首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   38篇
  免费   1篇
林业   4篇
农学   1篇
  5篇
农作物   7篇
水产渔业   7篇
畜牧兽医   14篇
植物保护   1篇
  2022年   1篇
  2021年   2篇
  2019年   6篇
  2018年   3篇
  2017年   2篇
  2016年   2篇
  2014年   3篇
  2013年   4篇
  2012年   2篇
  2011年   5篇
  2010年   5篇
  2009年   2篇
  2005年   1篇
  2004年   1篇
排序方式: 共有39条查询结果,搜索用时 15 毫秒
21.
This study was conducted to evaluate the effects of dietary Tenebrio molitor larvae meal (TM meal) inclusion on the performance, carcass traits, caecum microbiota and blood parameters of broiler chickens. A total of 180-day-old chickens were allocated to three dietary groups with five replicate pens (12 birds/pen). Experimental diets were included a corn-soybean basal diet, and two diets with 2.5% and 5% TM. TM-included diets have been administered for periods of starter (1–10 days) and grower (11–25 days). A regular finisher diet was given to all groups during the 26–42 days of age. Diets containing TM meal did not influence feed intake and mortality percentage. Feed conversion ratio was lower with the 2.5% TM meal diet compared with the control group at starter period (p < .05). Besides, broiler chickens fed TM meal included diet had a higher body weight gain than the control group during 1–10 days of age (p < .05). The carcass characteristics and length and weight of different parts of small and large intestines were not influenced by diets. TM meal inclusion decreased the albumin-to-globulin ratio compared with the control group (p < .05). Additionally, lower total count of aerobic and Escherichia coli bacteria was observed in response to diet inclusion of 5% TM meal. Overall, the inclusion of TM meal in broilers' diet improved body weight gain and feed conversion ratio in the starting period, decreased albumin-to-globulin ratio and E. coli bacteria content.  相似文献   
22.
Abstract

Many methods have been proposed to recommend phosphorus fertilizer, but none of them can quantitatively determine the plant phosphorus required. In this method, which is called “Integrated Plant and Soil System” (IPSS), the required phosphorus of the plant is calculated quantitatively, based off of the correlation between soil phosphorus, soil properties, and plant organs phosphorus. For this purpose, 39 Orange orchards were chosen in Jahrom (Iran). In each orchard during two consecutive years, samples were taken from the plant organs and soil of the root zone and phosphorus was measured. A multivariable regression was established between variables that had a significant correlation with soil phosphorus. The result of IPSS was two regression models between soil and fruit phosphorus. A regression model for high yield orchards (Y2?=?–121.3799?+?0.1256308X2), and the other for orchards that have a phosphorus deficiency (Y1?=?–96.4673?+?0.120549X1). According to these regressions, calculating the amount of phosphorus required for orange trees is possible.  相似文献   
23.
In order to investigate the effects of nitrogenous fertilizers (biological, chemical, integrative) on quantity and quality of forage-medicine in the additive intercropping of sorghum with fenugreek, an experiment was performed in two agronomic years 2010–2011 and 2011–2012 in the Research Farm of Agricultural Faculty of Tehran University located in Dolatabad, Karaj, as split-plot in the form of randomized complete block design (RCBD) with three replications. The main treatments consisted of the control or without fertilizer (N0), biofertilizer (Nbi) (Azotobacter, Rhizobium, Azospirillum, mycorrhiza), chemical nitrogen fertilizer (Nch 100) and integrative fertilizer including biofertilizer plus 50% chemical nitrogen fertilizer (Nbi + Nch50). The subtreatments included sole cultivation of fenugreek without weeds (T0), sole cultivation of fenugreek with weeds (Tw), sole cultivation of sorghum without weeds (S0), sole cultivation of sorghum with weeds (Sw), cultivation of sorghum + 50% fenugreek (ST50) and cultivation of sorghum + 100% fenugreek (ST100). Based on the results, the highest effective extract of fenugreek (trigonelline) and fenugreek dry matter was gained through the application of biological fertilizer + the sole fenugreek treatment (no weeds). Moreover, the highest sorghum dry mater was yielded by the use of the integrative fertilizer + the sole sorghum (no weeds) treatment; however, the highest total dry matter was observed to be more in the mixed treatment of integrative fertilizer and sorghum + 50% fenugreek. The lowest weed biomass was also linked to the integrative treatment biological fertilizer and sorghum + 100% fenugreek.  相似文献   
24.
Ali  Nawab  Anjum  Muhammad Mehran  Khan  Gul Roz  Ali  Rovaid 《Gesunde Pflanzen》2022,74(1):41-52

Water resources are increasingly scarce, and in drought prone production systems, the capability of the plant to recover its adverse effects is important for yield stability. There is an urgent need to develop water-saving strategies for wheat production. Water stress at critical growth stages diminishes wheat production and has harmful effects on crop growth and development; however, regulated water deficit and potassium foliar application ameliorates its adverse effect up to a certain extent. Consequently, the water deficit effect at different growth stages of the crop with exogenous application of potassium was evaluated in a screenhouse experiment in a complete randomized design (CRD) having four repeats. Varieties of wheat, i.e. Lalma (drought resistant) and Pakhtunkhwa-2015 (drought susceptible), were sown. Water deficit, i.e. mild water stress (50% of water required for field capacity) and severe stress (no application of water), at different growth stages of the crop were imposed. Potassium (K) foliar spray (1%) from potassium sulfate (K2SO4) was applied at the respective stage subjected to water deficit levels. Internal water status, i.e. relative water content (RWC) and water retention capacity (WRC), were attained maximum at tillering stage under mild stress than the rest of the stages with maximum for Lalma. Conversely, water saturation deficit (WSD) and water uptake capacity (WUC) were higher under severe stress imposed at grain filling stage. Theses indices were maintained by foliar potassium application. Similarly, dry matter (DM) allocation varied for stress level imposition and translocation to other parts were improved under foliar K application. The chlorophyll indices, i.e., soil plant analysis development (SPAD) value, also decreased with the severity of water deficit. Grain yield was higher under stress imposition at grain filling stage than the rest of the stages, though severe water stress decreased yield significantly. The Potassium (K) foliar spray showed no prominent effect at grain filling. Canopy temperature increased with stress severity and was maintained under K foliar spray. Osmotic adjustment, water and turgor potential were affected by water stress and maintained with foliar K spray. Grain quality and biochemical traits of wheat were affected severely under water deficit. Potassium foliar spray was found to decrease the adverse effect of the water stress and hence maintained the quality and biochemical characters. It is concluded that application of foliar potassium decreases the adverse effects of water stress at any growth stage, minimises the stress indices drastic effect and maintains the internal water balance of the crop at different stages subjected to water deficit.

  相似文献   
25.
This study was conducted to evaluate drought tolerance and persistence in a germplasm of smooth bromegrass and association of forage productivity with different traits. Thirty‐six genotypes of smooth bromegrass were clonally propagated and evaluated under two soil moisture environments for three years (2013–2015). High genotypic variation was observed among genotypes for all the measured traits. Drought stress decreased mean values for traits related to productivity. Also, the long‐term stress for three years reduced the persistence of plants. Results indicated that indirect selection based on components of forage yield, which had high heritability and high correlation with yield, would be more effective to improve drought tolerance in this germplasm. The results of principal component analysis showed that there was a negative relationship between phenological traits with the persistence‐related traits and yield production. This suggests that selection for earliness may indirectly promote persistent genotypes. The results showed that some Hungarian genotypes are valuable gene sources for persistence. The most persistent genotypes from both groups (Iranian and foreign) were identified using the biplot method. These genotypes may be useful for the development of populations for future studies.  相似文献   
26.
We investigated the effects of soybean phosphatidylcholine (PtCho) on the growth, fatty acid (FA) profile, and body composition of juvenile Caspian brown trout. Juvenile trout, initial average weight 0.8 ± 0.12 g, were fed semi-purified formulated diets supplemented with 2, 4, and 6% PtCho for 5 weeks. Results showed that fish with diets containing 4 or 6% PtCho had significantly greater growth. The FA profiles of both the polar lipids (PL) and neutral lipids (NL) in juvenile tissues were influenced by dietary FA, although the effects of PtCho supplementation were more marked for PL than for NL. Fish fed PtCho in the diet also had higher levels of 18:2n-6, 20:4n-6 and n-6, and significantly lower levels of docosahexaenoic acid and eicosapentaenoic acid in both PL and NL. The lipid contents of whole-body tissues and liver were positively affected by PtCho percentage in the diet. Specific growth rate, hepatosomatic index, visceralsomatic index, and protein efficiency ratio were also significantly influenced by dietary PtCho. The results of our study indicate that dietary PtCho has a growth-promoting effect and that juvenile Caspian brown trout have a relatively moderate PtCho requirement (at least 4% dry weight of the diet).  相似文献   
27.
The effects of supplemental dietary phosphatidylcholine (PtCho) on the growth performance, survival and digestive enzyme activity of Caspian brown trout (Salmo trutta caspius Kessler 1877) alevins were investigated in this study. Alevin (initial weight 0.8 ± 0.12 g) was fed for 5 weeks with an isoproteic‐ and isolipidic‐formulated diet with increased levels of PtCho from 0 to 60 g kg?1 dry matter and decreasing levels of soybean oil. The increase in dietary PtCho up to 4% led to an increase in alevin final weight, suggesting that moderate PtCho levels are needed during this stage of Caspian brown trout. Survival was not affected by the dietary PtCho level. Phosphatidylcholine incorporation into the diet caused higher phospholipase A2‐specific activity. Phosphatidylcholine did not show a beneficial effect on the specific activity of amylase and protease. Lipase‐specific activity was significantly higher in the PtCho groups compared with the control group. The hepatosomatic index (HSI) was significantly influenced by the dietary PtCho level. The results of the present study indicated that the dietary supplementation of PtCho in the diet of Caspian brown trout alevin improved growth and lipolytic enzyme activity.  相似文献   
28.
29.
Ryegrass (Lolium perenne L.) is a putative turf and forage plant characterized as mainly outcrossing in which the extent of self‐fertilization and its consequences has not been investigated. In this study, selfed and half‐sib family seeds were obtained from ten clonally propagated ryegrass plants among which two were endophyte‐free (EF) and eight were endophyte‐infected (EI). Then, 20 seed populations plus two commercial varieties of Speedy and Vigor were sown and evaluated in a biennial experiment for their turf and forage characteristics. Selfing caused significant inbreeding depression for plant fresh and dry weight and leaf length and width in the first year for both EI and EF genotypes. In the second year, only leaf length remained depressed among these characters. Also, for the most growth, turf and reproductive traits, EI populations showed less depression. The presence of endophyte in self‐pollinated populations made an increasing effect for the number of seed per spike and days to heading, although seed weight was reduced. Some of the populations derived from self‐pollination and infected with fungal endophyte including S9 and S10 were even superior to the two commercial varieties in terms of both seed production and turf characteristics. However, for seed‐related characteristics including number of spikes per plant, seed weight and seed yield, EF populations including Speedy and Vigor were more reproductive than EI populations. It is concluded that selfing may increase the discrimination between EI and EF ryegrass plants because endophyte infection may mitigate the negative consequences of inbreeding depression in prone populations.  相似文献   
30.
Changes in the content of biogenic amines (BA; e.g., putrescine, tyramine, and histamine) and the mesophilic and psychrotrophic bacterial counts of tiger-tooth croaker (Otolithes ruber) were monitored during ice storage for 18 days. BA and bacterial loads gradually increased (p < 0.05) with storage time. On the first day of storage, no amines were detected, and no histamine was detected up to 6 days. The best linear regressions between BA and bacterial counts were found between putrescine and psychrotrophic bacteria. Furthermore, it was found that psychrotrophs were the dominant microorganisms during storage and showed significant (p < 0.05) differences with storage time. The initial concentration of putrescine was 1.27 μg g?1 and reached 18.8 μg g?1 when the psychrotrophic bacterial load was over 108 CFU g?1. The results suggest that the level of putrescine is a suitable indicator of freshness for O. ruber, and the shelf life of O. ruber stored in ice as determined by BA content and microbiological data was 10 days.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号