fractions (Gholami, 2011; Morovat, 2011). Mycorrhizal symbiosis increased absolute amounts of Zn carbonate and organic forms and decreased extractability of Mn oxides and residual forms of Zn in the rhizosphere of maize (Gholami, 2011). Mycorrhizal symbiosis decreased P chemical forms bound to iron (Fe-P), but increased calcium phosphate hydroxyapatite in the rhizosphere of sunflower (Morovat, 2011). Maize is an effective host of AM in infertile and drought conditions (Christopher and Tony, 2008) and its root system consists of different root types that are formed during different stages of root development (Hochholdinger, 2009). There is no information in the literature on the characterization of K forms and minerals weathering affected by AMF, PGPR and their co-application treatments under maize cultivation. Therefore, the objective of this study was to evaluate the effects of Glomus intraradices, Pseudomonas fluorescens (as a PGPR bacterium) and soil drying on different forms of K and changes of clay minerals induced by the treatments in a calcareous soil under maize cultivation.
To that end, we expanded the ﬁndings of Ippolito et al. (2012b) who suggested that a low pyrolysis temperature, low pH biochar could improve environmental quality by reducing nutrient losses in calcareous soils. Here, in a proof-of-concept study we designed a low pH, steam activated biochar for potentially improving the soil physicochemical status of an eroded calcareous soil in south-central Idaho. Topsoil in many locations of the area have been eroded due to 100 years of ﬂood irrigation, leaving the cal- careous subsoil (pH 7.8–8.2; USDA-NRCS, 2001) exposed. Subsoil organic C content has been measured as about half of the soil sur- face (0.45% vs 0.94% organic C; Robbins et al., 2000) in this area of south-central Idaho. Lower organic matter content in eroded soils has been shown to signiﬁcantly reduce available soil water content as compared to non-eroded soils (e.g., Frye et al., 1982). Thus, our hypotheses were that increasing application rates of an acidic pH biochar to an eroded calcareous soil will (1) improve the soil water status by reducing evaporative losses, (2) lower soil pH and (3) increase plant nutrient availability. In theory, an acidic pH designed biochar could neutralize excess soil OH groups and thus
The effects of biochar application to calcareous soils are not well documented. In a laboratory incubation study, a hardwood-based, fast pyrolysis biochar was applied (0, 1, 2, and 10% by weight) to a calcareous soil. Changes in soil chemistry, water content, microbial respiration, and microbial community structure were monitored over a 12-mo period. Increasing the biochar application rate increased the water-holding capacity of the soil–biochar blend, a trait that could be beneficial under water-limited situations. Biochar application also caused an increase in plant-available Fe and Mn, soil C content, soil respiration rates, and bacterial populations and a decrease in soil NO 3 –N concentration. Biochar rates of 2 and 10% altered the relative proportions of bacterial and fungal fatty acids and shifted the microbial community toward greater relative amounts of bacteria and fewer fungi. The ratio of fatty acid 19:0 cy to its precursor, 18:1w7c, was higher in the 10% biochar rate soil than in all other soils, potentially indicating an environmental stress response. The 10% application rate of this particular biochar was extreme, causing the greatest change in microbial community structure, a physiological response to stress in Gram-negative bacteria, and a drastic reduction in soil NO 3 –N (85–97% reduction compared with the control), all of which were sustained over time.
A collapsible calcareous soil may withstand relatively large applied vertical stress with small settlement while at a low water content, but this soil will exhibit settlement (that could be large) after wetting with no additional increase in stress. Large applied vertical stress is not necessary for collapse. The oedometer test procedure is performed by taking the weight of soil is equal to the volume of cylindrical specimen ring .The oedometer specimen ring diameter 60mm and height 20mm. The specimen ring cleaned and weighed it empty. The soil is compacted in specimen ring to the required OMC and the flush off the sample smoothly with the top and the bottom of the ring. The specimen ring cleaned from outside and weighed with the specimen. The porous stones are saturated for 24 hours. The specimen is assembled as the porous stone are arranged at the top and bottom of the specimen providing filter papers in between. The pressure pad is placed centrally on the top porous stone. The assembly is placed in the loading frame and adjusted to centre such that the load is applied axially. The dial gauge is positioned to measure the vertical compression of the specimen. The first load of intensity 0.2 kg/cm 2 and the initial dial gauge reading is noted. The dial gauge reading is recorded at various time intervals. The test is repeated for successive load increments of 0.2, 0.8, 1.8, 3.0, 6.4 and 8 kg/cm 2 . The specimen is saturated at different loads for example: sample 1 should be saturated at 0.2kg/cm 2 , sample 2 should be at 0.8kg/cm 2 , sample 3 should be at 1.8kg/cm 2 , sample 4 should be at 3.0kg/cm 2 , sample 5 should be at 6.4kg/cm 2 and sample 6 should be at 8kg/cm 2 . The collapse point and the load of intensity of the sample noted. The sample is mixed with 1% of cement and the specimen is saturated at the point of load intensity collapsed. Thus the cement admixture controls the collapse of the soil specimen.
On both the low- and high-P soils, tissue Zn concentrations increased with increasing manure applications up to 100 mg P kg j1 , whereas tissue Zn concentrations either remained level or decreased slightly with increasing compost and MAP appli- cations. Several studies have reported increased tissue Zn con- centrations and Zn uptake by plants when organic amendments were used as a fertilizer source (Pagliari et al., 2009; Wong et al., 1999; Raj and Gupta, 1986). The enhanced uptake of Zn may have been due to a combination of factors. The manure con- tained signiﬁcantly more Zn (0.21 mg kg j1 ) than either the compost (0.09 mg kg j1 ) or MAP (no Zn added with MAP), which could have had a positive effect on plant uptake. In ad- dition, the manure treatment applied a greater amount of C than the MAP and compost treatments, which would produce greater amounts of both humic and fulvic acids during decomposition. Stevenson and Ardkani (1972) reported that these acids act as chelating agents and are capable of complexing Zn, thereby rendering it more available to plants. Garcı´a-Mina et al. (2004) TABLE 5. Dry Matter Production and Corn Tissue Concentrations With Increasing P Application Rate of Dairy Manure, Dairy Compost, and MAP on a Calcareous Soil From Southern Idaho With High Soil Test P
Contamination of soils by heavy metals is one of the most important environmental issues throughout the world, and the cleanup of these soils is a difficult task. One possible decontamination technique is ex-situ soil washing using a variety of agents such as acids, surfactants, electrolytes and chelating agents. Chelating agents are the most popular extraction reagents for soil washing. Since chelating agents such as ethylene-diaminetetraacetic acid (EDTA), ethylenediamine- N,N’-disuccinic acid (EDDS), diethylene triaminepentaacetic acid (DTPA) and nitrilotriacetic acid (NTA) form stable complexes with most heavy metals over a broad pH range, they have proven to be the most efficient at heavy metal removal. Unfortunately, they also have disadvantages such as persisting in the environment (particularly EDTA), adversely affecting health (particularly NTA) and being expensive (particularly EDDS), which have excluded their
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with the forward speed of tractor, which makes a more number of cultivated circles per unit area and increases the degree of the fragmentation of soil clods. The evaluation process for circular chisel plow was performed by carrying out two field experiments in Maryut Research Station in Alexandria governorate through calcareous sandy clay loam soil as follows: The first field experiment conducted to select the optimum rotation velocity for the circular chisel plow so that three rotation velocity were tested (30, 60 and 90 r.p.m) the results showed that velocity of 90 r.p.m achieved the pest results compared with other velocities 30 and 60 r.p.m, where obtained the highest increasing percentage in actual field capacity, field efficiency, soil porosity and fuel consumption. But achieved the highest decreasing percentage in soil bulk density, soil penetration resistance, soil mean weight diameter, soil surface roughness, pulling force and the tillage cost.
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This study was conducted to evaluate the effect of sesbania in increasing efficiency of reclamation of chemically amended salt affected soil. Phosphogypsum and elemental Sulfur were the two amendments used for reclamation of saline alkali soil at Al-Tuwaitha salinity research station 20km south east of Baghdad. Sesbania- barley crop rotation was implemented for two consecutive years. Sesbania (Sesbania aculeate L.), as a legume crop, was utilized as a source for organic carbon. It was harvested at the flowering stage. The harvested biomass was air-dried, chopped and thoroughly incorporated with the upper 40 cm of soils, and incubated for 8 weeks at moisture level equivalent to 1/3 bar suction. The plots were then cropped to barley (Hordium vulgare L.). Sesbania incorporation in soil was repeated for two consecutive seasons. Organic carbon was increased by 25.4% and 13.5% in soils amended with phosphogypsum and elemental sulfur respectively. Available nutrients N, P, and K, under phosphogypsum, were up to 639, 52.4 286 mg.kg -1 soil
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X-ray absorption spectroscopic (XAS) and X-ray dif- fraction (XRD) measurements were conducted at the Canadian Light Source (CLS) synchrotron in Saskatoon, SK., Canada. The Canadian Light Source operates a stor- age ring at 2.9 GeV and between 150 and 250 mA. All P K-edge XANES measurements were collected at the SXRMB beamline (06B1-1) utilizing an InSb (111) mono- chromator in fluorescence mode under vacuum condi- tions with a 4-element Vortex detector. Concentrated reference standards were diluted with boron nitride to ~ 1 wt. % total P to minimize self-absorption effects. Soil samples were dried, ground to a uniform particle with mortar and pestle, and applied to the beamline sample holder as a thin layer on carbon tape. The beam spot size was 1 × 3 mm giving a bulk representation of the P spe- ciation of each soil sample. See supplemental information for the preparation conditions for adsorption standards. The Ca and Mg phosphate mineral reference standards were synthesized by Hilger . All other compounds were purchased and were reagent grade or better.
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Nickel is a heavy metal distributed ubiquitously in nature. It accumulates in soil as a result of human activities, including mining and industries development. It may be poisonous to plants, humans, animals and microorganisms. The present study was implemented as a factorial experiment with a Randomized Complete Block Design (RCBD), of three replications in calcareous soils of Karaj and in greenhouse conditions for detection of the effect of nickel polluted soil, Ni125, Ni250, Ni500, Ni1000 (mgkg¯ 1 ) in comparison with control (Ni0). The inoculant of resistant native bacteria to
Biochar co-application with manure has not been extensively studied, despite that manure is already commonly applied to agri- culture soils (6.5 million hectares in the US; USDA, 2006) where there is interest in also applying biochar. Thus, a need exists to identify the effects of biochar and manure soil co-applications. To this end, organic C sources such as manures, when added to soils, often leads to a positive priming effect due to increased microbial activity (Sorensen, 1974) associated with supplied energy sources and nutrient release. Furthermore, it is plausible that various rates of biochar can cause either a positive or negative priming effect of added labile organic C sources (e.g., Keith et al., 2011; Liang et al., 2010; Hamer et al., 2004). Based on our previous observations where biochar was applied alone (Ippolito et al., 2014), we hypoth- esized that relatively low biochar application rates (e.g., 1% and 2% by wt.) would cause no effect, while an excessive biochar applica- tion (e.g., 10% by wt.) would cause a negative priming effect even in the presence of manure. Thus, a 12 month laboratory incubation study was conducted with the objective to assess the effect of bio- char–manure co-application on soil water content, nutrient con- centrations, microbial respiration, bacterial abundance, and microbial community structure in relation to priming effect.
Several alternative soil-test P methods are available. Water soluble P correlates well with P plant uptake    ; however, water extractable P may be inadequate to accurately reflect P solubility over time. Anion exchange and Fe-oxide  or Fe-Al oxide (FeAlO)   impregnated strips are nondestructive methods and simulate plant-root extraction of dissolved P from soil solution . Vadas and White  in- dicate that the amount of P absorbed in an anion exchange resin  is equivalent to labile or plant-available P. Lin et al .  found that anion-exchange resin and Fe-oxide strips correlated well with P plant uptake in wheat seedlings. Dils and Heathwaite  indicate that Fe oxide-impregnated strips are accurate for the determination of bio- available P. Van der Zee et al .  found that FeAlO strips could be used during rou- tine soil analysis to determine available P but that Mehlich and Olsen were not as relia- ble. Sharpley  found that the amount of P extracted using FeAlO strips and the Olsen extractant was correlated in calcareous soil but not acidic soil, and the opposite was true for soils extracted with M3. Sharpley  also found that FeAlO-extractable P was closely correlated to resin-extractable P, which is accepted as plant-available P, for all soils studied and concluded that FeAlO-P is highly correlated with plant-available P in a wide range of soils. Thus, FeAlO is the commonly accepted method for determination of plant available P in a research setting  .
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To investigate the effect of low soil pH caused by fertilization on soil available zinc in calcareous soil, this study was conducted based on a long-term experiment consisting of: (a) no fertilization (CT); (b) mineral fertilizer applica- tion coupled with 7500 kg/ha of wheat straw (WS-NPK); (c) mineral fertilizer application coupled with 3750 kg/ha of wheat straw (1/2WS-NPK); (d) mineral fertilizer application alone (NPK). Long-term fertilization results in a sig- nificant increase in soil DTPA-extractable zinc. However, the increased soil DTPA-extractable zinc is unavailable to crops and mainly confined to 0.25 mm > and 0.25 mm to 1 mm aggregates. Compared to CT, soil DTPA-extractable zinc under fertilization is more than 9.67% and 122.36% higher in 0.25 mm > and 0.25 mm to 1 mm aggregates, respectively. Furthermore, plant-available zinc in the 0–15 cm soil layer and wheat grain zinc are both significantly positive related to soil DTPA-extractable zinc in > 2 mm aggregates. Therefore, plant-available zinc in the 0–15 cm layer is closely associated with DTPA-extractable zinc in > 2 mm aggregates, and the low soil pH caused by long- term fertilization could not enhance plant-available zinc in the surface soil layer nor elevate wheat grain zinc con- centration because of the occlusive effect of soil aggregates.
A pot experiment with factorial design involving normal and calcareous soil and five genotypes with differential response to iron deficiency chlorosis (IDC) viz., ICGV 86031 and A30b (Resistant), TG 26 (moderately Resistant), TAG 24 and TMV 2 (susceptibe) were tested for various traits like VCR and SCMR, chlorophyll a, b and total chlorophyll, active iron content, specific activity of peroxidase at five different stages and also know the effect of IDC on yield and yield components. Iron deficiency chlorosis resistant genotypes recorded significantly lower VCR, higher SCMR, higher active iron content, chlorophyll a, b and total chlorophyll and peroxidase activity in leaf across all stages compared to susceptible genotypes. A strong and positive correlation was observed between peroxidase activity and leaf iron content. Yield and yield components were significantly reduced in susceptible genotypes compared to resistant genotypes.
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Following the DTPA-TEA extraction the desorbed- and adsorbed- Zn were evaluated at the end of sorption experiments (18). A 20-mL DTPA-TEA solution was added to each centrifuge tube containing Zn-sorbed samples. The tubes were then shaken for 2 h on the reciprocating shaker, the samples were centrifuged, and the supernatant solutions were filtered and analyzed for Zn content by ICP OES (inductively coupled plasma–optical emission spectroscopy). The amount of DTPA extracted-Zn was corrected for Zn concentration in the interstitial solution based on preweighed tubes, soil weight, and solution weight. The corrected DTPA extractable Zn was designated as the labile pool, whereas Zn unextractable by DTPA was considered as the nonlabile Zn.
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Zinc functions as an activator of certain enzymes which concerns protein metholism (Kumar, 2003). In recent researches Zn deficiency in soils has been reported in Northern region and its application was observed useful (Kumar, 2003). With this view experiments were conducted for growth and development of spike and florets. Nitrogen is the one of the most important nutrients producing growth and yield responses in gladiolus. The quantity of Phosphorus required by gladiolus is about one-tenth of the nitrogen expressed in terms of foliar analysis. Foliar application with NPK in addition to soil application significantly affects vegetative growth and floral Characters (Ray et al., 1995). Nutrition plays an important role in the overall growth performance of the gladiolus crop. Plant analysis has been found to be a useful diagnostic tool to work out the amount of fertilizers to be applied (Rajhansa et al. 2010).
ABSTRACT: Sissoo (Dalbergia sissoo, Roxb.) is a nitrogen fixing leguminous tree species with natural habitat in the lowland region of Nepal called Terai up to an altitude of 1,000 m. For the last few years, this economically important tree species has been dying rapidly in the plantation forests. On the contrary, its status in the natural forest in riverine areas has been unknown yet. The paper compares the nutrient status of natural and healthy sissoo forest with declining plantation sissoo one. It is evident from this study that both stands do not differ very much with respect to their soil and plant nutrients. Therefore it was concluded that the waterlogging of soil was the main factor responsible for the decline of plantation sissoo forest.
directly requires either bender element test,resonant column test, or seismic cone penetration test. Test used to find shear elastic modulus and damping characteristics of soils. A soil sample is placed in a cylinder where the bottom of the container is fixed and the top is able to disturb the sample through longitudinal or torsional vibrations, where the soils response is then measured. An electromagnetic drive system is used to generate these vibrations with varying frequencies. This test is used to find the same desired data as an RC test but uses a different method. A CPT probe is placed in to the soil at a desired depth to generate a seismic wave by hitting the seismic plate using a sledgehammer. The shear waves will pass through the soil and stimulate the accelerometer on the CPT probe which then displays the data. Bender element involves using different kinds of tests through loading. The types of loading involved are hoop tension loading, longitudinal tension loading, and maximum shear loading. These results are then translated to generate the maximum small strain stiffness of a soil.
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Observation of soil profile. Strongly acidic soils often have poor incorporation of the organic surface layer with the underlying mineral layer. The mineral horizons are distinctively layered in many cases, with a pale eluvial (E) horizon beneath the organic surface; this E is underlain by a darker B horizon in a classic podzol horizon sequence. This is a very rough gauge of acidity as there is no correlation between thickness of the E and soil pH. E horizons a few feet thick in Florida usually have pH just above 5 (merely "strongly acid") while E horizons a few inches thick in New England are "extremely acid" with pH readings of 4.5 or below. In the southern Blue Ridge Mountains there are "ultra acid" soils, pH below 3.5, which have no E horizon. Observation of predominant flora. Calcifuge plants (those that prefer an acidic soil) include Erica, Rhododendron and nearly all other Ericaceae species, many Betula (birch), Digitalis (foxgloves), gorse, and Scots Pine. Calcicole (lime loving) plants include Fraxinus (Ash), Honeysuckle (Lonicera), Buddleia, Cornus spp (dogwoods), Lilac(Syringa) and Clematis spp. Observation of symptoms that might indicate acidic or alkaline conditions, such as occurrence of the plant diseases mentioned above or salinisation of alkaline soils. The house hydrangea (Hydrangea macrophylla) produces pink flowers at pH values of 6.8 or higher, and blue flowers at pH 6.0 or below. Use of an inexpensive pH testing kit based on barium sulfate in powdered form, where in a small sample of soil is mixed with water which changes colour according to the acidity/alkalinity.Use of litmus paper. A small sample of soil is mixed with distilled water, into which a strip of litmus paper is inserted. If the soil is acidic the paper turns red, if alkaline, blue.Use of a commercially available electronic pH meter, in which a rod is inserted into moistened soil and measures the concentration of hydrogen ions.
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Soil texture is an important soil property that relates soil physical properties to chemical reactions, structure of the plant community, ecological potential and management of resources. It also, greatly influences soil hydraulic properties, water movement and retention through the profile . Soil texture is used to describe the relative proportion of different grain sizes of mineral particles in a soil. Particles are grouped according to their size into what are called soil separates. These separates are typically named clay, silt, and sand  . Soil texture classification is based on the fractions of soil separates present in a soil. The USDA soil texture triangle is a diagram often used to figure out a soil textural class of the soil. Soil separates are specific ranges of particle sizes. In the United States, the smallest particles are clay particles and are classified by the USDA as having diameters of less than 0.002 mm. The next smallest particles are silt particles and have diameters between 0.002 mm and 0.05 mm. The largest particles are sand particles and are larger than 0.05 mm in diameter. Furthermore, large sand particles can be described as very coarse to coarse, intermediate as medium, and the smaller as fine and very fine . Other countries have their own particle size classifications. Soils of the arid and semi-arid are subjected to more physical weathering by insolation or freezing and sowing and less chemical weathering due to limited amount of water that causes chemical weathering. Therefore, these soils are likely to be related in their properties to the local rocks(parent materials) particularly at the early stages of soil formation in residual soils (non- transported soils). They are, as well, usually calcareous if they have developed (or still are developing) on calcareous parent material (e.g. limestone)