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By Zohar, Iris; Shaviv, Avi; Young, Megan; Kendall, Carol; Silva, Steve; Paytan, Adina From Geoderma (2010), 159(1-2), 109-121. | Language: English, Database: CAPLUS

Transformations of phosphate (Pi) in different soil fractions were tracked using the stable isotopic compn. of oxygen in phosphate (δ 18Op) and Pi concns. Clay soil from Israel was treated with either reclaimed waste water (secondary, low grade) or with fresh water amended with a chem. fertilizer of a known isotopic signature. Changes of δ 18Op and Pi within different soil fractions, during a month of incubation, elucidate biogeochem. processes in the soil, revealing the biol. and the chem. transformation impacting the various P pools. P in the soil soln. is affected primarily by enzymic activity that yields isotopic equil. with the water mols. in the soil soln. The dissolved P interacts rapidly with the loosely bound P (extd. by bicarbonate) . The oxides and mineral P fractions (extd. by NaOH and HCl, resp.) , which are considered as relatively stable pools of P, also exhibited isotopic alterations in the frst two weeks after P application, likely related to the activity of microbial populations assocd. with soil surfaces. Specifcally, isotopic depletion which could result from org. P mineralization was followed by isotopic enrichment which could result from preferential biol. uptake of depleted P from the mineralized pool. Similar transformations were obsd. in both soils although transformations related to biol. activity were more pronounced in the soil treated with reclaimed waste water compared to the fertilizer treated soil. 6. Method for the Analysis of Oxygen Isotopic Composition of Soil Phosphate Fractions

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Shavit U

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Hagin J

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Linker Raphael

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Master Y

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Du Changwen

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Shavit Uri

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Laughlin R J

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7. In situ evaluation of net nitrifcation rate in Terra rossa soil using a Fourier transform infrared attenuated total refection 15N tracing technique Full Text

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By Du, Changwen; Linker, Raphael; Shaviv, Avi; Zhou, Jianmin From Applied Spectroscopy (2009), 63(10), 1168-1173. | Language: English, Database: CAPLUS

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Nitrifcation and mineralization of org. nitrogen (N) are important N transformation processes in soil, and mass spectrometry is a suitable technique for tracing changes of 15N isotopic species of mineral N and estg. the rates of these processes. However, mass spectrometric methods for tracing N dynamics are costly, time consuming, and require long and laborious prepn. procedures. This study investigates mid- IR attenuated total refection (ATR) spectroscopy as an alternative method for detecting changes in 14NO3-N and 15NO3-N concns. There is a signifcant shift of the ν 3 absorption band of nitrate according to N species, namely from the 1275 to 1460 cm -1 region for 14NO3- to the 1240- 1425 cm -1 region for 15NO3-. This shift makes it possible to quantify the N isotopes using multivariate calibration methods. Partial least squares regression (PLSR) models with fve factors yielded a detn. error of 6.7- 9.2 mg N L -1 for aq. solns. and 5.9- 7.8 mg N kg -1 (dry soil) for pastes of a Terra rossa soil. These PLSR models were used to monitor the changes of 15NO3-N and 14NO3-N content in the same Terra rossa soil during an incubation expt. in which [ 15NH4]2SO4 was applied to the soil, allowing the estn. of the contributions of applied N and mineralized N to the net nitrifcation rate, the potential losses of the applied 15NH4-N, and the net mineralization of soil org. N. Full Text

By Tang, Deyuan; Du, Changwen; Wang, Huoyan; Zhou, Jianmin; Shaviv, Avi From Turang (Nanjing, China) (2007), 39(6), 884-889. | Language: Chinese, Database: CAPLUS

Release characteristics of nitrate in static water were checked by monocomponent and multi- component coated controlled release fertilizers treated with different temps. and granule radii. The nitrate release rate increased at higher temp., and was promoted under smaller granule radius. Comparing with monocomponent coated fertilizer, the linear period of multi- component coated fertilizer turned shorter, the nitrate release rate increased signifcantly, and the activation energy increased accordingly. The nitrate release rate was directly related with the variety and concn. of ion in granule, diffusion coeff., coating thickness and diffusion area. The

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18OP) of various soil fractions may shed light on P The isotopic signature of oxygen in phosphate (δ transformations, including phosphorus (P) recycling by soil microorganisms, uptake by plants and P adsorption, pptn. and release by oxides and minerals, thus increasing our understanding on P cycling and lability in soils. We developed and tested a protocol to ext. and purify inorg. phosphate (Pi) from different soil fractions distinguished by binding strength and ppt. it as silver phosphate (Ag 3PO4) for δ 18OP anal. Soil P is extd. sequentially using water, NaHCO 3, NaOH and HCl and Pi in each soln. is purifed and pptd. as Ag 3PO4. The unique characteristics and possible interferences of the soil soln. exts. are addressed. Two agricultural soil samples receiving reclaimed wastewater or fresh water were analyzed, and results indicate that all soil fractions analyzed have been impacted to some degree by biol. enzyme mediated cycling of P in the soil.

8. Release characteristics of nitrate from polymer-coated fertilizers

Shaviv Abraham

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By Zohar, Iris; Shaviv, Avi; Klass, Tatania; Roberts, Kathryn; Paytan, Adina From Environmental Science & Technology (2010), 44(19), 7583-7588. | Language: English, Database: CAPLUS

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Shaviv A 5. Phosphorus dynamics in soils irrigated with reclaimed waste water or fresh water - A study using oxygen isotopic

composition of phosphate

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release profles of coated fertilizer can be evaluated by the lag period, linear period, decay period and activation energy, which gives a new way for the development and application of coated fertilizer. ✔

9. Release characteristics of ammonium from polymer-coated compound fertilizers

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By Tang, Deyuan; Du, Changwen; Wang, Huoyan; Zhou, Jianmin; Shaviv, Avi From Turang Xuebao (2008), 45(2), 274-279. | Language: Chinese, Database: CAPLUS

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Mono-component and multi- component coated controlled- release fertilizers were used to check the characteristic of ammonium release in the static water treated with different temps. and granule radii. The results showed that the release rate of ammonium increased signifcantly under high temp. and small granule radius. Moreover, the components of fertilizer core had a signifcant infuence on ammonium release because different components of fertilizer core had variable ions, which would change the satd. concn. of ammonium related with the impetus of ammonium release. The lag and linear periods of ammonium release were also infuenced by temp., granule radius and components of fertilizer core. The activation energy was introduced as a sensitivity indicator of release rate change under different temps. The activation energy was also directly related with the granule radius and components of fertilizer core. The release profles of coated fertilizer could be evaluated by the lag period, linear period, decay period and the activation energy, which gave new thoughts for the development and application of coated fertilizer. ✔

11. Characterization of soils using photoacoustic mid-infrared spectroscopy

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By Du, Changwen; Linker, Raphael; Shaviv, Avi From Applied Spectroscopy (2007), 61(10), 1063-1067. | Language: English, Database: CAPLUS

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This study investigates the use of photoacoustic spectroscopy (PAS) for rapid soil anal. Photoacoustic spectroscopy requires very minimal sample prepn. (air- drying), which is a major advantage compared to the more traditional transmittance technique, which requires timeconsuming prepn. of pellets. The amt. of information contained in the PAS spectra appears to be similar to that contained in transmittance spectra, and the PAS spectra exhibit a large no. of bands that can be assocd. with various soil constituents such as quartz, calcium carbonate, and various types of clay. Comparison with attenuated total refection (ATR) spectra of satd. soil pastes shows that the PAS spectra provide much more information than the ATR spectra due to the strong water bands present in the latter. PAS quant. anal. of clay, calcium carbonate, and org. matter is presented, with resp. detn. errors of 12% clay, 5% CaCO 3, and 0.2% org. matter. ✔

15. Characteristics of potassium release from polymer-coated controlled-release fertilizer and its modeling

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By Du, Changwen; Zhou, Jianmin; Shaviv, Avi From Nongye Gongcheng Xuebao (2006), 22(2), 18-21. | Language: Chinese, Database: CAPLUS

Two kinds of polymer-coated controlled-release fertilizers (Multicoate) were used to study the characteristics of potassium release in the medium of water or watersatd. silicon sand in the column. The results show that the potassium release is mainly infuenced by temp. and granule radius and shape. There is no signifcant difference in the potassium release rate in the medium of water and watersatd. silicon sand. Based on a theoretic model of nutrients release from polymercoated controlled- release fertilizer, the factors that infuenced the nutrients release in the water were studied, and sensitivity anal. was carried out. Temp., fertilizer granule radius and membrane thickness infuence the nutrients release signifcantly. The exptl. value is signifcantly related with modeling one. However, the modeling value is signifcantly lower which is due to two factors: one is the granule shape that is not exactly spherical, the surface area (diffusion area) of granule used in the expt. is larger than modeling one. The other factor is the granule thickness which is not completely uniform and nutrients can easily release from the thinner part. Though there is a certain difference between exptl. value and modeling value, the model is still very useful with great potential in the development of application in the polymer-coated controlled-release fertilizers. ✔

16. Release Characteristics of Nutrients from Polymer-coated Compound Controlled Release Fertilizers

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By Du, Chang-wen; Zhou, Jian-ming; Shaviv, Avi From Journal of Polymers and the Environment (2006), 14(3), 223-230. | Language: English, Database: CAPLUS

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Reliable information regarding release characteristics of nutrients from a polymer- coated controlled release fertilizer (CRF) is essential for benefcial agronomic and environmental results. Signifcant knowledge regarding nitrogen release from polymer- coated urea was gained while the information regarding the release of the different nutrients contained in polymer- coated compd. N-P-K CRF remains limited. An expt. in which major factors affecting the differential release of nutrients from two coated compd. CRF was performed in free water, water satd. sand and sand at feld capacity. In general, nitrate release was the fastest, followed by ammonium and potassium whereas phosphate was signifcantly slower, with a rate of linear release in free water 45- 70% slower than that of nitrate. Little differences were obtained for the lag periods of nitrate, ammonium and potassium release (2-10 days) under the exptl. conditions, whereas for P they were one order of magnitude larger. The main factor slowing the release was assumed to be the lower soly. of ions with P being the least sol. Release into free water was, expectedly, somewhat faster than that into satd. sand and signifcantly faster as compared to sand at feld capacity and particularly so for P. Raising the temp. from 20 °C to 40 °C increased the rate of linear release of the different nutrients. The energy of activation, EA rel, estd. for the linear release, of the different nutrients, was narrow ranging between 37 to 46 (KJ mol -1) whereas the mean values obtained for the two CRF, differing by 50 % in coating thickness, was non- signifcant. However, EArel was signifcantly different in different media. The complex effect of temp. on the lag period and nutrient interactions during release deserve further investigation. ✔

18. Nitrate determination using anion exchange membrane and mid-infrared spectroscopy

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By Linker, Raphael; Shaviv, Avi From Applied Spectroscopy (2006), 60(9), 1008-1012. | Language: English, Database: CAPLUS

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This study studies the combined use of an anion exchange membrane and transmittance mid- IR spectroscopy 2

https://scifnder.cas.org/scifnder/view/scifnder/scifnderExplore.jsf[5/19/2013 6:51:08 PM]


for detg. nitrate concn. in aq. solns. and soil pastes. The method is based on immersing a small piece (2 cm ) of anion exchange membrane into 5 mL of soln. or soil paste for 30 min, after which the membrane is removed, rinsed, and wiped dry. The absorbance spectrum of the charged membrane is then used to det. the amt. of nitrate sorbed on the membrane. At the levels tested, the presence of carbonate or phosphate does not affect the nitrate sorption or the spectrum of the charged membrane in the vicinity of the nitrate band. Sulfate affects the spectrum of the charged membrane but does not prevent nitrate detn. For soil pastes, nitrate sorption is remarkably independent of the soil compn. and is not affected by the level of soil constituents such as org. matter, clay, and Ca carbonate. Partial least squares anal. of the membrane spectra shows that there exists a strong correlation between the nitrate charge and the absorbance in the 1000- 1070 cm-1 interval, which includes the ν 1 nitrate band located around 1040 cm -1. The prediction errors range from 0.8 to 2.1 μeq, which, under the specifc exptl. conditions, corresponds to 2 to 6 ppm N-NO3- on a soln. basis or 2 to 5 mg [N]/kg [dry soil] on a dry soil basis. ✔

19. Environmental friendly nitrogen fertilization

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By Shaviv, Avi From Science in China, Series C: Life Sciences (2005), 48(Spec. Issue), 937-947. | Language: English, Database: CAPLUS

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A review. With the huge intensifcation of agriculture and the increasing awareness to human health and natural resources sustainability, there was a shift towards the development of environmental friendly N application approaches that support sustainable use of land and sustain food prodn. The effectiveness of such approaches depends on their ability to synchronize plant nitrogen demand with its supply and the ability to apply favored compns. and dosages of Nspecies. They are also infuenced by farming scale and its sophistication, and include the following key concepts: (i) Improved application modes such as split or localized ("depot") application; (ii) use of bio- amendments like nitrifcation and urease inhibitors and combinations of (i) and (ii) ; (iii) use of controlled and slow release fertilizers; (iv) Fertigationfertilization via irrigation systems including fully automated and controlled systems; and (v) precision fertilization in large scale farming systems. The paper describes the approaches and their action mechanisms and examines their agronomic and environmental signifcance. The relevance of the approaches for different farming scales, levels of agronomic intensifcation and agro-tech. sophistication is examd. as well. 20. Soil identifcation and chemometrics for direct determination of nitrate in soils using FTIR-ATR mid-infrared spectroscopy Full Text

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By Linker, Raphael; Shmulevich, Itzhak; Kenny, Amit; Shaviv, Avi From Chemosphere (2005), 61(5), 652-658. | Language: English, Database: CAPLUS

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The use of mid- IR attenuated total refectance (ATR) spectroscopy enables direct measurement of nitrate concn. in soil pastes, but strong interfering absorbance bands due to water and soil constituents limit the accuracy of straightforward detn. Accurate subtraction of the water spectrum improves the correlation -1. However, this correlation is soilbetween nitrate concn. and its ν 3 vibration band around 1350 cm dependent, due mostly to varying contents of carbonate, whose absorbance band overlaps the nitrate band. In the present work, a two- stage method is developed. First, the soil type is identifed by comparing the "fngerprint" region of the spectrum (800- 1200 cm -1) to a ref. spectral library. In the second stage, nitrate concn. is estd. using the spectrum interval that includes the nitrate band, together with the soil type previously identifed. Three methods are compared for estg. nitrate concn.: integration of the nitrate absorbance band, cross- correlation with a ref. spectrum, and principal component anal. (PCA) followed by a neural network. When using simple band integration, the use of soil specifc calibration curves leads to detn. errors ranging from 5.5 to 24 mg[N] /kg[dry soil] for the mineral soils tested. The cross- correlation technique leads to similar results. The combination of soil identifcation with PCA and neural network modeling improves the predictions, esp. for soils contg. calcium carbonate. Typical prediction errors for light non- calcareous soils are about 4 mg[N] /kg[dry soil], whereas for soils contg. calcium carbonate they range from 6 to 20 mg[N] /kg[dry soil], which is less than four percent of the concn. range investigated. ✔

22. Model Demonstrating the Potential for Coupled Nitrifcation Denitrifcation in Soil Aggregates

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By Kremen, Arie; Bear, Jacob; Shavit, Uri; Shaviv, Avi From Environmental Science and Technology (2005), 39(11), 4180-4188. | Language: English, Database: CAPLUS

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A model of reactive, multi-species diffusion has been developed to describe N transformations in spherical soil aggregates, emphasizing the effects of irrigation with reclaimed wastewater. Oxygen demand for respiratory activity has been shown to promote the establishment of anaerobic conditions. Aggregate size and soil respiration rate were identifed as the most signifcant parameters governing the existence and extent of the anaerobic vol. in aggregates. The inclusion of kinetic models describing mineralization, nitrifcation, and denitrifcation facilitated the investigation of coupled nitrifcation /denitrifcation (CND) , subject to O 2 availability. N- transformations are shown to be affected by effuentborne NH 4+-N content, in addn. to elevated BOD and pH levels. Their incremental contribution to O 2 availability has been found to be secondary to respiratory activity. At the aggregate level, signifcant differences between apparent and gross rates of Ntransformations were predicted (e.g., NH 4+ oxidn. and N 2 formation), resulting from diffusive constraints due to aggregate size. With increasing anaerobic vol., the effective nitrifcation rate detd. at the aggregates level decreases until its contribution to nitrifcation is negligible. It was found that the nitrifcation process was predominantly limited to aggregates