Influence Of Water Table Research Articles

Long-term rainfall and water table influence on groundwater nutrient dynamics from an oil palm plantation

ABSTRACT Conservation of groundwater quality is of paramount importance for sustainable agricultural management. Hydrological factors such as rainfall patterns and water table (WT) management, including drainage practices, play a crucial role in groundwater recharge. This in turn has a significant impact on WT fluctuations, nutrient losses in the soil, and the leaching of fertilizers into groundwater which leads to groundwater pollution. Consequently, this study evaluates the long-term influence of seasonal rainfall and WT fluctuations on groundwater nutrient dynamics in tropical peatlands from an oil palm plantation (OPP). Linear regression analyses and Pearson correlation matrices were adopted to evaluate the relationships between seasonal rainfall, WT, and groundwater chemical parameters. The results showed that there was a significant increase in mean pH, NO3 −, Na+, Ca2+, and PO4 3- values during the wet season compared to the dry season which could be attributed to the leaching of nutrients into groundwater due to rainfall, nutrient runoff from drainage systems and increased nitrification rate. A significant positive correlation (p < 0.01) was found between groundwater pH and NO3 − during the wet season, suggesting that increased groundwater pH due to heavy rainfall directly affects the nitrification process. It was also observed that low WT promotes denitrification in shallow groundwater, with this effect being more significant (p < 0.05) during the dry season. This was reflected in the higher correlation values between the WT fluctuations and the NH4 + concentrations in the groundwater. This research represents the first study to explore the long-term impacts of rainfall and WT fluctuations on groundwater quality in tropical peatlands. The insights gained from this study offer valuable guidance for WT management strategies aimed at conserving groundwater quality in such environments, ultimately contributing to sustainable agricultural practices.

Influence of Water Table and Peat Thickness on Dissolved Organic Carbon of Tropical Peat Soil with Sulfidic Substratum from Central Kalimantan, Indonesia

Peatlands are important due to their high carbon storage, their role in suppressing climate change processes, and their importance for local and global communities’ livelihood. Large amounts of organic carbon pools in peatlands can be released into the environment as gaseous emitted carbon and lost through waterways (fluvial). The carbon released through the water stream consists of organic and inorganic forms and is partly in the form of CO2 and CH4 gases. The organic form consists of dissolved organic carbon (DOC) and particulate organic carbon, where DOC is the most dominant organic carbon in water sourced from peatlands. This research's objectives were to study the DOC concentration of peat water resulting from the hydrological condition's difference and the peat thickness overlaying the sulfidic substratum. The study was carried out in the Pangkoh area of Pulang Pisau district of Central Kalimantan. Peat water is taken on PVC pipes installed on each plot representing different peat thicknesses (deep, moderate, and shallow peat) at a depth of 25, 50, 100, 150, 200, and 250 cm from the soil surface. The water sampling was conducted on the peak wet season, during the transition from wet season to dry season and during the peak dry season. The results showed that DOC was influenced by peat thickness, depth of sulfidic material, and groundwater level. The release of DOC is higher from the deep peat than from the thin and moderate peat. The difference in DOC concentration between peat thickness is also related to the electrical conductivity of the peat water. The results showed a negative correlation between electrical conductivity and DOC concentration. The negative correlation was significant in the observation of the rainy and dry seasons, while in the transitional season, it was not significant.

Medium-term fertilization strategies on extensive grain cropping systems under water table influence

CONTEXTHistorical increases in grain yields have been associated with an undermining of soil organic matter (SOM) and a reduction of nutrient cycling capacity. Nutrient limitations for grain crop production are ubiquitous, and while yield and economic response to fertilization has been exhaustively evaluated on several crops across different environments, the focus has been mainly on individual crops rather than on the cropping system. Benefits of increased fertilization beyond a single cropping season need to be assessed to help preventing the current soil nutrient mining process in the Argentine Pampas. OBJECTIVESi) Evaluate the effect of different fertilization strategies over crop yields across rotation cycles and locations (and their interactions); ii) determine the relationship between crop yield response to fertilization and the physical and chemical soil variables; iii) evaluate the economic profit of each fertilization strategy; and iv) determine the residual effect on a soybean crop after six years following different fertilization strategies. METHODSThe study was conducted across environments in the Salado “A” Basin of the Inland Pampas of Argentina and included seven experiments with a crop rotation of soybean - wheat/second soybean - maize that was managed with different fertilization strategies (with increasing levels of nitrogen N, phosphorus P, and sulfur S), including a non-fertilized control, along six seasons. Additionally, an extra soybean crop was grown in the seventh year to determine the residual influence of previously imposed fertilization treatments. RESULTS AND CONCLUSIONSThe yield response to fertilization was highest under the more intensified treatments and larger for wheat (up to 150%) and maize (up to 100%) than for soybean (up to 40%) and second soybean (up to 30%). Overall crop yield response to increasing N and P inputs was negatively correlated with initial soil extractable P while the response to S was higher in sites with high proportion of sand and low SOM. The economic profit increased as fertilization was intensified although differences were not always significant across treatments within sites. On average, intensification resulted in an additional profit of U$S187 ha−1 compared to the typical fertilization strategy followed by farmers in the area without considering a residual positive yield response (10–13%) observed in a successive soybean crop. SIGNIFICANCEThis study provided elements to improve the understanding of complex interactions determining crop yield response to fertilization strategies to help optimizing long-term management decisions affecting the cropping systems with large impact at regional level.

Pedogenetic Calcretes In Early Syn-Rift Alluvial Systems (Upper Jurassic, West Cameros Basin), Northern Spain

Exceptional pedogenetic calcretes occur in the earliest syn-rift sedimentary record (Tithonian) of the west Cameros Basin. These calcretes show different types of pedogenetic facies (nodular, massive, laminar, and brecciated–pisolithic) and microfabrics: brecciated intraclasts, carbonate nodules, coated clasts and grains, etched quartz grains, rhizocretions, pedotubules and fragmented alveolar–septal structures. In addition, calcrete fragments have been observed in the conglomerate and sandy channelized deposits that form the alluvial systems, indicating the reworking of previous calcrete deposits. Calcrete facies appear organized in several sequences developed over different architectural elements in three different types of alluvial systems. The type of calcrete sequence is different depending on the architectural arrangement of each alluvial-fan system. Laminar (L (MN)–S) and brecciated–pisolithic (BP (L)–S) calcrete sequences are predominant in the alluvial sedimentary record of poorly channelized alluvial systems. These calcretes are thick, morphologically complex, and laterally continuous, due to the formation of long-term stable subaerial surfaces favored by the intermittent behavior of the alluvial systems. Massive-nodular (M (N)–S) and laminar (L (MN)–S) sequences are predominant in highly channelized alluvial systems and develop only locally in interchannel or floodplain areas where sedimentation stops temporally. Calcrete sequences in the distributive fluvial fan systems can be considered as poorly developed, being massive-nodular (M (N)–S) and nodular (N–S). After analyzing the location of these calcrete sequences in the studied record and their genesis and environmental significance, their variations can be related to different autocyclic factors such as sedimentation rate, channel network organization, texture of the host sediment, and water-table influence. Also three main allocyclic factors such as climate, tectonics, and drainage area controlled the carbonate sedimentation and therefore the development of the calcretes.

Atributos químicos e matéria orgânica em complexos florestais periodicamente inundados na restinga da Marambaia - RJ

http://dx.doi.org/10.5902/1980509812337Esse trabalho teve como objetivo avaliar as propriedades químicas e caracterizar a matéria orgânica de solos sob duas formações florestais periodicamente inundadas, na ilha da Marambaia, RJ. Essas formações apresentam diferenças quanto ao grau de saturação hídrica do solo, causada pela influência do lençol freático, sendo que na formação 1 (F1) o lençol apresenta-se mais próximo à superfície em comparação à formação 2 (F2). Amostras foram coletadas nas camadas 0,00-0,05, 0,05-0,10 e 0,10-0,20 m. As propriedades edáficas avaliadas foram: pH, H++Al+3; Ca+2, Mg+2, Na+, K+, P, N, carbono orgânico total (COT) e saturação por bases (V%); carbono da fração humina (C-HUM), carbono da fração ácido húmico (C-FAH) e carbono da fração ácido fúlvico (C-FAF). Valores estatisticamente superiores de pH foram observados para F1. Em F2 verificaram-se maiores valores de Mg+2, P, N e V%. Foi verificada correlação entre os teores de Mg+2, N, ácido húmico e ácido fúlvico em F1 com o lençol freático, e do lençol em F2 com os elementos Na+ e K+. A fração C-HUM foi a mais representativa do carbono orgânico total, seguida por C-FAH e C-FAF. Os teores de COT foram maiores na formação F1. A relação C/N foi menor em F2, com valores variando entre 9 e 12, e em F1 foram verificados maiores valores dessa relação, variando de 9 a 15. Dentre as vias de formação dos solos de constituição orgânicas, em ambas as áreas a principal via de acumulação da matéria orgânica é a de herança.

Water table depth affects Populus alba fine root growth and whole plant biomass

1 To increase understanding of the water table's influence on both fine-root growth and whole-plant growth of tree species in arid and semi-arid regions, we exposed Populus alba L. cuttings to contrasting soil water conditions via various water table gradients. 2 One-year-old rooted cuttings were grown individually in pots containing sandy soil in a greenhouse for 90 days in four water-table depth treatments: constant depth at 45 cm from the soil surface, constant depth at 30 cm, constant depth at 15 cm, and fluctuating depths between 45 and 30 cm. Growth responses, biomass partitioning, and structure and morphology of leaves and roots were determined for harvested trees every 30 days. 3 Fine (< 1-mm diameter) root growth was affected by water-table levels and water profiles, even in the fluctuating water-table depth treatment. Fine root proliferation was inhibited below the water table and was stimulated in the layers just above the water table and near the soil surface. 4 At the whole-plant level, with deeper water tables, P. alba allocated more biomass to roots and root morphology changed, but total root length did not increase, suggesting that trees faced with soil water deficits are not likely to increase root surface area to obtain more water. 5 Total biomass and root length in each treatment were positively correlated and the relationships were similar among the treatments, although the growth responses varied under the various water-table conditions. These results suggest that variation in root length may have an important effect on the biomass of the rooted cuttings across a gradient of water-table depths.

FRUPAT: A TOOL TO QUANTIFY INPUTS AND OUTPUTS OF PATAGONIAN FRUIT PRODUCTION SYSTEMS

A software called FRUPAT was developed for calculating input and output coefficients (Technical Coefficients) of fruit production systems in South Patagonia. FRUPAT combined locations (Rio Chubut valley; Sarmiento valley; Los Antiguos valley; Rio Chico valley), edaphic environment (good quality soil with water-table depth exceeding 2 m; good quality soil with water-table depth between 1 and 2 m; low water holding capacity soil without water-table influence), fruit-tree crops (sweet cherry; plum; peach; apple; walnut), training systems (tatura; central leader; vase), irrigation systems (drip; furrow) and frost control systems (sprinkler irrigation; heating; passive) that provided 1080 multi-annual fruit production activities. Parameters have been identified as default values and most of those can be easily modified by the user. Relevant inputs and outputs can be estimated, such as gross value of product, expenditures, financial result, biocide use, N-fertiliser surplus and labour. As an example of how FRUPAT can be used, some results are presented for a single physical environment (good quality soil with water-table depth exceeding 2 m, in the Rio Chubut valley) using sprinkler irrigation as frost control method. First, 5 crops under a single production technique (vase with furrow irrigation) are compared in terms of their monetary technical coefficients. Subsequently, results of sweet cherry under different production techniques (3 training systems with 2 irrigation systems) are presented. Finally, the time course of gross value of product, total expenditures, financial result and cumulative financial result are analyzed for a single activity (sweet cherry, trained as tatura under drip irrigation). FRUPAT may be used as a stand-alone tool for simple analysis as demonstrated here or as an intermediate step for linear programming

Influence of water table and nitrogen management on residual soil NO 3− and denitrification rate under corn production in sandy loam soil in Quebec

Nitrate-N (NO 3 −) effluents from agricultural ecosystems contributing to the degradation of water quality has become a serious environmental problem. A field experiment was conducted in 1996 and 1997 at St. Emmanuel, Que., Canada, to investigate the combined effects of water table management (WTM) and N fertilization on soil NO 3 − level and denitrification rates in the top soil layer (0–0.15 m). The field was planted to corn ( Zea mays L.) in both years. Treatments consisted of a factorial combination of two water table treatments, free drainage (FD) at about 1.0 m and subirrigation (SI) at 0.6 m below the soil surface, and two N fertilizer rates, 200 kg ha −1 (N 200) and 120 kg ha −1 (N 120). SI reduced NO 3 − concentration in the top soil layer by 42 and 16% in 1996 and 1997, respectively. Nitrate levels in soil were 50% lower in N 120 plots in 1996, and 20% in 1997 compared to the N 200 plots. Denitrification was higher in SI compared to FD, but not influenced by N rate. As a consequence, WTM practices have implications for both water quality and greenhouse gas emissions. Climatic conditions played a large role in regulating N dynamics in the soil. Due to drier and cooler conditions in 1997, denitrification rates were lower than in 1996, leaving higher residual NO 3 − in the soil profile following corn harvest.

Relationships between environmental conditions and the diagenetic evolution of organic matter derived from higher plants in a modern mangrove swamp system (Guadeloupe, French West Indies)

The sedimentary organic matter content of a series of 2-m-deep cores was investigated along a sea-land transect at five sites representing five species of mangrove and salt-marsh vegetation. The vegetation was settled at the same place for at least 1000 years and therefore sedimentary organic matter deriving from the decay of higher plants has accumulated in large amounts. The global morphological and chemical preservation of the organic matter attested by various sedimentary parameters, including the proportions of cellulose-bearing tissues, the TOC contents, the C/N ratios, the total sulphur contents and the δ 13C compositions, reveals that the sedimentary organic matter is less degraded when it has been under the influence of the marine water table for a long time. This is indicated by a good correlation between the salinities of interstitial waters, the redox potentials measured in the wet sediments and the chemical composition of the organic matter. Moreover, the concentration of organic sulphur shows a positive correlation with the hydrogen index (HI), only under the marine water-table influence, suggesting the very local presence of sulphur–HC compounds.

Influence of Water Table On Bearing Capacity of Adjacent Strip Footings On Sand Exhibiting Anisotropy

It is possible that many footings become inundated due to a rising water table or flooding at some stage during their structural life. The effect of water table on the ultimate bearing capacity of footings on anisotropic soils has not get received much attention. The purpose of this investigation therefore was to study the effect of water table on the ultimate bearing capacity of adjacent strip footings on Toyoura sand possessing anisotropy in the angle of internal friction using the method of characteristics. It was found that the influence of water table on the shape of stability lines is considerable and is negligible for the location of maximum pressure for both isolated and interfering footings. The results show that due to the effect of water table, the ultimate bearing capacity can be reduced by 38% for Toyoura sand. The study also revealed that the influence of anisotropy in the angle of internal friction for Toyoura sand on the ultimate bearing capacity of adjacent footings for a given depth of water table was considerable.

Simulation of soil moisture profiles for wheat in Brazil

A computer model to estimate components of the water balance for a cropped, layered soil profile without the influence of water table is described. Infiltration and soil water redistribution are governed by Darcy's law and evapotranspiration is partioned into three components: soil evaporation, transpiration, and evaporation of intercepted precipitation on the crop canopy. Those terms depend on the atmospheric demand, soil water availability, root water extraction and crop growth characteristics. In addition to evapotranspiration, model output also includes fluxes, pressure head, and soil moisture at different depths of the profile and runoff and ponding at the soil surface. The model was validated for a subtropical humid region in Paraná State, Brazil, under six wheat cropping periods. Predictions of soil water contents and evapotranspiration were in close agreement with field data. The model was considered appropriate for long term simulations of the water balance and irrigation requirements.

Influence of water table on carbon dioxide, carbon monoxide, and methane fluxes from Taiga Bog microcosms

Hydrological changes, particularly alterations in water table level, may largely overshadow the more direct effects of global temperature increase upon carbon cycling in arctic and subarctic wetlands. Frozen cores (n=40) of intact soils and vegetation were collected from a bog near Fairbanks, Alaska, and fluxes of CO2, CH4, and CO in response to water table variation were studied under controlled conditions in the Duke University phytotron. Core microcosms thawed to a 20‐cm depth over 30 days under a 20 hour photoperiod with a day/night temperature regime of 20/10°C. After 30 days the water table in 20 microcosms was decreased from the soil surface to −15 cm and maintained at the soil surface in 20 control cores. Outward fluxes of CO2 (9–16 g m−2 d−1) and CO (3–4 mg m−2 d−1) were greatest during early thaw and decreased to near zero for both gases before the water table treatment started. Lower water table tripled CO2 flux to the atmosphere when compared with control cores. Carbon monoxide was emitted at low rates from high water table cores and consumed by low water table cores. Methane fluxes were low (&lt;1 mg m−2 d−1) in all cores during thaw. High water table cores increased CH4 flux to 8‐9 mg m−2 d−1over 70 days and remained high relative to the low water table cores (&lt;0.74 mg m−2 d−1). Although drying of wetland taiga soils may decrease CH4 emissions to the atmosphere, the associated increase in CO2 due to aerobic respiration will likely increase the global warming potential of gas emissions from these soils.

Influence of Water Table and Atmospheric CO 2 Concentration on the Carbon Balance of Arctic Tundra

Carbon balance of intact arctic tundra microcosms (soil cores with vegetation) has been shown to be sensitive to small changes in water table. The persistence of the effect of water table on CO/sub 2/ flux in darkness, and the large reduction of such an effect in sand-culture microcosms without peat-degrading microorganisms have led to the conclusion that rates of microbial degradation of peat are most likely responsible for the bulk of previously observed effects of water table on net ecosystem CO/sub 2/ flux of arctic tundra microcosms. In an experiment using sand cultures, no significant effects of changes in water table or of increasing the atmospheric CO/sub 2/ concentration on the growth of plants was detected in two dominant graminoid species (Dupontia fisheri and Carex aquatilis). 16 references, 3 tables.

Influence of Water Table and Atmospheric CO 2 Concentration on the Carbon Balance of Arctic Tundra

Influence of Water Table and Atmospheric CO ₂ Concentration on the Carbon Balance of Arctic Tundra