Pressmud Subdue Phytoremediation Indices in Lead-Contaminated Soils: A Human Health Perspective.

Direct discharge of waste into water bodies and mining are two major sources of lead contamination in ecosystems. Water scarcity promoted the usage of industrial effluent-contaminated waters for crop production, mainly in peri-urban areas. These wastewaters may contain heavy metals and pollute crop ecosystems. These metals can reach the living cell via contaminated raw foodstuffs that grow under these conditions and cause various ill effects in metabolic activities. In this study, graded levels of pressmud (0, 2.5, 5, 10 g/kg) were applied on lead imposed soil with different contamination levels (0, 100, 150, 300 mg/kg) and metal dynamics was studied in spinach crop. Experimental results showed that the addition of pressmud upto 10 mg/kg had decreased different phytoremediation indices in spinach crop. Whereas, increasing Pb level enhanced the indices' values, indicating accumulation of significant amount of Pb in spinach biomass. However, application of pressmud (upto 10 mg/kg) reduced the bioconcentration factor (BCF) from 0.182 to 0.136, transfer factor (TF) from 0.221 to 0.191, translocation efficiency 66.11-59.34%; whereas, Pb removal enhanced from 0.063 to 0.072 over control treatment. These findings suggest that application of pressmud declined Pb concentration, the BCF and the TF in test crop which lead to less chances of adverse effect in human. These information are very useful for effectively managing wastewater irrigated agricultural crop production systems.

Potassium fractions in black soil mediated by integrated nutrient management modules under maize-chickpea cropping sequence.

A field experiment was conducted at the Research Farm of the ICAR-Indian Institute of Soil Science, Bhopal (India) to study influence of different integrated nutrient management (INM) modules on soil potassium (K) fractions. The experiment comprised with twelve treatments laid out in randomized block design (RBD) with three replications under maize-chickpea cropping sequence. The treatments included general recommended dose (GRD), soil test crop response (STCR) dose; combinations of inorganic and organic inputs and only organic modules. The soil samples were collected at crop harvest and analyzed for various K fractions viz., water soluble-K, available-K, exchangeable-K, HNO3-K, lattice-K and total-K. The results indicated that potassium fractions were significantly (p = 0.05) affected by different treatments. Different INM modules significantly enhanced significantly K availability in soil. Among various INM modules studied, treatment 11 (application of 20 t ha-1 FYM in maize with 5 t ha-1 FYM every year in chickpea) proved most beneficial for improving the soil K fractions. Findings of this type are important for K fertilizer management during crop production in areas with low soil fertility.

Management of plant nutrient dynamics under alkaline soils through graded application of pressmud and gypsum.

An incubation experiment was conducted to monitor the effect of different organic matter inputs with the graded application of gypsum at different time intervals on soil pH, sodium (Na) content and available plant nutrients like nitrogen (N) and sulphur (S) in alkaline soil. The experiment was formulated with nine treatments, i.e. control (T1), recommended dose of fertilizer (RDF) (T2), RDF+Gyp1 (T3), RDF+FYM5+Gyp2 (T4), RDF+FYM10+Gyp1 (T5), RDF+PM5+Gyp2 (T6), RDF+PM10+Gyp1 (T7), RDF+FYM2.5+PM2.5+Gyp2 (T8), RDF+FYM5+PM5+Gyp1 (T9) with three replications. Periodical soil samples were taken at six and twelve months intervals. Results showed that the addition of organic matter reduced the pH and Na content in the soil. More reduction was observed at one year period as compared to six months. The addition of farmyard manure (FYM) and pressmud (PM) at 10 t/ha with gypsum (1 t/ha) improved available N and available S content as compared to organic inputs (5 t/ha) with gypsum (2 t/ha) in soil. Pressmud application with FYM showed better availability of plant nutrients and a reduction of soil pH (8.39 to 7.79) and Na content from 626 to 391 mEq/L in the soil during the incubation period. During the study, the application of treatment T9 (FYM and PM in equal ratio with 1 t/ha gypsum) showed a better availability of available N (175 to 235 kg/ha) and S (15.44 to 23.24 kg/ha) and reduced the active ion concentration of Na. This study is very useful for the management of sodium toxicity, improving soil health and the mineralization rate of organic matter through the application of organic inputs for sustainable crop production.

Management of acid and alkaline phosphatase, dehydrogenase activities by sugarcane industry waste under lead contamination- A case study of Indian Vertisol.

Soil fertility management and crop productivity both are inter-related need extensive attention for sustainability. Industries are being built, which over time produces a lot of effluents containing heavy metal(s), which is then dumped on healthy soils and water bodies. Long-term discharge of lead (Pb)-containing wastewater resulted in significant Pb buildup as well as a decrease in soil biological activity. In this experiment, graded dose of Pb, i.e. 0, 100, 150 and 300 mg/kg and pressmud (PM) (0, 2.5, 5, 10 g/kg) were applied to monitor the Pb toxic effect on soil acid and alkaline phosphatase, dehydrogenase activity. Different treatment combinations were formulated and the experiment was conducted in a completely randomized design (CRD) with three replications. In this experiment, spinach crop was used as a test crop. According to the findings, increased Pb levels in the soil lowered dehydrogenase activity (DHA), acid and alkaline phosphatase. The addition of PM enhanced enzymatic activities by decreasing the labile fraction of Pb in the soil. Incorporation of PM improved the soil enzymatic activities as alkaline phosphatase activity > DHA > acid phosphatase activity in the study. This study suggested that the addition of 10 g/kg PM reduced Pb toxicity (contamination level 300 mg/kg) and improved the soil microbial properties in black soil. These findings are very useful for the remediation of Pb contaminated soil with the help of PM, particularly in peri-urban Pb effluent irrigated areas.

Can Application of Pressmud Mediated Plant Nutrient Dynamics Under Lead Contaminated Soils of Indian Vertisol?

Long- term application of marginal quality water accumulated significant amount of pollutant into the soil. It reduces soil health parameters, and crop yield and their quality. In this regards, graded application of pressmud (PM), i.e. 0, 2.5, 5 and 10 g/kg was applied on lead (Pb) contamination level (0, 100, 150, 300 mg/kg) and evaluated interaction effect on plant nutrients uptake by spinach. Analytical data showed that increasing the PM levels enhanced the macro (phosphorus, potassium, sulphur) and micro-nutrient (zinc, copper, manganese, iron) concentration into the soil. Whereas, increasing the level of Pb significantly (p ≤ 0.05) reduced the P, K and S nutrient concentration and uptake pattern by spinach crop. Increasing PM levels (control to 10 g/kg soil) improved P, K and S by 46.99, 98.96 and 76.79%, respectively in soil. This study is useful to formulate management strategies for minimizing Pb contamination in the food chain by the application of PM mostly in peri-urban areas.

Pressmud overcome lead toxicity by improving spinach biomass in lead-contaminated soils.

Lead (Pb) pollution is a severe problem that primarily affects food chain in developing countries. Continuous use of Pb containing effluent for growing food crops builds up measurable concentration of Pb in soils; and adversely affects the soil properties and crop produce quality. To reduce the Pb metal toxicity in contaminated soil, a pot experiment was conducted with graded doses of pressmud (PM) (0, 2.5, 5.0, and 10.0 g/kg) and Pb (0, 100, 150, and 300 mg/kg soil). Various metal dynamics parameters were computed after spinach crop was harvested. Result showed that higher doses of Pb (300 mg/kg) diminished the spinach root and shoot biomass during the study; whereas, application of PM improved the spinach biomass. However, increasing the pressmud reduced the Pb concentration in shoot from 6.16, 5.99, 4.94, and 3.39 µg/g. Maximum reduction was measured in highest PM applied treatment in shoot (44.92%) and root (57.33%). In this experiment, increasing level of Pb significantly uptake was recorded with higher application rate of Pb (150 and 300 mg/kg). However, elevated doses of PM from control initially enhanced the small chunk of Pb and drastically reduced the shoot Pb uptake (0.060 to 0.049 mg/pot) in maximum level of PM applied treatment. This study is very useful to improve the soil health by immobilizing the labile fraction of Pb by addition of PM in Pb-contaminated soils.

Reuse of poor-quality water for sustainable crop production in the changing scenario of climate.

The availability of freshwater is limited for agriculture systems across the globe. A fast-growing population demands need to enhance the food grain production from a limited natural resources. Therefore, researchers and policymakers have been emphasized on the production potential of agricultural crops in a sustainable manner. On the challenging side, freshwater bodies are shrinking with the pace of time further limiting crop production. Poor-quality water may be a good alternative for fresh water in water scarce areas. It should not contain toxic pollutants beyond certain critical levels. Unfortunately, such critical limits for different pollutants as well as permissible quality parameters for different wastewater types are lacking or poorly addressed. Marginal quality water and industrial effluent used in crop production should be treated prior to application in crop field. Hence, safe reuse of wastewater for cultivation of food material is necessary to fulfil the demands of growing population across the globe in the changing scenario of climate.

Maturity indices as an index to evaluate the quality of sulphur enriched municipal solid waste compost using variable byproduct of sulphur.

The aim of this study was to assess the maturity indicators of municipal solid waste compost (MSWC) enrichment with different byproduct of (sugar and fertilizer industry) sulphur (S). The concentration of total S (TS), water-soluble S (WSS), HCl extractable S and available S were significantly different in composts prepared through different byproduct of S with MSW. WSS varied from 4.6 to 5.9% of TS after 120 days of the composting period, whereas, available S varied from 14.5 - 8.6% of TS. S enriched MSW compost had lower C/N, C/S ratio and higher nitrification index as well as lower phyto-toxicity, demonstrating that composts are properly matured and stabilised. Highest compost quality index (0.97) was recorded with S1 compost. Arylsulphatase activity significantly increased with compost maturity. Results stated that all S enriched products maintained a superior amount of plant nutrients and quality indices, indicating that S enriched compost could be a possible substitute for expensive fertilizers.