CHEMICAL CHARACTERISTICS OF SOILS UNDER SPRUCE-FIR FORESTS IN EASTERN MAINE

1985 ◽  
Vol 65 (1) ◽  
pp. 61-69 ◽  
Author(s):  
I. J. FERNANDEZ ◽  
R. A. STRUCHTEMEYER

Soils supporting even-aged spruce-fir stands in eastern Maine are highly acid with soil pH often found to be a useful indicator of potential tree growth. This investigation examined the chemical characteristics of these soils at 22 spruce-fir sites and the relationship between soil chemical properties and site productivity. Each major soil horizon exhibited a distinctly different chemical environment. Spruce-fir site productivity was found to be significantly correlated with B horizon organic-P, O horizon pH, and the total organic matter content of the mineral soil horizons. Soil pH increased with depth in the profile ranging from a mean value of 3.13 in the O horizon (i.e. F + H) to 4.91 in the C horizon. Significant correlations were exhibited between pH and exchangeable Ca, exchangeable Al, and extractable Al throughout the profile. Fractionation of P in the B horizons demonstrated that occluded-P was the most concentrated of the fractions measured, with the order of relative abundance for the P fractions being occluded-P > Al-P > organic-P > Fe-P > Ca-P > extractable-P. Sampling of soils for evaluating the potential for forest growth in this region must be carried out by horizons, as these differ remarkably with respect to those variables that have been shown to have an influence on tree growth. Key words: pH, site quality, organic matter, phosphorus, aluminum, spruce-fir

Agronomy ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1326
Author(s):  
Calvin F. Glaspie ◽  
Eric A. L. Jones ◽  
Donald Penner ◽  
John A. Pawlak ◽  
Wesley J. Everman

Greenhouse studies were conducted to evaluate the effects of soil organic matter content and soil pH on initial and residual weed control with flumioxazin by planting selected weed species in various lab-made and field soils. Initial control was determined by planting weed seeds into various lab-made and field soils treated with flumioxazin (71 g ha−1). Seeds of Echinochloa crus-galli (barnyard grass), Setaria faberi (giant foxtail), Amaranthus retroflexus (redroot pigweed), and Abutilon theophrasti (velvetleaf) were incorporated into the top 1.3 cm of each soil at a density of 100 seeds per pot, respectively. Emerged plants were counted and removed in both treated and non-treated pots two weeks after planting and each following week for six weeks. Flumioxazin control was evaluated by calculating percent emergence of weeds in treated soils compared to the emergence of weeds in non-treated soils. Clay content was not found to affect initial flumioxazin control of any tested weed species. Control of A. theophrasti, E. crus-galli, and S. faberi was reduced as soil organic matter content increased. The control of A. retroflexus was not affected by organic matter. Soil pH below 6 reduced flumioxazin control of A. theophrasti, and S. faberi but did not affect the control of A. retroflexus and E. crus-galli. Flumioxazin residual control was determined by planting selected weed species in various lab-made and field soils 0, 2, 4, 6, and 8 weeks after treatment. Eight weeks after treatment, flumioxazin gave 0% control of A. theophrasti and S. faberi in all soils tested. Control of A. retroflexus and Chenopodium album (common lambsquarters) was 100% for the duration of the experiment, except when soil organic matter content was greater than 3% or the soil pH 7. Eight weeks after treatment, 0% control was only observed for common A. retroflexus and C. album in organic soil (soil organic matter > 80%) or when soil pH was above 7. Control of A. theophrasti and S. faberi decreased as soil organic matter content and soil pH increased. Similar results were observed when comparing lab-made soils to field soils; however, differences in control were observed between lab-made organic matter soils and field organic matter soils. Results indicate that flumioxazin can provide control ranging from 75–100% for two to six weeks on common weed species.


2005 ◽  
Vol 35 (9) ◽  
pp. 2178-2187 ◽  
Author(s):  
J C Neff ◽  
J W Harden ◽  
G Gleixner

Boreal ecosystems contain a substantial fraction of the earth's soil carbon stores and are prone to frequent and severe wildfires. In this study, we examine changes in element and organic matter stocks due to a 1999 wildfire in Alaska. One year after the wildfire, burned soils contained between 1071 and 1420 g/m2 less carbon than unburned soils. Burned soils had lower nitrogen than unburned soils, higher calcium, and nearly unchanged potassium, magnesium, and phosphorus stocks. Burned surface soils tended to have higher concentrations of noncombustible elements such as calcium, potassium, magnesium, and phosphorus compared with unburned soils. Combustion losses of carbon were mostly limited to surface dead moss and fibric horizons, with no change in the underlying mineral horizons. Burning caused significant changes in soil organic matter structure, with a 12% higher ratio of carbon to combustible organic matter in surface burned horizons compared with unburned horizons. Pyrolysis gas chromatography – mass spectroscopy also shows preferential volatilization of polysaccharide-derived organic matter and enrichment of lignin- and lipid-derived compounds in surface soils. The chemistry of deeper soil layers in burned and unburned sites was similar, suggesting that immediate fire impacts were restricted to the surface soil horizon.


2020 ◽  
pp. 6-12
Author(s):  
Tahsina Sharmin Hoque ◽  
Shafia Afrin ◽  
Israt Jahan ◽  
Md. Joinul Abedin Mian ◽  
Mohammad Anwar Hossain

Soil depth can significantly influence the availability of nutrients in soil. An experiment was conducted with seven soil samples from seven land use types to observe the effect of soil depth on soil properties under various land use systems. Soil pH, electrical conductivity (EC), organic matter, available phosphorus (P), available sulphur (S) and different forms of potassium (K) such as water soluble, exchangeable and non-exchangeable were determined from the soil samples collected from four soil depths (viz. 0-10, 10-20, 20-30 and 30-40 cm). Soil pH varied from 6.30-7.39 irrespective of depths and land uses and it increased with increasing soil depth. Electrical conductivity of the soils ranged from 42-310 µS cm-1 and organic matter status of most of the soils was very low to medium in level. Both EC and organic matter content decreased with the increase of soil depth. Available P concentration showed no specific changing trend with soil depth whereas available S concentration under different land use systems decreased with increasing soil depth. The concentrations of water soluble, exchangeable and non-exchangeable K in soils varied from 12.30-39.60, 20.90-53.16 and 163.30-684.30 mg kg-1, respectively and showed no specific changing pattern with soil depth. Water soluble K content was higher in rice growing fertilizer and manure-treated soil but higher exchangeable and non-exchangeable K contents were observed in banana growing soil. In rice growing soils, nutrient concentration is mostly higher in nitrogen (N), P and K + farm yard manure (FYM) - treated plots compared to rice growing control plots.


1998 ◽  
Vol 131 (4) ◽  
pp. 455-464 ◽  
Author(s):  
B. J. CHAMBERS ◽  
T. W. D. GARWOOD

Lime loss rates were determined for 11 agricultural soils across England (1987–92) under arable cropping (six sites) and grassland management (five sites), receiving commercial rates of fertilizer inputs. Lime additions in the range 0–1500 kg ha−1 CaCO3 (250 kg ha−1 CaCO3 increments) were made annually to the sites. Soil pH (water and 0·01 m CaCl2) and exchangeable calcium concentrations were measured annually. The annual lime loss rates were calculated as the amount of lime needed to maintain the initial site pH or exchangeable Ca concentrations.Lime loss rates based on soil water pH varied between 40 and 1270 kg ha−1 CaCO3, on the basis of CaCl2 pH between 0 and 1370 kg ha−1 CaCO3, and exchangeable Ca between 0 and 1540 kg ha−1 CaCO3. There was a positive relationship between the lime loss rate (based on water pH) and initial soil pH value (r=0·75; P<0·01), and a negative relationship with soil organic matter content (r=0·63; P<0·05) was based on soil pH, organic matter content and nitrogen (N) fertilizer input. Lime loss rates were approximately double those predicted by previous models developed in the 1970s, reflecting the greater quantities of inorganic N fertilizer now being applied to agricultural land.


2020 ◽  
Vol 17 (8) ◽  
pp. 545
Author(s):  
Jeonghyeon Ahn ◽  
Guiying Rao ◽  
Mustafa Mamun ◽  
Eric P. Vejerano

Environmental contextAssessing environmental and human health impacts of chemical spills relies on information about how chemicals move across multiple environments. We measured volatile contaminants in the air above soil saturated with water to provide estimates of air concentrations of selected chemicals released to soil from an oil refinery in Texas during Hurricane Harvey. Estimated concentrations were below recommended exposure limits, even in a worst-case scenario. AbstractThe emission of volatile organic compounds (VOCs) from soil into air is affected by soil moisture dynamics, soil temperature, solar irradiance and carbon availability. The high amount of water in soil can modify its properties, which changes how VOCs interact. We conducted a comprehensive measurement of the soil–air partition coefficient (KSA) of VOCs into water-saturated soil with both low and high water contents for polar, weakly polar and nonpolar VOCs into a mineral soil (S-clay) and soil containing a high amount of organic matter (S-om) under a water-saturated condition. Partitioning of non-polar substituted aromatics (1,2-dichlorobenzene and toluene) was sensitive to the organic matter content in water-saturated soil. 1,2-Dichlorobenzene and toluene had higher affinities to S-om than to S-clay at all investigated water contents because of their strong interaction with the organic matter in soil. KSA decreased with elevated water content only for non-polar substituted aromatic VOCs. Less hydrophobic VOCs (benzene and trichloroethylene) exhibited similar partitioning into both soils by sorbing onto the air-water interface and dissolving in soil water, while the organic matter did not affect partitioning. The weakly polar and polar VOCs (methyl tert-butyl ether and 1-butanol) showed similar partitioning into both soils by dissolving in soil water while sorption to the organic matter was significant only at high soil water contents. KSA of VOCs on soil with high organic matter content correlated strongly with psat and Koa, but not on mineral soil. Estimates of the air concentrations for a subset of VOCs released from one refinery during Hurricane Harvey in 2017 in Harris County, Texas were lower than the recommended exposure limits, even under a worst-case scenario.


2011 ◽  
Vol 57 (No. 5) ◽  
pp. 228-234 ◽  
Author(s):  
G. Xu ◽  
J.N. Sun ◽  
R.F. Xu ◽  
Y.C. Lv ◽  
H.B. Shao ◽  
...  

Little is known about the effects of air-drying and freezing on the transformation of phosphorus (P) fractions in soils. It is important that the way in which soils respond to such perturbations is better understood as there are implications for both P availability and loss to surface waters from soils. In this study, the effects of air-drying and freezing were investigated using two soils, one being a forest soil (FS) high in organic matter and the other being a sterile soil (SS) low in organic matter. Soil P was fractionated using a modified Hedley fractionation method to examine the changes of phosphorus fractions induced by air-drying and freezing. Generally, there were no significant differences of total phosphorus among the three treatments (CV% &lt; 10%). Compared with field moist soils, freezing the soil evoked few changes on phosphorus fractions except that the resin-P increased in FS soil. On the contrary, air-drying significantly changed the distribution of phosphors fractions for both soils: increased the labile-P (especially resin-P) and organic-P (NaHCO<sub>3</sub>-Po, NaOH-Po and Con.HCl-Po) at the expense of NaOH-Pi and occlude-P (Dil.HCl-P and Con.HCl-Pi). Resin-P significantly increased by 31% for SS soil and by 121% for FS soil upon air-drying. The effect of air-drying seemed to be more pronounced in the FS soil with high organic matter content. These results indicated that drying seem to drive the P transformation form occlude-P to labile-P and organic-P and accelerated the weathering of stable P pool. This potentially could be significant for soil P supply to plants and P losses from soils to surface waters under changing patterns of rainfall and temperature as predicted by some climate change scenarios. &nbsp;


Soil Research ◽  
2016 ◽  
Vol 54 (1) ◽  
pp. 11 ◽  
Author(s):  
Melinda R. S. Moata ◽  
Ashlea L. Doolette ◽  
Ronald J. Smernik ◽  
Ann M. McNeill ◽  
Lynne M. Macdonald

Organic phosphorus (P) plays an important role in the soil P cycle. It is present in various chemical forms, the relative amounts of which vary among soils, due to factors including climate, land use, and soil type. Few studies have investigated co-variation between P types or stoichiometric correlation with the key elemental components of organic matter– carbon (C) and nitrogen (N), both of which may influence P pool structure and dynamics in agricultural soils. In this study we determined the organic P speciation of twenty Australian Red Chromosols soils, a soil type widely used for cropping in Australia. Eight different chemical forms of P were quantified by 31P NMR spectroscopy, with a large majority (>90%) in all soils identified as orthophosphate and humic P. The strongest correlations (r2 = 0.77–0.85, P < 0.001) between P types were found among minor components: (i) between two inositol hexakisphosphate isomers (myo and scyllo) and (ii) between phospholipids and RNA (both detected as their alkaline hydrolysis products). Total soil C and N were correlated with phospholipid and RNA P, but not the most abundant P forms of orthophosphate and humic P. This suggests an influence of organic matter content on the organic P pool consisting of phospholipid and RNA, but not on inositol P or the largest organic P pool in these soils – humic P.


1996 ◽  
Vol 26 (1) ◽  
pp. 72-86 ◽  
Author(s):  
Marcel Prévost

Two types of scarification (cone and disk) were applied at two intensities (simple and double passes), in a randomized complete block design, established alongside buffer stands of spruce protective of water courses, that provided a natural seed source. Treatment effects on seedbed evolution, natural seeding of black spruce (Piceamariana (Mill.) BSP), competing vegetation, and soil physical and chemical properties were examined over a 3-year period. In situ nitrogen mineralization was also studied, using the buried-bag method. All scarification treatments created a surface horizon (0–10 cm) with 80% less organic matter content than the control treatment. However, treatments tended to loosen the exposed deep layers, creating microsites whose compactness appeared adequate for root development (1.07–1.22 Mg/m3). The organic matter loss mainly decreased exchangeable K and Mg in the surface 20 cm of scarified microsites. Scarification had little impact on total N of sampled profiles and clearcutting did not increase N mineralization with regard to the forest, during the first year after disturbance. The weak soil warming and the stability of temperatures under the unscarified humus suggest that clearcutting did not significantly enhanced microbial activity on the site. However, removal of the insulating humus layer allowed a significant summer soil warming in the furrows. Despite this, scarified microsites were characterized by N immobilization during the first growing season after treatment. However, net N production was positive during the winter period, presumably because of a N-flux phenomenon. Scarification improved black spruce regeneration by natural seeding. Three years after treatment, stocking levels reached 40 to 51% in the scarified sectors while they reached 31% in the controls, this gap being mainly attributed to the second germination year. The difference can be explained by the improved receptivity of bare mineral soil, well-decomposed humus, and mixed mineral–organic seedbeds that covered 12–20% of the scarified areas immediately after treatment. Generally, results indicate that microsites created by a light scarification are as receptive as microsites created by a severe perturbation. Finally, every scarification treatment efficiently controlled the ericaceous shrub cover during the first 3 years after treatment.


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