scholarly journals Soil Disturbance and the Potential for Erosion After Mechanical Site Preparation

2002 ◽  
Vol 19 (1) ◽  
pp. 5-13 ◽  
Author(s):  
Jorge Alcázar ◽  
Paul M. Woodard ◽  
Richard L. Rothwell
Keyword(s):  
Soil Erosion ◽  
Mineral Soil ◽  
High Water ◽  
Soil Disturbance ◽  
Site Preparation ◽  
Treatment Area ◽  
Soil Movement ◽  
Mechanical Site Preparation ◽  
Physical Conditions ◽  
Water Contents

Abstract Physical soil properties created by three mechanical site preparation treatments (ripper ploughing, disc trenching, and blading) and a control were evaluated to determine the success of these different mechanical site preparation treatments in creating plantable microsites and to estimate the potential for soil erosion created by each treatment. Three sites with fine textured soils and high water contents near Whitecourt, Alberta, Canada), were selected for study. The topography at all sites was similar and characterized by slopes 3.7 to 20% in steepness and approximately 190 to 270 m in length extending from the height of land to stream bottoms. The number of planting sites and the soil characteristics suggest ripper ploughing as the best site preparation treatment in this study, with the hinge microsite as the preferred planting spot. All three treatments significantly improved the physical conditions of the soil compared to the control, although the differences among treatments were small. Soil erosion was observed on areas where blading and ripper ploughing exposed mineral soil. Gullies, which exposed the roots of seedlings, were created by water erosion in the blading treatment area. Sediment deposition in trenches was observed on ripper ploughed areas, and at times, seedlings within this treatment area were partially buried as a result of this soil movement.

scholarly journals Mechanical site preparation: Key to microsite creation success on Clay Belt paludified sites

2015 ◽  
Vol 91 (02) ◽  
pp. 187-196 ◽  
Author(s):  
Mohammed Henneb ◽  
Osvaldo Valeria ◽  
Nicole J. Fenton ◽  
Nelson Thiffault ◽  
Yves Bergeron
Keyword(s):  
Organic Matter ◽  
High Water ◽  
Site Preparation ◽  
Tree Regeneration ◽  
High Water Content ◽  
Organic Layer ◽  
Forest Sector ◽  
Mechanical Site Preparation ◽  
Rooting Zone ◽  
Before And After

Paludification is the accumulation of partially decomposed organic matter over saturated mineral soils. It reduces tree regeneration and growth, mainly because of low temperatures and high water content in the rooting zone, reduced organic matter decomposition, and hence, low nutrient availability. On the Clay Belt of western Québec and eastern Ontario, forests tend to paludify naturally but this process might be promoted by logging methods. Our objective was to identify which of two commonly used mechanical site preparation (MSP) techniques is best adapted to reduce organic layer thickness (OLT) and generate favourable planting microsites post-harvest in paludified sites. Nine experimental blocks (between 20 ha–61 ha each) were delimited within a 35 km2 forest sector with variable levels of paludification. The forest sector was harvested by careful logging to protect advance growth and soils and subsequently the nine experimental blocks were treated with either forest harrowing, disc trenching (T26) or left as untreated controls (harvesting only) with three replicate blocks per treatment. We measured OLT before and after MSP and determined planting microsite quality within each block. Results revealed significant differences in OLT between MSP treatments and harvesting only. Overall, harrowing was the best technique, as it reduced OLT more than T26 scarification and generated the highest percent of good microsites, except where initial OLT was 44 cm–56 cm. Our results contribute to the successful use of MSP in paludified forests.

Soil microclimate and nitrogen availability 10 years after mechanical site preparation in northern British Columbia

2005 ◽  
Vol 35 (8) ◽  
pp. 1854-1866 ◽  
Author(s):  
M D MacKenzie ◽  
M G Schmidt ◽  
L Bedford
Keyword(s):  
British Columbia ◽  
Soil Temperature ◽  
Soil Water ◽  
Nitrogen Availability ◽  
Mineral Soil ◽  
Growing Season ◽  
Site Preparation ◽  
Total Carbon ◽  
Significant Treatment ◽  
Mechanical Site Preparation

Mechanical site preparation (MSP) changes the distribution and character of forest floor and mineral soil and may affect soil nutrient availability, soil water content, and soil temperature. The effects of different kinds of MSP were compared to a control in the tenth growing season at two research sites in northern British Columbia. To compare MSP results with those of the natural disturbance regime, a burned windrow treatment was also included in the analysis. The bedding plow, fire, and madge treatments all had significantly greater crop-tree growth compared to the control. The bedding plow and madge treatments had significantly lower soil bulk density, higher soil temperature, and lower soil water throughout the growing season compared with that of the control. The bedding plow also resulted in significantly higher concentrations of total carbon, total nitrogen, NH4+, and NO3–than that of the control, at both the 0–10 and 10–20 cm depths. The madge rotoclear resulted in significantly greater potential mineralizable N than that of the control. Ionic resins bags, installed for one growing season, did not show any significant treatment differences in available soil nitrogen. MSP did not reduce soil fertility on these sites when compared with an untreated control, but it is difficult to say that it improved it.

scholarly journals Decomposition rates of surface and buried forest-floor material

2017 ◽  
Vol 47 (8) ◽  
pp. 1140-1144 ◽  
Author(s):  
Cindy E. Prescott ◽  
Anya Reid ◽  
Shu Yao Wu ◽  
Marie-Charlotte Nilsson
Keyword(s):  
Forest Floor ◽  
Mineral Soil ◽  
Site Preparation ◽  
Soil C ◽  
Mechanical Site Preparation ◽  
C Stocks ◽  
Mesh Bags ◽  
Regional Climates ◽  
Floor Material

Mechanical site preparation is assumed to reduce soil C stocks by increasing the rate at which the displaced organic material decomposes, but the evidence is equivocal. We measured rates of C loss of forest-floor material in mesh bags either placed on the surface or buried in the mineral soil at four sites in different regional climates in British Columbia. During the 3-year incubation, buried forest-floor material lost between 5% and 15% more C mass than material on the surface, with the greatest difference occurring at the site with the lowest annual precipitation. Studies of the long-term fate of buried and surface humus are needed to understand the net effects of site preparation on soil C stocks.

Impacts of harvesting and mechanical site preparation on soil chemical properties of mixed-wood boreal forest sites in Alberta

1996 ◽  
Vol 76 (4) ◽  
pp. 531-540 ◽  
Author(s):  
M. G. Schmidt ◽  
S. E. Macdonald ◽  
R. L. Rothwell
Keyword(s):  
Boreal Forest ◽  
Mineral Soil ◽  
Chemical Properties ◽  
Site Preparation ◽  
Available Phosphorus ◽  
Organic Layer ◽  
Mechanical Site Preparation ◽  
Forest Sites ◽  
Mineralizable Nitrogen ◽  
Surface Mineral

We examined the impacts of harvesting and mechanical site preparation (MSP) on soil chemical properties of mixed-wood boreal forest sites in west central Alberta. Treatments included: 1) disc trencher, hinge, and trench microsites; 2) ripper plow, hinge, and trench microsites; 3) blading thin (organic layer depth < 2 cm), and thick (organic layer depth > 2 cm) microsites; 4) harvested with no site preparation; and 5) unharvested. Twenty months after harvesting, the forest floor of harvested areas with no MSP (vs. unharvested) had higher carbon:nitrogen ratios lower pH, and lower concentrations of total and mineralizable nitrogen, available phosphorus, and exchangeable bases Fifteen months after MSP, treated areas had either reduced or unchanged concentrations of total nitrogen and carbon, available phosphorus, and mineralizable nitrogen in the surface mineral soil, compared with harvested sites with no site preparation. The MSP-treated areas also had increased or unchanged pH, base saturation, and exchangeable base concentrations. Microsites adjacent to the displaced forest floor (hinge for disc and ripper treatments) or with a thicker organic layer (thick for blading) generally had higher concentrations of total nitrogen and carbon, and mineralizable nitrogen in the surface mineral soil as compared to trench and thin microsites. Key words: Forest soils, mechanical site preparation, harvesting, N, P, mixed-wood boreal forest

A review of the composition and evolution of hydrocarbon gases during solidification of the Ilímaussaq alkaline complex, South Greenland

2001 ◽  
pp. 159-166 ◽  
Author(s):  
Jens Konnerup-Madsen
Keyword(s):  
Nepheline Syenite ◽  
Subsequent Development ◽  
High Water ◽  
Vapour Phase ◽  
Low Carbon ◽  
Low Oxygen ◽  
Alkaline Complex ◽  
Hydrocarbon Gases ◽  
Wide Range ◽  
Water Contents

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article, for example: Konnerup-Madsen, J. (2001). A review of the composition and evolution of hydrocarbon gases during solidification of the Ilímaussaq alkaline complex, South Greenland. Geology of Greenland Survey Bulletin, 190, 159-166. https://doi.org/10.34194/ggub.v190.5187 _______________ Fluid inclusions in minerals from agpaitic nepheline syenites and hydrothermal veins in the Ilímaussaq complex and in similar agpaitic complexes on the Kola Peninsula, Russia, are dominated by hydrocarbon gases (predominantly methane) and hydrogen. Such volatile compositions differ considerably from those of most other igneous rocks and their formation and entrapment in minerals reflects low oxygen fugacities and a wide range of crystallisation temperatures extending to a low-temperature solidus. Their composition reflects initial low carbon contents and high water contents of the magma resulting in the exsolution of a waterrich CO2–H2O dominated vapour phase. Fractionation of chlorides into the vapour phase results in high salinities and the subsequent development of a heterogeneous vapour phase with a highly saline aqueous-rich fraction and a methane-dominated fraction, with preferential entrapment of the latter, possibly due to different wetting characteristics. The light stable isotope compositions support an abiogenic origin for the hydrocarbons in agpaitic nepheline syenite complexes.

scholarly journals Impact of Weed Control by Hand Tools on Soil Erosion under a No-Tillage System Cultivation

Agronomy ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 974
Author(s):  
Rafael Blanco-Sepúlveda ◽  
Amilcar Aguilar-Carrillo ◽  
Francisco Lima
Keyword(s):  
Soil Erosion ◽  
Weed Control ◽  
Soil Cover ◽  
Soil Surface ◽  
Conservation Agriculture ◽  
Soil Disturbance ◽  
No Tillage ◽  
Tropical Mountains ◽  
Litter Cover ◽  
Vegetal Cover

In conservation agriculture, the no-tillage cultivation system and the retention of permanent vegetal cover are crucial to the control of soil erosion by water. This paper analyses the cultivation of maize under no-tillage, with particular reference to the effect produced on soil erosion when weed control is performed by a hand tool (machete), which disturbs the surface of the soil, and to the behavior of the soil cover in these circumstances. The study area is located in the humid tropical mountains of northern Nicaragua (Peñas Blancas Massif Nature Reserve). The results obtained show that 59.2% of the soil surface was affected by appreciable levels of sheet and splash erosion, although the vegetal cover of the soil was relatively high (with average weed and litter cover of 33.9% and 33.8%, respectively). The use of machetes for weed control provoked considerable soil disturbance, which explained the high rates of erosion observed. Moreover, this form of soil management disturbs the litter layer, making it less effective in preventing erosion. The litter remains loose on the soil surface, and so an increase in soil cover does not achieve a proportionate reduction in the area affected by erosion; thus, even with 80–100% weed and litter cover, 42% of the cultivated area continued to present soil erosion.

Constraints on the formation of the giant Daheishan porphyry Mo deposit (NE China) from whole-rock and accessory mineral geochemistry

2021 ◽  
Author(s):  
Kai Xing ◽  
Qihai Shu ◽  
David R Lentz
Keyword(s):  
High Water ◽  
Accessory Mineral ◽  
Ne China ◽  
Accessory Minerals ◽  
Slab Rollback ◽  
Continental Arc ◽  
Arc Setting ◽  
Porphyry Mo Deposit ◽  
T Values ◽  
Water Contents

Abstract There are more than 90 porphyry (or skarn) Mo deposits in northeastern China with Jurassic or Cretaceous ages. These are thought to have formed mainly in a continental arc setting related to the subduction of the Paleo-Pacific oceanic plate in the Jurassic and subsequent slab rollback in the early Cretaceous. The Jurassic Daheishan porphyry Mo deposit is one of the largest Mo deposits in NE China, which contains 1.09 Mt Mo with an average Mo grade of 0.07%. To better understand the factors that could have controlled Mo mineralization at Daheishan, and potentially in other similar porphyry Mo deposits in NE China, the geochemical and isotopic compositions of the ore-related granite porphyry and biotite granodiorite, and the magmatic accessory minerals apatite, titanite and zircon from the Daheishan intrusions, were investigated so as to evaluate the potential roles that magma oxidation states, water contents, sulfur and metal concentrations could have played in the formation of the deposit. Magmatic apatite and titanite from the causative intrusions show similar εNd(t) values from -1.1 to 1.4, corresponding to TDM2 ages ranging from 1040 to 840 Ma, which could be accounted for by a mixing model through the interaction of mantle-derived basaltic melts with the Precambrian lower crust. The Ce and Eu anomalies of the magmatic accessory minerals have been used as proxies for magma redox state, and the results suggest that the ore-forming magmas are highly oxidized, with an estimated ΔFMQ range of + 1.8 to + 4.1 (+2.7 in average). This is also consistent with the high whole-rock Fe2O3/FeO ratios (1.3–26.4). The Daheishan intrusions display negligible Eu anomalies (Eu/Eu* = 0.7–1.1) and have relatively high Sr/Y ratios (40–94) with adakitic signatures; they also have relatively high Sr/Y ratios in apatite and titanite. These suggest that the fractionation of amphibole rather than plagioclase is dominant during the crystallization of the ore-related magmas, which further indicates a high magmatic water content (e.g., &gt;5 wt%). The magmatic sulfur concentrations were calculated using available partitioning models for apatite from granitoids, and the results (9–125 ppm) are indistinguishable from other mineralized, subeconomic and barren intrusions. Furthermore, Monte Carlo modelling has been conducted to simulate the magmatic processes associated with the formation of the Daheishan Mo deposit, and the result reveals that a magma volume of ∼280 km3 with ∼10 ppm Mo was required to form the Mo ores containing 1.09 Mt Mo in Daheishan. The present study suggests that a relatively large volume of parental magmas with high oxygen fugacities and high water contents is essential for the generation of a giant porphyry Mo deposit like Daheishan, whereas a specific magma composition (e.g., with unusually high Mo and/or S concentrations), might be less critical.

scholarly journals Bedding and Fertilization Ameliorate Effects of Designated Wet-Weather Skid Trails after Four Years for Loblolly Pine (Pinus taeda) Plantations

1998 ◽  
Vol 22 (4) ◽  
pp. 222-226 ◽  
Author(s):  
W. Michael Aust ◽  
James A. Burger ◽  
William H. McKee ◽  
Gregory A. Scheerer ◽  
Mark D. Tippett
Keyword(s):  
Pinus Taeda ◽  
Loblolly Pine ◽  
Water Movement ◽  
Block Design ◽  
Site Preparation ◽  
Site Productivity ◽  
Mechanical Site Preparation ◽  
Wet Weather ◽  
Four Levels ◽  
Study Sites

Abstract Wet-weather harvesting operations on wet pine fiats can cause soil disturbances that may reduce long-term site productivity. Site preparation and fertilization are often recommended as ameliorative practices for such disturbances, but few studies have actually quantified their effects on restoration. The purposes of this study were to quantify the effects of wet-weather harvest traffic in designated skid trails on soil properties and loblolly pine (Pinus taeda) growth, and to evaluate the ameliorative effects of site preparation. Study sites were established on wet pine flats of the lower Coastal Plain within the Francis Marion National Forest (Berkeley County, SC). Treatments were arranged in a split-split plot within a randomized complete block design. Treatments were two levels of traffic (nontrafficked, trafficked), four levels of mechanical site preparation (none, disking, bedding, disking + bedding), and two levels of fertilization (none, 337 kg /ha of 10-10-10 fertilizer). initially, the trafficking increased soil bulk densities and reduced soil water movement and subsequent growth of loblolly pine (years 1 and 2). Bedding combined with fertilization restored site productivity to non trafficked levels within 4 yr, but disking or fertilization treatments alone were not effective at ameliorating the traffic effects. The effectiveness of the bedding and fertilization treatments for amelioration of traffic effects was probably facilitated by the relatively small area of disturbed skid trails (<10%) found on these sites. Areas having more severe disturbance or higher percentages of disturbance might not be ameliorated as rapidly. South. J. Appl. For. 22(4):222-226.

Silvicultural treatments, microclimatic conditions and seedling response in Southern Interior clearcuts

1998 ◽  
Vol 78 (1) ◽  
pp. 115-126 ◽  
Author(s):  
R. L. Fleming ◽  
T. A. Black ◽  
R. S. Adams ◽  
R. J. Stathers
Keyword(s):  
Soil Moisture ◽  
Seedling Establishment ◽  
Initial Period ◽  
Mineral Soil ◽  
Soil Disturbance ◽  
Near Surface ◽  
Lower Elevation ◽  
Organic Horizons ◽  
Soil Temperatures ◽  
Microclimatic Conditions

Post-harvest levels of soil disturbance and vegetation regrowth strongly influence microclimate conditions, and this has important implications for seedling establishment. We examined the effects of blading (scalping), soil loosening (ripping) and vegetation control (herbicide), as well as no soil disturbance, on growing season microclimates and 3-yr seedling response on two grass-dominated clearcuts at different elevations in the Southern Interior of British Columbia. Warmer soil temperatures were obtained by removing surface organic horizons. Ripping produced somewhat higher soil temperatures than scalping at the drier, lower-elevation site, but slightly reduced soil temperatures at the wetter, higher-elevation site. Near-surface air temperatures were more extreme (higher daily maximums and lower daily minimums) over the control than over exposed mineral soil. Root zone soil moisture deficits largely reflected transpiration by competing vegetation; vegetation removal was effective in improving soil moisture availability at the lower elevation site, but unnecessary from this perspective at the higher elevation site. The exposed mineral surfaces self-mulched and conserved soil moisture after an initial period of high evaporation. Ripping and scalping resulted in somewhat lower near-surface available soil water storage capacities. Seedling establishment on both clearcuts was better following treatments which removed vegetation and surface organic horizons and thus enhanced microclimatic conditions, despite reducing nutrient supply. Such treatments may, however, compromise subsequent stand development through negative impacts on site nutrition. Temporal changes in the relative importance of different physical (microclimate) and chemical (soil nutrition) properties to soil processes and plant growth need to be considered when evaluating site productivity. Key words: Microclimate, soil temperature, air temperature, soil moisture, clearcut, seedling establishment

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