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11.
Seasonal fodder production responses of five shrubs (Centrosema arenarium, Desmodium strigillosum, Desmodium velutinum, Phyllodium pulchellum, and Tadehagi triquetrum)and five trees (Albizia gummifera, Berlinia grandiflora, Albizia niopoides, Bauhinia monandra, and Inga edulis) to pruning heights ranging from 15 to 75 cm were evaluated during the main-wet, minor-wet, and dry seasons of 1993 and 1994 in the forest-savanna transition zone of West Africa. Fodder from the main-wet season was analysed for nitrogen (N) and phosphorus (P), and dry matter degradation characteristics after 6, 12, 24, 48, 72 and 96 h of incubation in rumen-fistulated N'Dama steers. In the minor-wet season, fodder production of all species increased in response to increasing pruning height with the exception of P. pulchellum and A. gummifera. Highest fodder production was attained at a pruning height of 45 cm for the Desmodium species, 50 cm for P. pulchellum, and 75 cm for the rest of the species. Concentrations of N and P varied significantly among the species; for N the ranges were 28.7–38.8 g kg–1 (shrubs) and 25.3–44.5 g kg–1 (trees), while for P the ranges were 3.26–7.04 g mg–1 (shrubs) and 3.58–6.76 g mg–1 (trees). Dry matter degradation characteristics differed significantly among shrubs and trees; ranges for shrubs were: soluble fraction (a), 128–185; degradable fraction (b), 664–703; potential degradability (PD), 793–857, as g kg–1; rate of degradation (c), 0.0241–0.0308 as % h–1 while for trees ranges were: (a), 139–160; (b), 651–826; (PD), 824–970, as g kg–1; (c), 0.0143–0.0227 as % h–1. Based on fodder production and quality, C. arenarium, D. strigillosum, D. velutinum, B. monandra, I. edulis, and A. niopoides were the most promising species for the development of animal agroforestry technologies in the west African forest-savanna transition zone and similar environments in the tropics.This revised version was published online in November 2005 with corrections to the Cover Date.  相似文献   
12.
The current study examined the influence of source and concentration of dietary phosphorus (P) on the apparent ileal digestibility (AID) and apparent total tract digestibility (ATTD) of P in growing pigs. Eighteen cannulated barrows (25 ± 5 kg) were allotted to a triplicate 6 × 3 incomplete Latin square design with six diets and three periods. The diets comprised of soybean meal (SBM) or distillers' dried grain with solubles ( DDGS) as sole sources of dietary P, and three concentrations of P (2.0, 2.5 or 3.0 g/kg) in a 2 × 3 factorial arrangement. The AID and ATTD of P were not different (p = 0.37) in all diets. Apparent digestibility of P was affected (p < 0.01) by source and concentration of P. There was no interaction between source and concentration of dietary P on the apparent digestibility of P. Determined by regression analysis, the true ileal digestibility of P was 58.3% or 57.6%, and true total tract digestibility of P was 56.0% or 62.6%, for SBM or DDGS, respectively. The regression-derived ileal endogenous P loss (EPL) was 0.61 or 0.13 g/kg DM intake, and total tract EPL was 0.53 or 0.35 g/kg DM intake, for SBM or DDGS, respectively. In conclusion, the study demonstrated that both the source and concentration of dietary P affect the digestibility of P in growing pigs.  相似文献   
13.
Millettia thonningii (Schum. & Thonn.) Bak., a nitrogen fixing shrub native to Africa and Albizia lebbeck Benth, were harvested at 0.50 m above ground level after one year of establishment to determine edible forage production. Harvests were made at the end of the main (April–August) and minor (September–November) wet, and dry (December–March) seasons for two years. Dry season edible forage samples were analyzed for concentrations of crude protein (CP), neutral detergent fibre (NDF), acid detergent fibre (NDF), acid detergent lignin (ADL), cellulose (CL), soluble phenolics (SOPH) and proanthocyanidins (PAs). In sacco dry matter (DM) and nitrogen (N) degradation and in vitro gas production (GP) characteristics were also determined on dry season edible forage samples. Edible forage production of M. thonningii was significantly lower than A. lebbeck during the wet seasons. Millettia thonningii had relatively lower CP and PAs, but higher NDF, ADF, ADL, CL and SOPH than A. lebbeck. In sacco DM and N degradation and in vitro GP parameters of M. thonningii were significantly lower than A. lebbeck. Parameters of in sacco DM degradation and in vitro GP were highly correlated. Millettia thonningii appeared to be of lower feed value than A. lebbeck based on edible forage production, chemical composition, in sacco DM and N degradation and in vitro GP characteristics.  相似文献   
14.
Short-term effect of organic and inorganic amendments on soil physical quality (SPQ) is marked when dealing with tropical soils which are naturally exposed to a high risk of water erosion. This study assessed the suitability of Tithonia diversifolia (Mexican Sunflower) when incorporated as green manure (GM) and also composted with poultry manure (PM) and other organic-based and inorganic fertilizers to improve some hydraulic properties of an Alfisol subject to excessive drainage. Treatments applied include fresh T. diversifolia (GM), PM, T. diversifolia composted with PM, organo-mineral fertilizers (OMF), neem fertilizer (NF), inorganic fertilizer (20-10-10 NPK), and control in a randomized complete block design and replicated four times. Soil samples were collected at 0–20 cm depth to determine near steady-state infiltration rates (Is), sorptivity, transmissivity, saturated hydraulic conductivity (Ks), macroporosity (MacP), microporosity (MicP), air capacity (AC), and relative water capacity (RWC). The Is rates were significantly (P ≤ 0.05) reduced to optimum range with the addition of the organic fertilizers over very high value (128.7 cm hr?1) observed for control. Whereas, Ks was enhanced in the order: GM > compost (CP) > NF > inorganic fertilizer > control > organo-mineral fertilizer > PM. Sorptivity and transmissivity were highest in control and inorganic fertilizer plots, indicating that the addition of organic fertilizers lowered these parameters while MacP, MicP, AC, and RWC were generally increased with the addition of organic-based and inorganic fertilizers. Specifically, NF increased MicP by 34% over control. Values for RWC which were within the optimum range (0.60–0.70) were only obtained with NF (0.74), OMF (0.72), NPK (0.70), and GM (0.60). The SPQ parameters assessed in this study were enhanced by the addition of fresh T. diversifolia applied as GM and CP compared to other treatments. Therefore, T. diversifolia usually burned by farmers should instead be incorporated into the soil as manure.  相似文献   
15.
In view of the difficulties in stand volume estimation in natural forests, we derived real form factors and models for volume estimation in these types of forest ecosystems, using Katarniaghat Wildlife Sanctuary as a case study. Tree growth data were obtained for all trees (dbh >10 cm) in 4 plots (25 × 25 m) randomly located in each of three strata selected in the forest. The form factor calculated for the stand was 0.42 and a range of 0.42 0.57 was estimated for selected species (density >10). The parameters of model variables were consistent with general growth trends of trees and each was statistically significant. There was no significant difference (p>0.05) between the observed and predicted volumes for all models and there was very high correlation between observed and predicted volumes. The output of the performance statistics and the logical signs of the regression coefficients of the models demonstrated that they are useful for volume estimation with minimal error. Plotting the biases with respect to considerable regressor variables showed no meaningful and evident trend of bias values along with the independent variables. This showed that the models did not violate regression assumptions and there were no heteroscedacity or multiculnarity problems. We recommend use of the form factors and models in this ecosystem and in similar ones for stand and tree volume estimation.  相似文献   
16.
A study was carried out to evaluate the growth parameters and nutritive qualities of Moringa oleifera, Millettia griffoniana and Pterocarpus santalinoides. The main objective of the study was to assess the potential of the MPTS in supplementing the feed of ruminant animals during the dry season when grasses are scarce and their quality generally fall short of animal requirements. Leaf samples were randomly collected from the trees for estimation of the proximate composition, neutral detergent fibre, acid detergent fibre and gas production using the in vitro technique. Samples were collected three times to represent seasonal variations as follows: November: Early Dry; February: Mid Dry and April: Late Dry seasons. Gas production was recorded at 3, 6, 9, 12, 15, 18, 21, 24, 48, 72 and 96 h of incubation. Mortality rate was less than 5%. M. oleifera recorded the best overall growth respectively followed by P. santalinoides and M. griffoniana. P. santalinoides and M. oleifera retained more leaves in the dry season than M. griffoniana. The dry matter (DM) and ether extract (EE) contents of the MPTS were significantly (P < 0.05) affected by seasons and plant species while there were significant (P < 0.05) species effects on the CP and ADF values. The gas production values and the fermentation parameters indicated the presence of potentially degradable nutrients in the MPTS, which underscores the importance of the tree species as sources of nutrient for ruminant animals during the dry season.  相似文献   
17.
BACKGROUND: Phytophthora nicotianae Breda de Haan is a common pathogen of ornamental plants in recycled irrigation systems. In a previous study, annual vinca (Catharanthus roseus Don) inoculated with zoospore suspensions using a CO2‐pressurized sprayer had less foliage blight than plants inoculated using a hand sprayer. Here, the impact of hydrostatic pressure, agitation and aeration with CO2 on the survival of P. nicotianae zoospores was examined. RESULTS: Exposure of zoospores to 840 kPa hydrostatic pressure for 8 min or agitation at a mixing intensity (G) of 6483 s?1 for 4 min at 22–23 °C did not kill zoospores, but resulted in viable cysts. Motile and forcefully encysted zoospores of P. nicotianae were equally infectious on vinca or lupine (Lupinus polyphylus Lindl.). Bubbling CO2 into zoospore‐infested water at 110.4 mL (0.2 g) min?1 for 5 min caused 81% reduction in the number of germinated zoospores. Pressure at 630 kPa (16.3 g CO2) or 70 kPa (3.85 g CO2) facilitated CO2 injection and shortened the zoospore inactivation time to 30 s. When air was bubbled through the suspension, germination was similar to the control. CONCLUSIONS: Exposure to CO2 killed P. nicotianae zoospores in water. Neither pressure nor agitation had an effect on zoospore viability or infectivity. Based on results of this study, the authors designed a recycling CO2 water treatment system that is currently under evaluation. Copyright © 2010 Society of Chemical Industry  相似文献   
18.
Influence of compost-derived Humic Acid (HA) on nephrotoxicity in juvenile African mud catfish (Clarias gariepinus) was evaluated in static water culture. Fish samples were exposed to different HA concentrations (0, 100, 250, 500 and 1000 mg L(-1)) for 45 days at 5 samples per aquarium. Renal function was assessed spectrophotometrically via levels of serum albumin, measured using bromocresol green, creatinine by Jaffe method and urea by Nesslerization method. Results revealed that the mean value of albumin or urea in the exposed group (1), at each HA concentration, was lower than the value found in the control group (II). Creatinine was relatively higher in I relative to II. Significant (p < 0.05) variations for I and II were obtained at 250 to 1000 mgHA L(-1) for the three biomarkers. Relative to increasing HA concentration, decreasing albumin (0.84 to 0.43 g dL(-1): r = -0.114; p > 0.10), urea (5.21 to 1.95 mg dL(-1); r = -0.586; p > 0.10) and increasing creatinine (0.20 to 1.53 mg dL(-1): r = +0.704; p > 0.10) were recorded; r is correlation coefficient. Changes in urea were not predictive of nephrotic syndrome but alterations in albumin and creatinine revealed induced nephrotoxicity, especially at elevated HA concentrations (above 100 mg L(-1)). Overall, the effect of humic acid was dose-dependent. Further studies at various humic acid concentrations, especially below 100 mg L(-1), are required to establish the actual nephrotoxic dose.  相似文献   
19.
The objectives of this study were to investigate the relationships between body weight and morpho-structural indices to predict body weight from their orthogonal body shape characters using principal component analysis and to morphologically classify the chicken genotypes using multivariate discriminant analysis. Data used were from 273 randomly selected 12-weeks-old indigenous chickens of normal-feathered (NF), frizzle-feathered (FF), naked-neck (NN) and Anak Titan (AT) genotypes. Phenotypic correlation among body weight and most biometric traits ranged from 0.227-0.876, -0.7-0.901, 0.034-0.968 and -0.207-0.849 for NF, NN and AT chickens, respectively. Factor analysis with varimax rotation of interrelated traits revealed three principal components which accounted for 83.1%, 74.4%, 78.8% and 76.5% of the total variance in NF, FF, NN and AT chickens in the order listed. Breast girth, keel length, thigh length, shank length and wing length were found to be the most discriminating variables to separate the chicken genotypes. The longest distance (72.54) occurred between AT and NF genotypes while the shortest distance (4.27) was recorded for FF and NN genotypes. Classification results showed that 85.2% of AT genotype was correctly classified into their source population. However, 22.7% of NF was misclassified as NN, while 33.3% of NN was misclassified as NF chickens. These results suggest that there is high rate of gene flow between these two indigenous chicken genotypes. Information obtained from this study may be considered useful in breed improvement programmes for selection, characterization, conservation and better management of Nigerian indigenous chickens.  相似文献   
20.
A feeding trial was conducted to evaluate the effect of pawpaw–onion powder (POP) mixture on the growth, and haemato‐biochemical and antioxidant responses of Clarias gariepinus (4.02 ± 0.01g/fish) for 60 days. Five trial diets were formulated as control (without POP or antimicrobial growth promoter (AGP)), AGP (basal diet + 10ml AGP/kg diet), POP 2.5 (basal diet + 2.5g POP/kg diet), POP 5.0 (basal diet + 5.0g POP/kg diet) and POP 10 (basal diet + 10g POP/kg diet). Two hundred and twenty‐five fish were equally distributed into five groups in triplicate and fed twice daily. The results indicate that AGP or POP supplementation exerted no effects on the growth and blood profile among the various groups, but a significantly higher lymphocyte count was observed in POP 10g/kg. The highest whole‐body protein and lipid contents were noticed in fish fed the control diet (p < .05), whereas POP 5.0g/kg group recorded the highest hepatosomatic value. Furthermore, the cholesterol level was found to be lower in the AGP‐ and POP‐fed fish compared with the higher level recorded in the control. The glucose concentration and superoxide dismutase enzyme activity were found to be higher in POP 2.5‐fed fish, whereas POP 10‐fed fish showed higher catalase activities compared with other groups (p < .05). Based on the result obtained, this study showed that dietary POP had no significant impact on the growth performance but has direct effects on the whole‐body lipid content, lymphocyte count, cholesterol level, alanine aminotransferase, alkaline phosphatase and antioxidant response of Clarias gariepinus.  相似文献   
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