Abstract
An inadequate soil sampling time leads to difficulties in interpreting soil tests, to incorrect recommendations for soil amendments and fertilizers, and to inappropriate environmental protection restrictions. Soil samples may be collected from agricultural fields before, during, or after the crop growth period. Since the time of soil sample collection can affect soil tests results, the objective of this study was to evaluate the effect of sampling time on measurements representativity of 15 fertility indicators in two fields located in La Pocatière (Québec, Canada). The soils were of fine (G1) and medium (G2) textural groups and were sampled weekly for 33 weeks per year during four years. Data analyses included descriptive statistics, time-series decomposition, and time autocorrelation function (ACF). Since results of these analyses showed a clear seasonal effect only for Mehlich-3 extracted phosphorus (PM3), soil phosphorus saturation index (SPS) for both G1 and G2 soils, and for pHW for G1 only, we recommend that the sampling calendar should be restricted to the first five weeks of spring (until the end of May) and to the entire fall period (starting in early September). Also, the temporal autocorrelation was four weeks on average. This implies that, for an initial year, whichever date is chosen for the sampling, the following annual sampling should be done within a four-week time window (i.e., two weeks before until two weeks after the initial sampling date). Time series are an important element to consider in selecting a representative sampling period for soil fertility indicators.
Highlights
An inadequate soil sampling time leads to difficulties in interpreting soil tests, to incorrect recommendations for soil amendments and fertilizers, and to inappropriate environmental protection restrictions
Data analyses included: descriptive statistics, time series decomposition, and time autocorrelation function (ACF). Since results of these analyses showed a clear seasonal effect only for Mehlich-3 extracted phosphorus (PM3), soil phosphorus saturation index (SPS) for both G1 and G2 soils, and for pHwater for G1 only, we recommend that the sampling calendar should be restricted to the first five weeks of spring and to the entire fall period
As for the other indicators, CuM3 has the highest standard deviation ratio (SDR) in the range [23 - 55%] which upper limit is comparable to the temporal SDR of 43.8% for bioavailable Cu reported by Cameron et al (1994)
Summary
An inadequate soil sampling time leads to difficulties in interpreting soil tests, to incorrect recommendations for soil amendments and fertilizers, and to inappropriate environmental protection restrictions. Data analyses included: descriptive statistics, time series decomposition, and time autocorrelation function (ACF) Since results of these analyses showed a clear seasonal effect only for Mehlich-3 extracted phosphorus (PM3), soil phosphorus saturation index (SPS) for both G1 and G2 soils, and for pHwater for G1 only, we recommend that the sampling calendar should be restricted to the first five weeks of spring (until the end of May) and to the entire fall period (starting in early September). Fertility indicators values may increase during one season and decrease the one and vice versa (Cameron et al 1994; Lockman and Molloy 1984) These temporal variations are often intra- and inter-annual and depend on cropping practices and soil management methods (Dai et al 2011).
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
