Soil moisture and nutrient variation within an undulating Manitoba landscape

Abstract

Soil moisture and nutrient variation within an undulating Manitoba landscape. Can. J. Soil Sci. 81: [449][450][451][452][453][454][455][456][457][458]. The use of discrete management units for variable-rate N fertilization requires that factors influencing grain yield response to N fertilizer are adequately characterized by delineating landscapes into such management units. The objective of this study was to compare the use of topographically derived landform element complexes (LEC) and the use of individual soil series as management units. Soil volumetric moisture content, nitrate-N, exchangeable ammonium-N, extractable phosphorus, exchangeable potassium, and sulphate-sulphur were studied in 10 intensively sampled transects in an undulating glacial till landscape near Miniota, Manitoba. The study site was delineated into upper, mid and lower LEC using a digital elevation model derived from relative elevation data. The LEC were useful in capturing gross variability at a manageable landscape scale. Among LEC there was a general trend of lower > mid > upper for median values of soil moisture, nitrate, phosphate, potassium and sulphate, as these attributes generally increased with convergent landscape character. Differences among LEC were often statistically significant, and relative distributions exhibited temporal persistence. The site was also stratified by soil series, including Newdale, Varcoe and Angusville soils (Black Chernozems), which were identified by examination of individual soil cores at each sample point. Stratifying the site into management units using soil genetic information, which is reflective of historical moisture conditions and biomass production, was expected to be superior. There was little advantage, however, in using soil series rather than LEC. Spatial distributions of the most agronomically relevant attributes (soil moisture and nitrate) were expressed at a landscape scale broader than that at which soil series occurred within the site. While there were important differences among soil series with respect to nutrients such as phosphate and sulphate, the site was better stratified by LEC with respect to soil moisture and nitrate. Pour fertiliser le sol avec une quantité variable d'engrais azoté, il est essentiel de bien caractériser les facteurs qui affectent la réaction du rendement grainier à l'engrais en divisant le terrain en unités agronomiques. L'étude devait comparer l'utilité de complexes d'éléments topographiques (CET) et de séries de sols comme unités agronomiques. Les auteurs ont déterminé la quantité d'eau, de N sous forme de nitrates ou d'ammonium échangeable, de phosphore extractible, de potassium échangeable et de soufre-sulfate dans un grand nombre d'échantillons prélevés le long de dix transects, sur un terrain de till glaciaire, près de Miniota, au Manitoba. Le site a été subdivisé en CET de haute, de moyenne et de faible altitude grâce à un système de modélisation numérique des hauteurs, à partir de la hauteur relative. Les CET permettent de saisir les variations gros...

Bromide redistribution as influenced by landscape morphology and pedogenic properties in a variable glacial till landscape: A qualitative examination

“…Organic carbon analysis was conducted on Ap/Ah horizon soils from each plot using a LECO 2000 CNS determinator (Nelson and Sommers 1982) following sample preparation based on Tiessen et al (1983). Additional bulk soil samples were taken for determination of particle size analysis by the hydrometer method (Gee and Bauder 1986).…”

“…Redistribution of water and associated solutes affects crop yield via losses of valuable fertilizer nutrients (Farrell et al 1996;Manning et al 2001b) and negatively impacts groundwater quality (Schuh et al 1993;Seelig and Richardson 1994). This has obvious agronomic, economic and environmental implications.…”

“…Bromide has been used extensively in field studies as a tracer for water and solute movement through the soil profile (Smith and Davis 1974;Bruce et al 1985;Butters et al 1989;Bathke and Cassel 1991;Bathke et al 1992;Afyuni et al 1994;Olson and Cassel 1999). The use of bromide allows for the study of processes of water and soluble nutrient movement in natural soil environments.…”

Strategies for improving nitrogen use efficiency: A review

“…In most of the crop production systems, N is supplied in larger quantity through inorganic source (chemical fertilizers) due to its faster availability to plant while small quantity N is added through organic sources i.e. crop residues, organic manure, biological N fixation and organic manures (Manning et al, 2001).…”

“…N transformation is a complex phenomenon involves fixation of ambient free N, mineralization of N from inorganic sources and finally its immobilization by various microbes (Manning et al, 2001). Mineralization is simply the process where organic form of N get transformed into inorganic form of N (NO 3 -and NH 4 + ) with the help of soil microbes .…”