scholarly journals The ash content of the plough layer of peat lands cultivated by different methods

1961 ◽  
Vol 33 (1) ◽  
pp. 215-222
Author(s):  
Yrjö Pessi

The results of this investigation justify the conclusion that the ash content of peat increases under cultivation through the effects of the administered fertilizers and soil improving agents. The ash content is increased in a particularly remarkable degree by addition of mineral soil as a soil improving agent. The ash content in the plough layer of cultivated peat lands which had received an addition of mineral soil as long as 37 years ago was found to be quite high. This would seem to indicate a prolonged effect of mineral soil on the properties of the plough layer. The increase of the ash content in the plough layer of cultivated peat land is obviously one of the factors responsible for the phenomenon that long-term cultivation of peat land slowly deprives the peat of its original character.

1962 ◽  
Vol 34 (1) ◽  
pp. 44-54 ◽  
Author(s):  
Yrjö Pessi

The investigation is a report on the pH-reaction in the plough layer of the soil improvement and fertilizing tests carried on at the Experimental Station of Leteensuo during several decades. The tests were located on two areas with a peat layer consisting of Sphagnum peat with pH 3.3, derived from S. fuscum moss in one case, and of forest sedge peat with pH 4.1 in the other. The clay and sand employed as soil improving agents had pH 5.9 and 4.4, respectively. The effect of liming has proved to be relatively prolonged on Sphagnum bog as well as on fen soil. In the test with different rates of lime addition on Sphagnum bog, the pH value was found to increase linearly with the lime quantity. Addition of mineral soil has produced a remarkable increase in pH. Its effect, too, has been highly prolonged. In spite of their different inherent reactions, the sand and clay have exerted largely similar effects on the pH value of the plough layer. Stable manure possesses an effect resulting in an increase of the pH value and this value is also increased by calcium nitrate fertilization, whereas fertilizing with potassium salt and with superphosphate or fine-ground rock phosphate did not affect the reaction of the peat in any noteworthy and distinct degree.


Author(s):  
V. А. Shevchenko ◽  
A. V. Nefedov ◽  
A. V. Ilinskiy ◽  
А. Е. Morozov

Long-term observations of the drained soil of peat-podzolic-gley light loam on ancient alluvial sands state on the example of the meliorative object "Tinky-2" showed that under the influence of agricultural use in the soil, the organic matter mineralization processes are accelerated. During the drainage process, the soil evolutionarily suffered the following changes: the peat layer was compacted, humified and mineralized, which was a reason of the transformation them into the humus horizon. Based on the monitoring studies results it was established that during 21 intensive use years the peat layer thickness was decreased by 74.5% and amounted to 5.51 inch, which in the following 20 years was decreased to a layer of 1.18 inch, and for another 14 years it became a homogeneous humus horizon containing difficulty identifiable plant remains. For half a century, the bulk density increased by 6 times and the total moisture capacity of the soil decreased by 3.6 times. Other indicators were changed significantly. So, the ash content by 2016 increased from 11.2% to 52.7%. It was a reason of the plough-layer decreasing and it mixes with the mineral sand horizon during plowing. It should also be noted that the total nitrogen content in the soil decreased by 1.13%, and total carbon by 15.3% from 1982 to 2016. The dynamics of changes in the soil acidity, phosphorus and potassium content is associated with the introduction of calcareous, organic and mineral fertilizers in the 1980s. The unsystematic exploitation of such soils leads to decrease in the agricultural products productivity and increase in energy costs. When planning these soils usage in agricultural production, it is necessary to develop and implement modern melioration technologies and techniques aimed to increase soil fertility.


2019 ◽  
Vol 99 (6) ◽  
pp. 905-916
Author(s):  
E.W. Bork ◽  
M.P. Lyseng ◽  
D.B. Hewins ◽  
C.N. Carlyle ◽  
S.X. Chang ◽  
...  

While northern temperate grasslands are important for supporting beef production, it remains unclear how grassland above- and belowground biomass responds to long-term cattle grazing. Here, we use a comprehensive dataset from 73 grasslands distributed across a broad agro-climatic gradient to quantify grassland shoot, litter, and shallow (top 30 cm) root biomass in areas with and without grazing. Additionally, we relate biomass to soil carbon (C) concentrations. Forb biomass was greater (p < 0.05) in grazed areas, particularly those receiving more rainfall. In contrast, grass and total aboveground herbage biomass did not differ with grazing (total: 2320 kg ha−1 for grazed vs. 2210 kg ha−1 for non-grazed; p > 0.05). Forb crude protein concentrations were lower (p < 0.05) in grazed communities compared with those that were non-grazed. Grasslands subjected to grazing had 56% less litter mass. Root biomass down to 30 cm remained similar between areas with (9090 kg ha−1) and without (7130 kg ha−1) grazing (p > 0.05). Surface mineral soil C concentrations were positively related to peak grassland biomass, particularly total (above + belowground) biomass, and with increasing forb biomass in grazed areas. Finally, total aboveground shoot biomass and soil C concentrations in the top 15 cm of soil were both positively related to the proportion of introduced plant diversity in grazed and non-grazed grasslands. Overall, cattle grazing at moderate stocking rates had minimal impact on peak grassland biomass, including above- and belowground, and a positive contribution exists from introduced plant species to maintaining herbage productivity and soil C.


SOIL ◽  
2020 ◽  
Vol 6 (1) ◽  
pp. 195-213
Author(s):  
Benjamin Andrieux ◽  
David Paré ◽  
Julien Beguin ◽  
Pierre Grondin ◽  
Yves Bergeron

Abstract. Following a wildfire, organic carbon (C) accumulates in boreal-forest soils. The long-term patterns of accumulation as well as the mechanisms responsible for continuous soil C stabilization or sequestration are poorly known. We evaluated post-fire C stock changes in functional reservoirs (bioreactive and recalcitrant) using the proportion of C mineralized in CO2 by microbes in a long-term lab incubation, as well as the proportion of C resistant to acid hydrolysis. We found that all soil C pools increased linearly with the time since fire. The bioreactive and acid-insoluble soil C pools increased at a rate of 0.02 and 0.12 MgC ha−1 yr−1, respectively, and their proportions relative to total soil C stock remained constant with the time since fire (8 % and 46 %, respectively). We quantified direct and indirect causal relationships among variables and C bioreactivity to disentangle the relative contribution of climate, moss dominance, soil particle size distribution and soil chemical properties (pH, exchangeable manganese and aluminum, and metal oxides) to the variation structure of in vitro soil C bioreactivity. Our analyses showed that the chemical properties of podzolic soils that characterize the study area were the best predictors of soil C bioreactivity. For the O layer, pH and exchangeable manganese were the most important (model-averaged estimator for both of 0.34) factors directly related to soil organic C bioreactivity, followed by the time since fire (0.24), moss dominance (0.08), and climate and texture (0 for both). For the mineral soil, exchangeable aluminum was the most important factor (model-averaged estimator of −0.32), followed by metal oxide (−0.27), pH (−0.25), the time since fire (0.05), climate and texture (∼0 for both). Of the four climate factors examined in this study (i.e., mean annual temperature, growing degree-days above 5 ∘C, mean annual precipitation and water balance) only those related to water availability – and not to temperature – had an indirect effect (O layer) or a marginal indirect effect (mineral soil) on soil C bioreactivity. Given that predictions of the impact of climate change on soil C balance are strongly linked to the size and the bioreactivity of soil C pools, our study stresses the need to include the direct effects of soil chemistry and the indirect effects of climate and soil texture on soil organic matter decomposition in Earth system models to forecast the response of boreal soils to global warming.


2020 ◽  
Vol 66 (6) ◽  
pp. 761-769
Author(s):  
Matt Busse ◽  
Ross Gerrard

Abstract We measured forest-floor accumulation in ponderosa pine forests of central Oregon and asked whether selected ecological functions of the organic layer were altered by thinning and repeated burning. Experimental treatments included three thinning methods applied in 1989 (stem only, whole tree, no thin—control) in factorial combination with prescribed burning (spring 1991 and repeated in 2002; no burn—control). Forest-floor depth and mass were measured every 4–6 years from 1991 to 2015. Without fire, there was little temporal change in depth or mass for thinned (270 trees ha−1) and control (560–615 trees ha−1) treatments, indicating balanced litterfall and decay rates across these stand densities. Each burn consumed 50–70 percent of the forest floor, yet unlike thinning, postfire accumulation rates were fairly rapid, with forest-floor depth matching preburn levels within 15–20 years. Few differences in forest-floor function (litter decay, carbon storage, physical barrier restricting plant emergence, erosion protection) resulted from thinning or burning after 25 years. An exception was the loss of approximately 300 kg N ha−1 because of repeated burning, or approximately 13 percent of the total site N. This study documents long-term forest-floor development and suggests that common silvicultural practices pose few risks to organic layer functions in these forests. Study Implications: Mechanical thinning and prescribed fire are among the most widespread management practices used to restore forests in the western US to healthy, firewise conditions. We evaluated their effects on the long-term development of litter and duff layers, which serve dual roles as essential components of soil health and as fuel for potential wildfire. Our study showed that thinning and burning provided effective fuel reduction and resulted in no adverse effects to soil quality in dry ponderosa pine forests of central Oregon. Repeated burning reduced the site carbon and nitrogen pools approximately 9–13 percent, which is small compared to C located in tree biomass and N in mineral soil. Litter accumulation after burning was rapid, and we recommend burning on at least a 15–20-year cycle to limit its build-up.


2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Huimei Wang ◽  
Wei Liu ◽  
Wenjie Wang ◽  
Yuangang Zu

Thinning management is used to improve timber production, but only a few data are available on how it influences ecosystem C sink capacity. This study aims to clarify the effects of thinning on C sinks of larch plantations, the most widespread forests in Northeastern China. Both C influx from biomass production and C efflux from each soil respiration component and its temperature sensitivity were determined for scaling-up ecosystem C sink estimation: microbial composition is measured for clarifying mechanism for respiratory changes from thinning treatment. Thinning management induced 6.23 mol C m−2 yr−1increase in biomass C, while the decrease in heterotrophic respiration (Rh) at the thinned sites (0.9 mol C m−2 yr−1) has enhanced 14% of this biomass C increase. This decrease inRhwas a sum of the 42% decrease (4.1 mol C m−2 yr−1) in litter respiration and 3.2 mol C m−2 yr−1more CO2efflux from mineral soil in thinned sites compared with unthinned control. Increases in temperature, temperature sensitivity, alteration of litters, and microbial composition may be responsible for the contrary changes inRhfrom mineral soil and litter respiration, respectively. These findings manifested that thinning management of larch plantations could enhance biomass accumulation and decrease respiratory efflux from soil, which resulted in the effectiveness improvement in sequestrating C in forest ecosystems.


2018 ◽  
Vol 409 ◽  
pp. 872-889 ◽  
Author(s):  
Mélanie Court ◽  
Gregory van der Heijden ◽  
Serge Didier ◽  
Claude Nys ◽  
Claudine Richter ◽  
...  

2002 ◽  
Vol 139 (2) ◽  
pp. 115-127 ◽  
Author(s):  
MARTYN SILGRAM ◽  
BRIAN J. CHAMBERS

The effects of straw incorporation (early and late cultivation) and straw burning were contrasted in a split-plot study examining the impact of long-term straw residue management, and six fertilizer nitrogen (N) rates on soil mineral nitrogen, crop fertilizer N requirements and nitrate leaching losses. The experiments ran from 1984 to 1997 on light-textured soils at ADAS Gleadthorpe (Nottinghamshire, UK) and Morley Research Centre (Norfolk, UK).Soil incorporation of the straw residues returned an estimated 633 kg N/ha at Gleadthorpe and 429 kg N/ha at Morley on the treatment receiving 150 kg/ha per year fertilizer N since 1984. Straw disposal method had no consistent effect on grain and straw yields, crop N uptake, or optimal fertilizer N rates. In every year there was a positive response (P<0·001) to fertilizer N in straw/grain yields, N contents and crop N offtakes at both sites. Nitrate leaching losses were slightly reduced by less than 10 kg N/ha where straw residues had been incorporated, while fertilizer N additions increased nitrate leached at both sites.At both sites there was a consistent effect (P<0·001) of straw disposal method on autumn soil mineral N, with values following the pattern burn>early incorporate>late plough. The incorporation of straw residues induced temporary N immobilization compared with the treatment where straw was burnt, while the earlier timing of tillage on the incorporate treatment resulted in slightly more mineral N compared with the later ploughed treatment. Fertilizer N rate increased (P<0·001) soil mineral nitrogen at both sites. At Morley, there was more organic carbon in the plough layer where straw had been incorporated (mean 1·09 g/100 g) rather than burnt (mean 0·89 g/100 g), and a strong positive relationship between organic carbon and fertilizer N rate (r2=93·2%, P<0·01). There was a detectable effect of fertilizer N on readily mineralizable N in the plough layer at both Gleadthorpe (P<0·001) and Morley (P<0·05). At Morley, there was a consistent trend (P=0·06) for readily mineralizable N to be higher where straw had been incorporated rather than burnt, indicating that ploughing-in residues may contribute to soil nitrogen supply over the longer term.


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