Search Results
The objectives of this study were to examine the correlation between factors of great significance for crop production, especially between irrigation and fertilization, and to evaluate the effects of irrigation and fertilization on maize yields over four growing seasons (2001-2004) in a long-term field experiment set up at the Látókép Experimental Station of the Centre for Agricultural Sciences of Debrecen University. The results showed that irrigation and fertilization were strongly correlated with the yield. The effect of irrigation depended on the natural water and nutrient supplies of the soil, and on the specific fertilizer rates. The results indicated that both fertilization and irrigation had a significant effect on the yield. The correlation between the year and the crop production factors was also significant. The yield-increasing effect of irrigation and fertilization differed significantly in the experimental years.
The number of stomata and the concentration of macro- and microelements in four new winter wheat genotypes: Lenta, Lara, Perla and Fiesta were investigated in two localities in Croatia in the 1997/98 growing season. The stomata number per mm2 was determined by a standard method. N was established by the micro-Kjeldahl method, P spectrophotometrically and K, Ca, Mg, Zn, Cu, Fe and Mn by the AAS method. The interrelation of the investigated parameters was determined by multiple regression and correlation analysis. The results obtained indicate that the number of stomata per mm2 and the macro- and microelement concentrations depended on the genotype, the phenophase and the locality. A statistically significant correlation was found between the stomata number per mm2 and the macro- (N, P, K, Ca, Mg) and microelement (Zn, Cu, Fe, Mn) concentrations.
A survey was carried out in the 1996/97 and 1997/98 growing seasons on a field planted in three replicates with five clones of cassava at the International Institute of Tropical Agriculture, Ibadan, located in a transition forest, to determine the effects of cassava genotype and climate on the development of African cassava mosaic geminivirus (ACMV) and changes in the Bemisia tabaci population. Cassava genotype, climate and their interactions have significant (P<0.01) effects on the population of B. tabaci and the development of ACMV. The incidence of ACMV was significantly (P<0.01) higher in clones 81/01635 and 92/0520 than in TMS 30572 and 94/0239, while 91/02327 showed the greatest resistance. A positive correlation between the incidence and severity of ACMV was observed, but this did not correlate with the whitefly population density.
The mite fauna of bulbaceous ornamental plants in Ankara, Turkey was investigated during 2000-2002. A total of 12 astigmatid species belonging to 6 genera and 13 prostigmatid species belonging to 12 genera were identified. The pest potential of Rhgizoglyophus, Acarus and Tyrophagus spp. is considered and it was concluded that Rhizoglyphus robini (Claparéde) is the most common and harmful mite species occurring on bulbs of ornamental plants throughout the growing season and in storage. Acarus farris (Oudemans) and Tyrophagus putrescentiae (Schrank) were also abundant on bulbs. Hypopicheyla elongata Volgin (Cheyletidae) and Anoplocheylus taurcicus Berlese (Pseudocheylidae), and the astigmatid Tyrophagus robertsonae Lynch, 1989 (Tyroglyphidae) are new records for the Turkish fauna. Astigmatid species prefer bulbaceous plants and prostigmatids occasionally occur on the same host plants. Dahlia hybrida was the preferred and most populated bulbaceous host plants.
The field experiment with four rates of phosphorus (P) fertilization was conducted in spring of 2004 with treatments as follows: a) ordinary fertilization (kg/ha: 200 N + 80 P 2 O 5 + 120 K 2 O); b) a + 500 kg P 2 O 5 ; c) a + 1000 kg P 2 O 5 ; and d) a + 1500 kg P 2 O 5 . The triplephoshate enriched with sulphur and zinc (45% P 2 O 5 + 1,2% S + 0,06% Zn) was used as a source of P. Maize (Bc5984 and OsSK494 hybrids, for the growing season 2004 and 2005, respectively) was grown on the experimental plot. P fertilization significantly influenced on decreases of the leaf Mg by 38%, Mn by 30%, Zn by 48% and Mo by 53% compared to the control (mg kg −1 on the control: 1526 Mg, 44.3 Mn, 45.2 Zn, 2.62 Mo) and increases of the leaf Sr by 31% and Cd by 84% (mg kg −1 on the control: 62.3 Sr and 0.25 Cd), while differences of the remaining measurable elements (P, K, S, Fe, Cu, Ni, Cr, B, Ba, Na, and Al) were nonsignificant. Also, the leaf As, Hg and Se concentrations were under detectable levels of the method. In general, grain composition was less dependent on the fertilization in comparison with the leaf composition. For the 2005 growing season, only ordinary fertilization was applied. As affected by applied fertilization maize grain yields increased up to 32% and 17% compared to the control, for 2004 and 2005, respectively.
Summary
Application of chemotaxonomy to the plant kingdom can be regarded as a future challenge to the traditional binomial classification system. Construction of a classification system based on the chemical composition of plants has only recently become possible with the development of sophisticated chromatographic and hyphenated techniques. Successful chemotaxonomy can, however, be achieved only if sufficient experimental evidence is collected confirming the reproducibility of the chemical composition of plant species (irrespective of the specimen, its growing season, location of the collection site, etc.). The objective of this study was to compare, by use of gas chromatography with mass spectrometric detection (GC-MS) the efficiency of isolation of volatile compounds from five different Salvia L. (sage) species (S. lavandulifolia, S. staminea, S. hians, S. triloba, and S. nemorosa) by use of four different techniques [head-space extraction at 70 and 80°C, vapour distillation in a Deryng apparatus, and accelerated solvent extraction (ASE)]. We also compared the composition of the volatile fractions of these species collected during two different seasons (2007 and 2008). It was established that the composition of the volatile fractions is very dependent on the species considered and, in a much less pronounced way, on the growing season. This statement is valid irrespective of the technique used to isolate the volatile compounds from the plant matrix. The seasonal reproducibility of the compounds regarded as chemotaxonomic markers and chemotaxonomic advice compounds (and the repeated absence of such compounds from a species) makes the volatile fraction suitable for chemotaxonomic evaluation of sage. Finally, it was shown that head-space extraction of the volatile fraction at 70°C was the best extraction technique for the purpose of this study.
We tested the prediction that we are more likely to create persistent, species-rich plant communities by increasing the number of species sown and allowing communities to assemble over six or seven growing seasons. Treatments consisted of four initial seed mixtures comprising 4, 8, 12 and 16 species that represent four functional groups C3 graminoids, C4 grasses, N-fixing species, and late-flowering composites) that predominate within North American prairies. Once seeded, half of the plots were left alone to develop without subsequent reseeding. To provide multiple opportunities for establishment, we reseeded the remaining plots with any target species that failed to establish after two growing seasons. There were two 16 x 16 m (256 m2) replicates per treatment established in 1994 and 1996 on former agricultural land. Annually, we measured total species richness and evenness, total cover, and establishment success defined as target species richness and total percentage cover by target species, collectively. In some instances, significant treatment x year interactions indicated that treatment effects on variables varied among years. Both richness and rate of establishment of target communities were higher in the more species-rich mixtures. Moreover, richness of resident species in the plots declined with increasing target species richness. Reseeding had no measurable effect on any of the variables, nor on the eventual establishment of target communities or individual target species. Our results, indicating that establishment of species-rich plant communities can be enhanced by starting with larger numbers of species at the outset, have implications for projects in which community biodiversity creation and maintenance are key goals.
Összefoglalás
Polifaktoriális tartamkísérletben, két aszályos évjáratban (2007. és 2009.) vizsgáltuk a talaj nedvességkészlete és a kukorica terméseredménye közötti összefüggéseket. A vízhiányértékekből látszik, hogy a kukorica számára a bikultúrás vetésváltás a legkedvezőbb, az egész tenyészidőszakot vizsgálva itt kaptuk a legkisebb értékeket. A 2007. év alacsony terméseredményei a magas vízhiányértékeknek tulajdoníthatóak, ezzel szemben a 2009. év ugyancsak kedvezőtlen csapadékellátottsága ellenére a terméseredmények jóval nagyobbak voltak. Ez a jelentős mennyiségű júniusi csapadék következtében alakult így. A 30 éves átlagtól is több csapadék jó hatással volt a kukorica virágzási-terméskötési időszakában megnövekvő vízigényének kielégítésére, ezáltal a magasabb terméseredmények kialakulására, “termésmentő” szerepe volt. Az öntözött parcellák esetében a májusi vízutánpótlás a kukoricának még egyenletesebb vízellátást biztosított a tenyészidőszak első felében, így erőteljesebb vegetatív fejlődés, még nagyobb terméseredmények realizálódtak. A vizsgálatok alapján bebizonyosodott, hogy aszályos évjáratokban a megfelelő agrotechnikai elemek alkalmazásával enyhíthetünk a csapadékhiány által generált stresszhelyzeteken, a nagyobb mérvű termésdepresszión.
The effect of rainfall quantity and distribution and of N, P, K, Ca and Mg fertilisation on the yields of rye, potato, winter wheat and triticale were evaluated in the 42 years of a long-term mineral fertilisation experiment [soil (acidic, sandy, brown forest) × fertilisation (N, P, K, Ca, Mg) × rainfall (quantity, distribution) × crop (rye, potato, winter wheat, triticale)] set up in 1962 under fragile agro-ecological conditions in the Nyírlugos-Nyírség region of Eastern Hungary. The soil had the following agrochemical characteristics: pH (H2O) 5.9, pH (KCl) 4.7, hydrolytic acidity 8.4, hy1 0.3, humus 0.7%, total N 34 mg kg-1, ammonium lactate (AL)-soluble P2O5 43 mg kg-1, AL-K2O 60 mg kg-1 in the ploughed layer. From 1962 to 1980 the experiment consisted of 2×16×4×4=512 plots and from 1980 of 32×4=128 plots in split-split-plot and factorial random block designs. The gross plot size was 10×5=50 m2. The average fertiliser rates in kg ha-1 year-1 were nitrogen 45, phosphorus 24 (P2O5), potassium 40 (K2O), magnesium 7.5 (MgO) until 1980 and nitrogen 75, phosphorus 90 (P2O5), potassium 90 (K2O), magnesium 140 (MgCO3) after 1980. The main results and conclusions were as follows: The rainfall quantities averaged over many years and in the experimental years, and during the growing season, averaged over many years and in the experimental years, were 567, 497, 509, 452 mm for rye and 586, 509, 518 and 467 mm for winter wheat. Rainfall deviations from the many years' average -3% and -13% in the experimental years and during the growing season for potato and 2% and -3% for triticale. During the vegetation period the relationships between rainfall quantity, NPKCaMg nutrition and yield could be characterised primarily by quadratic correlations. Maximum yields of 4.0 t ha-1 for rye, 21.0 t ha-1 for potato, 3.4 t ha-1 for winter wheat and 5.0-6.0 t ha-1 for triticale were recorded when the natural rainfall amounted to 430-500, 280-330, 449-495 and 550-600 mm, respectively. At values above and below these figures there was a considerable reduction in the yield. The results showed that the crop yields were strongly influenced (quadratic correlation) by interactions between N, P, K, Ca and Mg fertilisation and rainfall quantity and distribution.
Abstract
The popular areca nuts were sampled and their stuffed white and red lime were collected simultaneously from four marketplaces in Taiwan in different growing seasons. Samples of areca nut were treated via homogenizer prior to freeze drying, about 100–150 mg each of the areca nut and lime were packed into PE bag. Samples were irradiated with neutron flux about 1012 n·cm–2·s–1. A total of 17, 18, and 13 elements was analyzed with INAA for white lime, red lime, and areca nut, respectively. The results indicated that Ca have the highest concentration in both limes. Most elements in collected samples have wide range of concentrations among different seasons and marketplaces. It is suggested that the elemental concentration of areca nut and limes exists in divergence originated from various farms in Taiwan. In addition, four elements of Ca, Fe, Mg, and Sc are probably overtaken by persons having chewing habit of areca nut and their effects on oral cancer are discussed.
