THE EFFECT OF WATER TABLE DEPTH IN ORGANIC SOIL ON SUBSIDENCE AND SWELLING

1984 ◽  
Vol 64 (2) ◽  
pp. 273-282 ◽  
Author(s):  
J. A. MILLETTE ◽  
R. S. BROUGHTON

The effects of two water table depths (WTD), 0.6 and 0.9 m below the soil surface on subsidence, subsidence rate and swelling of an organic soil were observed in large undisturbed cores under greenhouse conditions. Measurements were made in two tiers, 0–0.3 m (top tier) and 0.3 m to WTD (bottom tier) during the growth of a carrot crop with WTD as above, and continued following a rise in the water table. The WTD of 0.9 m caused the top tier to subside twice as much as the same tier in the 0.6 m WTD. Top tier subsidence seemed irreversible in both WTD because minor swelling was observed following a rise in the water table. Most of the reversible subsidence occurred in the bottom tier. Raising the water table reduced the total profile subsidence by 36 and 24% for the 0.6 and 0.9 m WTD, respectively. After correction for oxidation, subsidence accounted for 3.2 and 5.9% of the 0.6- and 0.9-m profiles, respectively. The bulk density increase in the 0.6-m profile before and after the end of the experiment was not significant but a significant increase of 11% was measured in the 0.9-m profile. Subsidence rates decreased in both tiers during the growing period reaching a minimum in both WTD at harvest time. The subsidence rate in 0.9-m profile at 100 days after seeding was 2.5 times the rate in the 0.6-m profile. Key words: Organic soil, subsidence, swelling, water table

1983 ◽  
Vol 63 (3) ◽  
pp. 739-746 ◽  
Author(s):  
J. A. MILLETTE

Carrots and onions were grown on organic soil in a greenhouse over four water table levels, 10, 20, 40, 70 cm from the soil surface. Carrot yields were reduced over the shallowest water table level only, whereas the onion yields were depressed by the 10-, 20-, and 40-cm water table levels. The longest carrots were produced in the 40- and 70-cm water table levels. Evapotranspiration for the carrots was the same in all treatments but the water use efficiency was greatest in the 40- and 70-cm water table levels. Evapotranspiration for the onions and water use efficiency were the greatest in the 70-cm water table level. The evapotranspiration curves for the carrots showed two peaks, the second one corresponding to a rapid growth from the 50th day after seeding. The evapotranspiration curves for the onions showed one peak following the 70th day after seeding. Onions appear to be much more sensitive than carrots to high soil water content.Key words: Carrot, onion, water table, organic soil, vegetables


2017 ◽  
Vol 4 (2) ◽  
pp. 227-245
Author(s):  
Cahit Kahraman ◽  
İlhan Güneş ◽  
Nanae Kahraman

1989 göçü öncesi, dünyada eşzamanlı olarak gittikçe gelişen ve zenginleşen mutfak kültürü, Bulgaristan Türklerini de etkilemiştir. Pazardaki çeşitlilik arttıkça, yemek alışkanlıkları da değişime uğramıştır. Büyük göçten sadece 30-40 sene evvel kısıtlı imkânlar ile sınırlı sayıda yemek çeşidi üretilirken, alım gücünün artmasıyla yemek kültüründe de hızlı gelişmeler olmuştur. Artan ürün çeşitliliği yemeklere de yansımış, farklı lezzetler mutfaklara girmiştir. Göçmen yemekleri denilince hamur işleri, börek ve pideler akla gelir. Ayrıca, göçmenlerin çok zengin turşu, komposto ve konserve kültürüne sahip oldukları da bilinir. Bu çalışma, 1989 öncesi Bulgaristan’ın farklı bölgelerinde yaşayan Türklerin yemek alışkanlıklarına ışık tutmakla birlikte, göç sonrasında göçmen mutfak kültüründe bir değişiklik oluşup oluşmadığını konu almaktadır. Bu amaçla, 1989 yılında Türkiye’ye göç etmiş 50 kişiye 8 sorudan oluşan anket düzenlenmiştir. Bu verilerden yola çıkarak oluşan bulgular derlenmiş ve yeni tespitler yapılmıştır. Ayrıca, Türkiye’nin farklı bölgelerine yerleşen göçmenler, kendi göçmen pazarlarını kurmuşlardır. Bulgaristan’dan getirilen ürünlerin bu pazarlarda satılması böyle bir arz talebin hala devam ettiğine işaret etmektedir.ABSTRACT IN ENGLISHThe Diversity in Cuisine Culture of the Immigrants from Bulgaria After 1989 MigrationThe Cuisine culture that has been developing and getting rich day by day contemporaneously in the world before 1989 migration has also had an impact on Bulgarian Turks. By the increase in diversity in the market, eating habits have changed. While producing a limited number of food types with limited opportunities just some 30 or 40 years before the ‘Big Migration’, there has been a rapid progress in food culture by the help of the increase in purchase power. Enhancing product range has been reflected in food, and different tastes have entered the cuisines. When we say immigrant, the first things that come to our mind are pastry, flan and pitta bread. Moreover, it is also known that immigrants have a very rich cuisine culture of pickle, stewed fruit, and canned food. This study aims both to disclose the eating habits of Turks living in different regions of Bulgaria before 1989 and to determine whether there has been a difference in immigrant cuisine culture before and after the migration. For this purpose, a questionnaire consisting of 8 questions has been administered to 50 people who migrated to Turkey in 1989. The results gathered from these data have been compiled and new determinations have been made. In addition, immigrants that settled in different regions of Turkey have set their own immigrant markets. The fact that the products brought from Bulgaria are being sold in these markets shows that this kind of supply and demand still continues.


2006 ◽  
Vol 41 (1) ◽  
pp. 63-71 ◽  
Author(s):  
Nicolas Stämpfli ◽  
Chandra A. Madramootoo

Abstract Recent studies have shown subirrigation (SI) to be effective in reducing nitrate losses from agricultural tile drainage systems. A field study was conducted from 2001 to 2002 in southwestern Québec to evaluate the effect of SI on total dissolved phosphorus (TDP) losses in tile drainage. In an agricultural field with drains installed at a 1-m depth, a SI system with a design water table depth (WTD) of 0.6 m below the soil surface was compared with conventional free drainage (FD). Subirrigation increased drainage outflow volumes in the autumn, when drains were opened and water table control was interrupted for the winter in the SI plots. Outflows were otherwise similar for both treatments. Throughout the study, the TDP concentrations in tile drainage were significantly higher with SI than with FD for seven out of 17 of the sampling dates for which data could be analyzed statistically, and they were never found to be lower for plots under SI than for plots under FD. Of the seven dates for which the increase was significant, six fell in the period during which water table control was not implemented (27 September 2001 to 24 June 2002). Hence, it appears that SI tended to increase TDP concentrations compared with FD, and that it also had a residual effect between growing seasons. Almost one-third of all samples from the plots under SI exceeded Québec's surface water quality standard (0.03 mg TDP L-1), whereas concentrations in plots under FD were all below the standard. Possible causes of the increase in TDP concentrations in tile drainage with SI are high TDP concentrations found in the well water used for SI and a higher P solubility caused by the shallow water table.


2021 ◽  
Vol 11 (7) ◽  
pp. 2979
Author(s):  
Maxime Fortin Faubert ◽  
Dominic Desjardins ◽  
Mohamed Hijri ◽  
Michel Labrecque

The Salix genus includes shrub species that are widely used in phytoremediation and various other phytotechnologies due to their advantageous characteristics, such as a high evapotranspiration (ET) rate, in particular when cultivated in short rotation intensive culture (SRIC). Observations made in past field studies suggest that ET and its impact on soil hydrology can also lead to increases in soil pollutant concentrations near shrubs. To investigate this, sections of a mature willow plantation (seven years old) were cut to eliminate transpiration (Cut treatment). Soil concentrations of polychlorinated biphenyls (PCBs), aliphatic compounds C10–C50, polycyclic aromatic hydrocarbons (PAHs) and five trace elements (Cd, Cr, Cu, Ni and Zn) were compared between the Cut and the uncut plots (Salix miyabeana ‘SX61’). Over 24 months, the results clearly show that removal of the willow shrubs limited the contaminants’ increase in the soil surface, as observed for C10–C50 and of 10 PAHs under the Salix treatment. This finding strongly reinforces a hypothesis that SRIC of willows may facilitate the migration of contaminants towards their roots, thus increasing their concentration in the surrounding soil. Such a “pumping effect” in a high-density willow crop is a prominent characteristic specific to field studies that can lead to counterintuitive results. Although apparent increases of contaminant concentrations contradict the purification benefits usually pursued in phytoremediation, the possibility of active phytoextraction and rhizodegradation is not excluded. Moreover, increases of pollutant concentrations under shrubs following migration suggest that decreases would consequently occur at the source points. Some reflections on interpreting field work results are provided.


Water ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 961
Author(s):  
Meryem Touzani ◽  
Ismail Mohsine ◽  
Jamila Ouardi ◽  
Ilias Kacimi ◽  
Moad Morarech ◽  
...  

The main landfill in the city of Rabat (Morocco) is based on sandy material containing the shallow Mio-Pliocene aquifer. The presence of a pollution plume is likely, but its extent is not known. Measurements of spontaneous potential (SP) from the soil surface were cross-referenced with direct measurements of the water table and leachates (pH, redox potential, electrical conductivity) according to the available accesses, as well as with an analysis of the landscape and the water table flows. With a few precautions during data acquisition on this resistive terrain, the results made it possible to separate the electrokinetic (~30%) and electrochemical (~70%) components responsible for the range of potentials observed (70 mV). The plume is detected in the hydrogeological downstream of the discharge, but is captured by the natural drainage network and does not extend further under the hills.


Forests ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 732
Author(s):  
Gusti Z. Anshari ◽  
Evi Gusmayanti ◽  
Nisa Novita

Drainage is a major means of the conversion of tropical peat forests into agriculture. Accordingly, drained peat becomes a large source of carbon. However, the amount of carbon (C) loss from drained peats is not simply measured. The current C loss estimate is usually based on a single proxy of the groundwater table, spatially and temporarily dynamic. The relation between groundwater table and C emission is commonly not linear because of the complex natures of heterotrophic carbon emission. Peatland drainage or lowering groundwater table provides plenty of oxygen into the upper layer of peat above the water table, where microbial activity becomes active. Consequently, lowering the water table escalates subsidence that causes physical changes of organic matter (OM) and carbon emission due to microbial oxidation. This paper reviews peat bulk density (BD), total organic carbon (TOC) content, and subsidence rate of tropical peat forest and drained peat. Data of BD, TOC, and subsidence were derived from published and unpublished sources. We found that BD is generally higher in the top surface layer in drained peat than in the undrained peat. TOC values in both drained and undrained are lower in the top and higher in the bottom layer. To estimate carbon emission from the top layer (0–50 cm) in drained peats, we use BD value 0.12 to 0.15 g cm−3, TOC value of 50%, and a 60% conservatively oxidative correction factor. The average peat subsidence is 3.9 cm yr−1. The range of subsidence rate per year is between 2 and 6 cm, which results in estimated emission between 30 and 90 t CO2e ha−1 yr−1. This estimate is comparable to those of other studies and Tier 1 emission factor of the 2013 IPCC GHG Inventory on Wetlands. We argue that subsidence is a practical approach to estimate carbon emission from drained tropical peat is more applicable than the use of groundwater table.


1971 ◽  
Vol 16 (3) ◽  
pp. 173-182 ◽  
Author(s):  
Gavin Shaw ◽  
Bernard Groden ◽  
Evelyn Hastings

The establishment, staffing and structure and observations made in the first year of the existence of coronary care in an intensive care unit in a general hospital are recorded. Two hundred and twenty eight patients were admitted during the year in whom the diagnosis of myocardial infarction was confirmed. There were 29 deaths in the unit and 14 deaths occurred in the wards of the hospital after discharge from the unit. 49.1 per cent of the patients were admitted within 4 hours of the onset of symptoms and the mean duration of stay in the unit was 86.5 hours. The type of arrhythmia detected in the unit, and the treatment given to the patients both before and after admission to the intensive care unit are described.


1979 ◽  
Vol 36 (7) ◽  
pp. 764-769 ◽  
Author(s):  
Peter H. Pearse ◽  
James E. Wilen

The available statistical data are analyzed to appraise the success of Canada's Pacific salmon fleet rationalization program, in terms of the extent to which it has prevented fishing costs from rising in pace with the value of the catch. It is found that while the fleet's revenues increased at about the same rate before and after the scheme was introduced in 1969, the real capital employed increased more slowly under the controls than earlier. The program has, nevertheless, failed in its purpose of preventing further expansion of redundant capital in the fleet. The reasons for this failure, and for certain apparent shifts in the structure of the fleet, are discussed. Key words: Pacific salmon fishery, capitalization, economic rationalization, resource rent


1981 ◽  
Vol 97 (3) ◽  
pp. 557-568 ◽  
Author(s):  
R. K. Belford

SUMMARYThe response of winter wheat cv. Maris Huntsman to waterlogging was studied in two experiments in soil columns outdoors. Winter waterlogging treatments increased nodal root production and the proportion of aerenchyma within roots, but caused chlorosis and premature senescence of leaves, and decreased tillering. For all treatments, grain losses were much less than expected from the extent of tiller loss in winter; losses after single waterlogging events ranged from 2% (after 47 days with the water-table at 5 cm) to 16% (after 80 days with the water-table at the soil surface). Yield losses after three waterloggings at the seedling, tillering and stem elongation stages of growth were additive, and totalled 19%. In many treatments, grain loss was associated with lighter individual grain weights, suggesting that the size of the root system or efficiency of water and nutrient uptake by roots at the later stages of growth may have been less after earlier waterlogging. The importance of nitrogen fertilizer in maintaining a satisfactory plant nitrogen status was shown when nitrogen was with held before a 3-week waterlogging treatment during stem elongation; tiller and floret survival was subsequently greatly restricted and grain yields decreased 22% below those of plants waterlogged at the same stage of growth but supplied with nitrogen.


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