Spatial variability of boron availability in canola

Abstract

The spatial variability of hot water soluble boron (HWS-B) and yield responses of canola to B fertilization was assessed at sites in the Grey soil Zone using a linear sampling transect. At each site, 128 soil samples were taken at 3-meter intervals and analyzed for HWS-B, physical and chemical soil properties. Results indicate that the organic matter content, particularly in acidic soils, strongly influenced HWS-B content. To a lesser extent, soil pH and texture also contributed to HWS-B variability. On the alkaline site, apparent yield increases to foliar B were correlated to soil pH in a positive and significant manner. The HWS-B test failed to predict the yield responses to B fertilization. In the year of the study eat and drought stress occurred during a period when canola is most sensitive to a B deficiency (flowering) and also may have contributed to the yield increases. Results of a geostatistical analysis, known as wavelet analysis, revealed that at spatial scales > 50m, variability in HWS-B content is significant. Therefore, significant responses to B fertilization may not be detected with the traditional random complete block design.