The chemical composition of the soil in a factorial experiment with citrus. I. Exchangeable metal cations and their effect on the cation content of citrus

1960 ◽  
Vol 11 (2) ◽  
pp. 208 ◽  
Author(s):  
H Groenewegen ◽  
D Bouma
Keyword(s):  
Field Experiment ◽  
Cover Crops ◽  
Laboratory Experiments ◽  
Appreciable Effect ◽  
Exchangeable Calcium ◽  
Cation Content ◽  
Two Factors ◽  
Exchangeable Magnesium ◽  
Citrus Leaves ◽  
Exchangeable Form

In a factorial field experiment with citrus it was found that application of ammonium sulphate caused a greater proportionate reduction in the exchangeable calcium of the soil than in the exchangeable potassium. Short-term laboratory experiments with virgin soil, to which ammonium was added, suggested that at least two factors were involved. If solutions of high electrolyte concentrations were added, a greater release of exchangeable calcium than of potassium occurred, relative to the amounts of these ions originally present in exchangeable form. Secondly, a release of potassium from non-exchangeable to exchangeable form also occurred. In the 0–4 in. layer of the field experiment, exchangeable magnesium was reduced in the same proportion as exchangeable calcium. In the 4–12 in. layer, exchangeable magnesium was reduced relatively more than calcium. The same trend was apparent in laboratory experiments. In one experiment, for example, the original amount of magnesium was reduced by 76 per cent., and calcium by 66 per cent. A comparison between cultural treatments showed that the potassium content of the soil from a bare surface treatment was much lower than that from treatments with cover crops. The changes in soil composition had no appreciable effect on the cation content of citrus leaves, and some reasons for this are discussed.

scholarly journals Inhibition or Facilitation? Contrasted Inter-Specific Interactions in Sphagnum under Laboratory and Field Conditions

Plants ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 1554
Author(s):  
Chao Liu ◽  
Zhao-Jun Bu ◽  
Azim Mallik ◽  
Yong-Da Chen ◽  
Xue-Feng Hu ◽  
...  
Keyword(s):  
Field Experiment ◽  
Species Interactions ◽  
Laboratory Experiments ◽  
Resource Competition ◽  
Specific Interactions ◽  
Interaction Type ◽  
Negative Effects ◽  
Experiment Data ◽  
The Stability ◽  
Positive Effect

In a natural environment, plants usually interact with their neighbors predominantly through resource competition, allelopathy, and facilitation. The occurrence of the positive effect of allelopathy between peat mosses (Sphagnum L.) is rare, but it has been observed in a field experiment. It is unclear whether the stability of the water table level in peat induces positive vs. negative effects of allelopathy and how that is related to phenolic allelochemical production in Sphagnum. Based on field experiment data, we established a laboratory experiment with three neighborhood treatments to measure inter-specific interactions between Sphagnum angustifolium (Russ.) C. Jens and Sphagnum magellanicum Brid. We found that the two species were strongly suppressed by the allelopathic effects of each other. S. magellanicum allelopathically facilitated S. angustifolium in the field but inhibited it in the laboratory, and relative allelopathy intensity appeared to be positively related to the content of released phenolics. We conclude that the interaction type and intensity between plants are dependent on environmental conditions. The concentration of phenolics alone may not explain the type and relative intensity of allelopathy. Carefully designed combined field and laboratory experiments are necessary to reveal the mechanism of species interactions in natural communities.

Measuring Calcium and Magnesium Contents on the Sludge Composting with Different Treatments

2012 ◽  
Vol 518-523 ◽  
pp. 3150-3154
Author(s):  
Jian She Yang ◽  
Ying Ding
Keyword(s):  
Ammonium Acetate ◽  
Single Treatment ◽  
Edta Complex ◽  
Exchangeable Calcium ◽  
Exchangeable Ca ◽  
Exchangeable Magnesium ◽  
Calcium And Magnesium ◽  
Sludge Composting

Abstract: Calcium and magnesium contents of sludge composting are measured by using the method of ammonium acetate-EDTA complex metric titration here, through Fermentation accelerant and increased nutrient agent treatments. The results showed as following: 1, exchangeable Ca and Mg contents of sludge single treatment increased more 6.83% and5.12% at the end of composting, than at the beginning of composting. 2, Fermentation accelerant added in sludge from 8% to 40%,，the exchangeable calcium and magnesium are more 4.38% ~ 10.58% and 6.77% ~ 13.78% at the end of composting than at the beginning of composting. The exchangeable Ca increased 19.51% ~ 104.83%, but 6.05% of a decreased trend for exchangeable magnesium, Compared with the sludge single compost. 3, as increasing the amount of nutrient agent from 30% to 50%, the exchangeable calcium and magnesium are more 3.88%~7.75%and 5.24%~9.18% at the end of composting than at the beginning of composting. The exchangeable Ca increased in 11.35%~41.13%,but 49%~-3.96% of a decreased trend for exchangeable magnesium, Compared with the sludge single compost. 4, under the condition added 24% of the Fermentation accelerant agent to the sludge, as the Increased nutrient agents from 8% to 32%, the exchangeable calcium and magnesium measured are increased 2.63%~5.54%and3.6%~4.19% at the end of composting , compared with The beginning of composting. The exchangeable Ca increased in 52.34%~112.04%,but -10.15%~-15.59% for exchangeable magnesium, Compared with the sludge single compost.

scholarly journals Effect of a dragonfly (<i>Bradinopyga strachani</i> Kirby, 1900) on the density of mosquito larvae in a field experiment using mesocosms

Web Ecology ◽  
2018 ◽  
Vol 18 (1) ◽  
pp. 81-89 ◽  
Author(s):  
Daniel Acquah-Lamptey ◽  
Roland Brandl
Keyword(s):  
Field Experiment ◽  
Laboratory Experiments ◽  
Water Bodies ◽  
Mosquito Population ◽  
Mosquito Larvae ◽  
Promising Strategy

Abstract. Laboratory experiments with food-deprived larvae of odonates suggested that these predators may have the potential to control mosquito populations. However, it remains unclear whether larvae of odonates co-occur with mosquito larvae in the field and whether larvae of odonates reduce the density of mosquito larvae in the field. We exposed 35 water-filled concrete containers in the field in shady and sunny conditions. Some of these containers were partially covered (for simplicity called closed containers, allowing only mosquitoes to lay eggs), whereas others remained open. The density of mosquito larvae was higher in shaded containers and in closed containers. The multivoltine odonate Bradinopyga strachani colonized open containers and the occurrence of these predators resulted in a clear reduction of the mosquito population. Our results indicate that increasing the colonization of water bodies by Bradinopyga strachani is a promising strategy for controlling populations of mosquitoes.

HALOMORPHISM OF SOME CLAY SOILS IN MANITOBA

1958 ◽  
Vol 38 (2) ◽  
pp. 105-115
Author(s):  
W. A. Ehrlich ◽  
R. E. Smith
Keyword(s):  
Exchangeable Cations ◽  
Water Soluble ◽  
Clay Soils ◽  
Exchangeable Sodium ◽  
Soluble Salts ◽  
Exchangeable Calcium ◽  
Causative Agents ◽  
Exchangeable Magnesium ◽  
Soluble Calcium

The analysis of the principal horizons of 11 halomorphic profiles was undertaken in an attempt to ascertain, chiefly, the kind and quantity of soluble salts and exchangeable cations assumed to be the main causative agents in the formation of solonetzic soils in Manitoba. The results showed that water-soluble sodium was equal to or greater in quantity than water-soluble calcium or water-soluble magnesium; that exchangeable calcium followed closely by exchangeable magnesium dominated the exchange complexes; and that exchangeable sodium in excess of 15 per cent of the exchangeable cations was found only in some horizons of the Solonchak, Solonetz and Solodized-Solonetz soils in the Chesterfield Association.

The uptake of magnesium under exhaustive cropping

1963 ◽  
Vol 61 (3) ◽  
pp. 421-425 ◽  
Author(s):  
B. C. Salmon ◽  
P. W. Arnold
Keyword(s):  
White Clover ◽  
Wetting And Drying ◽  
Rye Grass ◽  
Exchangeable Magnesium ◽  
Exchangeable Form

1. A range of soils were cropped exhaustively by perennial rye-grass for up to eleven months in the glasshouse; some were also cropped with Dutch white clover.2. At least 100 lb./acre of magnesium was taken up from most soils, and some soils supplied more than 200 lb./acre. The amounts of magnesium taken up decreased with successive harvests, suggesting that the available magnesium was progressively depleted. Although the ‘exhaustion’ magnesium (Mg taken up by crops+residual exchangeable magnesium) was greater than the initial exchangeable magnesium, these two measurements were closely correlated (r = 0·99). If non-exchangeable magnesium was released during cropping, the releases were proportional to the initial exchangeable magnesium contents. However, the exchangeable magnesium measurements may have extracted only a proportion of the magnesium available naturally.3. Any releases of magnesium were small compared with the amounts available from the outset, and the crops obtained magnesium mainly from the exchangeable form. Rye-grass and white clover gave similar results.4. The exchangeable magnesium in some exhausted soils was increased by wetting and drying. This effect may occur in the field, where the magnesium lost in cropping could be replenished by only small releases of non-exchangeable magnesium.

scholarly journals Announcements of Support and Public Good Provision

2017 ◽  
Vol 107 (12) ◽  
pp. 3760-3787 ◽  
Author(s):  
Judd B. Kessler
Keyword(s):  
Public Goods ◽  
Field Experiment ◽  
Prosocial Behavior ◽  
Public Good ◽  
Large Scale ◽  
Laboratory Experiments ◽  
Public Good Provision ◽  
Scale Field ◽  
Large Scale Field ◽  
Good Provision

Providing information about contributions to public goods is known to generate further contributions. However, it is often impossible to provide verifiable information on contributions. Through a large-scale field experiment and a series of laboratory experiments, I show that nonbinding announcements of support for a public good encourage others to contribute, even when actual contributions might not or cannot be made. Providing a way to easily announce support for a charity increases donations by $865 per workplace fundraising campaign (or 16 percent of average giving). I discuss implications for understanding prosocial behavior and for organizations aiming to increase contributions to public goods. (JEL C93, D64, D83, H41, L31)

Nitrous oxide production from granular nitrogen fertilizers applied to a silt loam soil

2003 ◽  
Vol 83 (5) ◽  
pp. 521-532 ◽  
Author(s):  
M. Tenuta and E. G. Beauchamp
Keyword(s):  
Nitrous Oxide ◽  
Field Experiment ◽  
Laboratory Experiment ◽  
Laboratory Experiments ◽  
N Fertilizer ◽  
Nitrogen Fertilizers ◽  
Silt Loam ◽  
N Fertilizers ◽  
Oxide Production ◽  
Nitrous Oxide Production

One field and two laboratory experiments were conducted to determine the relative magnitude and pattern of N2O production from several granular N fertilizers including urea, ammonium nitrate, calcium nitrate, ammonium sulfate and, in a laboratory experiment, monoammonium and diammonium phosphates. Several parameters, in particular soil water content, were studied for their roles in N2O production with these fertilizers. The field experiment was conducted at the Elora Research Station (20 km north of Guelph) on Conestoga silt loam during July on a site previously cropped to barley. Three methods were employed to assess N2O production following N fertilizer treatments in the field experiment, viz., soil cover, soil core and profile distribution. The data with each method revealed that incorporated urea produced the greatest quantity of N2O especially in the first few days following application. Shortly after urea application and incorporation (10 cm), N2O was detected at a depth of 50 cm indicating gas produced in the tilled layer was transported to lower depths. Data obtained with the intact core method showed that nitrification preceeded denitrification as the source of N2O produced during a wetting event as air-filled porosity decreased from 65% to less than 50%, respectively. The laboratory experiments showed that under aerobic conditions N2O production was generally greater with urea than the other N fertilizers. The greater production of N2O with urea was associated with N2O-accumulation. In the second laboratory experiment, saturating the soil following 14 d of aerobic incubation showed enhanced N2O production with ammonium phosphate fertilizers. Our findings indicate refinement of methods to predict N2O emissions based on N fertilizer source use and moisture can reduce uncertainties in national estimates of N2O emissions from agricultural soils. Key words: Nitrous oxide production, nitrogen fertilizers, soil atmosphere profiles, nitrification, denitrification, air-filled porosity

Exchangeable calcium, magnesium and sodium and the dispersion of illites in water. II. Dispersion of illites in water

Soil Research ◽  
1977 ◽  
Vol 15 (3) ◽  
pp. 255 ◽  
Author(s):  
WW Emerson ◽  
CL Chi
Keyword(s):  
Water Content ◽  
Particle Aggregation ◽  
The Other ◽  
Clay Particles ◽  
Exchangeable Calcium ◽  
Soil Clays ◽  
Exchangeable Magnesium ◽  
Calcium Magnesium ◽  
Calcium And Magnesium ◽  
Dominant Cation

Samples of illites, two extracted from soils, one from a shale, prepared with a range of exchangeable calcium, magnesium, sodium were immersed dry into water. The extent of dispersion with time was estimated visually and also deduced from the O.D. of the suspensions derived from the dispersed clay. The dispersion of wet calcium and magnesium soil illites sheared at a given water content and then immersed in water was also assessed visually. The dispersion of all three illites was enhanced when magnesium was the dominant cation rather than calcium. For the soil clays a lower ESP was required to initiate dispersion of the dry clay when immersed in water. Both calcium and magnesium forms of the shale illite dispersed partially over a period of several days when immersed dry into water, the magnesium to a greater extent than calcium. The magnesium form of the coarser of the two soil illites also dispersed slowly. By comparing the calcium-magnesium and calcium-sodium forms of the last clay, it was deduced that about 10 times the equivalent concentration of exchangeable magnesium as sodium was needed to cause the same degree of dispersion. For the other soil illite the water content for dispersion of the wet, sheared magnesium clay was found to be less than for the calcium clay. The O.D. of suspensions of the clays was found to decrease with increasing ESP and when magnesium was the dominant cation rather than calcium. This is explained in terms of particle aggregation. The ease of dispersion of the illites was correlated with particle size. Possible reasons for this, and the effect of magnesium, as opposed to calcium, on the forces between the clay particles are discussed.

Alternatives to Glyphosate in conservation agriculture: effects on carbon sequestration in a field experiment in northern Italy

2020 ◽  
Author(s):  
alessia perego ◽  
marco acutis ◽  
calogero schillaci
Keyword(s):  
Carbon Sequestration ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Field Experiment ◽  
Biomass Production ◽  
Cover Crops ◽  
Management Practices ◽  
Block Design ◽  
Northern Italy ◽  
Cash Crop

&lt;p&gt;Conservative Agriculture (CA) practices are recognized to enhance soil organic carbon stock and in turn to mitigate the effect of climate change. One of the CA principles is to integrate cover crops (CC) into the cropping systems. The termination of CC before the cash crop sowing and the weeds control are the most critical aspects to manage in the CA. The technique currently adopted by farmers for the termination of CC implies the use of Glyphosate. However, the European Commission is currently discussing the possibility of banning the use of this herbicide due to the negative effects on human health and the agro-environment. The disk harrow (DH) or the roller-crimper (RC) can be adopted in CA as an alternative to the use of Glyphosate for the devitalization of CC, their incorporation into the soil (in the case of the disk harrow), and the reduction of weed pressure on the subsequent cash crop.&lt;/p&gt;&lt;p&gt;From November 2017 to October 2019, soil organic carbon (SOC, g kg&lt;sup&gt;-1&lt;/sup&gt;) and crop biomass production were observed in a 2-year field experiment located in Lodi (northern Italy), in which minimum tillage (MT) has been applied for the last 5 years. The soil was loamy and SOC was 16.2 g kg&lt;sup&gt;-1&lt;/sup&gt; at the beginning of the experiment. The winter CC was barley (from November to May) and the cash crop was soybean (from June to October). The experiment consisted in three treatments replied for two consecutive years in a randomized block design: Glyphosate spray + DH + sowing + hoeing (MT-GLY); DH + sowing + hoeing (MT-ORG); RC + sod seeding (NT-ORG).&lt;/p&gt;&lt;p&gt;At the end of 2019, SOC resulted in a higher increase in MT-GLY (+15%) and in MT-ORG (+14%) than in NT-ORG (+6%; p&lt;0.01). This was due to the fact that CC litter in NT-ORG was not in direct contact with soil particles and the process of immobilization was lower than in the other treatments.&lt;/p&gt;&lt;p&gt;Moreover, the increase in SOC resulted positively correlated to the CC biomass (2018+2019), which was significantly lower in NT-ORG. In particular, no differences of soybean and CC between the three treatments were observed at the end of 2018, but MT-GLY resulted in significantly higher CC and soybean biomass at the end of the second year (+32%, p&lt;0.01). MT-GLY allows to stock more carbon via photosynthesis that in turn results in higher SOC content.&lt;/p&gt;&lt;p&gt;However, if we consider the tractor fuel consumption (for Glyphosate spray, DH, RC, hoeing), along with the biomass production, the carbon sequestration did not vary between the three treatments.&lt;/p&gt;&lt;p&gt;Further studies are needed for the definition of optimized field management practices to reduce the passage of machinery while increasing crop production and SOC.&lt;/p&gt;

scholarly journals Pertumbuhan dan Hasil Karabenguk (Mucuna pruriens) sebagai Tanaman Penutup Tanah pada Dua Musim Berbeda

2018 ◽  
Vol 19 (1) ◽  
pp. 18
Author(s):  
Supriyono Supriyono ◽  
Tohari Tohari ◽  
Abdul Syukur ◽  
Didik Indradewa
Keyword(s):  
Cover Crops ◽  
Cover Crop ◽  
Rainy Season ◽  
Organic Fertilizer ◽  
Dry Season ◽  
Growth And Yield ◽  
Soil Tillage ◽  
Mucuna Pruriens ◽  
Velvet Bean ◽  
Two Factors

<p>This research does to known: 1) the effect of season, 2) the effect of cover crop kind and organic fertilizer, and 3) the interaction of two factors on growth and yield of velvet bean as cover crops. This research was conducted in Tancep, Ngawen, Gunungkidul at 170 m usl, litosol, 5-17 cm level of soil tillage, 9-10<sup>o</sup> elevation level, was started at December 2002 and finished at August 2003.</p><p>This research design was factorial-RCBD, 1<sup>st</sup> factor was planting season on 2 level, rainy and dry seasons, 2<sup>nd</sup> factor was cover crop kind on 6 levels, rase and putih gunungkidul velvet bean, Cm and Cp as conventional cover crops, rase and putih gunungkidul with organic fertilizer velvet bean. Per planting hole with 1 plant for velvet bean and 10 plant for coventional cover crop.</p><p>The result of this research were: 1<sup>st</sup>, velvet bean growth on rainy season very high than dry season, 2<sup>nd</sup> vegetative growth rate on velvet bean higher than conventional cover crop, 3<sup>rd</sup> without fertilizer, velvet bean have some growth and yield comparing by fertilizer velvet bean and 4<sup>th</sup> some yield variable, dry season was indicated better than rainy season.</p>

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