Effects of Long-Term Fertilization on Different Nitrogen Forms in Paddy along Soil Depth Gradient

An exploratory examination has been made of three different kinds of hardpans found in humus podzols (Humods and Aquods) of the coastal lowlands of southern Queensland, by means of slaking tests, a reactive aluminium test, acid oxalate and pyrophosphate extractions and electron microscopy. Samples from three indurated layers exposed by erosion or sand-mining in large coastal dunes were included for comparison. The investigation confirmed that, a pan in a bleached A2 (albic E) horizon is most likely caused by particle packing and that a pan in a black B2h (spodic) horizon is cemented by an aluminium-organic complex. Yellow-brown pans underlying black organic pans (spodic horizons) were found to be cemented by both a proto-imogolite/allophane complex and an organic substance. An inorganic reactive Al complex differing from the proto-imogolite allophane recorded in the overlying giant podzols appeared to be main cement of three indurated layers in the nearby coastal sand dunes. Mechanical disturbance of the pans, e.g. ripping, is unlikely to improve drainage and effective soil depth in the long term, because the disturbed zones are expected to be re-sealed by packed particles or by the aluminium-organic complex cement.

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Change of mineral and organic nitrogen forms in a long term fertilization experiment (literature)

Acta Agraria Debreceniensis ◽

10.34101/actaagrar/56/1932 ◽

2014 ◽

pp. 43-47

Author(s):

Judit Horváth ◽

János Kátai

Keyword(s):

Organic Nitrogen ◽

Inorganic Nitrogen ◽

Essential Element ◽

Nitrogen Forms ◽

Organic Form ◽

The Sustainable Development ◽

Nitrogen Turnover ◽

Mineralization Processes ◽

Living Organisms

The research topic has timeliness, since the rational utilization and protection of the soil, besides the conservation of its diverse functions is part of the sustainable development. Research of the long-term experiments is esentially important, because it can model the term effects in the same place, under the same conditions. If we want to get accurate informations about the occured changes, way and danger of changes, we should track the resupply and effect of the mineral nutrients and the removed quantity of nutrients with the harvest. Nitrogen is an essential element for living organisms, it is present in the soil mainly in organic form. In general only only a low percentage of the total nitrogent content can be used directly by plants in the soil. This inorganic nitrogen is produced by the transformation of organic contents through mineralization processes and it get into the soil by the fertilization. The plants incorporote the mineral nitrogen into our bodies. This is how nitrogen turnover is realized when mineral forms become organic and organic forms become mineral. The purpose of our paper is to make a literature before our research.

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Soil acidification and the carbon cycle in a cropping soil of north-eastern Victoria

Soil Research ◽

10.1071/s96095 ◽

1998 ◽

Vol 36 (2) ◽

pp. 273 ◽

Cited By ~ 22

Author(s):

W. J. Slattery ◽

D. G. Edwards ◽

L. C. Bell ◽

D. R. Coventry ◽

K. R. Helyar

Keyword(s):

Soil Depth ◽

Organic C ◽

Soil Layers ◽

Soil C ◽

Soil Zone ◽

North Eastern ◽

Soil Buffering ◽

The Impact ◽

Total Organic C

Changes in soil organic matter were determined for a long-term (1975–95) experiment at the Rutherglen Research Institute in north-eastern Victoria. The crop rotations in this experiment were continuous lupins (LL) and continuous wheat (WW). The soil at this site was a solodic or Yellow Dermosol with a soil pH of 6·08 (pH in 0·01 М CaCl2 1 : 5) in 1975 in the surface 10 cm, which had declined by 0·8 and 1·5 pH units for WW and LL, respectively, in the 0–20 cm soil zone by 1992. Acidification rates decreased with increasing soil depth. The acidification rate in the 0–60 cm soil zone was 12·5 kmol(H+)/ha·year for the LL rotation and 4·6 kmol(H+)/ha·year for the WW rotation. The amount of CaCO3 required to neutralise the acidification of wheat-lupin rotations as calculated in this paper was up to 3·8 t/ha ·10 years for a WLWL rotation or 3 ·3 t/ha ·10 years for a WWL rotation; these amounts are significantly higher than previously reported rates. In this paper, we calculate the impact of changes in soil carbon (C) status over time, and therefore soil buffering, on the rates of acidification in incremental soil layers to a depth of 60 cm. Total organic C for these rotations in 1992 was 1·12% for WW and 1·17% for LL in the 0–10 cm soil zone. An investigation of the humic and fulvic acid fractions of these 2 rotations to a depth of 60 cm showed that the LL rotation had significantly higher (P < 0·05) C at depth than the WW rotation. Acidification due to the net decrease in soil C over the 15-year study period plus acidification due to the alkali removed in the seed was calculated to be –4·88 kmol(H+)/ha·year for the LL rotation and –6·52 kmol(H+)/ha·year for the WW rotation.

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Assessing the sustainability of wheat-based cropping systems using APSIM: model parameterisation and evaluation

Australian Journal of Agricultural Research ◽

10.1071/ar06186 ◽

2007 ◽

Vol 58 (1) ◽

pp. 75 ◽

Cited By ~ 12

Author(s):

Carina Moeller ◽

Mustafa Pala ◽

Ahmad M. Manschadi ◽

Holger Meinke ◽

Joachim Sauerborn

Keyword(s):

Organic Matter ◽

Soil Water ◽

Management Practices ◽

Soil Depth ◽

Crop Productivity ◽

Water Dynamics ◽

Soil Water Dynamics ◽

Mineral N ◽

N Use

Assessing the sustainability of crop and soil management practices in wheat-based rotations requires a well-tested model with the demonstrated ability to sensibly predict crop productivity and changes in the soil resource. The Agricultural Production Systems Simulator (APSIM) suite of models was parameterised and subsequently used to predict biomass production, yield, crop water and nitrogen (N) use, as well as long-term soil water and organic matter dynamics in wheat/chickpea systems at Tel Hadya, north-western Syria. The model satisfactorily simulated the productivity and water and N use of wheat and chickpea crops grown under different N and/or water supply levels in the 1998–99 and 1999–2000 experimental seasons. Analysis of soil-water dynamics showed that the 2-stage soil evaporation model in APSIM’s cascading water-balance module did not sufficiently explain the actual soil drying following crop harvest under conditions where unused water remained in the soil profile. This might have been related to evaporation from soil cracks in the montmorillonitic clay soil, a process not explicitly simulated by APSIM. Soil-water dynamics in wheat–fallow and wheat–chickpea rotations (1987–98) were nevertheless well simulated when the soil water content in 0–0.45 m soil depth was set to ‘air dry’ at the end of the growing season each year. The model satisfactorily simulated the amounts of NO3-N in the soil, whereas it underestimated the amounts of NH4-N. Ammonium fixation might be part of the soil mineral-N dynamics at the study site because montmorillonite is the major clay mineral. This process is not simulated by APSIM’s nitrogen module. APSIM was capable of predicting long-term trends (1985–98) in soil organic matter in wheat–fallow and wheat–chickpea rotations at Tel Hadya as reported in literature. Overall, results showed that the model is generic and mature enough to be extended to this set of environmental conditions and can therefore be applied to assess the sustainability of wheat–chickpea rotations at Tel Hadya.

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Competitive Interactions of Flowering Rush (Butomus umbellatus L.) Cytotypes in Submersed and Emergent Experimental Aquatic Plant Communities

Diversity ◽

10.3390/d12010040 ◽

2020 ◽

Vol 12 (1) ◽

pp. 40 ◽

Cited By ~ 1

Author(s):

Nathan E. Harms

Keyword(s):

Plant Communities ◽

Invasive Plants ◽

Aquatic Plant ◽

Invasive Plant ◽

Common Garden ◽

Competitive Interactions ◽

Depth Gradient ◽

Common Garden Experiments

The ability to invade communities in a variety of habitats (e.g., along a depth gradient) may facilitate establishment and spread of invasive plants, but how multiple lineages of a species perform under varying conditions is understudied. A series of greenhouse common garden experiments were conducted in which six diploid and four triploid populations of the aquatic invasive plant Butomus umbellatus L. (Butomaceae) were grown in submersed or emergent conditions, in monoculture or in a multispecies community, to compare establishment and productivity of cytotypes under competition. Diploid biomass overall was 12 times higher than triploids in the submersed experiment and three times higher in the emergent experiment. Diploid shoot:root ratio was double that of triploid plants in submersed conditions overall, and double in emergent conditions in monoculture. Relative interaction intensities (RII) indicated that triploid plants were sixteen times more negatively impacted by competition under submersed conditions but diploid plants were twice as impacted under emergent conditions. Recipient communities were similarly negatively impacted by B. umbellatus cytotypes. This study supports the idea that diploid and triploid B. umbellatus plants are equally capable of invading emergent communities, but that diploid plants may be better adapted for invading in submersed habitats. However, consistently lower shoot:root ratios in both monoculture and in communities suggests that triploid plants may be better-adapted competitors in the long term due to increased resource allocation to roots. This represents the first examination into the role of cytotype and habitat on competitive interactions of B. umbellatus.

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Soil characteristics at a long-term ecological research site in Taylor Valley, Antarctica

Soil Research ◽

10.1071/sr02112 ◽

2003 ◽

Vol 41 (3) ◽

pp. 351 ◽

Cited By ~ 16

Author(s):

I. B. Campbell

Keyword(s):

Particle Size ◽

Water Content ◽

Soil Depth ◽

Ecological Research ◽

Taylor Valley ◽

Research Site ◽

Long Term Ecological Research ◽

Water Contents ◽

Experimental Plots

Soils at a Long Term Ecological Research site near Lake Hoare in Taylor Valley, Antarctica, were investigated during November/December 1999. The soils alongside 6 experimental plots at the research site were described, repeatedly sampled over a 17-day period, and the gravimetric water content, particle size, and conductivity determined daily. At one nearby location, the soil water content was repeatedly measured after a plot irrigation, while at another, the water content of soil adjacent to a snow patch was repeatedly measured to determine the rate of water loss during thawing of snow. Soils at 2 sites at higher elevations outside the research area were also examined for comparison.The soils at the experimental plots were generally similar but differed in stoniness, the presence of occasional silty layers, and the depth to ice-cemented ground. Water contents (gravimetric) of surface horizons were <0.5% and increased with depth through the active layer to 12% or greater in the ice-cemented permafrost. There were small variations in the water content of surface horizons over the 17-day sampling period with larger variations at depth. A few siltier horizons had higher water contents. The water content profiles and <2 mm% particle size trends were broadly similar for all the sites. Conductivities were low, except in silty horizons where values were markedly higher. At the irrigated site, water was progressively lost over the first 9 days, after which values were close to those at unirrigated sites. There was a less marked loss of water from the soil alongside the thawing snow patch but an increased loss after all snow had thawed. The higher elevation soils outside the experimental area were more weathered and had higher salinities indicating a significantly greater soil age.Small changes in water content in the surface horizons appeared to be related to changing weather conditions, whereas at greater soil depth, changes in the water content corresponded with the increasing thawing depth. The results illustrate the dynamic nature of soil moisture over short periods of time in Antarctic Cold Desert soils.

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Recharge estimation and soil moisture dynamics in a Mediterranean karst aquifer

Hydrology and Earth System Sciences Discussions ◽

10.5194/hessd-11-8803-2014 ◽

2014 ◽

Vol 11 (7) ◽

pp. 8803-8844 ◽

Cited By ~ 1

Author(s):

F. Ries ◽

J. Lange ◽

S. Schmidt ◽

H. Puhlmann ◽

M. Sauter

Keyword(s):

Soil Moisture ◽

Groundwater Recharge ◽

Unsaturated Soil ◽

Soil Depth ◽

Climatic Gradient ◽

Soil Moisture Dynamics ◽

Soil Zone ◽

Moisture Dynamics ◽

Hydrus 1D

Abstract. Knowledge of soil moisture dynamics in the unsaturated soil zone provides valuable information on the temporal and spatial variability of groundwater recharge. This is especially true for the Mediterranean region, where a substantial fraction of long-term groundwater recharge is expected to occur during high magnitude precipitation events of above-average wet winters. To elucidate process understanding of infiltration processes during these extreme events, a monitoring network of precipitation gauges, meteorological stations, and soil moisture plots was installed in an area with a steep climatic gradient in the Jordan Valley region. In three soil moisture plots, Hydrus-1D was used to simulate water movement in the unsaturated soil zone with soil hydraulic parameters estimated by the Shuffled Complex Evolution Metropolis algorithm. To generalize our results, we modified soil depth and rainfall input to simulate the effect of the pronounced climatic gradient and soil depth variability on percolation fluxes and applied the calibrated model to a time series with 62 years of meteorological data. Soil moisture measurements showed a pronounced seasonality and suggested rapid infiltration during heavy rainstorms. Hydrus-1D successfully simulated short and long-term soil moisture patterns, with the majority of simulated deep percolation occurring during a few intensive rainfall events. Temperature drops in a nearby groundwater well were observed synchronously with simulated percolation pulses, indicating rapid groundwater recharge mechanisms. The 62 year model run yielded annual percolation fluxes of up to 66% of precipitation depths during wet years and of 0% during dry years. Furthermore, a dependence of recharge on the temporal rainfall distribution could be shown. Strong correlations between depth of recharge and soil depth were also observed.

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