The District of Narbatah – Landscape Unit 25

2016 ◽  
pp. 339-434
Keyword(s):  
Landscape Unit

scholarly journals Lime and gypsum to improve root depth of orange crop in an Ultisol of the Coastal Tablelands

2009 ◽  
Vol 13 (suppl) ◽  
pp. 836-839 ◽  
Author(s):  
Lafayette F. Sobral ◽  
Fernando L. D. Cintra ◽  
Jot T. Smyth
Keyword(s):  
Root Growth ◽  
Root Length ◽  
Citrus Sinensis ◽  
Total Porosity ◽  
Root Depth ◽  
Soil Density ◽  
North East ◽  
The North ◽  
Landscape Unit ◽  
Set Up

Coastal Tableland is a landscape unit in the North East of Brazil in which the main soils are Ultisols. In these soils, a compacted layer denominated "cohesive horizon" occurs and root growth is limited by it. An experiment with five treatments and six replications was set up in order to study how liming and gypsum could improve root depth of orange (Citrus sinensis L. Osbeck) crop in an Ultisol in which a compacted layer was found at 0.3 m. Treatments were: A - No liming and no gypsum; B - Liming to achieve 60% base saturation; C - B + 1 t of gypsum ha-1 ; D - B + 2 t of gypsum ha-1 and E - B + 3 t of gypsum ha-1. Gypsum increased calcium and sulfate in the cohesive horizon. Surface application of lime and gypsum did not cause changes in soil density and total porosity in the cohesive horizon. An improvement of root length was observed at the cohesive horizon.

Assessment of land degradation in Mediterranean forests and grazing lands using a landscape unit approach and the normalized difference vegetation index

2017 ◽  
Vol 86 ◽  
pp. 8-21 ◽  
Author(s):  
Matteo Jucker Riva ◽  
Ioannis N. Daliakopoulos ◽  
Sandra Eckert ◽  
Elias Hodel ◽  
Hanspeter Liniger
Keyword(s):  
Land Degradation ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Mediterranean Forests ◽  
Landscape Unit ◽  
Grazing Lands

Sensitivity of selected water retention functions to compaction and inherent soil properties

Soil Research ◽  
1998 ◽  
Vol 36 (2) ◽  
pp. 317 ◽  
Author(s):  
V. Rasiah ◽  
L. A. G. Aylmore
Keyword(s):  
Soil Properties ◽  
Water Retention ◽  
Linear Regression Analysis ◽  
Coefficient Of Determination ◽  
Strongly Correlated ◽  
Limited Information ◽  
Field Scale ◽  
Soil Water Retention ◽  
Landscape Unit ◽  
Retention Characteristics

It is known that field-scale variations in subsurface hydraulic characteristics are influenced, to a large extent, by soil properties. Limited information, however, exists on the sensitivity of hydraulic functions to field-scale variations in soil properties. The sensitivity of 4 soil water retention functions, θ(h), to variations in soil properties and changes in bulk density (ρ) across and within soils along a 500-m transect has been assessed in this study. The θ(h) functions compared are those of van Genuchten, Brooks and Corey, Campbell, and Gardner. Water retention characteristics for 7 soils, each packed to 2 relative ρ, were established for each function. The coefficient of determination, R 2 , for the best fit of water retention ranged from 0·79 to 0· 98 for the Gardner and Campbell functions, from 0· 92 to 0·99 for the Brooks and Corey function, and from 0·83 to 0·99 for the van Genuchten function. Simple linear regression analysis indicated the nonlinear slope parameters of the 4 functions were more strongly correlated with soil properties. However, only the van Genuchten slope parameters were sensitive to changes in ρ. No consistency existed between the sensitivity of the linear parameters of the 4 functions and soil properties, and none were sensitive to changes in ρ. Except for the a parameter in the van Genuchten function, all the parameters in this function can be predicted with satisfactory confidence from soil properties and ρ. The results indicate that, of the 4 functions assessed, the van Genuchten θ(h) function is the most sensitive to field-scale variations in soil properties along a transect in a landscape unit and to changes in ρ.

Landscape-scale variability in soil organic carbon storage in the central Canadian Arctic

2014 ◽  
Vol 94 (4) ◽  
pp. 477-488 ◽  
Author(s):  
A. Brett Campeau ◽  
Peter M. Lafleur ◽  
Elyn R. Humphreys
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Land Cover ◽  
Carbon Storage ◽  
Canadian Arctic ◽  
Landscape Scale ◽  
Soil Organic Carbon Storage ◽  
Landscape Unit ◽  
Organic Carbon Storage ◽  
Up Scaling

Campeau, A. B., Lafleur, P. M. and Humphreys, E. R. 2014. Landscape-scale variability in soil organic carbon storage in the central Canadian Arctic. Can. J. Soil Sci. 94: 477–488. Arctic soils constitute a vast, but poorly quantified, pool of soil organic carbon (SOC). The uncertainty associated with pan-Arctic SOC storage estimates – a result of limited SOC and land cover data – needs to be reduced if we are to better predict the impact of future changes to Arctic carbon stocks resulting from climate warming. In this study landscape-scale variability in SOC at a Southern Arctic Ecozone site in the central Canadian Arctic was investigated with the ultimate goal of up-scaling SOC estimates with a land cover classification system. Total SOC was estimated to depths of 30 cm and 50 cm for 76 soil pits, together representing eight different vegetation communities in seven different broad landscape units. Soil organic carbon to 50 cm was lowest for the xerophytic herb community in the esker complex landscape unit (7.2±2.2 SD kg m−2) and highest in the birch hummock terrain in the lowland tundra landscape unit (36.4±2.8 kg m−2), followed by wet sedge and dry sedge communities in the wetland complex (29.8±9.9 and 22.0±2.0 kg m−2, respectively). The up-scaled estimates of mean SOC for the study area (excluding water) were 15.8 kg m−2 (to 50 cm) and 11.6 kg m−2 (to 30 cm). On a landscape scale, soil moisture content was found to have an important influence on SOC variability. Overall, this study highlights the importance of SOC variability at fine scales and its impact on up-scaling SOC in Arctic landscapes.

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