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1.
Application of organic wastes to cultivated lands can replace mineral fertilizers but may also alter soil physical properties and enhance pollution potential. The objective of this study was to investigate the effects of biosolids [composted manure (MC) and activated sludge (AS)] and specific biosolid component [orthophosphate (OP), phytic acid (PA) and humic acid (HA)] application on soils differing in texture [loamy‐sand (Ramat‐HaKovesh, RH), loam (Gilat, GL) and clay (Bet‐Dagan, BD)], infiltration rate, runoff volume and soil sediment loss. The soils were packed in erosion boxes (400 × 200 × 40 mm) and subjected to six consecutive simulated rainstorms, each of 186 mm deionized water. The results showed that runoff volume and sediment loss from untreated soils increased with increasing clay contents. In treated soils, the response to AS application differed from the response to other amendments; in the BD clay and GL loam, it was the only amendment that caused a decrease in sediment removed by runoff. In the RH loamy‐sand, all amendments reduced the final infiltration rate, but only AS and HA increased the measured runoff. It is proposed that the difference in the response of the soils to the amendments is associated with the soil's ability to attenuate changes in the negative charge on the clay edges following the increase in the specific adsorption of charged anions, thus controlling clay swelling and maintaining aggregate integrity. The effects of amending soils with a source of organic matter in order to control runoff and soil erosion are not straight forward and depend on soil and amendment properties. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   
2.
Perennial plants are known to be one of the most influential parameters in desert ecosystems affecting microbial activity. In this study, we examined the importance of these perennial shrubs and attempted to determine the most influential factor that contributes the most to the ecosystem by separating the physical part and the organic contribution of perennial plants. The study site is located in the northern Negev Desert, Israel, where 50 Hammada scoparia shrubs and 50 artificial plants were randomly marked to be used as a tool for the above objectives. Soil samples were collected monthly in the vicinity of the canopies of both shrubs while control samples were collected from the open areas between the shrubs. All samples were collected from the upper (0–10 cm) and the deeper (10–20 cm) soil layers. The contribution to microbial activity was measured by evaluation of the microbial community functions in soil. The results of the research showed a trend of a strong influence of the perennial H. scoparia shrubs on microbial community function. The functional aspects of the microbial community that were measured were CO2 evolution, microbial biomass, microbial functional diversity, and the physiological profile of the community. High values for all parameters were observed under the vicinity of the H. scoparia shrubs, while the artificial plants were found to have a weaker effect on the community according to soil depth. The upper-soil layer at both locations (artificial plant canopy and control samples) showed higher values of the functioning parameters than that of the deeper soil layer. The results indicate the importance of the organic contribution (plant litter) in comparison to the physical part of desert shrubs.  相似文献   
3.
Nutrient source limitation in desert ecosystems enhances competition among plant communities, leading to creation of microhabitats beneath the shrubs that can determine composition and abundance of soil organisms. The aim of the study was to determine the effect of plant ecophysiological adaptation on soil nematode communities in the rhizosphere of tightly interweaving shrubby communities. Soil samples were collected monthly under the canopies of three perennial desert shrubs: Artemesia herba-alba, possessing the allelopathic ability to dominate in relationships with other plants; Reaumuria negevensis, a salt-resistant plant; and Noea mucronata, a typical dry desert shrub. An inter-plant area was used as a control. The results demonstrated that soil water content (SWC) and total organic carbon (Corg) were significantly different under different plants and inter-plant areas, with the highest values found under R. negevensis (SWC) and N. mucronata and R. negevensis (Corg). Plant parasite and omnivore-predator nematodes were more sensitive to the ecophysiological individual features of observed plants versus the total number of nematodes and bacteria- and fungi-feeding nematodes. Generally accepted ecological indices such as Wasilewska (WI), trophic diversity (T), maturity (MI, MMI), basal (BI), enrichment (EI), structure (SI), and channel (CI), pointed to specific ecological conditions under canopies of the observed plants.  相似文献   
4.
The objective of this study was to measure the effect of feeding two total mixed rations (TMRs), differing in their roughage content and in vitro dry matter digestibility, on the respiratory rate, body temperature, eating behavior and energy balance of lactating cows. The partitioning of metabolizable energy intake (MEI) between heat production (HP) and retained energy (RE) of cows held under heat load conditions was measured. Forty-two lactating cows were divided into two similar sub-groups, each of 21 animals, and were fed either a control (CON) ration containing 18% roughage neutral detergent fiber (NDF) or an experimental (EXP) TMR that contained 12% roughage NDF and used soy hulls as partial wheat silage replacer. The in vitro DM digestibility of the CON and EXP TMRs was 75.3 and 78.6%, respectively (P < 0.05). The EXP diet reduced rectal temperature and respiratory rate of the cows while increasing their number of meals per day by 32.7% as compared with the CON fed cows, and these meals were shorter in duration and were eaten faster. The EXP diet increased total DM intake from 19.6 to 21.5 kg/cow/d, milk yield from 32.3 to 34.6 kg, and yield of energy corrected milk from 30.9 to 32.2 kg, as compared with the CON group. Cows fed the EXP TMR had increased RE in milk and body tissue, as compared with the CON group, but the diets had no effect on the measured HP that was maintained similar (121 vs. 127 MJ/cow/d) in the two groups. The measured MEI (MEI = RE + HP) and the efficiency of MEI utilization for RE production, were similar in the two dietary groups.  相似文献   
5.
Soil biota play a crucial role in soil ecosystem stability, promoting organic matter decomposition and nutrient cycling. Compared to conventional farming,organic farming is known to improve soil properties such as aggregation. Despite the importance of soil microbial communities in soil biogeochemical processes, our knowledge of their dynamics is rudimentary, especially under different agricultural management practices. Here we studied the effects of vineyard management practices(conventional an...  相似文献   
6.

The effect of environmental conditions, and especially soil water content, on microbial community structure was quantified during a 15-month sampling period (1994-1995) in a Negev Desert soil system by determination of phospholipid fatty acids (PLFAs). Two rainy seasons were observed during the study period: (1) the rainy season of 1993-1994, with a total rainfall of 58mm, and (2) the rainy season of 1994-1995, with a total of 140mm, which is 55% more than the multiannual average. Soil samples collected from the 0-10cm layer exhibited changes in soil moisture and PLFA composition. Palmitic acid (nC16:0) was found to be the most common acid, with a maximum abundance found in May 1994 (27.2%). Oleic acid (C18:1 omega 9) was found to be the second highest in abundance, with high levels in January 1994 (14%), decreasing gradually to 1.3% of total ion current in January 1995. This decrease was interpreted as being caused by abiotic factors affecting the microbial community, resulting in fatty acid profile and lipid abundance. Other acids were found to be present in relatively small amounts. The iC17:1 omega 9 and C18:2 omega 8, 11 were found among the major PLFAs during the study period. The data obtained in this study were found to be similar to data obtained in soils of temperate climates, in spite of the hypothesis that the total PLFAs of the desert soil microbes are triggered and depend on soil water availability. This can afford special data interpretation of the viable biomass of the soil microbes and their metabolic status.  相似文献   
7.
In order to evaluate the protection conferred by an experimental inactivated vaccine against infectious coryza, three challenge trials were undertaken using 112 1-day-old broilers. The vaccine "Hepa Inmuno NC" included bacterial antigens of Avibacterium paragallinarum (serogroups A, B, variant B, and C) as well as antigens of Newcastle virus and hepatitis virus. Fifty-six broiler chicks were vaccinated at the first day of life at the hatchery while another 56 chicks were left unvaccinated. Three infection trials were conducted simultaneously using each of the three serogroups A, B, or C of Av. paragallinarum. In each trial, 17 vaccinated and 17 unvaccinated broilers were used. Challenge was performed at day 31 of life by injection, into the left infraorbital sinus, of approximately 1 x 10(5) colony forming units of the corresponding Av. paragallinarum strain. Clinical signs were recorded on day 2 postchallenge. All broilers were euthanatized and both infraorbital sinuses were bacteriologically examined for the presence of Av. paragallinarum on day 5 postchallenge. In comparison with the unvaccinated broilers, the vaccine significantly reduced the number of broilers with clinical signs after challenge with serogroup B, and significantly fewer vaccinated broilers were positive for the presence of Av. paragallinarum after challenge with serogroup C. On the other hand, no significant protection was observed when broilers were challenged with Av. paragallinarum from serogroup A. Despite the high infection rates in vaccinated chicks after an experimental infection with Av. paragallinarum, it was possible to reduce colonization of Av. paragallinarum (serogroup B) and clinical signs (serogroup C) in broiler chicks by vaccination at the first day of life. Further cross-protection trials should be done, including other Av. paragallinarum strains in the vaccine, especially those from serogroup A.  相似文献   
8.
Journal of Crop Science and Biotechnology - Fusarium head blight (FHB) is one of the destructive diseases in wheat-producing areas of the world. Field experiments were conducted during the 2019...  相似文献   
9.
能在热带荒漠地区进行商业化栽培的作物种类是有限的,园艺作物尤其如是。本研究的目的就是通过引种驯化为热带荒漠区开发新品种。我们以下述两个来源的多年生植物为基础:干旱区和半干旱区人民食用的有营养价值的水果或干果的野生植物种;第二是从当地市场或栽培者那里能收集到的珍稀种类。以色列的内盖夫荒漠气候条件变幅宽广,水土类型多样,是本项研究的理想地点。本研究利用内盖夫的异质特点对向荒漠区引种驯化的不少植物的适宜性进行了预选试验。本文总结了从1984年开始的4年工作,并叙述了总的进展,详细介绍了六种预选植物。  相似文献   
10.
Different marula clones domesticated in the arid Negev desert were evaluated for their horticultural behavior physiological and antioxidant characteristics of their fruits. Two types of abscission pattern were detected, early and late. Fruit yields fluctuated from year to year (6–45 kg/tree) with large differences between clones (few fruits to 45 kg/tree). The clones also differed in fruit weight (34.41 ± 0.91 to 56.74 ± 1.65 g), shape, and juice content. Ascorbic acid content was found to be high in all the clones with significant differences among clones and time post-abscission. Clone no 12 at 1 week post-abscission had the higher ascorbic acid content, 21.177 mg/g dry weight and clone no 4 at the abscission day had the lower ascorbic acid content, 7.142 mg ascorbic acid/g dry weight. The total antioxidant and polyphenol content of the juice varied among clones and with time post-abscission, as did the activity of superoxide dismutase (about 1.40 IU/g dry weight of SOD at week 0 for all clones, to 2.67 IU/g dry weight at the third week post-abscission). Fresh marula juice had, on average, four times more antioxidant than the juice of either orange or pomegranate (marula ascorbic acid equivalent: 8.52 ± 0.76 mM to 23.26 ± 2.20 mM versus 2.72 ± 0.39 mM to 7.38 ± 0.18 mM and 2.56 ± 0.41 mM to 3.92 ± 0.18 mM, respectively), considered to be rich in antioxidants. Marula ice cream and jam manufactured according to industrial protocols were rich in ascorbic acid 45 days post-production. In conclusion, selected genotypes of marula exhibited superior horticultural traits and high antioxidant contents. These data should be of value in selecting marula clones for commercial planting.  相似文献   
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