Effect of biochar and nitrapyrin on nitrous oxide and nitric oxide emissions from a sandy loam soil cropped to maize

A field experiment was conducted to evaluate the combined or individual effects of biochar and nitrapyrin (a nitrification inhibitor) on N₂O and NO emissions from a sandy loam soil cropped to maize. The study included nine treatments: addition of urea alone or combined with nitrapyrin to soils that had been amended with biochar at 0, 3, 6, and 12 t ha^?1 in the preceding year, and a control without the addition of N fertilizer. Peaks in N₂O and NO flux occurred simultaneously following fertilizer application and intense rainfall events, and the peak of NO flux was much higher than that of N₂O following application of basal fertilizer. Mean emission ratios of NO/N₂O ranged from 1.11 to 1.72, suggesting that N₂O was primarily derived from nitrification. Cumulative N₂O and NO emissions were 1.00 kg N₂O-N ha^?1 and 1.39 kg NO-N ha^?1 in the N treatment, respectively, decreasing to 0.81–0.85 kg N₂O-N ha^?1 and 1.31–1.35 kg NO-N ha^?1 in the biochar amended soils, respectively, while there was no significant difference among the treatments. NO emissions were significantly lower in the nitrapyrin treatments than in the N fertilization-alone treatments (P?<?0.05), but there was no effect on N₂O emissions. Neither biochar nor nitrapyrin amendment affected maize yield or N uptake. Overall, our results showed that biochar amendment in the preceding year had little effect on N₂O and NO emissions in the following year, while the nitrapyrin decreased NO, but not N₂O emissions, probably due to suppression of denitrification caused by the low soil moisture content.     

Paratuberculosis in cattle and free-living exotic deer.

Paratuberculosis was studied among dairy cows and exotic deer that shared grazing areas at Point Reyes National Seashore, California. Of the 10 dairy herds tested, 5 (50%) were infected with Mycobacterium paratuberculosis (based on results of fecal culture). Mycobacterium paratuberculosis was cultured from 9 (8.7%) of the 103 bovine fecal samples and from 4 (3.9%) of the 103 bovine rectal mucosa scapings tested. Of 89 fecal samples from 52 axis deer (Axis axis) and 37 fallow deer (Dama dama), 5 (9.6%) and 3 (8.1%), respectively, contained M paratuberculosis. Culture of intestinal necropsy samples from the same deer indicated that 3 (5.8%) of the axis deer and 2 (5.4%) of the fallow deer were infected with M paratuberculosis. The cows were tested for serum antibodies by the complement-fixation test and by radioimmunoassay. Of 95 sera tested by complement fixation, 15 (15.8%) were positive, as were 15 (14.7%) of 102 sera tested by radioimmunoassay. Culture results and serologic test results were compared on a herd basis.     

Biochemical effect of steroid anaesthesia on some liver function tests in goat

Saffan, as a type of steroid anaesthetic, was tested to demonstrate the effect of its administration on liver function in goat. For this purpose, 40 healthy animals were divided into 4 equal groups. The 1st 2 groups were given 2 or 4 mg saffan/kg body weight (B.W.), respectively. A mixture of saffan (1 mg) and xylazine (0.1 mg)/kg B.W. was given to the 3rd group. Xylazine alone was offered to the 4th group in a concentration of 0.1 mg/kg B.W. Serum samples from all groups were analysed to measure the quantities of glucose, total protein, total and direct bilirubin as well as the activity levels of transaminases. Increased glucose levels resulted from administration of saffan which evoked more hyperglycaemia than its mixture with xylazine or xylazine alone. The hyperglycaemic effect of both doses of saffan was equivocal beyond 2 hours. The effect then differed, and glucose elevation reached the 4 fold level by 2 mg saffan and the 3 fold level by 4 mg. Total serum protein, direct and total bilirubin as well as GPT and GOT were not changed in the 4 experimental groups. This was a good indication to normal liver function in the course of administration of steroid anaesthetics to goat.     

Municipal Solid Waste Compost Improves Crop Productivity in Saline-Sodic Soil: A Multivariate Analysis of Soil Chemical Properties and Yield Response

A pot experiment was conducted in sandy clay loam saline-sodic soil to assess the effects of farm yard manure (FYM), municipal solid waste (MSW) composts and gypsum application on nitrate leaching, soil chemical properties and crop productivity under rice-wheat cropping system. It also aims at establishing the correlation between soil phsico-chemical properties and yield response using principle component analysis and Pearson correlation analysis. The MSW was decomposed aerobically, an-aerobically and co-composted. Maximum nitrate leaching was observed during rice (75.9 mg L^?1) and wheat (37.2 mg L^?1) with an-aerobically decomposed MSW as compared with control treatment. Results revealed a decrease in soil pH (?6.95% and ?8.77%), electrical conductivity (EC) (?48.13% and ?51.04%), calcium carbonate (CaCO₃) (?40.30% and ?48.96%), and sodium adsorption ratio (SAR) (?40.27% and ?45.98%) with an-aerobically decomposed MSW compost during rice and wheat, respectively. In this treatment, organic matter (OM) (93.55% and 121.51%) and cation exchange capacity (CEC) (19.31% and 31.79%) were the highest as compared with control treatment during rice and wheat, respectively. Rice and wheat growth were significantly (p≤ 0.05) increased by an-aerobically decomposed MSW followed by co-compost, aerobically decomposed MSW, FYM, gypsum and control. Furthermore, Pearson correlation coefficients predicted significant positive correlation of yield with soil OM, and CEC while inverse relationship was observed with EC, pH, CaCO₃, and nitrogen use efficiency. Soil amelioration with organic and gypsum amendments was further confirmed with principal component analysis. This study has proved an-aerobically decomposed MSW as an effective solution for MSW disposal, thereby improving soil chemical properties and crop productivity from sandy clay loam saline-sodic soil.     

Nitrous oxide emissions from a rainfed-cultivated black soil in Northeast China: effect of fertilization and maize crop

Nitrous oxide emission (N₂O) from applied fertilizer across the different agricultural landscapes especially those of rainfed area is extremely variable (both spatially and temporally), thus posing the greatest challenge to researchers, modelers, and policy makers to accurately predict N₂O emissions. Nitrous oxide emissions from a rainfed, maize-planted, black soil (Udic Mollisols) were monitored in the Harbin State Key Agroecological Experimental Station (Harbin, Heilongjiang Province, China). The four treatments were: a bare soil amended with no N (C0) or with 225?kg?N ha^?1 (CN), and maize (Zea mays L.)-planted soils fertilized with no N (P0) or with 225?kg?N ha^?1 (PN). Nitrous oxide emissions significantly (P?<?0.05) increased from 141?±?5?g N₂O-N?ha^?1 (C0) to 570?±?33?g N₂O-N?ha^?1 (CN) in unplanted soil, and from 209?±?29?g N₂O-N?ha^?1 (P0) to 884?±?45?g N₂O-N?ha^?1 (PN) in planted soil. Approximately 75?% of N₂O emissions were from fertilizer N applied and the emission factor (EF) of applied fertilizer N as N₂O in unplanted and planted soils was 0.19 and 0.30?%, respectively. The presence of maize crop significantly (P?<?0.05) increased the N₂O emission by 55?% in the N-fertilized soil but not in the N-unfertilized soil. There was a significant (P?<?0.05) interaction effect of fertilization?×?maize on N₂O emissions. Nitrous oxide fluxes were significantly affected by soil moisture and soil temperature (P?<?0.05), with the temperature sensitivity of 1.73–2.24, which together explained 62–76?% of seasonal variation in N₂O fluxes. Our results demonstrated that N₂O emissions from rainfed arable black soils in Northeast China primarily depended on the application of fertilizer N; however, the EF of fertilizer N as N₂O was low, probably due to low precipitation and soil moisture.     

细虫草资源研究现状及开发利用进展

细虫草(Ophiocordyceps gracilis)是一种虫生真菌,为传统的哈萨克民族药,一直以来被作为冬虫夏草的替代品使用,具有重要的食用和药用价值。本文从分布、生境、形态特征、系统发育分类、生物活性成分、药理作用、人工培养菌丝体及寄主昆虫等方面对细虫草的研究进展进行总结,并对其研究前景进行了展望,为今后细虫草的研究和开发利用提供参考。     

Phytotoxic potential of Chrysopogon aciculatus (Retz.) Trin. (Poaceae)

The creeping weed, Chrysopogon aciculatus (Retz.) Trin., is widely known for its use as folk medicine, while its phytotoxic potential has not been examined. Therefore, we carried out an investigation into the phytotoxic potential of C. aciculatus to identify phytotoxic substances. C. aciculatus extracts showed inhibitory effects on shoot and root growth of cress, lettuce, rapeseed, and Italian ryegrass. Inhibition was both species‐dependent and concentration‐dependent. Two substances, (9S,10E,12Z)‐9‐hydroxyoctadeca‐10,12‐dienoic acid (9‐HO‐ODDEA) and rhizopycnin A, were isolated using chromatographies and characterized by spectral analysis. 9‐HO‐ODDEA retarded shoot and root growth of cress at concentrations higher than 1.0 and 0.3 mM, respectively, while on cress seedling by rhizopycnin A, the inhibition began from 1.0 mM. The concentrations needed for 50% inhibition of the shoot and root growth of test plants ranged from 1.71–2.31, and 0.71–0.72 mM for 9‐HO‐ODDEA and rhizopycnin A, respectively. These results indicate that these substances may contribute, to a certain extent, to the phytotoxic activity of C. aciculatus.     

Preparation and characterization of jute fabrics reinforced urethane based thermoset composites: Effect of UV radiation

Jute fabrics reinforced thermoset composites were prepared with different formulations using urethane acrylate oligomer, methanol, and benzyl peroxide. Jute fabrics were soaked in the prepared formulations and fiber content in the composites was optimized with the extent of mechanical properties. Among all the resulting composites, 55 wt% jute content at oligomer:methanol:benzyl peroxide=75:24.5:0.5 (w/w/w) ratio showed best mechanical properties. The optimized jute fabrics were cured under UV radiation at different intensities and their mechanical properties were measured. Jute fabrics were treated with potassium permanganate (KMnO₄) solution of different concentrations (0.01, 0.02, 0.03, and 0.05 wt%) for different soaking times (1–5 min) before the composite fabrication. Optimized jute fabrics (jute fabrics treated with 0.02 wt% KMnO₄ for 2 min soaking time) were soaked in the optimized formulation and cured under UV radiation at different intensities and measured their mechanical properties. Scanning electron microscopic investigation showed that surface modification improves fiber/matrix adhesion. Water uptake and soil degradation test of the treated and untreated composite samples were also performed.     

Mechanical and electrical properties of photocured jute fabric with 2-hydroxy ethylacrylate

Jute fabric (hessian cloth) was grafted with 2-hydroxy ethylacrylate (HEA) and aliphatic urethane diacrylate oligomer (M-1200) under UV radiation at different intensities (16, 20, 30, 40, 50, and 60 pass) in order to improve the mechanical and electrical properties. The concentrations of the monomer (HEA), and oligomer (M1200), radiation dose, and soaking time were optimized with respect to mechanical property such as tensile strength (TS) of the treated and untreated hessian cloth. The 73 % HEA, 25 % oligomer (M-1200) and 2 % photoinitiator (Darocur-1116) in 1 minute soaking time showed the highest TS at 50th UV pass. The electrical properties such as dielectric constant and loss tangent of both treated and untreated sample were measured at frequency 10 kHz with the variation of temperature. It was observed that dielectric constant and loss tangent increased with increasing temperature up to the transition temperature and then decreased.