Phytotoxicity of Sunflower Residues against Some Summer Season Crops

The growth of four summer season crops, namely Cyamopsis tetragonoloba , Sorghum vulgare , Pennisetum americanum and Zea mays , in fields with or without residues of the preceding sunflower crop was poor. Crop density, weight of seed or grain and total yield were significantly lower in sunflower fields than in the control fields (i.e. those without previous sunflower crops). Growth in terms of plant height and biomass was drastically reduced after 60 days. The effect was more pronounced in the fields where sunflower residues were allowed to decompose than in those where residues were completely removed. The soil collected from sunflower fields (both with and without residues) was found to be rich in phenolics, which in a laboratory bioassay were found to be phytotoxic. The reduced growth and yield of crops can be attributed to the release of phytotoxic phenolics from decomposing sunflower residues.     

Integrated management of major wheat diseases in Brazil: an example for the Southern Cone region of Latin America

Wheat is an important crop in the Southern Cone region of Latin America. Some of the common wheat diseases in this region are Xanthomonas streak, spot blotch, tan spot, and leaf blotch and the rusts. Rice blast on wheat could also be a problem in certain years. Disease management through varietal resistance, cultural practices including appropriate fungicidal spraying schedule, levels of tolerance for field and seed infections and seed treatment criteria, have been integrated and used for several years in Brazil. Emphasis in integrated disease management (IDM) is on reduction in use of fungicides and consequently in the cost of production. Wheat productivity in Brazil has almost doubled during the past 10 years, owing mainly to the IDM approach. The IDM practices used in Brazil for each of the major diseases can also be adopted in other Latin-American countries with similar agroecosystems.     

Mitral Valve Replacement in Dogs Surgical Technique and Postoperative Management

Although techniques for the perioperative management of patients undergoing mitral valve replacement have been well established in humans, the use of these techniques has not been widely accepted in veterinary practice. The purpose of this study is to demonstrate that low morbidity and mortality could be achieved in the dog undergoing mitral valve replacement. Nine mongrel dogs (25-45 kg body weight) were subject to left thoracotomy and mitral valve replacement using cardiopulmonary bypass (CPB). The average time on CPB was 1 hour with an aortic cross-clamping time of 40 minutes using chemically induced cardiac arrest. CPB was performed under conditions of moderate systemic hypothermia (28-30 degrees C) and hemodilution (hematocrit, 25-35%). Operative mortality was 22% (2/9) with one death from excessive bleeding and the other from cerebral air embolism. All other animals recovered and were clinically normal 3 weeks after surgery. The authors conclude that successful mitral valve replacement is possible in the large dog.     

Assessment of allelopathic interference of Chenopodium album through its leachates,debris extracts,rhizosphere and amended soil

Abstract

A study conducted to assess the allelopathic interference of invasive weed Chenopodium album indicated that aqueous leachates of C. album plant parts (roots, whole plant, and leaves), debris extracts and rhizosphere soil deleteriously affected the germination and initial growth of two test plants – Cassia occidentalis (a weed) and Phaseolus aureus (a crop). Further, the plant growth in terms of height, biomass, chlorophyll and protein content was significantly lesser in soil amended with C. album debris. Aqueous leachates, debris extracts, rhizosphere soil and debris amended soil were found to contain significantly higher amounts of water-soluble phenolics – the known phytotoxins. These phytotoxins in root, above-ground parts and leaves were phenolic acids, namely gallic, chlorogenic, caffeic, vanillic, p-coumaric, syringic and ferulic. Among these, chlorogenic acid was present in the maximum amount in the leaves and roots. The study concludes that C. album releases phenolics into the soil and these are probably involved in the growth inhibitory effect of C. album.     

Phytotoxicity of lemon-scented eucalypt oil and its potential use as a bioherbicide

The effect of volatile oil from leaves of Eucalyptus citriodora against some plant species viz. Triticum aestivum, Zea mays, Raphanus sativus, Cassia occidentalis, Amaranthus viridis and Echinochloa crus-galli was investigated. In a laboratory bioassay seed germination of test plants was significantly reduced in response to the different concentrations of the eucalypt oil. Maximum germination inhibition was observed with A. viridis, whereas least effect was seen on R. sativus. Based on the germination response, dose-response curve was generated and LC₅₀ values were calculated. It was maximum for R. sativus whereas minimum for A. viridis. Further, seedling growth of the test plants and the chlorophyll content in the treated seedlings was significantly reduced at concentrations 0.12 and 0.3 mg/l. Not only the initial growth, but also the spray treatment on the 4-week-old mature plants of two weedy species viz. C. occidentalis and E. crus-galli adversely affected the chlorophyll content and cellular respiration, thereby indicating the adverse effect of eucalypt oil on the photosynthetic machinery and the energy metabolism of the target plants. Based on the study, it is concluded that volatile oil from E. citriodora is phytotoxic and could be utilized as bioherbicide for future weed management programmes.     

Blood metabolites and body temperature of single calves between 1 and 4 days of age in a dairy herd in New Zealand

AIM: Using specified indices, to determine the nutritional and thermal status of calves between 1 and 4 days of age.

METHODS: After birth, calves (n=106) were collected daily, according to farm practice. Over the following 4 days a jugular blood sample and rectal temperature were taken twice daily before feeding. Plasma concentrations of glucose, beta-hydroxybutyrate and urea, and gamma-glutamyl transferase (GGT) activities were determined. The significance of differences in plasma composition and rectal temperature between calves whose birth had been assisted or unassisted, and between calves with low and high plasma GGT activities 24 h after birth, was determined using repeated measures analysis of varianc

RESULTS: There were no marked differences in plasma metabolite levels or body temperature of assisted and unassisted calves. Calves that had high plasma GGT activities 24 h after birth had higher plasma glucose concentrations over the 4 days than calves that had low plasma GGT activities (p<0.001). Overall, compared to published data on poorly-fed and hypothermic calves, calves in this study were normoglycaemic, their plasma beta-hydroxybutyrate and urea concentrations were low and their rectal temperatures were normal, indicating that they were well fed and did not become hypothermic.

CONCLUSIONS: The nutritional and thermal status of at least 90% of the calves was compatible with good health and survival during the first 4 days after birth.     

Long-Term Organic Amendment Application Improves Influence on Soil Aggregation,Aggregate Associated Carbon and Carbon Pools under Scented Rice-Potato-Onion Cropping System after the 9th Crop Cycle

A field experiment was conducted to investigate the influence of long-term application of organic manures on aggregate stability, associated carbon concentrations and carbon pools as an important soil-quality parameter under a scented rice-potato-onion cropping system in silt-loam textured soil in Eastern Bihar, India (subtropical climatic condition). Five treatments were used: 1) nitrogen, phosphorus and potassium (NPK) – 100% recommended dose of NPK; 2) NPK+FYM (farmyard manure) – 50%NPK+50% N as FYM; 3) FYM+VC (vermicompost)+ NC (neem cake) – different organic sources each equivalent to 1/3 of the recommended N (FYM +VC +NC); 4) FYM+VC+NC+PSB (phosphate-solubilizing bacteria – different organic sources each equivalent to 1/3 of the recommended N (FYM +VC+NC)+biofertilizers containing N and P carriers (PSB) and 5) FYM+BFN+BM+PSB – 50% N as FYM + biofertilizer for N +Bone meal to substitute P requirement of crops + PSB. The aggregate size distribution (>250 μm) at different soil depths is higher in treatment FYM+VC+NC+PSB and is at par with FYM+VC+NC, followed by FYM+BFN+BM+PSB and NPK+FYM, and the lowest in treatment receiving 100% NPK. The mean carbon concentration in each soil fraction was higher in soil depth 0–10 cm, followed by 10–20 cm and 20–30 cm. The trend of mean weight diameter (MWD) in different treatments was FYM+VC+NC+PSB ≥ FYM+VC+NC > NPK+FYM > FYM+BFN+BM+PSB > NPK. The trend of carbon concentrations in different treatments was FYM+VC+NC+PSB ≥ FYM+VC+NC > FYM+BFN+BM+PSB ≥ NPK+FYM > NPK. Non-labile pool of carbon forms the major portion (60.14%) of the total soil organic carbon (SOC) irrespective of all depths. Bulk density (BD) has a significant role in stabilizing soil aggregates as well as increasing the SOC content in soil. SOC was negatively correlated with BD (r = ?0.870, p = 0.05), MWD (r = ?0.911, p = 0.01) and geometric mean diameter (GMD) (r = ?0.958, p = 0.05) irrespective of depth. This study took further steps toward understanding the enhancing of aggregate stability on organic manures addition for soil quality improvement.     

Phytotoxic effect of Parthenium residues on the selected soil properties and growth of chickpea and radish

The present study investigates the effect of residues of noxious weed Parthenium hysterophorus in soil as well as under laboratory conditions. Soils were infested with different amounts of Parthenium residues to determine the changes in soil chemistry, phenolic content and the phytotoxic effects on crops like chickpea ( Cicer arietinum ) and radish ( Raphanus sativus ). The modified soils and unmodified (control) soil were analyzed for pH, conductivity, organic carbon, organic matter, available nitrogen, phosphorus, potassium and micronutrients such as sodium, iron, manganese and zinc. The pH of all the modified soils decreased whereas the conductivity, organic carbon and organic matter increased. Further, the amount of sodium and potassium increased, whereas that of zinc decreased. In the soil infested with 4 g of Parthenium residue, the amount of available nitrogen decreased. The presence of significantly high amounts of phenolics in all modified soils indicated their possible interactions with soil chemical properties. This was also indicated by the correlation analysis between phenolics and various soil properties. The growth studies carried out in the modified soils indicated their phytotoxic nature, as seedling growth of both chickpea and radish was significantly decreased compared with seedlings grown in unmodified soils. The extracts prepared from Parthenium residues were also found to be phytotoxic to both the test crops and were also rich in phenolics. The presence of phenolics in Parthenium residues and their interference with soil chemistry upon release may be responsible for a decrease in the growth of radish and chickpea.