Crop yields and soil organic carbon fractions as influenced by straw incorporation in a rice–wheat cropping system in southeastern China

In agro-ecosystems, the relationship between soil fertility and crop yield is mediated by manure application. In this study, an 8-year field experiment was performed with four fertilizer treatments (NPK, NPKM₁, NPKM₂, and NPKM₃), where NPK refers to chemical fertilizer and M₁, M₂, and M₃ refer to manure application rates of 15, 30, and 45 Mg ha^?1 year^?1, respectively. The results showed that the NPKM (NPKM₁, NPKM₂, and NPKM₃) treatments produced greater and more stable yields (4.95–5.45 Mg ha^?1 and 0.59–0.75) than the NPK treatment (4.01 Mg ha^?1 and 0.50). Crop yields under the NPKM treatments showed two trends, with a rate of decrease of 0.48–0.83 Mg ha^?1 year^?1 during the first 4 years and a rate of increase of 0.10–0.25 Mg ha^?1 year^?1 during the last 4 years. The soil organic carbon (SOC) significantly increased under all treatments. The estimated annual SOC decomposition rate was 0.35 Mg ha^?1 year^?1 and the equilibrium SOC level was 6.22 Mg ha^?1. Soil total nitrogen (N), available N, total phosphorus (P) and available P under the NPKM treatments increased by 0.15–0.26, 15–33, 0.17–0.66 and 45–159 g kg^?1, respectively, compared with the NPK treatment. Manure application mainly influenced crop yield by affecting the soil TN, available N, and available P, which accounted for up to 64% of the crop yield variation. Taken together, applying manure can determine or at least improve the effects of soil fertility on crop yield in acidic soils in South China.     

Greenhouse gas emissions from soil under maize–soybean intercrop in the North China Plain

Intercrop systems can exhibit unique soil properties compared to monocultures, which influences the microbially-mediated processes leading to greenhouse gas emissions. Fertilized intercrops and monocultures produce different amounts of N₂O, CO₂ and CH₄ depending on their nutrient and water use efficiencies. The objective of this study was to compare the fluxes and seasonal emissions of N₂O, CO₂, and CH₄ from a maize–soybean intercrop compared to maize and soybean monocultures, in relation to crop effects on soil properties. The experiment was conducted during 2012, 2013 and 2014 at the WuQiao Experimental Station in the North China Plain. All cropping systems received urea-N fertilizer (240 kg N ha^?1 applied in two split applications). The cropping systems were a net source of CO₂ and a net sink of CH₄, with significantly (P < 0.05 in 2012) and numerically (2013 and 2014) lower N₂O flux and smaller seasonal N₂O emissions from the maize–soybean intercrop than the maize monoculture. The proportion of urea-N lost as N₂O was lower in the maize–soybean intercrop (1.6% during the 3-year study) and soybean monoculture (1.7%), compared to maize monoculture (2.3%). Soybean reduced the soil NO₃^?–N concentration and created a cooler, drier environment that was less favorable for denitrification, although we cannot rule out the possibility of N₂O reduction to N₂ and other N compounds by soybean and its associated N₂-fixing prokaryotes. We conclude that maize–soybean intercrop has potential to reduce N₂O emissions in fertilized agroecosystems and should be considered in developing climate-smart cropping systems in the North China Plain.     

Two approaches for net ecosystem carbon budgets and soil carbon sequestration in a rice–wheat rotation system in China

Few studies have comprehensively evaluated the method of estimating the net ecosystem carbon budget (NECB). We compared two approaches for studying the NECB components on the crop seasonal scale as validated by the soil organic carbon (SOC) changes measured over the 5-year period of 2009–2014. The field trial was initiated with four integrated soil–crop system management (ISSM) practices at different nitrogen application rates relative to the local farmer’s practices (FP) rate, namely, N1 (25 % reduction), N2 (10 % reduction), N3 (FP rate) and N4 (25 % increase) with no nitrogen (NN) and FP as the controls. Compared with the FP, the four ISSM scenarios of N1, N2, N3 and N4 significantly increased rice yields by 9.5, 19, 33 and 41 %, while increasing the agronomic nitrogen use efficiency (NUE) by 71, 75, 99 and 79 %, respectively. The SOC sequestration potentials were estimated to be ?0.15 to 0.35 Mg C ha^?1 year^?1 from the net primary production minus heterotrophic respiration approach and ?0.32 to 0.67 Mg C ha^?1 year^?1 from the gross primary production minus ecosystem respiration approach for the 2010–2011 rice–wheat annual cycle. Similarly, the annual topsoil carbon sequestration rate over 2009–2014 was measured to be ?0.22 Mg C ha^?1 year^?1 for the NN plot and 0.13–0.42 Mg C ha^?1 year^?1 for the five fertilized treatments. Both NECB approaches provided a sound basis for accurate assessment of the SOC changes. Compared to the SOC sequestration rate from the FP, the proposed N3 and N4 scenarios increased the SOC sequestration rates while also improving rice yield and NUE.     

Changes in soil organic carbon during 22 years of pastures,cropping or integrated crop/livestock systems in the Brazilian Cerrado

In Brazil’s central savanna region, government policy is to encourage the conversion of conventional plough tillage (PT) agriculture to no-till (NT) and raise the productivity of under-utilized pastures, including their conversion to integrated crop-livestock (ICL) systems, with the objective of increasing soil organic carbon (SOC) at the expense of atmospheric carbon dioxide. An experiment was established in 1991 by liming and fertilizing at two levels an area of native vegetation (NV). The treatments, replicated in randomized plots, included pastures, continuous cropping and ICL systems under PT or NT. The aim of this study was to quantify the SOC accumulation to 100 cm depth under these treatments over time. The high C:N ratios suggested that there was a high proportion of charcoal present in the soil. Increasing fertilizer inputs had no overall significant effect on SOC stocks. Stocks of SOC changed little under pastures. Analyses of ¹³C abundance showed that higher fertilizer inputs increased the decomposition rate of C derived from NV under pure grass pastures. Continuous cropping under NT preserved SOC and under PT there were significant losses. The highest SOC stocks were found under ILP treatments, but not all ILP treatments accumulated SOC even under NT. These results indicate that government initiatives to substitute PT with NT and to intensify beef cattle production will have only modest short-term gains in SOC accumulation.     

Relationship between residue quality,decomposition patterns,and soil organic matter accumulation in a tropical sandy soil after 13 years

The objectives of this study were to investigate decomposition patterns and soil organic matter (SOM) accumulation of incorporated residues (10 Mg ha⁻¹ year⁻¹) of different quality, and identify microbiological parameters sensitive to changes in SOM dynamics, in a 13-year-old field experiment on a sandy soil in Northeast Thailand. Mass loss was fastest in groundnut stover (high N), followed by rice straw (high cellulose) and tamarind (intermediate quality), and slowest in dipterocarp (high lignin and polyphenol) following a double exponential pattern. The decomposition rate k ₁ (fast pool) was positively correlated with cellulose (r = 0.70*) while k ₂ (slow pool) was negatively related to lignin (r = −0.85***) and polyphenol (r = −0.81**) contents of residues. Residue decomposition was sensitive to indigenous soil organic nitrogen (SON), particularly during later stages (R ² = 0.782**). Thirteen years’ addition of tamarind residues led to largest soil organic carbon (SOC) (8.41 Mg ha⁻¹) accumulation in topsoil (0–20 cm), while rice straw yielded only 5.54 Mg ha⁻¹ followed by the control (2.72 Mg ha⁻¹). The highest SON (0.78 Mg N ha⁻¹) was observed in the groundnut treatment. Increases in SOC were negatively correlated with cellulose content of residues (r = −0.92***) and microbial respiration (CO₂-C) losses, while SON was governed by organic N added. During later decomposition stages, there was a high efficiency of C utilization (low qCO₂) of decomposer communities especially under tamarind with the lowest qCO₂ and CO₂-C evolution loss. This study suggests that N-rich residues with low cellulose and moderate lignin and polyphenol contents are best suited to improve SOM content in tropical sandy soils.     

Model-based optimisation of nitrogen and water management for wheat–maize systems in the North China Plain

Excessive nitrogen fertiliser application and irrigation in the North China Plain leads to nitrate accumulation in sub-soil and water pollution. HERMES, a dynamic, process-oriented soil-crop model was used to evaluate the effects of improved nitrate and water management on nitrate leaching losses. The model was validated against field studies with a winter wheat (Triticum aestivum L.)–summer maize (Zea mays L.) double-cropping system. A real-time model-based nitrogen fertiliser recommendation (NFR) was carried out for one wheat crop within the rotation and compared to farmers’ practice and soil mineral nitrogen (N_min) content-based fertilisation treatments. Consequences of varying irrigation and annual weather variability on model-based NFR and further model outputs were assessed via simulation scenarios. A best-practice simulation scenario with model-based NFR and adapted irrigation was compared to reduced N and farmers’ practice treatments and to a dry and a wet scenario. Results of the real-time model-based NFR and the other treatments showed no differences in grain yield. Different fertiliser inputs led to higher nitrogen use efficiency (not significant) of the model-based NFR. Increasing amounts of irrigation resulted in significantly higher N leaching, higher N requirements and reduced yields. The impact of weather variation on model-based NFR was smaller. In the best-practice scenario simulation, nitrogen input could be reduced to 17.1 % of conventional farmers’ practice, irrigation water to 72.3 % and nitrogen leaching below 0.9 m to 1.8 % and below 2.0 m soil depth to 0.9 % within 2 years. The model-based NFR in combination with adapted irrigation had the highest potential to reduce nitrate leaching.     

Unconventional feeds for small ruminants in dry areas have a minor effect on manure nitrogen flow in the soil–plant system

In dry areas, unconventional feeds are increasingly used for mitigating feed shortages and rangeland degradation. We evaluated how feeding sheep diets containing olive leaves, saltbush leaves and olive cake affects manure quality compared to a barley straw based diet. Soil incubation and plant growth experiments were carried out to measure soil nitrogen (N) mineralization and N uptake by barley plants and to calculate N flow through the feed-animal-soil–plant system. Fresh feces, composts consisting of feces, urine and straw, and ammonium sulfate fertilizer were mixed with soil at rate of 90 mg N kg^?1 soil dry matter. Comparisons were made with non-amended soils (control) and soils amended with fresh olive cake applied at 90 and 22.5 mg N kg^?1 soil dry matter, respectively. The latter treatment enabled investigation of the effect of passage of olive cake through the digestive tract of sheep on N availability and phenol transformation. Applying fresh olive cake and feces, except the saltbush leaf derived feces, resulted in a net N immobilization. All composts resulted in net N mineralization, although not significantly different from the 0N control soil. Barley growing in soils with amendment that caused N immobilization took up less N than barley growing on the 0N treatment. Reduction in N uptake was most pronounced after amendment with fresh-olive cake. Treatments with net mineralization increased barley N uptake over the 0N treatment with 2–16 % of N applied being taken up. Dietary composition had a minor effect on N fertilizer value of either feces or compost, but feces N alone was not an efficient N source.     

Fate of labeled urea-15N as basal and topdressing applications in an irrigated wheat�Cmaize rotation system in North China Plain: I winter wheat

A field micro-plot experiment for winter wheat was conducted in an irrigated winter wheat (Triticum aestivum)-summer maize (Zea mays L.) rotation system in Mazhuang, Xinji of Hebei province in the North China Plain, using the ¹⁵N isotope method to determine the effects of N application (rates and timing), and irrigation frequency on urea-¹⁵N fate, residual-N and N recovery efficiency (NRE) of wheat. The experiment was conducted under two irrigation treatments (I2 and I3, representing for two and three irrigations, respectively), at three N rates (150, 210, and 270, kg ha^?1), divided between two ¹⁵N-labeled applications of basal-¹⁵N (90 kg ha^?1) and topdress-¹⁵N (60, 120, and 180, kg N ha^?1, respectively). The total N uptake by wheat (ranging from 186 to 238 kg ha^?1) and the fertilizer-derived N (Ndff, about 34?C55%) were measured. The Ndff from labeled basal-¹⁵N and from labeled topdress-¹⁵N were about 15?C22% and 16?C40%, respectively. The NRE (measured either as recovery in grain or as the total N recovery in the plant) was higher with I3 (39?C41 or 47?C49%) than with I2 (35?C40 or 42?C47%), showing maximum NRE in grain of about 40% both at N210 with I2 and at N150 with I3 treatment. The NRE by the first wheat crop (in grain or the total N recovery in plant) was higher with labeled topdress-¹⁵N (39?C48 or 45?C56%) as compared to that with labeled basal-¹⁵N (30?C37 or 36?C45%), while the unaccounted N losses were lower with labeled basal-¹⁵N (14?C22%) relative to labeled topdress-¹⁵N (14?C35%). Higher residual N in soils was found with labeled basal-¹⁵N (41?C51%), as compared to labeled topdress-¹⁵N (18?C35%). Residual N in the 0- to 150-cm soil depth ranged from 26 to 44% while the unaccounted N losses ranged from 14 to 30%. Recovery of residual N by the 2nd and 3rd crops in the rotation was 5?C10% in the maize crop and a further 1.7?C3.5% in the subsequent wheat crop. The accumulated N recovery and the unaccounted N losses in continuous wheat?Cmaize?Cwheat rotations derived from labeled topdress-¹⁵N were 54?C64% and 16?C37%, respectively while they were 47?C53% and 16?C28%, respectively from labeled basal-¹⁵N. This study also suggested that an N rate of 210 kg ha^?1 (with a ratio of basal-N to topdress-N of 1:1.3) with two irrigation applications could optimize wheat grain yields and NRE, under the water limited conditions in North China Plain.     

Diurnal variation in the water-soluble inorganic ions,organic carbon and isotopic compositions of total carbon and nitrogen in biomass burning aerosols from the LBA-SMOCC campaign in Rondônia,Brazil

Aerosol particles (PM_2.5) were collected during the day (n=6) and nighttime (n=9) from a tropical pasture site in Rondônia, Brazil during an intensive biomass burning period (16–26 September, 2002). Higher normalized (by K⁺, levoglucosan, or apparent elemental carbon, EC_a) mass concentrations of SO₄^2? and CH₃SO₃^? in daytime suggest their photochemical production, while the opposite trend for NO₃^? suggests its transfer to the aerosol phase at lower temperatures and higher humidities, as well as possibly production through hydrolysis of N₂O₅ on aqueous aerosol particles. About 4.2–7.5% of OC (5–13% of water-soluble organic carbon (WSOC)) could be characterized at the molecular level using GC-MS and GC-FID. Among the detected organic compound classes, abundances of anhydrosugars and aromatics were higher in night samples, but sugars/sugar alcohols, diacids, oxoacids and α-dicarbonyls were more abundant in day samples. Consecutive day and night samples showed that δ¹³C values of total carbon (TC) were lower in daytime samples, which can be interpreted as resulting from higher contributions of refractory TC depleted in ¹³C due to predominantly flaming combustion. The δ¹⁵N values of total nitrogen (TN) ranged from +23.5‰ to +25.7‰, however, there was no trend in day and night samples. Higher values of δ¹³C and δ¹⁵N for biomass burning particles than those of unburned vegetation reflect positive isotopic enrichment either during the formation of particles or after the emission of particles in the atmosphere.     

Effects of conservation tillage,crop residue and cropping systems on changes in soil organic matter and maize–legume production: a case study in Teso District

The effects of conservation tillage, crop residue and cropping systems on the changes in soil organic matter (SOM) and overall maize–legume production were investigated in western Kenya. The experiment was a split-split plot design with three replicates with crop residue management as main plots, cropping systems as sub-plots and nutrient levels as sub-sub plots. Nitrogen was applied in each treatment at two rates (0 and 60 kg N ha⁻¹). Phosphorus was applied at 60 kg P/ha in all plots except two intercropped plots. Inorganic fertilizer (N and P) showed significant effects on yields with plots receiving 60 kg P ha⁻¹ + 60 kg N ha⁻¹ giving higher yields of 5.23 t ha⁻¹ compared to control plots whose yields were as low as 1.8 t ha⁻¹ during the third season. Crop residues had an additive effect on crop production, soil organic carbon and soil total nitrogen. Crop rotation gave higher yields hence an attractive option to farmers. Long-term studies are needed to show the effects of crop residue, cropping systems and nutrient input on sustainability of SOM and crop productivity.     

Heterogeneous enantioselective carbon–carbon bond formation: role of the inorganic support in the synthesis and activity of supported chiral auxiliaries

Heterogeneous enantioselective alkylation of benzaldehyde with diethylzinc was performed using (-)-ephedrine grafted on mesoporous micelle templated aluminosilicates or silicates, as chiral auxiliary. Supports were characterized by a regular mesoporosity and a same initial pore diameter. Immobilization of the chiral aminoalcohol was performed through covalent anchoring of 3-halogenopropyltrimethoxysilane (XPTMS) and substitution of the halogen by (-)-ephedrine. Comparison of the efficiency of the catalysts was carried out. Results were analyzed taking into account the accessibility to the catalytic sites by changing their density (decrease of XPTMS concentration, spacing of the sites by alkyl goups) and the effect of the uncovered mineral surface on activities and enantioselectivities. This revised version was published online in June 2006 with corrections to the Cover Date.     

Effects of a low amount of C on the phase transformations in the AlN–Al2O3 pseudo-binary system

The effects of a low amount of C on the phase transformations in the AlN–Al₂O₃ pseudo-binary system are reported in samples having an AlN content in mol% ranging between 44 and about 0. Various complementary experimental techniques were used to determine the nature of the phase equilibria. Carbon is embedded in the components of three eutectics as a function of the average chemical composition of the sample in AlN. In two of them, a component belonging to the quaternary system Al–O–N–C and having a wide composition range was found. Its X-ray and neutron diffraction spectra are well refined with a hexagonal crystalline structure.     

Importance of the rheological properties of resorcinol–formaldehyde sols in the preparation of Cu-doped organic and carbon xerogel microspheres

The rheological properties of resorcinol–formaldehyde sols at the very beginning of the emulsion polymerization process have a profound impact on the final shape of the microparticles obtained. This is especially the case with Cu-doped organic hydrogels at reasonably large temperatures (40 °C), when an abrupt increase in viscoelastic properties is observed within only a few minutes.     

Thermal degradation of organic matter in the interlayer clay–organic complex: A TG-FTIR study on a montmorillonite/12-aminolauric acid system

The storage of natural organic matter within the interlayer space of layered silicate is an important type of clay–organic association in sediment. However, the role of the interlayer space of clay minerals in the thermal degradation of organics and the generation of hydrocarbons has not been well understood. In this study, an interlayer clay–organic complex was synthesized using montmorillonite (Mt) and 12-aminolauric acid (ALA). An Mt–ALA complex in which Mt and ALA were simply mixed was also prepared for comparison. Thermogravimetry coupled with Fourier transform infrared spectroscopy (TG-FTIR) was applied to monitor the thermal events and the corresponding products during the thermal degradation of the Mt–ALA complexes. In the absence of Mt, ALA decomposed at 467 °C via the cleavage of CC bonds, producing aliphatic hydrocarbon, N-containing compounds, and carboxylic acid. The decomposition temperatures of organic matter in the mixed Mt–ALA complex and the interlayer Mt–ALA complex decreased to 402 and 342 °C, respectively. The most characteristic products of the interlayer Mt–ALA complex were NH₃ and saturated hydrocarbons. The Brønsted acid sites in the interlayer space of Mt, arising from the dissociated interlayer water, initiated the deamination of ALA via the Hoffmann elimination pathway and significantly promoted the cracking of hydrocarbons via a carbonation mechanism. Lewis acid sites had little effect on the thermal degradation of ALA. This work indicated that the interlayer space of clay minerals provided the storage space for organic matter. Moreover, the active sites within the interlayer space strongly promoted the thermal degradation of organics.     

Tillage and residue management effects on soil carbon and CO<Subscript>2</Subscript> emission in a wheat–corn double-cropping system

The mitigation of CO₂ emission into the atmosphere is important and any information on how to implement adjustments to agricultural practices and improve soil organic matter (SOM) stock would be helpful. We studied the effect of tillage and residue management on soil carbon sequestration and CO₂ emissions in loam soil cropped in a winter wheat–corn rotation in northern China. There were five treatments: mouldboard ploughing, rotary tillage and no-tillage with chopped residues (MC, RC and NC), additional no-tillage with whole residue (NW) and mouldboard ploughing without residue (CK). After 5 years of each tillage system, MC and RC had higher annual CO₂ efflux from soil. The CO₂ effluxes were correlated with the ratio of dissolved organic carbon to soil microbial biomass (DOC/MBC) among treatments. This effect may be due to less immobilization of soil carbon by microorganisms under long-time intensive tillage. Although both MBC and DOC showed seasonal variability, when averaged across the sampling period only MBC discriminated between treatments. After 5 years of tillage, all treatments except CK increased SOM (0.16–0.99 Mg C ha⁻¹ year⁻¹) at 0–30 cm depth and NC was the greatest, resulting from historical SOM depletion and large C return from recent residues. Despite the lowest CO₂ flux being from the NW treatment, lower input residue from decreased biomass may have lowered C sequestration. To improve soil C sequestration in rotations, the input of residue and the CO₂ emission should be balanced by adopting appropriate tillage and residue management.     

Effects of Refractories on the Total Oxygen Content and Inclusions in the IF Steel

The effects of refractories of quarz-corundum consisting of 45 mass% quartz and 55 mass% corundum,fused corundum and fused magnesia on the total axygen content(TOC) and the composition of inclusions in intersitital free(IF) steel were studied,3 mass% microsilica was added into the three refractories as binder.The refractories were shaped as lining of the graphite crucible by castable method IF steel was placed in the crucibles,then they were heated at 1600℃ for 90min and 45min respectively.Oxygen contents of the steel samples were obtained by axygen determinator.Inclusions were analyzed by SEM and EDS.The results show that the TOC of steel increase with ncrease of Index of Oxygen Potetial (IOP) of the refractories.The steel sample coped with MgO refractories having the lowest IOP has the lowest TOC.     

Effects of additive LiF on the synthesis of cBN in the system of Li3N–hBN at HPHT

High-quality cBN single crystals were successfully synthesized in the system of Li₃N–hBN with additive LiF at high pressure and high temperature (HPHT). The lowest synthetic conditions of cBN decreased to 4.6 GPa, 1320 °C by employing 3 wt.% LiF, and it didn't change anymore though more than 3 wt.% LiF had been added. The quality of cBN crystals improved markedly. The cBN crystals and other products were examined by X-Ray diffraction and scanning electron microscopy. The X-Ray analysis reveals that the “graphitization index” (GI) of hBN increased by adding 3 wt.% LiF into the system of Li₃N–hBN at HPHT. The SEM photographs show that different growth steps were formed on the cBN crystal surface in systems of Li₃N–hBN and Li₃N–LiF–hBN, respectively.     

Structure and in vivo anticalcification properties of a polymeric calcium–sodium–phosphocitrate organic–inorganic hybrid

This paper describes the synthesis, characterization and crystal structure of an organic–inorganic polymeric hybrid composed of Ca, Na, and phosphocitrate (CaNaPC). CaNaPC is synthesized by reaction of CaCl₂·2H₂O and Na₄(HPC)·3H₂O in water, at pH 2. Its structure is polymeric with Ca(PC)₂(H₂O) “monomers” connected through Na⁺ bridges. The 9-coordinate Ca occupies the center of an irregular polyhedron defined by four phosphate, four carbonyl, and one H₂O oxygens. CaO(C) distances are in the 2.446(2)–2.586(2) Å range. There is a short distance of 2.477(1) Å between Ca and the ester O from C–O–PO₃H₂. All –COOH groups are protonated. There are three dissociated protons per two PC molecules, all coming from –PO₃H₂. Na ions are six-coordinate surrounded by –COOH’s. The anticalcification properties of CaNaPC on plaque growth were studied in vivo using rats as model systems. Na–phosphocitrate is an effective inhibitor, but its effectiveness diminishes when a lower dose is used (9.7 mg as H₅PC), resulting in only 30% plaque reduction. Superior inhibition activity becomes evident by following treatment with CaNaPC, at an equal dose (9.6 mg as H₅PC) giving nearly quantitative (95%) plaque inhibition.     

Novel organic–inorganic composite material as a cation exchanger from a triterpenoidal system of dammar gum: synthesis,characterization and application

A pioneer study has been conducted to synthesize novel hydrogel starting from a non-cellulosic raw material, gum dammar-a triterpenoidal system, and then converting this hydrogel into an organic–inorganic composite zirconium-based ion exchanger. Gum dammar was cross-linked with polyacrylamide zirconium (IV) iodo-oxalate [Gd-cl-poly(AAm)-Zr (IV) iodo-oxalate] by incorporating inorganic precipitates into the polymeric mixture. The polymeric mixture was synthesized using gum dammar (Gd), acrylamide (AAm), N, N′-methylene-bis-acrylamide (MBA) and potassium persulphate (KPS). The reaction conditions for synthesis of hydrogel and ion exchanger such as time (120 min), temperature (70 °C), solvent (4 mL), concentration of monomer (12.97 × 10^?3 mol/L), initiator (1.48 × 10^?4 mol/L), cross-linker (4.22 × 10^?4 mol/L) and ratio of zirconium oxychloride (0.1 M), potassium iodate (0.1 M) and oxalic acid (0.1 M) in ratio 2:3:2 were optimized to obtain maximum ion exchange capacity (2.02 meq/g). The morphology and structure of hydrogel and ion exchanger were studied using FTIR, SEM, XRD and TGA/DTA/DTG. The SEM study was followed by energy dispersive spectroscopy for elemental analysis. The ion exchanger was quite stable in various acids and bases at low concentration but it completely dissolved in acids and bases at high concentrations. Distribution studies showed that the synthesized ion exchanger had high selectivity for Pb²⁺ ions. Thus, the polymeric-inorganic hybrid material showed integration of both inorganic and organic characteristics within the composite material.