Evaluation of urea loaded nanoclay biopolymer composites with Zn and P solubilizing microbes for nitrogen uptake and use efficiency in maize (Zea mays)-wheat (Triticum aestivum) cropping system

A field experiment was conducted during rainy (kharif) 2022 (July 2022–October 2022) and winter (rabi) 2022–23 (November 2022–March 2023) seasons at ICAR-Indian Agricultural Research Institute, New Delhi to evaluate a series of Zn and P solubilizing microbial culture enriched nanoclay biopolymer composite (NCBPC) loaded with nitrogenous fertilizer (urea) and the efficiency of the products for maize (Zea mays L.) and wheat (Triticum aestivum L.). Experiment consisted of 10 treatments, viz. T1, Control; T2, 100% N though urea; T3; T5; T7; and T9, 75% N as urea loaded NCBPC-A (prepared using acrylic acid + acrylamide + mango kernel flour) alone or along with P or Zn or P + Zn solubilizers; T4; T6; T8 and T10, 75% N as urea loaded NCBPC-B (prepared using acrylic acid + acrylamide + maize flour) alone or along with P or Zn or P + Zn solubilizers in a randomized block design (RBD) and replicated thrice. In both maize and wheat crop, highest grain (5.09 and 5.32 t/ha) and straw yield (6.56 and 7.45 t/ha), apparent N recovery (51.26 and 47.26%) and agronomic efficiency (12 and 13.3 kg grain yield obtained/kg N application) were obtained in treatment T10 followed by T9. In addition, total N uptake significantly enhanced by 20.1–28.4% in maize and 22.1–30.8% in wheat (T9 and T10); apparent nitrogen recovery (ANR) improved by 12.9–18.2 and 15.2–21.1% and agronomic efficiency (AE) triggered by 19.5–21.2 and 15.4–20.8% in maize and wheat crops respectively, under T9 and T10 treatments over standard urea fertilization (T2). Thus, the study concludes that, 25% N requirement could be cut down through application of 75% N (urea) loaded NCBPCs in conjunction with Zn or P or Zn + P solubilizing microbial culture as compared to sole urea application under maize-wheat cropping system

Stability Performance of Inductively Coupled Plasma Mass Spectrometry-Phenotyped Kernel Minerals Concentration and Grain Yield in Maize in Different Agro-Climatic Zones

Deficiency of iron and zinc causes micronutrient malnutrition or hidden hunger, which severely affects ~25% of global population. Genetic biofortification of maize has emerged as cost effective and sustainable approach in addressing malnourishment of iron and zinc deficiency. Therefore, understanding the genetic variation and stability of kernel micronutrients and grain yield of the maize inbreds is a prerequisite in breeding micronutrient-rich high yielding hybrids to alleviate micronutrient malnutrition. We report here, the genetic variability and stability of the kernel micronutrients concentration and grain yield in a set of 50 maize inbred panel selected from the national and the international centres that were raised at six different maize growing regions of India. Phenotyping of kernels using inductively coupled plasma mass spectrometry (ICP-MS) revealed considerable variability for kernel minerals concentration (iron: 18.88 to 47.65 mg kg–1; zinc: 5.41 to 30.85 mg kg–1; manganese: 3.30 to17.73 mg kg–1; copper: 0.53 to 5.48 mg kg–1) and grain yield (826.6 to 5413 kg ha–1). Significant positive correlation was observed between kernel iron and zinc within (r = 0.37 to r = 0.52, p < 0.05) and across locations (r = 0.44, p < 0.01). Variance components of the additive main effects and multiplicative interactions (AMMI) model showed significant genotype and genotype × environment interaction for kernel minerals concentration and grain yield. Most of the variation was contributed by genotype main effect for kernel iron (39.6%), manganese (41.34%) and copper (41.12%), and environment main effects for both kernel zinc (40.5%) and grain yield (37.0%). Genotype main effect plus genotype-by-environment interaction (GGE) biplot identified several mega environments for kernel minerals and grain yield. Comparison of stability parameters revealed AMMI stability value (ASV) as the better representative of the AMMI stability parameters. Dynamic stability parameter GGE distance (GGED) showed strong and positive correlation with both mean kernel concentrations and grain yield. Inbreds (CM-501, SKV-775, HUZM-185) identified from the present investigation will be useful in developing micronutrient-rich as well as stable maize hybrids without compromising grain yield

Not Available

Not AvailableNot AvailableNot Availabl

Not Available

Not AvailableSoil organic carbon plays a major role in sustaining agroecosystems and maintaining environmental quality as it acts as a major source and sink of atmospheric carbon. The present study aims to assess the impact of agricultural management practices on soil organic carbon pools in a maize–wheat cropping system of Indo-Gangetic Plains, India. Soil samples from a split plot design with two tillage systems (bed planting and conventional tillage) and six nutrient treatments (T=control, T2=120 kg urea–Nha -1,T3=T2(25 % N) substituted by FYM), T4=T2(25 % N substituted bysewage sludge), T5=T2+cropresidue, T=100%organic source (50 % FYM+25 % biofertilizer+25 % crop residue) were used for determining the organic carbon pools. Results show that there was a significant improvement in WalkleyandBlackcarboninsoilunderintegratedand organic nutrient management treatments. KMnO4 -oxidizable carbon content of soil varied from 0.63 to 1.50 g kg-1 in soils and was found to be a better indicator for monitoring the impact of agricultural management practices on quality of soil organic carbon than microbial biomass carbon. Tillage and its interaction were found to significantly influence only those soil organic carbon fractions closely associated with aggregate stability viz, labile polysaccharides and glomalin. The highest amount of C4-derived carbon was found to be in plots receiving recommended doses of N as urea (29 %) followed by control plots (25 %). The carbon management index ranged between 82 to 195 and was better in integrated nutrient sources than ones receiving recommended doses of nutrients through mineral fertilizers alone.Not Availabl

Not Available

Not AvailableAn incubation experiment was conducted to determine the nitrification inhibition potential of Brachiaria humidicola (B. humidicola) and their effect on nitrification process. The pots soil was mixed 2 mg of nitrogen through ammonium sulphate. Seven treatments were evaluated viz. control, four root extracts of B. humidicola called as biological nitrification inhibitors (BNIs) (i.e., 70 % ethyl alcohol, 40 % ethyl alcohol, phosphate buffer solution and 2 M KCl salt solution extracts) and two standard chemical inhibitors i.e. dicyandiamide and neem oil coating. The amount of NH4?-N was reduced 20.66–11.91 lg g-1 soil and NO3--N increased 28.89–31.18 lg g-1 soil from 14th to 22nd day time interval. Percent nitrification inhibition was more in BNIs (70 and 40 % alcohol extract) treated soils compared to plant based and synthetic nitrification inhibitors. The nitrification inhibition by B. humidicola also varied it was maximum (64.71 %) observed at 14th day over 22nd day (49.63 %).Not Availabl

Not Available

Not AvailableThe aim of the present study was to see the release pattern of phosphorus from laboratory made coated phosphatic fertilizers in soil under different temperature and moisture regimes. Four fertilizer materials were prepared by reacting ammonia with phosphoric acid (Product - A and Product - B) and rock phosphate with sulphuric and phosphoric acid (Product - C and Product - D). These materials were coated with polyvinyl alcohol, liquid paraffin and methyl oleate at two levels (2 and 3 %). The coated phosphatic fertilizers along with diammonium phosphate were applied @ 500 mg P kg - 1soil and incubated at two temperatures (20 and 30 _C) and two moisture regimes (10 and 20). Results indicated that release of P showed a decline trend from first to fourth hour of incubation, then increased and finally reached to a steady state in all the products, except Product - C. The release pattern followed the order: diammonium phosphate Product - B Product - A Product - D Product - C, corresponding with the mean values of 337.4, 227.9, 211.6, 147.1 and 69.0 mg P kg - 1soil, respectively. Results also showed the superiority of polyvinyl alcohol coated products over liquid paraffin and methyl oleate coated products. The rate of release of P was greater with increase in temperature from 20 to 30 _C. Thus, it may be concluded that laboratory made coated fertilizers could be used as a source of P which would release P slowly than the water soluble P like diammonium phosphate and supply P for a longer period that synchronizes the crop demand and enhances P use efficiency.Not Availabl

Not Available

Not AvailableA 26 years old agroforestry plantation consisting of four multipurpose tree species (MPTs) (Michelia oblonga Wall, Parkia roxburghii G. Don, Alnus nepalensis D. Don, and Pinus kesiya Royle ex - Gordon) maintained at ICAR Research Complex, Umiam, Meghalaya, India were compared with a control plot (without tree plantation) for soil fertility status and CO2 efflux. The presence of trees improved all the physico - chemical and microbial biomass parameters studied in this experiment. Relative to control, soils under MPTs showed significant increases of 17 % soil organic carbon, 26 % available nitrogen (AN), 28 % phosphorus (AP), 50 % potassium (AK), 65 % mean weight diameter (MWD) of aggregates, 21 % moisture and 34 % soil microbial biomass carbon (MBC) while reducing the mean bulk density (7 %). However, these parameters significantly differed among the tree species i.e., soils under A. nepalensis and M. oblonga had higher values of these attributes except bulk density, than under other species. Irrespective of treatments, the values of all these attributes were higher in surface soils while bulk density was highest in subsurface (60–75 cm). Cumulative CO2 efflux under MPTs was significantly higher (15 %) and ranged from 1.71 g 100 g - 1 (M. oblonga) to 2.01 g 100 g - 1 (A. nepalensis) compared to control at 150 days of incubation. In all the treatments, increment in temperature increased the oxidation of soil organic matter, thereby increased the cumulative CO2 efflux from soils. Of the tree species, with increment in temperature, A. nepalensis recorded more CO2 efflux (2.50 g 100 g - 1) than other MPTs but the per cent increase was more in control plot. P. kesiya and A. nepalensis recorded highest activation energy (59.1 and 39 kJ mol - 1, respectively). Net organic carbon sequestered in soil was highest under A. nepalensis (25.7 g kg - 1) followed by M. oblonga (19.3 g kg - 1), whereas control showed the lowest values. Amount of net carbon stored in the soil had significant and positive correlation with MBC (r = 0.706 * *), MWD (r = 0.636 *), and AN (r = 0.825 * *).Not Availabl

Comparison of properties and aquatic arsenic removal potentials of organically modified smectite adsorbents

Arsenic (As)poses a tremendous threat to human health due to exposure through arsenic-contaminated drinking water and/or food. We aimed to develop organically modified clay adsorbents for the removal of As from aqueous solution. We modified a smectite sample using three organic agents, namely hexadecyl trimethylammonium (HDTMA), chitosan and citric acid, and characterized the products using X-ray diffraction, infrared spectroscopy, and scanning electron microscopy techniques. The characterization techniques suggested successful organic modifications of the smectite sample. The surfactant-modified smectite was the most efficient (66.9%)As removing adsorbent with a maximum adsorption capacity of 473.2 μg g−1. Kinetic study showed that the adsorbents reached As adsorption equilibrium within 3 h, and the data fitted reasonably well to power function and simple Elovich equations (R2 > 0.89). The adsorption data were explained well by the Freundlich and Sips isothermal models. The surfactant-modified and chitosan-grafted organoclays adsorbed As by electrostatic attraction and anion exchange, whereas the citric acid activated smectite followed ligand exchange and simple anion exchange mechanisms. This study thus demonstrated the potential of surfactant-modified clays in removing As from contaminated waters

Not Available

Not AvailableThis study evaluates the arsenic adsorption behavior of Fe-exchanged smectite and phosphate-bound kaolinite, in soil, tap water and double distilled water in the presence of competing anions such as silicate, phosphate, and sulfate, and at variable pH values. The maximum amounts of As adsorbed in soil are 620.6 and 607.6 μg g–1 at pH 5 by Fe-exchanged smectite and phosphate-bound kaolinite, respectively. The pH-modified Freundlich equation fits well (R2 > 0.96) to the adsorption data, distinguishing the effect of pH on adsorption. The coefficients of pH-value are 0.04 and 0.05 for phosphate-bound kaolinite and Fe-exchanged smectite, suggesting that low pH is suitable for the adsorption. The As adsorption is decreased in tap water at low pH compared to the soil due to the presence of iron (Fe2+/3+), sulfate, and bicarbonate in tap water. Among the competing anions in distilled water, phosphate is the most interfering anion for As adsorption. The competition coefficients of As-phosphate binary adsorption derived from the Sheindorf equation are 3.93 and 0.56 for Fe-exchanged smectite and phosphate-bound kaolinite at pH 5. The Fe-exchanged smectite can be used more effectively than phosphate-bound kaolinite for As remediation in systems having low pH (pH ≈5) and high phosphate concentration.Not Availabl

Not Available

Not AvailableNot AvailableNot Availabl