoriel en pots incluant comme re´fe´rence la chaux agricole commerciale a`texture fine ( B0,250 mm). Au cours d'une incubation de huit semaines, on a surve...

Lignin plus cutin (LIC) content and biological stability index (BSI) are well-recognized indexes of potentially recalcitrant carbon (C) in organic products, and C / nitrogen (N) and lignin/N ratios have been related to potentially mineralizable N (PMN).Our objective was to use Fourier-transform near-infrared (FT-NIR) spectroscopy to estimate PMN and BSI of plant residues, composts, and manures. We also evaluated FT-NIR for determining the C/N, LIC/N, and BSI/N ratios as indexes of N mineralization in selected organic products. We analyzed 148 organic products for biochemical composition and total C and N. A subset of 10 products was incubated in a sandy soil to determine PMN. The FT-NIR successfully determined lignin and cutin (LIC) and BSI from r 2 , the ratio of prediction to standard deviation, and the ratio error range criteria. The PMN was less closely related to the C/N ratio (r 2 = 0.64) than the BSI/N (r 2 = 0.84) and LIC/N (r 2 = 0.87) ratios. There was some N immobilization at an early stage of incubation when C/N, LIC/N, and BSI/N ratios exceeded 14, 10, and 15, respectively. There is a need to characterize a larger number of organic compounds in the soluble and LIC fractions to improve the BSI equation.