scholarly journals Overestimation of Crop Root Biomass in Field Experiments Due to Extraneous Organic Matter

2017 ◽  
Vol 8 ◽  
Author(s):  
Juliane Hirte ◽  
Jens Leifeld ◽  
Samuel Abiven ◽  
Hans-Rudolf Oberholzer ◽  
Andreas Hammelehle ◽  
...  
Keyword(s):  
Organic Matter ◽  
Root Biomass ◽  
Field Experiments ◽  
Crop Root

scholarly journals Do Grazing Systems and Species Composition Affect Root Biomass and Soil Organic Matter Dynamics in Temperate Grassland Swards?

2020 ◽  
Vol 12 (3) ◽  
pp. 1260 ◽  
Author(s):  
Martine J. J. Hoogsteen ◽  
Evert-Jan Bakker ◽  
Nick van Eekeren ◽  
Pablo A. Tittonell ◽  
Jeroen C. J. Groot ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Species Composition ◽  
Sandy Soil ◽  
Perennial Ryegrass ◽  
Tall Fescue ◽  
Root Biomass ◽  
Field Experiments ◽  
Arable Land ◽  
Grazing Systems

Elevating soil organic matter (SOM) levels through changes in grassland management may contribute to lower greenhouse gas concentrations in the atmosphere and mitigate climate change. SOM dynamics of grassland soils may be affected by grazing systems and plant species composition. We analyzed the effects of simulated grazing systems (continuous (CG), rotational (RG), and lenient strip grazing (LG)) and species composition (monocultures of perennial ryegrass fertilized (LP+) and unfertilized (LP−)), tall fescue (fertilized, FA+), and a mixture of these two species with white clover (fertilized, LFT+)) on root biomass and SOM dynamics in field experiments on loamy and sandy soils in the Netherlands. Dried cattle manure was added to all fertilized treatments. We hypothesized that SOM accumulation would be highest under CG and LG, and FA+ and LFT+ as a consequence of greater belowground biomass production. SOM was monitored after conversion from arable land for a period of two years (loamy and sandy soil) and five years (sandy soil). We found that management practices to increase SOM storage were strongly influenced by sampling depth and length of the grassland period. SOM increased significantly in nearly all fertilized treatments in the 0–60 cm layer. No differences between species compositions were found. However, when only the 30–60 cm soil layer was considered, significantly higher SOM increases were found under FA+, which is consistent with its greater root biomass than the other species. SOM increases tended to be higher under LG than RG. The results of this study suggest that it seems possible to comply with the 4-thousandth initiative during a period of five years with fertilized perennial ryegrass or tall fescue in monoculture after conversion from arable land. It remains to be investigated to which extent this sequestration of carbon can be maintained after converting grassland back to arable land.

scholarly journals Biotic and Abiotic Determinants of Soil Organic Matter Stock and Fine Root Biomass in Mountain Area Temperate Forests—Examples from Cambisols under European Beech, Norway Spruce and Silver Fir (Carpathians, Central Europe)

Forests ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 823
Author(s):  
Anna Zielonka ◽  
Marek Drewnik ◽  
Łukasz Musielok ◽  
Marcin K. Dyderski ◽  
Dariusz Struzik ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Norway Spruce ◽  
Root Biomass ◽  
Fine Root ◽  
Stand Density ◽  
European Beech ◽  
Fine Root Biomass ◽  
Silver Fir ◽  
Beech Forests

Forest ecosystems significantly contribute to the global organic carbon (OC) pool, exhibiting high spatial heterogeneity in this respect. Some of the components of the OC pool in a forest (woody aboveground biomass (wAGB), coarse root biomass (CRB)) can be relatively easily estimated using readily available data from land observation and forest inventories, while some of the components of the OC pool are very difficult to determine (fine root biomass (FRB) and soil organic matter (SOM) stock). The main objectives of our study were to: (1) estimate the SOM stock; (2) estimate FRB; and (3) assess the relationship between both biotic (wAGB, forest age, foliage, stand density) and abiotic factors (climatic conditions, relief, soil properties) and SOM stocks and FRB in temperate forests in the Western Carpathians consisting of European beech, Norway spruce, and silver fir (32 forest inventory plots in total). We uncovered the highest wAGB in beech forests and highest SOM stocks under beech forest. FRB was the highest under fir forest. We noted a considerable impact of stand density on SOM stocks, particularly in beech and spruce forests. FRB content was mostly impacted by stand density only in beech forests without any discernible effects on other forest characteristics. We discovered significant impacts of relief-dependent factors and SOM stocks at all the studied sites. Our biomass and carbon models informed by more detailed environmental data led to reduce the uncertainty in over- and underestimation in Cambisols under beech, spruce, and fir forests for mountain temperate forest carbon pools.

Soil stripping and replacement for the rehabilitation of bauxite-mined land at Weipa. I. Initial changes to soil organic matter and related parameters

Soil Research ◽  
2000 ◽  
Vol 38 (2) ◽  
pp. 345 ◽  
Author(s):  
G. D. Schwenke ◽  
D. R. Mulligan ◽  
L. C. Bell
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Field Experiments ◽  
Surface Soil ◽  
Soil Disturbance ◽  
Microbial Biomass C ◽  
Low Grade ◽  
Double Pass ◽  
Organic C ◽  
The Difference

At Weipa, in Queensland, Australia, sown tree and shrub species sometimes fail to establish on bauxite-mined land, possibly because surface-soil organic matter declines during soil stripping and replacement. We devised 2 field experiments to investigate the links between soil rehabilitation operations, organic matter decline, and revegetation failure. Experiment 1 compared two routinely practiced operations, dual-strip (DS) and stockpile soil, with double-pass (DP), an alternative method, and subsoil only, an occasional result of the DS operation. Other treatments included variations in stripping-time, ripping-time, fertiliser rate, and cultivation. Dilution of topsoil with subsoil, low-grade bauxite, and ironstone accounted for the 46% decline of surface-soil (0–10 cm) organic C in DS compared with pre-strip soil. In contrast, organic C in the surface-soil (0–10 cm) of DP plots (25.0 t/ha) closely resembled the pre-strip area (28.6 t/ha). However, profile (0–60 cm) organic C did not differ between DS (91.5 t/ha), DP (107 t/ha), and pre-strip soil (89.9 t/ha). Eighteen months after plots were sown with native vegetation, surface-soil (0–10 cm) organic C had declined by an average of 9% across all plots. In Experiment 2, we measured the potential for post-rehabilitation decline of organic matter in hand-stripped and replaced soil columns that simulated the DS operation. Soils were incubated in situ without organic inputs. After 1 year’s incubation, organic C had declined by up to 26% and microbial biomass C by up to 61%. The difference in organic C decline between vegetated replaced soils (Expt 1) and bare replaced soils (Expt 2) showed that organic inputs affect levels of organic matter more than soil disturbance. Where topsoil was replaced at the top of the profile (DP) and not ploughed, inputs from volunteer native grasses balanced oxidation losses and organic C levels did not decline.

Organic matter dynamics of fine roots in plantations of slash pine (Pinuselliottii) in north Florida

1986 ◽  
Vol 16 (3) ◽  
pp. 529-538 ◽  
Author(s):  
Henry L. Gholz ◽  
Laurel C. Hendry ◽  
Wendell P. Cropper Jr.
Keyword(s):  
Organic Matter ◽  
Boreal Forests ◽  
Fine Roots ◽  
Root Biomass ◽  
Root Diameter ◽  
Slash Pine ◽  
Root Turnover ◽  
Root Production ◽  
Seasonal Patterns ◽  
Turnover Rates

Seasonal patterns of live, dead, and unknown viability fine (diameter, ≤10 mm) roots of pine and other vegetation in a young and old slash pine stand were sampled using monthly soil coring over a 24-month period. A distinct unimodal pattern for roots <1 mm in diameter in the surface soil was observed. Live roots increased in the spring to a peak in midsummer and then declined. Larger roots and roots deeper in the soil showed less distinct seasonal patterns, although maximum and minimum annual biomass values were sometimes significantly different. Decomposition of fine roots in buried mesh bags averaged 15–20% per year for roots <5 mm in diameter. An analysis of seasonal dynamics and decompositon rates were combined to construct organic matter budgets for the forest floor and soil. Estimated net root production for roots ≤10 mm in diameter was 590 and 626 g m−2 year−1 in the young and old stand, respectively. Root turnover contributed 214 and 452 g m−2 year−1 to detrital pools on the two sites, with the balance of production accumulating as standing root biomass or lost in decomposition. Root production and turnover rates decreased with increasing root diameter; most production was from roots <1 mm. Pine root production was greater and nonpine production was less in the older stand than in the younger stand. Compared with other temperate and boreal forests, root biomass was high and net root production relatively low. The low production:biomass ratio may be characteristic of low latitude (warm) and (or) low nutrient forest types.

scholarly journals Peat decomposability in managed organic soils in relation to land use, organic matter composition and temperature

2018 ◽  
Vol 15 (3) ◽  
pp. 703-719 ◽  
Author(s):  
Cédric Bader ◽  
Moritz Müller ◽  
Rainer Schulin ◽  
Jens Leifeld
Keyword(s):  
Land Use ◽  
Organic Matter ◽  
Co2 Emissions ◽  
Field Experiments ◽  
Crop Residues ◽  
Organic Soils ◽  
Emission Rates ◽  
Data Set ◽  
Plant Materials ◽  
C Cycle

Abstract. Organic soils comprise a large yet fragile carbon (C) store in the global C cycle. Drainage, necessary for agriculture and forestry, triggers rapid decomposition of soil organic matter (SOM), typically increasing in the order forest < grassland < cropland. However, there is also large variation in decomposition due to differences in hydrological conditions, climate and specific management. Here we studied the role of SOM composition on peat decomposability in a variety of differently managed drained organic soils. We collected a total of 560 samples from 21 organic cropland, grassland and forest soils in Switzerland, monitored their CO2 emission rates in lab incubation experiments over 6 months at two temperatures (10 and 20 °C) and related them to various soil characteristics, including bulk density, pH, soil organic carbon (SOC) content and elemental ratios (C / N, H / C and O / C). CO2 release ranged from 6 to 195 mg CO2-C g−1 SOC at 10 °C and from 12 to 423 mg g−1 at 20 °C. This variation occurring under controlled conditions suggests that besides soil water regime, weather and management, SOM composition may be an underestimated factor that determines CO2 fluxes measured in field experiments. However, correlations between the investigated chemical SOM characteristics and CO2 emissions were weak. The latter also did not show a dependence on land-use type, although peat under forest was decomposed the least. High CO2 emissions in some topsoils were probably related to the accrual of labile crop residues. A comparison with published CO2 rates from incubated mineral soils indicated no difference in SOM decomposability between these soil classes, suggesting that accumulation of recent, labile plant materials that presumably account for most of the evolved CO2 is not systematically different between mineral and organic soils. In our data set, temperature sensitivity of decomposition (Q10 on average 2.57 ± 0.05) was the same for all land uses but lowest below 60 cm in croplands and grasslands. This, in turn, indicates a relative accumulation of recalcitrant peat in topsoils.

FATE OF N APPLIED AS GREEN MANURE OR AMMONIUM FERTILIZER TO SOIL SUBSEQUENTLY CROPPED WITH SPRING WHEAT AT THREE SITES IN WESTERN CANADA

1990 ◽  
Vol 70 (3) ◽  
pp. 313-323 ◽  
Author(s):  
H. H. JANZEN ◽  
J. B. BOLE ◽  
V. O. BIEDERBECK ◽  
A. E. SLINKARD
Keyword(s):  
Organic Matter ◽  
Ammonium Sulfate ◽  
Spring Wheat ◽  
Green Manure ◽  
Field Experiments ◽  
Soil Layer ◽  
Organic N ◽  
Wheat Crop ◽  
Western Canada ◽  
Annual Legumes

There is growing interest in the use of annual legumes as green manure crops to replace conventional summerfallow in the spring wheat production systems of western Canada. A series of field experiments was established at three sites in western Canada (Lethbridge, Swift Current, and Saskatoon) in each of two seasons to quantify the N contribution of green manure to subsequent crops and organic matter reserves. 15N-labelled plant material from two annual legume species [Tangier flatpea (Lathyrus tingitanus 'Tinga') and lentil (Lens culinaris 'Indianhead')], as well as 15N-labelled ammonium sulfate, was applied to field microplots in midsummer. The following spring, an additional ammonium sulfate treatment was established and all plots were seeded to spring wheat (Triticum aestivum 'Leader' or 'Katepwa'). On average, the wheat crop recovered 14% of the green manure N compared with 36% of the fertilizer N. Conversely, the relative contribution of the green manure to the organic N pool in the surface soil layer was approximately twice that of inorganic fertilizer. This residual organic N was relatively recalcitrant to further mineralization, as was evident from minimal uptake of applied N in the second year after application. These results suggest that annual legumes can be a significant source of N to subsequent crops in the rotation, provided that N yields are sufficient. The primary advantage of green manure production, however, may be the long-term replenishment of stable organic N reserves in the soil. Key words: N mineralization, organic matter, 15N, annual legumes, green manure, lentil, pea

Sign in / Sign up

Export Citation Format

Share Document