Effect of water and nitrogen management on aggregate size and carbon enrichment of soil in rice‐wheat cropping system     

Rojalin Tripathy  Anil Kumar Singh 《植物养料与土壤学杂志》2004,167(2):216-228

A study was carried out on a silty clay loam soil (Typic Haplustept) to evaluate the effect of farmyard manure (FYM) vis‐à‐vis fertilizer and irrigation application on the soil organic C content and soil structure. The fertilizer treatments comprised of eight different combinations of N and FYM and three water regimes. The results indicated that the application of FYM and increasing N rate increased soil organic carbon (SOC) content. Addition of FYM also increased the percentage of large sized water stable aggregates (> 5 mm) and reduced the percentage of smaller size aggregates. This was reflected in an increase in the mean weight diameter (MWD) and improved soil structure. The organic carbon content in macroaggregates (> 1 mm) was greater compared to microaggregates, and it declined with decrease in size of microaggregates. This difference in organic C content between macro‐ and microaggregates was more with higher N dose and FYM treated plots. The effect of residual FYM on MWD and organic C content of the soil after wheat harvest was not significant. The effect was less in deeper layers compared to surface layers of the soil. MWD was significantly correlated with the SOC content for the top two layers.  相似文献   

Novel method for isolation of major phenolic constituents from cashew (Anacardium occidentale L.) nut shell liquid     

Paramashivappa R  Kumar PP  Vithayathil PJ  Rao AS 《Journal of agricultural and food chemistry》2001,49(5):2548-2551

Commercially available cashew (Anacardium occidentale L.) nut shell liquid (CNSL) mainly contains the phenolic constituents anacardic acid, cardol, and cardanol. These phenolic constituents are themselves heterogeneous, and each of them contains saturated, monoene, diene, and trienes in the fifteen-carbon side chain. This communication describes the separation of anacardic acid, cardol, and cardanol for industrial application. Anacardic acid was selectively isolated as calcium anacardate. The acid-free CNSL was treated with liquor ammonia and extracted with hexane/ethyl acetate (98:2) to separate the mono phenolic component, cardanol. Subsequently, ammonia solution was extracted with ethyl acetate/hexane (80:20) to obtain cardol.  相似文献   

Leaching of pesticides in tea brew.   总被引：2，自引：0，他引：2  

S Jaggi  C Sood  V Kumar  S D Ravindranath  A Shanker 《Journal of agricultural and food chemistry》2001,49(11):5479-5483

A cup of tea that cheers can also be an important route of human exposure to pesticide residues. It is important to evaluate the percent transfer of pesticide residue from dried (made) tea to tea infusion, as tea is subjected to an infusion process prior to human consumption. To investigate the pesticide translocation, 13 pesticides commonly used on tea were studied by subjection of fortified teas to infusion. Analytes of interest were quantified by gas-liquid chromatography with nitrogen-phosphorus and electron capture detectors. Interestingly, water solubility of pesticides did not necessarily indicate a shift of residues toward their preferential accumulation in infusion. The pesticides with larger partition coefficient (K(ow)) values remained nonextractable in infusing water. Further, boiling for longer periods (extended brewing time) resulted in higher transfer of pesticides to tea brew.  相似文献   

Synthesis and quantitative structure-activity relationships of oxanilates as chemical hybridizing agents for wheat (Triticum aestivum L.)     

Chakraborty K  Devakumar C  Tomar SM  Kumar R 《Journal of agricultural and food chemistry》2003,51(4):992-998

Chemical hybridizing agents (CHAs) can facilitate two-line breeding in heterosis programs of crops. Twenty-seven oxanilates having different aromatic substitutions were synthesized and screened as CHAs on two genotypes of wheat, PBW 343 and HD 2733, during two Rabi (winter) seasons, 2000-01 and 2001-02. The oxanilates prepared by thermal condensation of anilines with diethyl oxalate or by acylation with ethoxycarbonyl methanoyl chloride were sprayed at 1000 and 1500 ppm at the premeiotic stage of wheat, when the length of the emerging spike of the first node was 7-8 mm. Pollen sterility and spikelet sterility were measured in each treatment. Ethyl oxanilates 5, 6, and 25,containing 4-F, 4-Br, and 4-CF(3) aromatic substituents, respectively, induced greater than 98% spikelet sterility, the desired level, at 1500 ppm. Quantitative structure-activity relationship analysis revealed a direct relationship between F(p) and molecular mass but an inverse relationship between MR, E(S), and R in influencing the bioactivity. Several F(1) hybrids were developed using 5, and at least one showed heterosis.  相似文献   

Synthesis of sildenafil analogues from anacardic acid and their phosphodiesterase-5 inhibition     

Paramashivappa R  Phani Kumar P  Subba Rao PV  Srinivasa Rao A 《Journal of agricultural and food chemistry》2002,50(26):7709-7713

Anacardic acid (6-pentadecylsalicylic acid), a major component of cashew nut shell liquid, consists of a heterogeneous mixture of monoenes, dienes, and trienes. The enes mixture of anacardic acid was hydrogenated to a saturated compound. Using saturated anacardic acid as a starting material, analogues of sildenafil [a potent phosphodiesterase-5 (PDE(5)) inhibitor and an orally active drug for the treatment of erectile dysfunction] were synthesized, to observe the effect of the pentadecyl side chain on PDE(5) inhibition. The synthesized compounds were characterized by spectral studies and tested for PDE(5) inhibition, and the results were compared with those obtained with sildenafil.  相似文献   

Uptake and bioconcentration of dieldrin,dimethoate, and permethrin by Tetrahymena pyriformis     

Pradeep Bhatnagar  Surendar Kumar  Rup Lal 《Water, air, and soil pollution》1988,40(3-4):345-349

A ciliate protozoan, Tetrahymenapyriformis was exposed to three insecticides, dieldrin, dimethoate, and permethrin for 12 hr to study the uptake and bioconcentration potential. Ciliates concentrated 922, 3547, and 1056 gg g^?1 dry wt. over an initial concentration of 1 gg mL^?1 of dieldrin, dimethoate, and permethrin, respectively. The highest bioconcentration factor for three insecticides was 2095, 3547, and 1110, respectively. It is suggested that if levels in the environment reach 1 gg mL^?1 the chief effects would be reduction of cell population, and accumulation of the toxicants by ciliates. Accumulation of insecticides by ciliates would permit the toxicants to enter aquatic food chains. Thus the compounds could exert toxic effects at higher trophic levels.  相似文献   

Soil Chemical and Biological Activities under Vegetable Intensive Colocasia-based Cropping System in Indian Sub-Himalayas     

Mangal Deep Tuti  Ramesh Singh Pal  Dibakar Mahanta  Brij Mohan Pandey  Jaideep Kumar Bisht 《Communications in Soil Science and Plant Analysis》2020,51(7):948-962

ABSTRACT

Lack of crop diversification with suitable vegetable-based cropping system is a major constraint in limiting the productivity and sustainability of north-western Indian sub-Himalayas. To find out a sustainable vegetable-based cropping system in this region, a three year colocasia-based vegetable intensive experiment was conducted at Hawalbagh, Almora, India in a sandy clay loam soil under sub-temperate climatic conditions. Seven colocasia-based vegetable cropping systems along with rice–wheat system were compared under recommended package and practices. The system productivity in terms of colocasia equivalent yield was highest under colocasia–onion–frenchbean (52.38 Mg ha^?1) system. Sustainable yield index was highest with colocasia–gardenpea–frenchbean system (0.86). After 3 years, total soil organic carbon (0–5%), available N (2–22%), P (–7% to 14%) and K (3–15%) concentrations were increased in all cropping systems except rice–wheat system, where negative balance of available P (7%) was observed over that of initial soil. Significantly higher soil microbial activity, soil carbohydrate, dehydrogenase, protease, acid and alkaline phosphatases activity were observed under colocasia–onion system. The results suggest that colocasia–onion–frenchbean system with higher productivity improves soil fertility and enhances enzymatic activities.  相似文献   

Nodule-specific expression of Rhizobium meliloti symbiotic promoters P1 and P2 in chickpea-Rhizobium sp. symbiosis     

S. P. S. Khanuja  A. Suman  G. Singh  V. Kumar 《Biology and Fertility of Soils》1994,18(2):132-136

Developmentally specific expression of Rhizobium spp. genes involved in symbiotic N₂ fixation is known to operate through cascade regulation of various nif and fix operons. Fusion constructs of lacZ under symbiotic promoters P1 (for nifHDK operon) and P2 (for fixABCX operon) of Rhizobium meliloti were mobilized into Rhizobium spp. (Cicer) strains Rcd301 and RCR13. The assays for -galactosidase activity to monitor the expression of lacZ under these promoters was performed in host backgrounds of Escherichia coli, R. meliloti, and Rhizobium spp. (Cicer). The enzyme assays indicated significant levels of expression from P1 and P2 promoters in chickpea rhizobia, specifically in symbiotic cells from nodules. However, as in R. meliloti, these promoters did not induce strong expression in free-living cells of Rhizobium spp. (Cicer). This indicates functional homology of R. meliloti promoters in rhizobium spp. (Cicer). Functional cross-reactivity of trans regulatory factors like NtrA, NtrC, and NifA between these rhizobia seems evident from the nodule-specific expression of P1 and P2 cis elements.  相似文献   

Heavy metals in coal carbonization wastewater and their complexation — Some observations     

R. A. Pandey  Animesh Kumar 《Water, air, and soil pollution》1990,50(1-2):31-38

Effluents from low temperature carbonization, high temperature carbonization and producer gas plants in India have been found to contain heavy metals. The level of metals differ from plant to plant and is attributed to operational conditions of carbonization units and quality of coal used. Phenols and organic bases present in the effluent can form organometallic complexes with metal ions present. Such complexes are of environmental significance being toxic, mutagenic and teratogenic in nature. The present investigation showed that LTC wastewater forms complexes with Fe, Cu, and Co, however it does not form any complex with Mn and Zn.  相似文献   

Effect of sewage sludge–coir pith pellets on dry matter yield and trace metal concentration in various plant parts of forage maize     

J. Somasundaram  R. Krishnasamy  P. Savithri  M. Vassanda Coumar  V. Arun Kumar  B. Satish Kumar 《Journal of plant nutrition》2016,39(11):1556-1569

Sewage sludge (SS), a highly heterogeneous semisolid fraction of sewage water (about 1% of the sewage water), contains various amounts of nitrogen (N) and phosphorus (P) as well as trace elements such as cadmium (Cd), lead (Pb), copper (Cu), nickel (Ni) and zinc (Zn) with extremely variable physical and chemical compositions. Application of SS improves soil properties, increases yield and simultaneously increases trace metal content in soil and plants. The difficulty in handling, transporting and applying SS and its adverse effect, especially trace metal content in soil and plant, can be overcome by SS–coir pith pelletization (SSCP) or mixing with sewage sledge–coir pith mixture (SSCM). A study was undertaken to evaluate the prepared SSCM and SSCP (1:1 ratio of SS and coir pith) along with SS on dry matter yield, trace metal content in soil and plant parts. The results showed that increased rates of application of SS or SSCM or SSCP increased the green and dry fodder yield of forage maize. Application of SS as either SSCM or SSCP at 1.2 and 2.4 g pot^?1 significantly reduced the trace metal content diethylene triamine pentaacetic acid (DTPA extractable) in soil and plant parts (leaves steam and root) compared to SS application. Therefore, in order to reduce the bioavailability of trace metal in soil and its uptake by plant, application of SSCM or SSCP at 1.2 or 2.4 g pot^?1 proved to be a better option than SS application.  相似文献