Nutrient management effects on organic carbon pools in a sandy loam soil under rice-wheat cropping

Agricultural management practices are known to influence soil organic C. While changes in total organic C (TOC) are relatively less discernible over short to medium-term, some extractable pools of TOC are considered early indicators of changes in TOC. Therefore, to devise nutrient management practices that can lead to C sequestration, it is important to study their effect on soil organic C pools that may respond rapidly to management. We studied the impact of balanced (NPK) and imbalanced (N, NP, NK and PK) application of fertilizer nutrients without and with farmyard manure (FYM) on total and labile pools of organic C viz. water soluble (WEOC), potassium permanganate oxidizable (KMnO₄-C), microbial biomass (MBC) and fractions of decreasing oxidizability after 5-cycles of rice-wheat cropping. Integrated use of NPK and FYM significantly increased TOC and extractable C pools in both surface (0–7.5 cm) and sub-surface (7.5–15 cm) soil. Majority of TOC (72%) was stabilized in less labile and recalcitrant fractions; the magnitude being higher under balanced (NPK+FYM) than imbalanced nutrient management (N+FYM). The results showed that balanced fertilizer application conjointly with FYM besides enlarging TOC pool favorably impacts soil organic matter composition under rice-wheat system.     

Dry Electrostatic Spray Coated Towpregs for Thermoplastic Composites

Though the processing steps for the manufacture of thermoplastic composites present little difficulty when compared to those for thermoset composites, it is not cost effective as a result of difficulty in accomplishing thorough infusion of resin into fibers and fibrous structures. Tremendously high viscosity for thermoplastic resin leads to numerous problems in the manufacturing process of thermoplastic composites. Pre-impregnation processes such as melt impregnation or solution impregnation, tend to form a stiff towpreg that cannot be used for any textile preforming operation. Powder coating can be a destined to be a cost effective as well as efficient processing technology to produce a flexible towpreg. A method for production of flexible towpregs for thorough infusion of resin into fibers using electrostatic spray gun, which involves powder coating a bundle of filaments is described. During the powder coating process using electrostatic spray gun, powder particles fetched by a conveying air stream, from a fluidizing hopper, are charged in the high voltage corona discharge by ion bombardment and transported to the fiber tow through the combination of electrostatic, aerodynamic and gravitational forces. Aerodynamic forces have the obligation to carry the powder particles to the tow where electrostatic forces dominate and cause the adherence of powder particles to the potentially grounded tow. After the powder deposition, tow is made to pass through convective oven where powder particles glue to the reinforcement as a result of partial liquefaction of the powder. The towpreg formed is then wound by the take up device. Take up device is equipped with dancer arm which ensures constant line tension and thereby consistent powder deposition. The effects of process variables of the electrostatic spray process such as corona voltage, fluidizing air pressure, conveying air pressure, distance of gun from tow and tow velocity on maximum powder deposition are investigated and reported.     

Pesticidal properties of parthenin (from Parthenium hysterophorus) and related compounds

Eleven sesquiterpene lactone derivatives of parthenin ( 1 ), obtained from wild feverfew, Parthenium hysterophorus, were prepared by chemical and photochemical transformations. The compounds tested were a pyrazoline adduct ( 2 ) of parthenin, its cyclopropyl ( 3 ) and propenyl ( 4 ) derivatives, anhydroparthenin ( 5 ), a dihydro‐deoxygenated product ( 6 ), a formate ( 7 ) and its corresponding alcohol ( 8 ) and acetate ( 9 ), a rearranged product ( 10 ), lactone ( 11 ) and hemiacetal ( 12 ). All these derivatives, along with parthenin, were tried for their antifeedant action against sixth‐instar larvae of Spodoptera litura, for insecticidal activity against the adults of store grain pest Callosobruchus maculatus, for phytotoxic activity against Cassia tora, and for nematicidal activity against the juvenile stage‐II (J₂) of the root knot nematode Meloidogyne incognita. Antifeedent bioassay revealed that parthenin is moderately antifeedant. Among the derivatives, the saturated lactone ( 11 ) was found to be about 2.25 times more active than parthenin. The pyrazoline adduct ( 2 ) was found to be the most effective as an insecticide, with LC₅₀ values after 24, 48 and 72 h of 96, 43 and 32 mg litre⁻¹, respectively, which are comparable with neem extract. Compound 4 was found to be the most effective inhibitor of germination and seedling growth of C tora, with ID₅₀ values for germination, plumule length and radicle length of 136, 326 and 172 compared with 364, 738 and 427 mg litre⁻¹, respectively, for parthenin. Compound 10 was found to be the most effective in terms of nematicidal activity. The LC₅₀ values for this compound were 273 and 104 mg litre⁻¹, respectively, after 48 and 72 h compared with 862 and 512 mg litre⁻¹ observed for parthenin after 48 and 72 h. © 2001 Society of Chemical Industry     

Molecular docking and simulation studies of 3‐(1‐chloropiperidin‐4‐yl)‐6‐fluoro benzisoxazole 2 against VP26 and VP28 proteins of white spot syndrome virus

White spot syndrome virus (WSSV), an aquatic virus infecting shrimps and other crustaceans, is widely distributed in Asian subcontinents including India. The infection has led to a serious economic loss in shrimp farming. The WSSV genome is approximately 300 kb and codes for several proteins mediating the infection. The envelope proteins VP26 and VP28 play a major role in infection process and also in the interaction with the host cells. A comprehensive study on the viral proteins leading to the development of safe and potent antiviral therapeutic is of adverse need. The novel synthesized compound 3‐(1‐chloropiperidin‐4‐yl)‐6‐fluoro benzisoxazole 2 is proved to have potent antiviral activity against WSSV. The compound antiviral activity is validated in freshwater crabs (Paratelphusa hydrodomous). An in silico molecular docking and simulation analysis of the envelope proteins VP26 and VP28 with the ligand 3‐(1‐chloropiperidin‐4‐yl)‐6‐fluoro benzisoxazole 2 are carried out. The docking analysis reveals that the polar amino acids in the pore region of the envelope proteins were involved in the ligand binding. The influence of the ligand binding on the proteins is validated by the molecular dynamics and simulation study. These in silico approaches together demonstrate the ligand's efficiency in preventing the trimers from exhibiting their physiological function.     

Effect of long-term application of rice straw,farmyard manure and inorganic fertilizer on potassium dynamics in soil

Knowledge of K-dynamics in soils can help devise practices for efficient K management in intensive rice-wheat systems. We studied the effect of long-term application of rice straw, farmyard manure (FYM) and inorganic fertilizer on total K and its distribution among different forms in 60-cm soil profile after 14 years of rice-wheat cropping. The exchangeable, the non-exchangeable and the lattice K respectively comprised 1%, 3–10% and 89–95% of total K in surface soil under different treatments. Application of rice straw and FYM positively impacted total K status of soil and its distribution among different forms. The greatest concentrations of total K, lattice K, exchangeable K and NH₄OAc-extractable K were observed in plots receiving both rice straw and FYM together and the lowest in inorganic fertilizer treated plots. On the contrary, the non-exchangeable K was the highest in inorganically fertilized plots and the lowest in rice straw amended plots. The exchangeable, the water soluble and the NH₄OAc-extractable K decreased with soil depth and did not indicate K movement beyond the rooting zone of the crops. The results showed that incorporation of rice residue in soil, instead of burning, besides reducing environmental pollution led to improved K-fertility of soils.     

Tuberculosis seroprevalence and comparison of hematology and biochemistry parameters between seropositive and seronegative captive Asian elephants of Nepal

We conducted a tuberculosis (TB) serosurveillance program of captive elephants in Nepal and compared hematology and biochemistry parameters between seropositive and seronegative elephants. A total of 153 elephants (male=20, female=133) from four national parks were tested for TB using the ElephantTB STAT-PAK^® Assay (ChemBio Diagnostic Systems, Inc., Medford, NY, USA). The mean reported age for 138 elephants was 38.5 years (range 2–71 years). Seroprevalence for TB was 21.56% (33/153). The majority of seropositive elephants were female (n=30) and from Chitwan National Park (n=29). The occurrence of TB seropositive cases in other more remote national parks suggests TB may be widespread among the captive elephant population of Nepal. Hematology and biochemistry analyses were performed on 13 and 22 seropositive elephants, respectively and, nine elephants from a seronegative TB herd for comparison. Hematology parameters (hemoglobin, packed cell volume, platelet, white blood cells, and erythrocyte sedimentation rate) were comparable between the two groups. Total protein, globulin, and lactate dehydrogenase were significantly higher in seronegative elephants, and bilirubin was significantly higher in seropositive elephants whereas blood urea nitrogen, creatinine, glutamic oxaloacetic transaminase/aspartate aminotransferase (GOT/AST), glutamic pyruvic transaminase/alanine aminotransferase (GPT/ALT), gamma glutamyl transferase (GT), and albumin were not significantly different. The range of biochemical parameters that were significantly different between seropositive and seronegative elephants had narrow ranges. Thus, the potential of these parameters as a direct biomarker for TB diagnosis is limited based on the findings in this study. We recommend including blood parameters in future TB surveillance studies.     

<Emphasis Type="Italic">In vitro</Emphasis> propagation of <Emphasis Type="Italic">Trichosanthus dioica</Emphasis> Roxb. for nutritional security

The pointed gourd (Trichosanthes dioica Roxb.) is an important cucurbit reported for its medicinal value, therapeutic potential, and as a popular delicacy (especially in Indian cuisine). Being nutritive and desirous, it has potential to feed the nations and addresses their nutritional security and economic prosperity. The plant is usually vegetatively propagated and cultivated for fruits during summer and rainy seasons. The limited supply of planting material, limits cultivation and production. The present study was in anticipation for direct organogenesis, callus induction, and somatic embryo formation from leaf and node explants of T. dioica Roxb. In this study, the MS medium supplemented with 0.5 mg/L BA and 0.5 mg/L 2,4-D was found to be most efficient for callus induction, followed by 0.5 mg/L Kn and 0.5 mg/L 2,4-D. The embryogenic callus was developed by sub-culturing of node callus in the same media. The scanning electron microscopic (SEM) analysis revealed the presence of embryogenic cell clusters having globular embryos, which were found irresponsive to develop further. Through direct organogenesis, the node explants have responded to produce true-to-type plants for propagation. It was observed that MS supplemented with 1.0 mg/L BA was efficient for shoot proliferation, and 0.5 mg/L IAA was found more efficient for root development. Notably, the plant remains unexplored in its potential for improvement involving molecular breeding and tissue culture. These results may be effective to produce genetically stable plants on a large scale and aid the genetic improvement of pointed gourds.     

Water productivity,nutrients uptake and quality of aerobic rice as influenced by varieties and iron nutrition

Field experiments were carried out at the research farm of ICAR-Indian Agricultural Research Institute (ICAR-IARI), New Delhi, India, during Kharif (June–October) seasons of 2011 and 2012 to study the effect of rice varieties and iron fertilization on water productivity, nutrient uptake and quality of aerobic rice. Treatments comprised of two rice varieties (PRH-10 and PS-5) and eight sources and modes of iron fertilization—control (no iron), iron sulphate @ 50 kg/ha + one foliar spray of 2.0% iron sulphate, iron sulphate @ 50 kg/ha + one foliar spray of 0.5% iron chelate, iron sulphate @ 100 kg/ha, two foliar sprays of 2.0% iron sulphate, three foliar sprays of 2.0% iron sulphate, two foliar sprays of 0.5% iron chelate and three foliar sprays of 0.5% iron chelate. Study results indicated that variety PRH-10 had higher concentration and uptake of nitrogen, phosphorus, potassium and iron than PS-5 variety in grain, straw and grain + straw. Three foliar sprays of 2.0% iron sulphate or 0.5% iron chelate favoured higher NPK and iron concentration and uptake in grain and straw of aerobic rice. Grain quality in respect of hulling, milling and head rice recovery was, however, superior in PS-5 than PRH-10. But the protein content was significantly higher in PRH-10 than in PS-5. Application of three foliar sprays of 2% iron sulphate and three foliar sprays of 0.5% iron chelate recorded significantly higher hulling, milling and head rice recovery as compared to control and remained statistically similar with each other. Irrigation and total water productivity was substantially higher in PRH-10 over PS-5. Growing of rice with PRH-10 recorded ~7.7% higher total water productivity as compared to PS-5, across iron fertilizations. Three or two foliar sprays of 2.0% iron sulphate or 0.5% iron chelate favoured higher irrigation and total water productivity of aerobic rice over control (no iron).     

Influence of leguminous cover crops on microbial and selected enzyme activities in soils of a plantation

A study dealing with ecological sustainability of plantation based land use initiated in 1991 in a 19 yr old coconut plantation consists of growing certain leguminous crops like Atylosia, Pueraria, Centrosema and Calopogonium as soil cover in separate plots with lemon grass as live bounds. These cover crops are grown during the rainy season and incorporated into the soil towards the end of the monsoon every year. The effect of such cover crops on soil microbial counts (total counts, fungi, actinomycetes and bacteria), biomass C, organic C, total N and on the activity of enzymes like urease, amidase, L-glutaminase, aryl sulphatase and dehydrogenase was determined in soils (Ap horizon) collected from these plots after 5 years. Soils with cover crops registered significantly higher microbial biomass, biomass C, organic C and total N compared to control. Consequently, all the enzymes were activated to different degrees in soils with cover crops. Significant and positive relationships of enzyme activities with organic C, mineral N and total N suggested that growing cover crops, increased C turnover and N availability and therefore, provided a conducive environment for microbial proliferation, enzyme synthesis and accumulation in the soil matrix.