Short-Range Spatial Variability of Nitrates and Phosphates
extracted from Anionic Exchange Membranes in Three Textural Soil Groups. (6090)
Authors:
M.C. Nolin* - AAFC, Quebec N. Ziadi - AAFC, Quebec
A.N. Cambouris - AAFC, Quebec
Abstract:
Anion exchange membranes (AEMs) are a method for determining the plant available N and P status of soils. The purpose of this study was to determine the short-range spatial distribution of soil NO3 and PO4 extracted from AEMs (NO3AEMs and PO4AEMs), and to discuss the implications of this variation on soil sampling strategy and precision farming applications. The AEMs were installed (10 cm deep) in a Montreal Lowlands (Quebec, Canada) corn field at six sampling points covering three soil types:
sandy loam, clay loam and clay. For each point, 64 AEMs (4 x 16 interrow locations) were positioned on a 300 cm x 228 cm grid at three sampling dates: before seeding (t1), 6-leaf stage (t2), and silk stage (t3). Very high short-range spatial variability (CV = 50-250%) was observed in this field. The
PO4AEMs variability was greater than the NO3AEMs variability. A greater variability was also
measured at t2 and t3 than at t1, due to the effect of banded fertilizers. Soil types and interrow locations had also significant effects on CV and mean values of these two soil properties. Although NO3AEMs and PO4AEMs are very good indicators of the plant available N and P status of soils, particularly for discriminating soil types and sampling dates, their short-range spatial variation is too high for reliably guiding variable rate application of N and P fertilizers.
Speaker Information: Michel C. Nolin, AAFC, Quebec, 979 de Bourgogne Ave. Local # 140, Quebec, QC G1W2L4; Phone: 418-648-7730 (ext. 24); E-mail: [email protected]
Session Information: Wednesday, November 3, 2004, 2:00 PM-4:00 PM Presentation Start: 2:00 PM (Poster Board Number: 2153)
Keywords: Random and Systematic Variation; Banded Fertilizer; Sampling Strategy; Precision Agriculture