Effects of different soil management practices on soil free-living nematode community structure, Eastern China

2008 ◽  
Vol 88 (1) ◽  
pp. 115-127 ◽  
Author(s):  
Daofeng Dong ◽  
Yun-Feng Chen ◽  
Yosef Steinberger ◽  
Zhi-Ping Cao
Keyword(s):  
Management Practices ◽  
Eastern China ◽  
Agricultural Management ◽  
Nematode Community ◽  
Maturity Index ◽  
Free Living ◽  
Plant Parasite ◽  
Free Living Nematode ◽  
The Difference

An investigation was conducted in a Shouguang agroecosystem, Shandong Province, Eastern China, in order to determine the long-term (10–15 yr) disturbances of three different agricultural management practices. In this study, the main focus was on free-living soil nematodes, as a tool which will help differentiate between treatments according to their sensitivity to physical, chemical, and biota composition. In this study, three treatments were implemented in each of a total of four investigated sites: greenhouses, conventional farmlands, and fallows. Diversity, maturity (MI) and weight indices were used to assess the nematode community. The results indicated that greenhouses have a lower richness (SR), diversity, modified maturity index (ΣMI), modified maturity index for all nematodes with c-p = 2–5 [ΣMI (2–5)], plant parasite index (PPI), PPI/MI values, and fungi-feeding/bacteria-feeding (F/B) ratio, as well as lower basal index (BI) and channel index (CI) and higher dominance. These results elucidated the difference between the three treatments, where the greenhouses were an enriched disturbed system compared with the other treatments and were dominated by bacterivorous nematodes, the fallows were a relatively infertile and stable system dominated by plant parasites, and the conventional farmlands can be positioned between the above two treatments. Key words: Agricultural management, nematode, disturbance, indices

Influence of agricultural management on soil organic carbon: A compendium and assessment of Canadian studies

2003 ◽  
Vol 83 (4) ◽  
pp. 363-380 ◽  
Author(s):  
A. J. VandenBygaart ◽  
E. G. Gregorich ◽  
D. A. Angers
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Management Practices ◽  
Agricultural Management ◽  
Organic Fertilizers ◽  
Published Data ◽  
Native Land ◽  
Soc Stocks ◽  
Long Term Studies

To fulfill commitments under the Kyoto Protocol, Canada is required to provide verifiable estimates and uncertainties for soil organic carbon (SOC) stocks, and for changes in those stocks over time. Estimates and uncertainties for agricultural soils can be derived from long-term studies that have measured differences in SOC between different management practices. We compiled published data from long-term studies in Canada to assess the effect of agricultural management on SOC. A total of 62 studies were compiled, in which the difference in SOC was determined for conversion from native land to cropland, and for different tillage, crop rotation and fertilizer management practices. There was a loss of 24 ± 6% of the SOC after native land was converted to agricultural land. No-till (NT) increased the storage of SOC in western Canada by 2.9 ± 1.3 Mg ha-1; however, in eastern Canada conversion to NT did not increase SOC. In general, the potential to store SOC when NT was adopted decreased with increasing background levels of SOC. Using no-tillage, reducing summer fallow, including hay in rotation with wheat (Triticum aestivum L.), plowing green manures into the soil, and applying N and organic fertilizers were the practices that tended to show the most consistent in creases in SOC storage. By relating treatment SOC levels to those in the control treatments, SOC stock change factors and their levels of uncertainty were derived for use in empirical models, such as the United Nations Intergovernmental Panel on Climate Change (IPCC). Guidelines model for C stock changes. However, we must be careful when attempting to extrapolate research plot data to farmers’ fields since the history of soil and crop management has a significant influence on existing and future SOC stocks. Key words: C sequestration, tillage, crop rotations, fertilizer, cropping intensity, Canada

scholarly journals Total and Active Soil Organic Carbon from Long‐term Agricultural Management Practices in West Tennessee

ael ◽  
2019 ◽  
Vol 4 (1) ◽  
pp. 180062 ◽  
Author(s):  
Sindhu Jagadamma ◽  
Michael E. Essington ◽  
Sutie Xu ◽  
Xinhua Yin
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Management Practices ◽  
Agricultural Management ◽  
West Tennessee

Effects of long-term turfgrass management practices on soil nematode community and nutrient pools

2008 ◽  
Vol 38 (2) ◽  
pp. 174-184 ◽  
Author(s):  
Z. Cheng ◽  
P.S. Grewal ◽  
B.R. Stinner ◽  
K.A. Hurto ◽  
H.B. Hamza
Keyword(s):  
Management Practices ◽  
Nematode Community ◽  
Soil Nematode ◽  
Nutrient Pools ◽  
Soil Nematode Community ◽  
Turfgrass Management

Effect of disturbances on trophic groups in soil nematode assemblages

Nematology ◽  
2011 ◽  
Vol 13 (5) ◽  
pp. 553-559 ◽  
Author(s):  
Robert McSorley
Keyword(s):  
Plant Cover ◽  
Parasitic Nematodes ◽  
Soil Nematode ◽  
Trophic Groups ◽  
Bare Ground ◽  
Short Term ◽  
Free Living ◽  
Free Living Nematode ◽  
A Site

AbstractFree-living nematodes in soil ecosystems are vital in the decomposition of organic matter and recycling of nutrients. The effects of various types of disturbances on nematode assemblages were examined in several experiments on a single soil: a short-term detrimental disturbance from solarisation, a short-term beneficial disturbance from amendment addition, and a long-term detrimental disturbance from bare ground without plant cover. Comparison of solarised and non-solarised field plots revealed lower numbers of fungivores in solarised plots. As a result, indices involving ratios of fungivores to bacterivores and fungivores to total free-living nematodes were decreased as well. Addition of an amendment increased numbers of bacterivores. This change was also reflected in calculated indices that expressed trophic groups as percentages of the total free-living nematodes. A severely disturbed site with bare ground that was without plant cover for more than 5 years was compared with an adjacent site maintained in grass. No plant-parasitic nematodes were recovered from the bare ground site, which contained lower numbers of nematodes in all trophic groups than the grass site. However, the structure of the free-living nematode assemblages in both sites was similar, as indicated by the proportions of various trophic groups and by ratios of fungivores and bacterivores. The free-living nematode assemblage in a site with a perceived severe long-term disturbance maintained a trophic structure similar to a site with perennial plant cover.

scholarly journals A Temperature Index Model to Estimate Long-term Freeze-risk of Satsuma Mandarins Grown on the Northern Coast of the Gulf of Mexico

2005 ◽  
Vol 130 (4) ◽  
pp. 500-507 ◽  
Author(s):  
R.C. Ebel ◽  
B.L. Campbell ◽  
M.L. Nesbitt ◽  
W.A. Dozier ◽  
J.K. Lindsey ◽  
...  
Keyword(s):  
Air Temperature ◽  
Cold Hardiness ◽  
Management Practices ◽  
Rating Scale ◽  
Daily Maximum ◽  
Northern Coast ◽  
Freeze Injury ◽  
Air Temperatures ◽  
The Difference

Estimates of long-term freeze-risk aid decisions regarding crop, cultivar, and rootstock selection, cultural management practices that promote cold hardiness, and methods of freeze protection. Citrus cold hardiness is mostly a function of air temperature, but historical weather records typically contain only daily maximum (Tmax) and minimum (Tmin) air temperatures. A mathematical model was developed that used Tmax and Tmin to estimate air temperature every hour during the diurnal cycle; a cold-hardiness index (CHI500) was calculated by summing the hours ≤10°C for the 500 h before each day; and the CHI500 was regressed against critical temperatures (Tc) that cause injury. The CHI500 was calculated from a weather station located within 0.1 km of an experimental grove and in the middle of the satsuma mandarin (Citrus unshiu Marc.) industry in southern Alabama. Calculation of CHI500 was verified by regressing a predicted CHI500 using Tmax and Tmin, to a measured CHI500 calculated using air temperatures measured every hour for 4 winter seasons (1999-2003). Predicted CHI500 was linearly related to measured CHI500 (r2 = 0.982). However, the slope was a little low such that trees with a CHI500 = 400, near the maximum cold-hardiness level achieved in this study, had predicted Tc that was 0.5 °C lower than measured Tc. Predicted and measured Tc were similar for nonhardened trees (CHI500 = 0). The ability of predicted Tc to estimate freeze injury was determined in 18 winter seasons where freeze injury was recorded. During injurious freeze events, predicted Tc was higher than Tmin except for a freeze on 8 Mar. 1996. In some freezes where the difference in Tc and Tmin was <0.5 °C there were no visible injury symptoms. Injury by the freeze on 8 Mar. 1996 was due, in part, to abnormally rapid deacclimation because of defoliation by an earlier freeze on 4-6 Feb. the same year. A freeze rating scale was developed that related the difference in Tc and Tmin to the extent of injury. Severe freezes were characterized by tree death (Tc - Tmin > 3.0 °C), moderate freezes by foliage kill and some stem dieback (1.0 °C ≤ Tc - Tmin ≤ 3.0 °C), and slight freezes by slight to no visible leaf injury (Tc - Tmin < 1.0 °C). The model was applied to Tmax and Tmin recorded daily from 1948 through 2004 to estimate long-term freeze-risk for economically damaging freezes (severe and moderate freeze ratings). Economically damaging freezes occurred 1 out of 4 years in the 56-year study, although 8 of the 14 freeze years occurred in two clusters, the first 5 years in the 1960s and 1980s. Potential modification of freeze-risk using within-tree microsprinkler irrigation and more cold-hardy cultivars was discussed.

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