Effects Of Various Amendments Research Articles

Effects of Different Soil Amendments on Growth, Yield and Nutrients Uptake of Stem Amaranth in Acidic Alluvial-and-Hill Soils in a Subtropical Area

ABSTRACT Sandy and acidic soil conditions are the major factors limiting the production of some vegetable crops in acidic soils. This study aims to examine the effect of various amendments on the growth, yield and mineral nutrients uptake of stem amaranth. Two pot experiments were conducted separately in two generic soils. Six treatments viz. T0 = control (without amendment), T1= lime, T2 = lime + wetland bottom sediment, T3 = lime + vermicompost, T4 = lime + rice straw biochar (RSB) and T5 = RSB were used for both experiments following CRD with four replications. Results revealed that plant heights (45.96 and 50.33 cm) of amaranth grown in alluvial and hill soils, respectively, were the highest in T4 treatment. Similarly, treatment T4 showed the highest fresh (118.53 and 116.11 g pot−1, respectively) and dry biomasses (16.98 and 19.54 g pot−1, respectively) for both soils. For both soils, treatment T4 resulted better nutrient uptake of N, P, K, S, Zn, Fe and Mn by edible stem, while non-amended soil gave the lowest result at all parameters. Analytical values of post-harvest soils indicated that T4 and/or T5 treatments resulted in an improvement in soil pH, organic carbon, total N, exchangeable K and extractable P, S and Zn. Treatment T3 showed elevated concentrations of extractable soils Fe and Mn. The amendment RSB combined with lime can be preferably used in strong acidic soils for cultivation of stem amaranth.

The influence of compost amendments on bioaccumulation of potentially toxic elements by pea plant cultivated in mine degraded soils

Potential toxic metal (PTE) accumulation in soil and water is one of the major sources of food crop contamination. PTE remediation from soil can be enhanced by the addition of organic matter to the growing media. An experiment was carried out to investigate the effect of different organic amendments on the accumulation of PTEs in pea plant grown on mine degraded soils. Mining soils from chromite mine (CM), soap stone mine (SSM), manganese mine (MM), and quartz mine (QM) were mixed with vermicompost (VC), leaf mould (LC), and spent mushroom compost (SMC) along with garden soil at 1:1:1 ratio. Various growth and yield-related attributes of pea plant as well as PTE concentrations in soil and plants were studied. The highest Cd (2.62 mg kg−1) and Cr (13.6 mg kg−1) concentration was reported in CM soil, while Pb (23.3 mg kg−1) and Mn (59.2 mg kg−1) concentration in SSM and MM soil, respectively. Mining soils significantly reduced the plant growth and yield, while organic amendments reduced the PTE availability and increased pea plant growth. Comparing the various organic fertilizers used, it was observed that VC efficiently reduced Cd, Cr, Pb, and Mn uptake by pea plant, subsequently, improved pea plant growth and productivity. In order to assess the effects of various amendments on PTE health risk reduction, various risk indices including plant tranfser factor, average daily intake, health risk, target hazard quotient, and target cancer risk were also calculated and the results revealed that application of compost particularly VC significantly reduced the dietary intake and health risks of PTEs.

Modulating effect of EDTA and SDS on growth, biochemical parameters and antioxidant defense system of Dahlia variabilis grown under cadmium and lead-induced stress

The present study investigated the influence of inorganic amendments viz., SDS (sodium dodecyl sulphate) and ethylenediaminetetraacetic acid (EDTA) in enhancing metal tolerance in plants. Seedlings of an important ornamental plant, Dahlia variabilis Cav. were grown under cadmium (Cd) and lead (Pb) stress. 30-days old seedlings were transferred to pots containing sterilized sand and supplemented with Hoagland’s medium. After 15 days of transplanting, four treatments (0, 10, 25, and 100 mg kg-1) of Cd and four treatments of Pb (0, 100, 500 and 5000 mg kg-1) were used with or without application of 2.0 mM SDS and 2.5 mM EDTA, separately and in combination. Seedlings were further grown for 60 days in culture media. Results revealed that both Cd and Pb significantly reduced plant growth, pigment content, and relative water content. Antioxidant enzymes viz., superoxide dismutase (SOD), peroxidase (POD), ascorbate peroxidase (APX), and catalase (CAT) along with protein and total soluble sugar contents showed a declining trend with an increase in Cd and Pb concentrations applied. The Cd and Pb treatment enhanced the production rate of reactive oxygen species (ROS) as depicted by the increased malondialdehyde (MDA) and hydrogen peroxide (H2O2) production in leaf. Inorganic amendments viz., EDTA+SDS applied either alone or in combination significantly alleviated Cd and Pb-induced toxic effects. However, a combination of EDTA+SDS showed significant results than used separately. These results revealed that the application of inorganic amendments in combination can enhance the phytoextraction capacity of the species studied. However, the effects of various amendments vary with the nature of the inorganic compound. The study suggests that the application of EDTA and SDS could be a useful strategy for enhancing the phytoextraction capability of Dahlia variabilis to remove Cd and Pb from contaminated soils.

Effects of inorganic and organic amendments on physiological parameters and antioxidant enzymes activities in Zea mays L. from a cadmium-contaminated calcareous soil

In situ stabilization is a promising remediation technology to decrease the hazard potential of contaminants in soils through converting them into their least-soluble, -mobile or -toxic forms. In the present study, the effectiveness of various amendments (e.g., biochar 640 °C, and biochar 420 °C) and selected low cost amendments (e.g., leca, pumice, bentonite, and zeolite) was investigated on Cd stabilization through testing their potential to decrease soil Cd bioavailability, and their effects on photosynthetic pigments, antioxidant enzyme activities and Cd uptake by maize (zea mays L.) in a polluted calcareous soil. By the end of the experiment, all amendments resulted in increased soil pH value and electrical conductivity (EC) relative to the control soil. The Toxicity Characteristic Leaching Procedure (TCLP) Cd was supposed to indicate the potential bioavailability of Cd in the soils. Generally, application of the amendments decreased the Cd bioavailability in the soils compared to un-amended soil. This decreased bioavailability of Cd in soil was accompanied by an increased antioxidant enzyme activities and photosynthetic pigments, and decreased plant uptake of Cd. Plant antioxidant enzyme activities {superoxide dismutase (SOD), catalase (CAT), peroxidase (PX), and ascorbate peroxidase (ASP)} and photosynthetic pigments (chlorophyll a, chlorophyll b, total chlorophyll, and carotenoids) were significantly increased in the amended soils. These increases may be due to a lower Cd accumulation in leaves. Zeolitse (%5) was the most effective amendment in decreasing cadmium concentration in maize.

Sustainable soil amendments for improving the soil quality, yield and nutrient content of Brassica juncea (L.) grown in different agroecological zones of eastern Uttar Pradesh, India

Sustainable soil amendments are important for enhancing the yield and nutritional quality of agricultural produce while reducing the soil carbon efflux. In this backdrop, a two-year field experiment was conducted to examine the effect of different soil amendments such as humicil, sheep manure and humicil + sheep manure on soil structure, organic carbon, microbial biomass carbon, soil and microbial respiration as well as the growth and yield of Brassica juncea (L.) grown in different agroecological zones of eastern Uttar Pradesh, India. For this, field experiments were performed at three different experimental sites in three different agroecological sub-zones i.e. Varanasi, Sultanpur and Gorakhpur of Uttar Pradesh, India. Experimental results indicate that the application of humicil + sheep manure significantly enhanced (p < 0.05) the soil moisture (29%), cation exchange capacity (6.5%) and soil aggregation (1.5-fold) maximum in Varanasi site followed by sheep manure and humicil. Furthermore, these changes were also lead to the enhancement in organic carbon (1.2 fold), available nitrogen (19.6%) and microbial biomass carbon (48.0%) content of the soil. Sheep manure addition resulted in higher bacterial and fungal counts (195.1 × 107 and 118.3 × 107 g−1 soil) than humicil and thereby enhanced the soil β-glucosidase activities (66–86%) than the combined amendments at different experimental site whereas the highest soil (43, 44 and 40%) and microbial (70, 73 and 64%) respiration was observed under sheep manure amendedment than humicil. The effect of various amendments on soil and microbial respiration was found in the order of sheep manure > humicil + sheep manure > humicil > control whereas maximum agroecological sub-zone wise variation was observed at Sultanpur followed by Varanasi and Gorakhpur. Increase in plant height (37–45%), biomass (33–45%), yield (140–190%) and harvest index of B. juncea was observed in combined amendment than the control. Similarly, the N, P, K, protein and oil content of the test plant was higher under the combined treatments. The present study conclude that combined application of humicil and sheep manure is better than the individual amendments and therefore, suitable package of practices based on such combined amendments must be validated at larger scale for improving the soil quality, yield and nutritional quality of agricultural crops while reducing the carbon emission.

Four-year effects of soil acidity amelioration on the yields of canola seeds and sweet potato and N fertilizer efficiency in an ultisol

A four-year field experiment was conducted in Langxi, Anhui province, China to investigate the ameliorated effects of various amendments on soil acidity, soil fertility properties, yields of canola seeds and sweet potato, nutrients uptake, and nitrogen utilization efficiency by the crops. The nine treatments used were control, lime, alkaline slag (AS), peanut straw (PS), canola straw (CS), organic manure (OM), AS + PS, AS + CS, AS + OM. The chemical fertilizers with 150.0 kg ha−1 N, 150.0 kg ha−1 P2O5, and 150.0 kg ha−1 K2O were applied for all treatments in canola season, while 90.0 kg ha-1 N, 90.0 kg ha−1 P2O5, and 90.0 kg ha−1 K2O in sweet potato season. Application of lime, AS, AS + PS, AS + CS, and AS + OM increased soil pH and decreased soil exchangeable Al3+. AS + OM showed the greatest ameliorating effect on soil acidity, and soil pH of the treatment increased by 0.45 compared with control. Application of AS + OM also led to greater reduction in soil exchangeable Al3+ and greater increase in soil exchangeable calcium and magnesium compared with lime, AS, AS + PS, and AS + CS. Applying amendments alone and combined promoted the physiological nitrogen use efficiency (PNUE) and nitrogen partial factor productivity (PFPN) of canola and sweet potato, thus increased the uptake of N, P, K, Ca, and Mg by the crops, and the yields of canola seeds and sweet potato. The application of AS + OM showed the greatest effect on the PFPN of canola among the treatments, while AS + CS was the best treatment for sweet potato in this aspect. The yield of canola seeds in AS + OM treatment was 2.61 Mg ha-1, and 5.84 times greater than that of control, while that of sweet potato in AS + CS treatment was 8.07 Mg ha-1, and 32% greater than control. In conclusion, AS + CS, AS + PS, and AS + OM were the good way to ameliorate soil acidity, increase use efficiency of nutrients and promote crop production and the AS + OM is the best one in these treatments.

A comparison study on heavy metal/metalloid stabilization in Maozhou River sediment by five types of amendments

River sediment pollution by heavy metals/metalloids has attracted widespread attention due to a serious threat to the ecosystem and human health. As an effective and economical alternative, the stabilization method was considered by previous studies for the remediation of sediments polluted by metals/metalloids. However, a comprehensive study is required for an extensive comparison on the effects of metal/metalloid immobilization based on the application of different materials as sediment amendments. In this study, the Maozhou River was selected as the study area, and the stabilization method was applied for the remediation of the river sediment polluted by metals and metalloids. Five materials (CaCO3, Ca(OH)2, zeolite, kaolin, FeCl2) were selected as amendments for the metal/metalloid stabilization in the collected sediment. A modified BCR procedure was employed for the speciation analysis of heavy metals and metalloid in the sediment before and after remediation. A TCLP (toxicity characteristic leaching procedure) investigation was performed to further evaluate the immobilization of heavy metals in acidic environment. The sediment of the Maozhou River was heavily polluted by heavy metals and metalloid. The speciation of As, Pb, Cr, and Mn mainly exists as residual fraction (F4), while that of Ni, Cu, and Zn was identified as exchangeable metal and carbonate-associated fraction (F1) and fraction associated with Fe-Mn oxides (F2). Moreover, the F2 fraction of Co was observed as the major speciation. Through the application of five materials (CaCO3, Ca(OH)2, zeolite, kaolin, FeCl2) as sediment amendments, the metal/metalloid speciation was transferred into F4. When five amendments were compared, the stabilization effect can be ordered as CaCO3 > zeolite > FeCl2 > kaolin > Ca(OH)2 based on the modified BCR results. TCLP results showed that using Ca(OH)2 and CaCO3 as amendments can significantly reduce the metal leachability in an acidic environment, while zeolite is effective for most of the heavy metals and metalloid. The results showed that the sediment of the Maozhou River was seriously polluted by a variety of heavy metals and metalloids. This study provided extensive information on the speciation of metals or metalloid and the effect of various amendments on metals and metalloid stabilization, which can be of vital importance for further remediation of metal/metalloid-polluted sediment.

Assessment of crop growth, soil properties and crop yield in an upland acidic soil with inorganic fertilizer blended with organic amendments in summer rice cropping seasons

PurposeIntensification of rice cultivation to meet the growing demand has imbalanced the nitrogen level in soil. Amendments of inorganic fertilizers increase yield, but at the same time affects the environment. Hence, different amendments are to be investigated which acting sustainably on soil and the environment upholds yield gains.MethodsA study was carried out on acidic sandy loam soil in the irrigated summer seasons of the years of 2015–2016 and 2016–2017 to examine the effects of various amendments on rice growth, soil health and yield. The applied amendments were inorganic fertilizer blended with crop residues, farm yard manure and compost made of daily household green wastes.ResultsThe highest yield of 53.33 ± 2.09 Q/ha was recorded with application of inorganic fertilizer blended with compost and the lowest yield of 32.71 ± 3.09 Q/ha without amendment. Strong positive correlations were found between soil moisture and volumetric water content (0.982 at p < 0.001), manganese and copper (0.900 at p < 0.001), whereas available phosphorus and manganese showed a strong negative correlation (− 0.901 at p < 0.001). Performing stepwise regression analysis, yield was found affected mostly by soil moisture and total carbon out of evaluated 17 soil traits.ConclusionThe inorganic fertilization blended with the compost increased rice yield by 13.61% over inorganic fertilizer but a higher yield associated with compost demoted total nitrogen contents in soil, leading to lower soil nitrogen fertility and providing a negative feedback to sustainable agriculture. More research is required on compost development and application in different rice agroecosystems.

Role of Enzymatic System of Screened Pleurots ostreatus IBL-02 in the Bio-Removal of Synthetic Dyes Effluent

White rot fungi have exclusive capacity to decolorize synthetic azo dyes. Five different fungal strains namely S. commune IBL-01 (SC), P. ostreatus IBL-02 (PO) P. chrysosporium IBL-03 (PC), T. versicolor IBL-04 (TV) and G. lucidum IBL-05 (GL) were used for the decolorization of synthetic dyes effluent. P. ostreatus IBL-02 showed maximum decolorization of synthetic textile effluent, so it was selected for the optimization of experimental factors. Different physico-chemical parameters were optimized using Pleutorus ostreatus IBL-02 (PO), for the maximum de-colorization of synthetic dyes effluent. Under optimum conditions, P. ostreatusIBL-02 (PO) decolorized the synthetic dyes effluent by 92.7%. Effect of various amendments like carbon and nitrogen sources on the decolorization and mineralization of synthetic dyes effluent by Pleutorus ostreatus IBL-02 was also studied. Ligninolytic enzymes at the end of each experiment were studied to find their role in decolorization and mineralization of synthetic dyes effluent. UV-Visible spectral analysis was used to indicate the decolourization of treated dyes effluent sample. A diminution in spectral line height displaying absorption maxima designated decolorization (%) while a move of spectral line to the UV-region depicted the degradation of synthetic dyes effluent.

The Effects of Various Amendments on Trace Element Stabilization in Acidic, Neutral, and Alkali Soil with Similar Pollution Index.

Many studies have examined the application of soil amendments, including pH change-induced immobilizers, adsorbents, and organic materials, for soil remediation. This study evaluated the effects of various amendments on trace element stabilization and phytotoxicity, depending on the initial soil pH in acid, neutral, and alkali conditions. As in all types of soils, Fe and Ca were well stabilized on adsorption sites. There was an effect from pH control or adsorption mechanisms on the stabilization of cationic trace elements from inorganic amendments in acidic and neutral soil. Furthermore, acid mine drainage sludge has shown great potential for stabilizing most trace elements. In a phytotoxicity test, the ratio of the bioavailable fraction to the pseudo-total fraction significantly affected the uptake of trace elements by bok choy. While inorganic amendments efficiently decreased the bioavailability of trace elements, significant effects from organic amendments were not noticeable due to the short-term cultivation period. Therefore, the application of organic amendments for stabilizing trace elements in agricultural soil requires further study.

Evaluation of soil reclamation techniques at the Key Lake uranium mine

Olatuyi, S. O. and Leskiw, L. A. 2015. Evaluation of soil reclamation techniques at the Key Lake uranium mine. Can. J. Soil Sci. 95: 153–176. Adequate soil nutrients and water supply are critical to vegetation establishment and creation of sustainable ecosystems in post-disturbed mining sites. This study investigated effects of various amendments and capping techniques on soil quality and moisture distribution on a reclaimed waste rock pile at the Key Lake uranium mine in northern Saskatchewan, Canada. Soil profiles were reconstructed in 2010 using locally available sandy glacial materials to create soil covers of 1 m thickness. The reclamation treatments consisted of a Control plot, commercial peat (Peat), a local lake sediment (Sediment), underlying flax straw (Straw), mulched forest floor and Ae (LFH), fertilizer (NPK), manure pellets (Pellets), and a demonstration plot (Demo) comprised of Sediment, LFH and Pellets. Soil amendments were applied by various techniques as broadcast, surface incorporation, below the surface or surface mounding. Annual plot monitoring was conducted from 2011 to 2013 and soil samples were analyzed for pH, electrical conductivity (EC), sodium adsorption ratio (SAR), available nutrients, cation exchange capacity (CEC), total organic carbon (TOC), total nitrogen (TN), and regulated metals. Volumetric moisture contents were measured periodically to examine soil moisture response to growing-season precipitation. In 2013, the topsoil of the Control plot was slightly acidic (pH of 6.3) while the Sediment and Demo plots had the lowest pH of 4.0. The EC and SAR values were below 1.0 in all treatment plots. The highest levels of available N, TN, TOC and CEC were in the Sediment and Demo plots, followed by the Peat. The concentration of arsenic exceeded the regulatory limit by 3.4- and 2.6-fold in the Sediment and Demo topsoil, respectively, while concentrations of other metals were below the limits in all treatment plots. The Sediment and Demo treatments were most effective in retaining water in the topsoil, while application of soil amendment by mounding enhanced infiltration and water transmission in the profile. In terms of soil fertility and moisture storage, the combination of organic amendments in multi-layers plus surface mounding, as in the Demo plot, is the most promising capping technique for restoring soil health, vegetative cover and ecosystem functions on the waste rock pile.

The effects of various amendments on the biostimulation of perchlorate reduction in laboratory microcosm and flowthrough soil columns

Perchlorate (ClO4-) is a contaminant of concern in groundwater and drinking water. In the presence of a suitable electron donor, perchlorate can be reduced to non-toxic chloride via either biotic or abiotic mechanisms. The objective of this study was to evaluate a variety of amendments (Emulsified Oil Substrate (EOS®598), EHC® and a compost/mulch mixture) and supplemental nutrients to stimulate in situ perchlorate bioremediation. Both laboratory microcosm and column experiments were conducted with groundwater from a contaminated site that had an initial perchlorate concentration of about 500μg/L. Complete perchlorate removal was observed within 5–12days in all the microcosms. The addition of 1g/L (NH4)2HPO4 as nutrient increased the reduction rate of perchlorate in EOS and compost/mulch microcosms, but had no effect in the EHC amended microcosms. Two different flowthrough experiments were conducted. Phase 1 used two parallel columns packed with EOS-amended compost/mulch/gravel media and EHC-amended compost/mulch/gravel media, while in Phase 2, a series of varying length columns ranging from 0.15m to 0.60m were packed with EOS-amended soil and EHC-amended soil. No perchlorate was detected in the effluent of both EOS- and EHC-amended compost/mulch/gravel columns after 20days. In Phase 2, no significant treatment difference was observed between the EOS- and EHC-amended soil columns. Complete perchlorate removal was observed after 6 to 11days in all different length columns when they were operated at a hydraulic loading rate of 0.15m3/m2-d. Perchlorate removal was completely lost in all the columns when the hydraulic loading rate was increased to 0.60m3/m2-d. Nitrate competed with perchlorate for electrons, and was a preferred acceptor over perchlorate. Overall, based on the results of this study, the two commercial amendments can be considered as effective means for perchlorate bioremediation, although EHC had a shorter period of effectiveness.

Relative Effectiveness of Various Amendments in Improving Yield and Nutrient Uptake under Organic Crop Production

In organic farming, artificial/synthetic inorganic fertilizers/chemicals are not applied to increase crop yields, but adequate amounts of nutrients are essential for sustainable high production from agricultural crops. Two 3-year (2008 - wheat, 2009 – pea, and 2010 - barley) field experiments were conducted on certified organic farms near Spalding (Dark Brown Chernozem – Typic Haploboroll) and Star City (Gray Luvisol – Typic Haplocryalf) in northeastern Saskatche-wan to determine the relative effectiveness of various organic amendments (compost, alfalfa pellets, wood ash, rock phosphate, Penicillium bilaiae, MykePro, or gypsum), and intercropping of non-legume (wheat, barley) and legume (pea) annual crops on seed yield, total biomass yield (TBY) and nutrient uptake in seed + straw of wheat, pea and barley. In 2008, seed yield, TBY and nutrient uptake of wheat increased (but small) with compost and alfalfa pellets. In 2010, seed yield, TBY and nutrient uptake of barley increased substantially with compost and alfalfa pellets and moderately with wood ash. Other amendments had little or no effect on crop yield and nutrient uptake. In 2009, there was no beneficial effect of any amendment on yield and nutrient uptake of pea, most likely due to fixation of N which is the most limiting nutrient in these soils. Intercropping of wheat or barley with pea produced greater seed yield and nutrient uptake per unit land area basis compared to wheat or barley grown as sole crops in most cases. In conclusion, our results suggest potential benefits in improving yield and nutrient uptake of wheat and barley from compost, alfalfa pellets and possibly wood ash, most likely by preventing deficiencies of some nutrients, especially N, lacking in these soils under organic farming. Our findings also suggest the need for future research to determine the feasibility of rock phosphate, Penicillium bilaiae, MykePro, gypsum or other amendments in preventing P and/or S deficiency in organic crops using soils extremely deficient in these nutrients.

Short-term residual effects of various amendments on organic C and N, and available nutrients in soil under organic crop production

Two 3-year (2008-2010, wheat-pea-barley) field experiments were conducted on certified organic farms near Spalding (Dark Brown Chernozem-Typic Haploboroll) and Star City (Gray Luvisol-Typic Haplocryalf) in northeastern Sas-katchewan, Canada, to determine the residual effects of compost, alfalfa pellets, wood ash, rock phosphate, Penicillium bilaiae, gypsum and MykePro on organic C and N (total organic C [TOC], total organic N [TON], light fraction organic C [LFOC], light fraction organic N [LFON]) and mineralizable N (Nmin) in the 0 - 15 cm soil layer, and ammonium-N, nitrate-N, extractable P, exchangeable K and sulphate-S in the 0 - 15, 15 - 30 and 30 - 60 cm soil layers in autumn 2010. Compared to the unamended control, mass of TOC, TON, LFOC and LFON increased with compost and alfalfa pellets in both soils. However, the increases were much more pronounced for LFOC (by 125% - 133%) or LFON (by 102% - 103%) than TOC (by 19% - 29%) or TON (by 25% - 40%). The Nmin also increased in these two treatments compared to the control, but the increases were much smaller for compost than alfalfa pellets. In general, residual nitrate-N increased with increasing rate of compost and alfalfa pellets in the 0 - 15 and 15 - 30 cm layers in both soils. Extractable P increased with compost and exchangeable K with alfalfa pellets, but only in the 0 - 15 cm soil layer. Sulphate-S increased with compost, but mainly in the 30 - 60 cm soil layer. Soil pH usually increased with compost and more so with wood ash, but no effect of any amendment on ammonium-N. Overall, the quantity of organic C and N, and available nutrients in soil increased with compost and/or alfalfa pellets, but the magnitude varied with amendment and/or soil type. In conclusion, our findings suggest that soil quality and fertility can be improved with these organic amendments, suggesting sustainability of production from organic crops.

Effect of Various Amendments on the Solids Properties and Gas Production of Biosolids

Effect of Various Amendments on the Solids Properties and Gas Production of Biosolids

Effects of Crude and Bioremediated Thermal Power Plant Effluents in Brassica Juncea

Crude phenol and cyanides are the major components of the effluents discharged by industries involved in the manufacture of many synthetic inorganic and organic compounds, pharmaceuticals, electroplating units, and thermal power plants. In this study, an effort was made to use effluents as manure. The effect of various amendments (10, 40, 70, and 100%) of bioremediated and crude effluents was checked on plants of Brassica juncea. Roots, shoot lengths, and the mean dry weights were maximum in the plants irrigated with 10% treated and 10% crude effluent as compared to the control plants. Total plant phenolics increased with an increase in the amendment of the effluents in the plants irrigated with bioremediated as well as crude effluents. Applications of lower amendments of treated and untreated effluents in Brassica juncea improved the chlorophyll levels in the experimental plants and the values obtained were similar to the control plants. Effect of bioremediated and crude effluents on antioxidant enzymes of Brassica juncea showed a differential effect. The activity of antioxidant enzymes peroxidase (POD), catalase (CAT), and superoxide dismutase (SOD) was observed to increase with an increase in the effluent concentration. Here we demonstrate that the industrial effluents, when bioremediated of their harmful components, can also serve as a nourishment for plants, which can further help in the rehabilitation of wastelands.

Evaluation of the effectiveness of various amendments on trace metals stabilization by chemical and biological methods

We evaluated the effects of five different kinds of amendments on heavy metals stabilization. The five amendments were: zero valent iron, limestone, acid mine drainage treatment sludge, bone mill, and bottom ash. To determine bioavailability of the heavy metals, different chemical extraction procedures were used such as, extraction with (Ca(NO 3) 2, DTPA; toxic characteristic leaching procedure (TCLP), physiologically based extraction test (PBET) that simulates gastric juice, and sequential extraction test. Bioavailability was also determined by measuring uptake of the heavy metals by lettuce ( Lactuca sativa L.) and earthworms ( Eisenia fetida). In addition, dehydrogenase activity was measured to determine microbial activity in the soil with the different amendments. The addition of amendments, especially limestone and bottom ash, resulted in a significant reduction in extractable metal contents. Biological assays using lettuce, earthworm, and enzyme activity were found as appropriate indicators of available metal fraction after in situ stabilization of heavy metals. In conclusion, TCLP and sequential extraction test appear to be promising surrogate measure of metal bioavailability in soils for several environment endpoints.

Coal fly ash and farmyard manure amendments in dry-land paddy agriculture field: Effect on N-dynamics and paddy productivity

A field study was conducted at a dry-land agricultural farm during paddy crop season to assess the effect of fly ash (FA) and farmyard manure (FYM) amendments on the dynamics of inorganic-N (NH 4 + and NO 3 −), N-mineralization and nitrification rates and paddy yields. Four treatments, each consisted of three replicates, were established in completely randomized block design. The treatments were: control, 50 t ha −1 FA, 50 t ha −1 FYM, and FA + FYM (each 50 t ha −1). The variations in soil physico-chemical properties due to treatments were statistically significant. Across different treatments, FA + FYM treated plot had significantly higher organic-C, total-N, total-P, water-holding capacity, but lower bulk density compared to control plot. The effect of various amendments and months was significant for soil inorganic-N (NH 4 + and NO 3 −) concentrations, soil moisture (SM) content, N-mineralization and nitrification rates. Across various amendments and sampling months, inorganic-N, SM, N-mineralization and nitrification rates were greatest in FA + FYM treated plot in August month. An exponential positive relationship existed between gravimetric SM content and N-mineralization ( R 2 = 0.865) and nitrification ( R 2 = 0.633) rates. The SM content was negatively correlated with NH 4 + ( R 2 = 0.841) and NO 3 − ( R 2 = 0.920). The various selected paddy agronomic parameters and yields differed significantly due to treatments. The most effective treatment noted for paddy grain yield was the combination of FA + FYM (92% increase over control) followed by FYM and FA. Significant correlation was noted among soil physico-chemical properties (except soil pH) and paddy productivity. The results suggested that FA and FYM amendments enhance the rates of N-transformation processes, plant available-N and paddy productivity. Thus, FA and FYM can be used as potential amendments to enrich soil productivity and crop yields for dry tropical nutrient poor soils.

Amendments and their combined application for enhanced copper, cadmium, lead uptake by Lolium perenne

Chemical amendments can enhance heavy metal phytoextraction by increasing metal bioavailability for plant root uptake and translocation to shoots, and by improving plant growth. This study assessed the effect of various amendments on plant growth and metal uptake over a 30-day period. An aminopolycarboxylic acid (EDDS), amino acid (histidine), organic acid (citric acid), biosurfactant (rhamnolipid), and inorganic ligand (sulfate) were applied as amendments individually or in combination to hydroponically grown ryegrass (Lolium perenne cv. SR4500) in the presence of a metal (Cu, Cd or Pb). EDDS (1 mM) was the most effective amendment (individually and in combinations) for enhancing Cu and Pb uptake to shoot tissue, while histidine was beneficial for increasing both Cu and Cd uptake. Individual treatments of citric acid, rhamnolipid and sulfate moderately enhanced shoot concentrations of Cu and Cd only. The combination of EDDS, rhamnolipid and citric acid resulted in the highest shoot metal levels, but also caused severe phytotoxicity. Translocation to shoot tissue was generally greater for amendments with higher affinity for the metal of interest, and metal mobility appeared to be influenced by speciation. Due to potential toxicity, amendment combinations may be more effective when applied shortly before harvesting.

Influence of pea and wheat growth on Pb, Cd, and Zn mobility and soil biological status in a polluted amended soil

In this paper we evaluated the effects of various amendments, notably zeolite, red mud (a by-product of aluminium manufacturing) and lime on decreasing the bioavailability and phytotoxicity of Pb, Cd and Zn present in a contaminated acidic soil (pH = 4.2). Pisum sativum and Triticum vulgare were grown in a glasshouse experiment on untreated-polluted (control) and amended soils and their yield and metal uptake determined. The influence of plants on the total concentration and mobility of Pb, Cd, and Zn, and on several soil microbiological and biochemical parameters was also evaluated and compared to unplanted (control and amended) soils on which we have previously reported. All the amendments enhanced plant yields significantly. Red mud and lime decreased Zn, Pb and Cd availability to plants, whilst zeolite was efficient only at blocking Pb. Red mud in particular decreased heavy metal uptake of pea and wheat by 60–34% (Pb), 79–80% (Cd), and 93–64% (Zn) respectively when compared to the control plants. After plant growth, Cd and Zn solubility in the amended soils was significantly higher than in respective unplanted soils. Likewise, the number of fast-growing heterotrophic bacteria and fungi was higher after pea and wheat compared to bare soil, and this was irrespective of the treatment applied. These data together with Biolog-derived parameters (AWCD and richness) and enzyme activities (dehydrogenase, urease and β-glucosidase) also suggested that pea rhizodeposits, in the different soils, were either more abundant or more readily-available to soil bacterial communities compared to wheat rhizodeposits.