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81.
Correlating phosphorus extracted by simple soil extraction methods with foliar phosphorus concentrations of Picea abies (L.) H. Karst. and Fagus sylvatica (L.)
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Phosphorus (P) concentrations in needles and leaves of forest trees are declining in the last years in Europe. For a sustainable forest management the knowledge of site specific P nutrition/availability in forest soils is vital, but we are lacking verified simple methods for the estimation of plant available P. Within this study, four soil P extraction methods [water ( ), double‐lactate (Plac), citric acid (Pcit), and sodium bicarbonate ( )], as well as total P content of the soil (Ptot) were tested to investigate which method is best correlated with foliar P concentrations of spruce [Picea abies (L.) H. Karst.] and beech [Fagus sylvatica (L.)]. Mineral soil samples from 5 depth levels of 48 forest sites of the Bavarian sample set of the second National Forest Soil Inventory (BZE II) were stratified according to tree species (spruce and beech) and soil pH (pH < 6.2 and > 6.2), covering the whole range of P nutrition. The extractable amount of P per mass unit of soil increased in the order << Plac < < Pcit, decreased with soil depth, and was higher in soils with pH < 6.2. Citric acid extracted up to 10% of Ptot in acidic soils. Whereas Pcit delivers adequate regression models for P nutrition in the case of spruce (R2 up to 0.53) and beech (R2 up to 0.58) for acidic soils, shows good results for spruce growing on acidic soils (R2 up to 0.66) and for beech on soils with pH > 6.2 (R2 up to 0.57). Plac produces adequate models only for beech on high pH soils (R2 up to 0.64), while did not produce acceptable regression models. Ptot seems suitable to explain the P nutrition status of beech on acidic (R2 up to 0.62) and alkaline soils (R2 up to 0.61). Highest R2s are obtained mostly in soil depths down to 40 cm. As and Pcit showed good results for both investigated tree species, they should be considered preferentially in future studies. 相似文献
82.
H. P. S. Abdul Khalil Tze Kiat Lai Ying Ying Tye M. T. Paridah M. R. Nurul Fazita A. A. Azniwati Rudi Dungani Samsul Rizal 《Fibers and Polymers》2018,19(2):423-434
Microcrystalline cellulose (MCC) isolated from cheap, fast-growing and abundant accessible Sacred Bali bamboo (Schizostachyum brachycladum) was utilized as reinforcement material in the seaweed-based composite film. Isolation of MCC was carried out by using a combination of pulping, bleaching and acid hydrolysis process. This study emphasized on the feasibility of MCC production from Sacred Bali bamboo by studying its properties using X-ray diffraction (XRD), scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). The commercial-MCC (CMCC) was used as reference material. Results showed that the production yield, moisture content (MC) and fiber length of bamboo-MCC (BMCC) were 83.37±1.48 %, 4.50±0.5 %, and 0.47±0.02 mm, respectively. According to the chemical analysis by FTIR, both lignin and hemicellulose were completely removed from BMCC, and thus, improved the crystallinity (78 %) and thermal stability (≈325 °C) of BMCC. This study also revealed that MCC produced from Sacred Bali bamboo demonstrated strong mechanical reinforcement effect in the seaweed-based film. Hence, Sacred Bali bamboo-MCC could be used as reinforcement material in the polymer. 相似文献
83.
Mohamad Nurul Azman Mohammad Taib Wageeh Abdulhadi Yehye Nurhidayatullaili Muhd Julkapli Sharifah Bee O. A. Abdul Hamid 《Fibers and Polymers》2018,19(2):383-392
Novel acetylation process by substitution of acetic anhydride substitution with hydroxyl groups on nanocellulose (NCC) has been explored to increase its dispersion and interaction in nitrile butadiene (NBR) matrix. The crystallinity index was increased after modification when compared to unmodified NCC, but no significant different with increases of treatment time from 1 hour to 3 hours treatments proven by X-ray diffraction (XRD) results. The Fourier transform infra-red (FTIR) showed the existent of acetyl groups on surface of the NCC after treatment by existent of the peak 1736 cm-1 that attributed to carbonyl groups some peaks were observed at 1430, 1361 and 1248 cm-1 and confirmed on the acetylation process. The nuclear magnetic resonance (NMR) also show the present of acetyl groups by existent of the signal of proton methyl group at 1.90 ppm and new peaks at 5.42, 4.70 and 4.34 ppm, for all ACN samples. The thermal results by thermo gravimetric analysis (TGA) and differential scanning calorimetry (DSC) showed that the acetylated NCCs were 10 % more thermally stable. Transmission electron microscopic (TEM) results showed that no significant changes were observed due to the acetylation process. The results also showed well distributed of individual NCC after acetylation, this improvement was primarily attributed to uniform dispersion of the ACN-NCC and less aggregated occurred. Due to its hydrophobic characteristics, highly crystalline and nano size, ACN-NCC brought a significant improvement up to 25 % on the mechanical properties of nitrile butadiene (NBR) rubber composites. 相似文献
84.
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86.
Effect of potassium (K) fertilization (0, 20, 40, 60, 80 and 100 kg K ha?1) on yield, nitrogen (N) and K nutrition of Boro (dry season) rice and apparent soil K balance was studied. Experiment was conducted at Bangladesh Rice Research Institute (BRRI) regional station farm, Habiganj, Bangladesh during 2007–2008 to 2009–2010 in a wetland rice ecosystem under haor area. Cropping pattern was Boro–Fallow–Fallow. A popular rice variety BRRI dhan29 was tested in a randomized complete block design with three replications. Results indicated that BRRI dhan29 maintained an average grain yield of 5.19 t ha?1 year?1 without K fertilization. Potassium fertilization significantly increased the grain yield to 6.86 t ha?1 year?1. Quadratic equations best explained the progressive increase of rice yield with increasing K rates. Optimum dose of K in 3 years ranged from 78 to 93 kg ha?1. Internal N use efficiency of rice decreased with increasing K rates. However, K use efficiency was inconsistent. Apparent K balance study revealed that application of 100 kg K ha?1 was not able to maintain a positive K balance in soil under wetland ecosystem with Boro–Fallow–Fallow cropping system. However, K fertilization decreased the negativity of K balance in soil. 相似文献
87.
Mohd Hadi Akbar Basri Md. Rezaul Karim Nasima Junejo Hazandy Abdul Hamid Noor Syahirah Norrashid 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2016,66(6):534-543
In tropical climate, huge amount of fertilizer need to be used for the cultivation of kenaf (Hibiscus cannabinus L.) in Beach Ridges Interspersed with Swales (BRIS) soil, however this approach is not cost effective and environmental friendly. Therefore, the optimizing of fertilizer rate for BRIS soils and selection of suitable soil amendments are crucial to get a higher yield. In this study, the effects of different combinations of urea, chicken manure and biochar on soil properties, growth performance and physiological characteristics of kenaf cultivated on the BRIS soil were investigated. Eight treatments were conducted namely: control (T1), biochar (T2), chicken manure (T3), urea (T4), chicken manure + urea (T5), biochar + chicken manure (T6), urea + biochar (T7) and biochar + chicken manure + urea (T8). The biomass and physiological characteristics of kenaf were recorded every month, while the soil was analyzed following a standard laboratory procedure. The application of organic and inorganic fertilizer (urea) significantly increased the nutrient content of the soil compared to the T1, whereas T3 showed the highest pH, cation exchange capacity, and exchangeable bases (Na, Mg, Ca). However, the mixing of biochar with organic and inorganic fertilizers showed the highest plant height, diameter of stem and number of leaves as well as dry biomass compared to other treatments. Furthermore, the application of nitrogen fertilizer significantly increased the photosynthesis rate and stomatal conductivity. The results suggest that the mixing of biochar with organic and inorganic fertilizers represents an effective approach for the cultivation of kenaf in tropical climate. 相似文献
88.
Fauziah Abdullah Partiban Subramanian Halijah Ibrahim Sri Nurestri Abdul Malek Guan Serm Lee Sok Lai Hong 《Journal of insect science (Online)》2015,15(1)
Dual choice bioassays were used to evaluate the antifeedant property of essential oil and methanolic extract of Alpinia galanga (L.) (locally known as lengkuas) against two species of termites, Coptotermes gestroi (Wasmann) and Coptotermes curvignathus (Holmgren) (Isoptera: Rhinotermitidae). A 4-cm-diameter paper disc treated with A. galanga essential oil and another treated with either methanol or hexane as control were placed in a petri dish with 10 termites. Mean consumption of paper discs (miligram) treated with 2,000 ppm of essential oil by C. gestroi was 3.30 ± 0.24 mg and by C. curvignathus was 3.32 ± 0.24 mg. A. galanga essential oil showed significant difference in antifeedant effect, 2,000 ppm of A. galanga essential oil was considered to be the optimum concentration that gave maximum antifeedant effect. The essential oil composition was determined using gas chromatography-mass spectrometry. The major component of the essential oil was 1,8-cineol (61.9%). Antifeedant bioassay using 500 ppm of 1,8-cineol showed significant reduction in paper consumption by both termite species. Thus, the bioactive agent in A. galangal essential oil causing antifeeding activity was identified as 1,8-cineol. Repellent activity shows that 250 ppm of 1,8-cineol caused 50.00 ± 4.47% repellency for C. gestroi, whereas for C. curvignathus 750 ppm of 1,8-cineol was needed to cause similar repellent activity (56.67 ± 3.33%). C. curvignathus is more susceptible compare to C. gestroi in Contact Toxicity study, the lethal dose (LD50) of C. curvignathus was 945 mg/kg, whereas LD50 value for C. gestroi was 1,102 mg/kg. Hence 1,8-cineol may be developed as an alternative control against termite in sustainable agriculture practices. 相似文献
89.
Effects of commonly used disinfectants on bacterial load,hatchability and survival of Bluefin Sea bream (Sparidentex hasta) eggs 下载免费PDF全文
The efficacy of four chemical reagents, iodophor, formalin, hydrogen peroxide and bronopol as fish egg surface disinfectants were evaluated in bluefin sea bream (Sparidentex hasta). Fertilized eggs were counted and subjected to a static bath dip treatment in different concentrations of the above chemicals for 4 min before being incubated at 20 ± 0.5°C for 40 h. Treatment efficacy of the different disinfectants was evaluated by assessing the bactericidal activity, egg hatch percentage and survival of larvae up to 3 days post hatch. Results showed that iodophor at medium concentrations (75 and 100 ppm) was the best of all tested disinfectants in bacterial killing ability (12% reduction in the bacterial counts), egg hatching per cent (99.8% and 99.6% respectively) and larval survival up to 3 days post hatch (50.8% and 54.8% respectively). Formalin was the second best disinfectant at levels of 100 and 150 ppm. Hydrogen peroxide gave good results compared with the control while, bronopol showed discouraging results. In conclusion, iodophor appeared to be suitable for bluefin sea bream eggs disinfection with a 4 min exposure to 75–100 ppm when applied 14–16 h after egg fertilization. 相似文献
90.
The present research was undertaken to explor the possibility of arbuscular mycorrhizal(AM) association with Asteraceae plants in the arid lands of Saudi Arabia(Al-Ghat, Buraydah, Thumamah and Huraymila). AM fungal colonization in the roots, spore numbers in the rhizosphere soil, fungal species diversity and correlation between AM properties and soil properties were determined. The highest colonization was in Conyza bonariensis(65%) from Al-Ghat, Anthemis cotula(52%) from Buraydah and C. bonariensis(53%) from Thumamah. The lowest was in Vernonia schimperi(41%) from Al-Ghat, Pulicaria undulata(25%) from Buraydah, Acanthospermum hispidum(34%) from Thumamah, Asteriscus graveolens(22%) and V. schimperi(22%) from Huraymila. Vesicular and arbuscular colonization were also presented in all plant species examined. The number of spores were 112–207 in Al-Ghat, 113–133 in Buraydah, 87–148 in Thumamah and 107–158 in Huraymila. Funneliformis mosseae, Glomus etunicatum, G. fasciculatum and G. aggregatum were identified. Relative frequency of AM fungal species varied widely and was irrespective of location and plant species. Diversity index varied with the rhizosphere soils of different plant species at various locations. Soil properties varied with locations and no distinct correlations were observed among the soil properties, root colonization and the number of spores. The results of the present study specified the association of AM fungi in different plants of Asteraceae and its significance in the ecological functioning of annual plants in the punitive environments of the rangelands in Saudi Arabia. 相似文献