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地膜覆盖对棉枯萎病发生的影响 总被引:1,自引:0,他引:1
地膜覆盖显著降低了棉花枯萎病的发病率与病情指数,极显著地提高了棉花的产量。 相似文献
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The effect of foliar-applied potassium chloride on Septoria tritici , the anamorph of Mycosphaerella graminicola , was quantified and possible modes of action investigated during controlled-environment and field experiments. A field experiment in harvest year 1997 showed c . 50% reduction in the area of leaf 2 of winter wheat plants affected by septoria leaf blotch after foliar application of potassium chloride, compared with untreated controls. Similarly, in harvest year 1998 potassium chloride reduced, by about one-third, the area of the flag and penultimate leaf affected by S. tritici . However, a significant yield increase was not observed, although grains m−2 did show an increase of borderline significance. Applications of epoxiconazole reduced the area of leaf 4 affected by S. tritici compared with untreated controls, whereas applications of chlorothalonil, potassium chloride or polyethylene glycol proved ineffective against disease development. This may suggest that potassium chloride is relatively immobile and possesses contact activity similar to that of chlorothalonil. In 1998, similar reductions in leaf area affected were observed with the inert osmoticum polyethylene glycol in the field, suggesting that the control provided by potassium chloride may be achieved by adverse osmotic effects on the pathogen. Scanning electron microscopy of germinating conidia on wheat plants showed inhibition of conidial germination by both potassium chloride and polyethylene glycol at the same calculated osmotic potential on the leaf surface. 相似文献
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Wyse CA McLellan J Dickie AM Sutton DG Preston T Yam PS 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2003,17(5):609-621
Gastric emptying is the process by which food is delivered to the small intestine at a rate and in a form that optimizes intestinal absorption of nutrients. The rate of gastric emptying is subject to alteration by physiological, pharmacological, and pathological conditions. Gastric emptying of solids is of greater clinical significance because disordered gastric emptying rarely is detectable in the liquid phase. Imaging techniques have the disadvantage of requiring restraint of the animal and access to expensive equipment. Radiographic methods require administration of test meals that are not similar to food. Scintigraphy is the gold standard method for assessment of gastric emptying but requires administration of a radioisotope. Magnetic resonance imaging has not yet been applied for assessment of gastric emptying in small animals. Ultrasonography is a potentially useful, but subjective, method for assessment of gastric emptying in dogs. Gastric tracer methods require insertion of gastric or intestinal cannulae and are rarely applied outside of the research laboratory. The paracetamol absorption test has been applied for assessment of liquid phase gastric emptying in the dog, but requires IV cannulation. The gastric emptying breath test is a noninvasive method for assessment of gastric emptying that has been applied in dogs and cats. This method can be carried out away from the veterinary hospital, but the effects of physiological and pathological abnormalities on the test are not known. Advances in technology will facilitate the development of reliable methods for assessment of gastric emptying in small animals. 相似文献
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Combined production of timber and forage species is considered to be a desirable land-use system to offset some of the current land management problems of Italy. This paper reports the early results of a study on intercropping young plants of walnut with alfalfa (Medicago sativa L.), with or without polyethylene mulching, in an experimental plantation in central Italy. Two genotypes of walnut were used:Juglans regia L. and the French hybrid NG23×RA. The seasonal changes of absolute and relative growth rates of walnut stem diameter and apical shoot length were investigated.During both growing seasons, alfalfa intercropping strongly decreased walnut growth, whereas polyethylene mulching promoted stem height and diameter growth. Stem growth of intercropped-and-mulched walnut was the same as that of sole walnut under clean cultivation management. The use of polyethylene mulching reduced or avoided the competitive effect of associated alfalfa on walnut growth. During both growing seasons, the intercropped-and-mulched walnut had higher relative growth rates than intercropped-unmulched walnut. The results show the effectiveness of polyethylene mulching in promoting early growth of walnut, even when intercropped with alfalfa during early stages of plantation establishment. 相似文献
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Effects of pistachio by‐products on digestibility,milk production,milk fatty acid profile and blood metabolites in Saanen dairy goats 下载免费PDF全文
R. Sedighi‐Vesagh A. A. Naserian M. H. Ghaffari H. V. Petit 《Journal of animal physiology and animal nutrition》2015,99(4):777-787
The objective of this study was to investigate the effects of pistachio by‐products (PBP) on nutrient digestibility, blood metabolites and milk fatty acid (FA) profile in Saanen dairy goats. Nine multiparous lactating Saanen goats (on day 90 post‐partum, 45 ± 2/kg BW) were randomly assigned to a 3 × 3 Latin square design with three treatment diets: 1) control diet (alfalfa hay based), 2) 32% PBP and 3) 32% PBP + polyethylene glycol (PEG‐4000; 1 g/kg dry matter). Each period lasted 21 days, including 14 day for treatment adaptation and 7 day for data collection. Pistachio by‐products significantly decreased (p < 0.01) crude protein (CP) digestibility compared with the control diet (64.4% vs. 58.7%), but PEG addition did not differ for CP digestibility of goats fed 32% PBP + PEG and those fed the two other diets. The digestibility of NDF tended (p = 0.06) to decrease for goats fed PBP compared with those fed the control diet. Yields of milk and 4% fat‐corrected milk were not affected by dietary treatments. Compared with the control diet, PBP supplementation appreciably changed the proportions of almost all the milk FA measured; the main effects were decreases (p < 0.01) in FA from 8:0 to 16:0 and increases (p < 0.01) proportions of cis‐9, trans‐11 18:2 and trans‐11 18:1, monounsaturated FA, polyunsaturated FA and long‐chain FA. The saturated FA, short‐chain FA and medium‐chain FA proportions were lower (p < 0.01) in goats fed the two PBP supplemented diet than in those fed the control diet and PEG addition led to intermediate proportions of saturated FA, unsaturated and monounsaturated FA. Inclusion of PBP in the diet decreased (p < 0.01) plasma concentrations of glucose and urea nitrogen compared with the control diet. It was concluded that PBP can be used as forage in the diet of dairy goats without interfering with milk yield. Inclusion of 32% PBP in the diet of dairy goats had beneficial effects on milk FA profile but PEG addition to PBP did not contribute to enhance further milk FA profile. 相似文献