Mechanisms of potassium release from calcareous soils to different salt, organic acid and inorganic acid solutions

Soil Research ◽  
2019 ◽  
Vol 57 (3) ◽  
pp. 301 ◽  
Author(s):  
M. Najafi-Ghiri ◽  
M. Niazi ◽  
M. Khodabakhshi ◽  
H. R. Boostani ◽  
H. R. Owliaie
Keyword(s):  
Citric Acid ◽  
Organic Acids ◽  
Calcareous Soils ◽  
Acid Solutions ◽  
Short Term ◽  
Term Experiment ◽  
Short And Long Term ◽  
Fixation Capacity ◽  
Short Term Experiment

Mechanisms of potassium (K) release and fixation in calcareous soils may differ from non-calcareous soils. In the current investigation, four soils with different properties were extracted three and 10 times (45 and 150min, defined as short- and long-term respectively) with 0.025molL−1 CaCl2, HCl and oxalic and citric acid solutions and the contents of calcium (Ca), magnesium (Mg), aluminium (Al) and K in the extracts were determined. Immediately after K extraction, 500mg kg–1 of K (as KCl) was added to the remaining soils and shaken for 24h and K-fixation capacity was determined. No significant difference was observed between CaCl2 and HCl solutions in K extraction from soils in the short- and long-term experiments; the concentrations of Ca, Mg and Al in the extractants showed that HCl was not able to dissolve soil minerals and the soils released K via exchange reaction of Ca (originated from CaCO3 dissolution by HCl) with interlayer K. The organic acids had similar behaviour to each other in the short-term experiment; however, partial dissolution of minerals by citric acid was observed. Oxalic acid extracted less K than other solutions in the short-term experiment due to precipitation of soluble Ca as oxalate salt and thereby less exchange of soluble Ca with non-exchangeable K. Oxalic and citric acids dissolved K-bearing minerals and released K in the long-term experiment, but oxalic acid was more effective. The K-fixation capacity of soils was lower when treated with organic acids than with CaCl2 and HCl, possibly due to the dissolution of K-fixing minerals like smectite and illite by oxalate and citrate. Long-term treatment of soils with different solutions decreased K-fixation capacity of soils due to dissolution of K-fixing minerals or flocculation of minerals by Ca and slower K diffusion to the interlayer. With respect to the highly calcareous nature of the studied soils, the soluble cations in calcareous soils (predominantly Ca and Mg) may have been exchanged with non-exchangeable K of clay minerals and buffered soluble K as well as organic acids produced by plant roots and microorganisms.

Predicting isoproturon long-term mineralization from short-term experiment: Can this be a suitable approach?

Chemosphere ◽  
2016 ◽  
Vol 144 ◽  
pp. 312-318 ◽  
Author(s):  
Fang Wang ◽  
Ulrike Dörfler ◽  
Xin Jiang ◽  
Reiner Schroll
Keyword(s):  
Short Term ◽  
Term Experiment ◽  
Short Term Experiment

scholarly journals Long-term resource addition to a detrital food web yields a pattern of responses more complex than pervasive bottom-up control

2017 ◽  
Author(s):  
Kendra L. Lawrence ◽  
David H Wise
Keyword(s):  
Field Experiments ◽  
Abiotic Factors ◽  
Short Term ◽  
Bottom Up ◽  
Term Experiment ◽  
Two Factors ◽  
Long Term Experiment ◽  
Short Term Experiment ◽  
Univariate Analyses

Background. Theory predicts strong bottom-up control in detritus-based food webs, yet field experiments with detritus-based terrestrial systems have uncovered contradictory evidence regarding the strength and pervasiveness of bottom-up control processes. Two factors likely leading to contradictory results are experiment duration, which influences exposure to temporal variation in abiotic factors such as rainfall and affects the likelihood of detecting approach to a new equilibrium; and openness of the experimental units to immigration and migration. To investigate the contribution of these two factors, we conducted a long-term experiment with open and fenced plots in the forest that was the site of an earlier, short-term experiment (3.5 months) with open plots (Chen & Wise 1999) that produced evidence of strong bottom-up control for 14 taxonomic groupings of primary consumers of litter and fungi (microbi-detritivores) and their predators. Methods. We added artificial high-quality detritus to ten 2 x 2-m forest-floor plots at bi-weekly intervals from April through September in three consecutive years (Supplemented treatment). Ten comparable Ambient plots were controls. Half of the Supplemented and Ambient plots were enclosed by metal fencing. Results. Arthropod community structure (based upon 18 response variables) diverged over time between Supplemented and Ambient treatments, with no effect of Fencing on the multivariate response pattern. Fencing possibly influenced only ca. 20% of the subsequent univariate analyses. Multi- and univariate analyses revealed bottom-up control by fall of Year 1 of some, but not all, microbi-detritivores and predators. During the following two years the pattern of responses became more complex than that observed by Chen & Wise (1999). Some taxa showed consistent bottom-up control whereas many did not. Variation across years could not be explained completely by differences in rainfall because some taxa exhibited negative, not positive, responses to detrital supplementation. Discussion. Our 3-yr experiment did not confirm the conclusion of strong, pervasive bottom-up control of microbi-detritivores and predators reported by Chen and Wise (1999). Our longer-term experiment revealed a more complex pattern of responses, a pattern much closer to the range of outcomes reported in the literature for many short-term experiments. Much of the variation in responses across studies likely reflects variation in factors such as rainfall and the quality of added detritus. Nevertheless, it is also possible that long-term resource enhancement can drive a community towards a new equilibrium state that differs from what would have been predicted from the initial short-term responses exhibited by primary and secondary consumers.

Implications of climate change for Daphnia in alpine lakes: predictions from long-term dynamics, spatial distribution, and a short-term experiment

Hydrobiologia ◽  
2011 ◽  
Vol 676 (1) ◽  
pp. 263-277 ◽  
Author(s):  
Janet M. Fischer ◽  
Mark H. Olson ◽  
Craig E. Williamson ◽  
Jennifer C. Everhart ◽  
Paula J. Hogan ◽  
...  
Keyword(s):  
Climate Change ◽  
Spatial Distribution ◽  
Alpine Lakes ◽  
Short Term ◽  
Term Experiment ◽  
Short Term Experiment

EFFECT OF HEAVY MUSCULAR WORK ON THE MORPHOLOGY AND HISTOCHEMISTRY OF THE RAT TESTIS

1963 ◽  
Vol 43 (2) ◽  
pp. 311-320 ◽  
Author(s):  
M. Härkönen ◽  
E. Kontinen ◽  
M. Kormano ◽  
M. Niemi
Keyword(s):  
Leydig Cells ◽  
Seminiferous Tubules ◽  
Interstitial Tissue ◽  
List Type ◽  
Muscular Work ◽  
Term Experiment ◽  
Long Term Experiment ◽  
Short And Long Term ◽  
Short Term Experiment

ABSTRACT The effect of short- and long-term muscular work on the Leydig cells of the rat was studied. The rats were allowed to run in a rotating wire cylinder for various periods. The amount of stress was evaluated by the involution of the thymus, ulceration of the gastric mucosa, enlargement of adrenal glands and their lipid and catecholamine contents. After a short-term experiment, periods of 16 + 10 hours' running with rest for 10 hours in between, accessory genital organs were slightly involuted 4 to 8 days following the stress. The testes were histologically and histochemically intact. Similar results were obtained after a long-term experiment, comprising continuous daily running for 10 hours over a period of 12 days. In a progressive long-term experiment, viz. daily running until exhaustion for 14 days, temporary degeneration of the Leydig cells occurred: the percentage of interstitial tissue and the size of the nuclei of the Leydig cells diminished and the number of degenerating Leydig cells significantly increased. Oxidative enzyme activity was markedly suppressed. DPN-diaphorase and β-hydroxybutyric dehydrogenase activity were very markedly decreased. The involution of the accessory genital organs was more pronounced than in the two former experiments. All these phenomena reverted to normal within ten days. In every experiment the seminiferous tubules remained histologically normal.

scholarly journals A Case Study on User Evaluation of Scientific Publication Summarization by Japanese Students

2021 ◽  
Vol 11 (14) ◽  
pp. 6287
Author(s):  
Shintaro Yamamoto ◽  
Ryota Suzuki ◽  
Tsukasa Fukusato ◽  
Hirokatsu Kataoka ◽  
Shigeo Morishima
Keyword(s):  
Scientific Publication ◽  
Automatic Summarization ◽  
Scientific Publications ◽  
Japanese University ◽  
Term Experiment ◽  
Long Term Experiment ◽  
Short And Long Term ◽  
Short Term Experiment

Summaries of scientific publications enable readers to gain an overview of a large number of studies, but users’ preferences have not yet been explored. In this paper, we conduct two user studies (i.e., short- and long-term studies) where Japanese university students read summaries of English research articles that were either manually written or automatically generated using text summarization and/or machine translation. In the short-term experiment, subjects compared and evaluated the two types of summaries of the same article. We analyze the characteristics in the generated summaries that readers regard as important, such as content richness and simplicity. The experimental results show that subjects are mainly judged based on four criteria, including content richness, simplicity, fluency, and format. In the long-term experiment, subjects read 50 summaries and answered whether they would like to read the original papers after reading the summaries. We discuss the characteristics in the summaries that readers tend to use to determine whether to read the papers, such as topic, methods, and results. The comments from subjects indicate that specific components of scientific publications, including research topics and methods, are important to judge whether to read or not. Our study provides insights to enhance the effectiveness of automatic summarization of scientific publications.

scholarly journals Aluminum or Low pH – Which Is the Bigger Enemy of Barley? Transcriptome Analysis of Barley Root Meristem Under Al and Low pH Stress

2021 ◽  
Vol 12 ◽  
Author(s):  
Miriam Szurman-Zubrzycka ◽  
Karolina Chwiałkowska ◽  
Magdalena Niemira ◽  
Mirosław Kwaśniewski ◽  
Małgorzata Nawrot ◽  
...  
Keyword(s):  
Cell Wall ◽  
Transcriptome Analysis ◽  
Low Ph ◽  
Ion Binding ◽  
Short Term ◽  
Root Meristems ◽  
Term Experiment ◽  
Short Term Experiment ◽  
Al Treatment

Aluminum (Al) toxicity is considered to be the most harmful abiotic stress in acidic soils that today comprise more than 50% of the world’s arable lands. Barley belongs to a group of crops that are most sensitive to Al in low pH soils. We present the RNA-seq analysis of root meristems of barley seedlings grown in hydroponics at optimal pH (6.0), low pH (4.0), and low pH with Al (10 μM of bioavailable Al3+ ions). Two independent experiments were conducted: with short-term (24 h) and long-term (7 days) Al treatment. In the short-term experiment, more genes were differentially expressed (DEGs) between root meristems grown at pH = 6.0 and pH = 4.0, than between those grown at pH = 4.0 with and without Al treatment. The genes upregulated by low pH were associated mainly with response to oxidative stress, cell wall organization, and iron ion binding. Among genes upregulated by Al, overrepresented were those related to response to stress condition and calcium ion binding. In the long-term experiment, the number of DEGs between hydroponics at pH = 4.0 and 6.0 were lower than in the short-term experiment, which suggests that plants partially adapted to the low pH. Interestingly, 7 days Al treatment caused massive changes in the transcriptome profile. Over 4,000 genes were upregulated and almost 2,000 genes were downregulated by long-term Al stress. These DEGs were related to stress response, cell wall development and metal ion transport. Based on our results we can assume that both, Al3+ ions and low pH are harmful to barley plants. Additionally, we phenotyped the root system of barley seedlings grown in the same hydroponic conditions for 7 days at pH = 6.0, pH = 4.0, and pH = 4.0 with Al. The results correspond to transcriptomic data and show that low pH itself is a stress factor that causes a significant reduction of root growth and the addition of aluminum further increases this reduction. It should be noted that in acidic arable lands, plants are exposed simultaneously to both of these stresses. The presented transcriptome analysis may help to find potential targets for breeding barley plants that are more tolerant to such conditions.

INCREASE IN THE LEVEL OF RETINAL MELATONIN AND PERSISTENCE OF ITS DIURNAL RHYTHM IN RATS AFTER PINEALECTOMY

1981 ◽  
Vol 91 (3) ◽  
pp. 477-481 ◽  
Author(s):  
H. S. YU ◽  
S. F. PANG ◽  
P. L. TANG
Keyword(s):  
Diurnal Rhythm ◽  
Feedback System ◽  
Male Rats ◽  
Long Term Effects ◽  
Term Experiment ◽  
Long Term Experiment ◽  
Short And Long Term ◽  
Short Term Experiment ◽  
Compensatory Effect

To study the short- and long-term effects of pinealectomy on the level of retinal melatonin, male rats adapted to a photoperiod of 12 h light: 12 h darkness (with lights on at 06.00 h) were pinealectomized. In the short-term experiment, the rats were decapitated 1 week after pinealectomy. In the long-term experiment, 1 month was allowed for recovery. Melatonin was extracted from retinae and quantified by radioimmunoassay. A diurnal rhythm of retinal melatonin was found to persist after pinealectomy in both experiments. An increase in retinal melatonin was demonstrated 1 month after pinealectomy, indicating a compensatory effect on melatonin in the retinae of pinealectomized rats. Thus, biosynthesis of melatonin in the retina may be modulated through a negative feedback system.

Long / Short Term Experimental Study on Chloride Penetration in Cracked Concrete

2009 ◽  
Vol 417-418 ◽  
pp. 765-768 ◽  
Author(s):  
In Seok Yoon ◽  
Erik Schlangen
Keyword(s):  
Chloride Penetration ◽  
Crack Healing ◽  
Short Term ◽  
Cracked Concrete ◽  
Term Experiment ◽  
Long Term Experiment ◽  
Set Up ◽  
Short Term Experiment ◽  
Penetration Behaviour

This study is focused on examining the effect of cracks on chloride penetration into concrete. In order to get reliable results, short-term and long term experiments were set up and chloride penetration behaviour through cracks was examined. It was noticed that chloride penetration through cracks tends to decrease with time. One of the explanations is crack-healing. Especially, this trend was obvious in concrete samples with larger crack width. However, measuring the border between chloride contaminated zone and healthy zone was clear in concrete of short-term experiment, while it was ambiguous in long term experiment.

scholarly journals Long-term resource addition to a detrital food web yields a pattern of responses more complex than pervasive bottom-up control

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3572 ◽  
Author(s):  
Kendra L. Lawrence ◽  
David H. Wise
Keyword(s):  
Field Experiments ◽  
Abiotic Factors ◽  
Short Term ◽  
Bottom Up ◽  
Term Experiment ◽  
Two Factors ◽  
Long Term Experiment ◽  
Short Term Experiment ◽  
Univariate Analyses

Background Theory predicts strong bottom-up control in detritus-based food webs, yet field experiments with detritus-based terrestrial systems have uncovered contradictory evidence regarding the strength and pervasiveness of bottom-up control processes. Two factors likely leading to contradictory results are experiment duration, which influences exposure to temporal variation in abiotic factors such as rainfall and affects the likelihood of detecting approach to a new equilibrium; and openness of the experimental units to immigration and emigration. To investigate the contribution of these two factors, we conducted a long-term experiment with open and fenced plots in the forest that was the site of an earlier, short-term experiment (3.5 months) with open plots (Chen & Wise, 1999) that produced evidence of strong bottom-up control for 14 taxonomic groupings of primary consumers of fungi and detritus (microbi-detritivores) and their predators. Methods We added artificial high-quality detritus to ten 2 × 2-m forest-floor plots at bi-weekly intervals from April through September in three consecutive years (Supplemented treatment). Ten comparable Ambient plots were controls. Half of the Supplemented and Ambient plots were enclosed by metal fencing. Results Arthropod community structure (based upon 18 response variables) diverged over time between Supplemented and Ambient treatments, with no effect of Fencing on the multivariate response pattern. Fencing possibly influenced only ca. 30% of the subsequent univariate analyses. Multi- and univariate analyses revealed bottom-up control during Year 1 of some, but not all, microbi-detritivores and predators. During the following two years the pattern of responses became more complex than that observed by Chen & Wise (1999). Some taxa showed consistent bottom-up control whereas others did not. Variation across years could not be explained completely by differences in rainfall because some taxa exhibited negative, not positive, responses to detrital supplementation. Discussion Our 3-year experiment did not confirm the conclusion of strong, pervasive bottom-up control of both microbi-detritivores and predators reported by Chen & Wise (1999). Our longer-term experiment revealed a more complex pattern of responses, a pattern much closer to the range of outcomes reported in the literature for many short-term experiments. Much of the variation in responses across studies likely reflects variation in abiotic and biotic factors and the quality of added detritus. Nevertheless, it is also possible that long-term resource enhancement can drive a community towards a new equilibrium state that differs from what would have been predicted from the initial short-term responses exhibited by primary and secondary consumers.

scholarly journals Effects of NaCl-salinity on growth and inorganic solute accumulation in young cashew plants

2001 ◽  
Vol 5 (2) ◽  
pp. 216-222 ◽  
Author(s):  
Ricardo A. Viégas ◽  
Joaquim A. G. da Silveira ◽  
Adeildo R. de Lima Junior ◽  
José E. Queiroz ◽  
Maria J. M. Fausto
Keyword(s):  
Fresh Mass ◽  
Short Term ◽  
Tissue Concentrations ◽  
Term Experiment ◽  
Whole Plant ◽  
Solute Accumulation ◽  
Long Term Experiment ◽  
Short Term Experiment ◽  
Hydroponically Grown

The NaCl effects on the growth and inorganic solute accumulation were studied on 30-day-old cashew plants (Anacardium occidentale L.) hydroponically grown for 8 days (short term) and 40 days (long-term) with NaCl at different levels. The shoot fresh mass yielded after 40 days, in response to 50 and 100 mol m-3 NaCl, decreased by 25 and 75%, respectively. This decrease was markedly low in root fresh mass, which did not change under 50 mol m-3 NaCl and decreased nearly to 30% under 100 mol m-3 NaCl, as compared to control plants. In short-term experiment, salinity induced only slight changes of K+ tissue concentrations in the whole plant. In the long-term experiment, K+ tissue concentrations were substantially decreased, particularly in roots. In response to time and increasing levels of salinity, Na+ and Cl- ions concentrations reached toxic levels in leaves. Thus, cashew plants already from the 4th day of salinity stress exhibited earlier symptoms of ionic toxicity, and therefore they were not able to regulate metabolic and physiological functions under these harmful conditions.

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