Solute transport in a hummocky landscape: I. Two-dimensional redistribution of bromide

Abstract

Olatuyi, S. O., Akinremi, O. O., Flaten, D. N. and Lobb, D. A. 2012. Solute transport in a hummocky landscape: I. Two-dimensional redistribution of bromide. Can. J. Soil Sci. 92: 609–629. Bromide has been widely used in field studies to estimate nitrate leaching in agricultural soils. This study examined the impacts of crop response to nitrogen fertilization on the vertical and lateral redistribution of bromide in the fall and spring seasons in a hummocky landscape. The study was carried out near Brandon, Manitoba, in 2007 and 2008, using two separate plots (Site-2007 and Site-2008). The plots were delineated into three landscape positions as upper (UPP), middle (MID) and lower (LOW) slope. A microplot at each landscape position received 15N labelled fertilizer (KNO3) at the rates of 0, 90 and 135 kg N ha−1, and KBr at the rate of 200 kg Br− ha−1. Site-2007 was seeded to canola while Site-2008 was seeded to winter wheat. Soil samples were taken within the microplot to a depth of 120 cm for vertical distribution, and up to 200 cm away from the microplot for lateral distribution of Br− in the top 20 cm depth. The downward movement of Br− in the soil was reduced under N fertilization. This resulted in the accumulation of Br− in fertilized plots, and a greater lateral movement of Br− in fertilized compared with unfertilized plots. The greatest vertical and lateral movement of Br− occurred at the LOW slope position. In the fall season following Br− application, 55 and 15% of the Br− applied were recovered in the vertical and lateral components of the landscape, respectively. Estimated loss of Br− due to vertical and lateral movement was 47% in the unfertilized treatment and 36% with N fertilization. The order of Br− loss in the two dimensions was: LOW (48%)>MID (40%)>UPP (37%). The study shows that crop response to N fertilization reduced the vertical movement of solute, thereby providing an experimental support for the “Campbell hypothesis” which states that N fertilization and proper rate of N application reduces nitrate leaching.

Cropping System and Type of Pig Manure Affect Nitrate‐Nitrogen Leaching in a Sandy Loam Soil

“…Soil sampling does not provide an accurate estimate of the quantity of NO 3 − ‐N leached because NO 3 − ‐N could have moved beyond the sampling depth (Olatuyi et al, 2012). However, the accumulation of NO 3 − ‐N with depth is an indirect evidence of leaching (Miller et al, 2011a).…”

“…The spatial power [SP(POW)] covariance structure was used in the model for the repeated measures data in which the depth intervals were unequal. Due to variability introduced by the manual application of manure, a predefined 0.1 significance level was used (Olatuyi et al, 2012; Zvomuya et al, 2003). Treatment differences were accepted if P < 0.1 using the Tukey–Kramer method.…”

“…Many of the studies that compared N‐based with P‐based nutrient management have concentrated on the accumulation of P with time, whereas the N dynamics and loss of NO 3 − ‐N from P‐based and N‐based manure management systems has not been thoroughly investigated. Moreover, several NO 3 − ‐N leaching studies relied solely on soil profile sampling, which can lead to erroneous conclusions regarding nutrient loss from the root zone (Olatuyi et al, 2012).…”

Nitrate Leaching in a Loamy Sand Soil Receiving Two Rates of Liquid Hog Manure and Fertilizer

“…The spatial power [SP(POW)] covariance structure was used in the model for the repeated measures data, in which the depth intervals were unequal. Treatment means were compared using the Tukey–Kramer test, assigning the significance level at P < 0.1, due to the inevitable variation in manure application by hand (Zvomuya et al, 2003; Olatuyi et al, 2012). Using Shapiro–Wilk's normality test, data for leachate and soil analysis were log 10 transformed, giving a normal distribution of residuals and homogeneity of variance, and back‐transformed data were presented in the tables and graphs.…”

Nitrogen and phosphorus uptake from solid and liquid pig manure in perennial and annual cropping systems

“…For total aboveground biomass and nutrient uptake/removal, the statistical model included block (with four levels) as a random factor and treatments (five levels) and cropping systems (two levels) as fixed factors. Due to the variability introduced by manual application of manure, a predefined 0.1 significance probability threshold was used (Zvomuya et al 2003;Olatuyi et al 2012). Treatment differences were accepted if p < 0.1 using the Tukey-Kramer method.…”