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1.
• Livestock manure was the main organic waste in urban and peri-urban areas.• Manure production will increase by a factor of 3–10 between 2015–2050.• Only 13%–38% of excreted N by livestock will be recycled in croplands.• Intensification of urban livestock production greatly increased N surpluses.• Reducing population growth and increasing livestock productivity needed.Urban population growth is driving the expansion of urban and peri-urban agriculture (UPA) in developing countries. UPA is providing nutritious food to residents but the manures produced by UPA livestock farms and other wastes are not properly recycled. This paper explores the effects of four scenarios: (1) a reference scenario (business as usual), (2) increased urbanization, (3) UPA intensification, and (4) improved technology, on food-protein self-sufficiency, manure nitrogen (N) recycling and balances for four different zones in a small city (Jimma) in Ethiopia during the period 2015-2050. An N mass flow model with data from farm surveys, field experiments and literature was used. A field experiment was conducted and N use efficiency and N fertilizer replacement values differed among the five types of composts derived from urban livestock manures and kitchen wastes. The N use efficiency and N fertilizer replacement values were used in the N mass flow model.Livestock manures were the main organic wastes in urban areas, although only 20 to 40% of animal-sourced food consumed was produced in UPA, and only 14 to 19% of protein intake by residents was animal-based. Scenarios indicate that manure production in UPA will increase 3 to 10 times between 2015 and 2050, depending on urbanization and UPA intensification. Only 13 to 38% of manure N will be recycled in croplands. Farm-gate N balances of UPA livestock farms will increase to>1 t·ha1 in 2050. Doubling livestock productivity and feed protein conversion to animal-sourced food will roughly halve manure N production.Costs of waste recycling were high and indicate the need for government incentives. Results of these senarios are wake-up calls for all stakeholders and indicate alternative pathways.  相似文献   
2.
Humans, like other animals, alter their behavior depending on whether a threat is close or distant. We investigated spatial imminence of threat by developing an active avoidance paradigm in which volunteers were pursued through a maze by a virtual predator endowed with an ability to chase, capture, and inflict pain. Using functional magnetic resonance imaging, we found that as the virtual predator grew closer, brain activity shifted from the ventromedial prefrontal cortex to the periaqueductal gray. This shift showed maximal expression when a high degree of pain was anticipated. Moreover, imminence-driven periaqueductal gray activity correlated with increased subjective degree of dread and decreased confidence of escape. Our findings cast light on the neural dynamics of threat anticipation and have implications for the neurobiology of human anxiety-related disorders.  相似文献   
3.
Journal of Crop Science and Biotechnology - Knowledge on the extent and pattern of diversity in crop species is a precondition for any crop improvement as it helps breeders in determining apt...  相似文献   
4.
Legumes are important components of sustainable agricultural production, food, nutrition and income systems of developing countries. In spite of their importance, legume crop production is challenged by a number of biotic (diseases and pests) and abiotic stresses (heat, frost, drought and salinity), edaphic factors (associated with soil nutrient deficits) and policy issues (where less emphasis is put on legumes compared to priority starchy staples). Significant research and development work have been done in the past decade on important grain legumes through collaborative bilateral and multilateral projects as well as the CGIAR Research Program on Grain Legumes (CRP‐GL). Through these initiatives, genomic resources and genomic tools such as draft genome sequence, resequencing data, large‐scale genomewide markers, dense genetic maps, quantitative trait loci (QTLs) and diagnostic markers have been developed for further use in multiple genetic and breeding applications. Also, these mega‐initiatives facilitated release of a number of new varieties and also dissemination of on‐the‐shelf varieties to the farmers. More efforts are needed to enhance genetic gains by reducing the time required in cultivar development through integration of genomics‐assisted breeding approaches and rapid generation advancement.  相似文献   
5.
Chickpea (Cicer arietinum L.) is a dry season food legume largely grown on residual soil moisture after the rainy season. The crop often experiences moisture stress towards end of the crop season (terminal drought). The crop may also face heat stress at the reproductive stage if sowing is delayed. The breeding approaches for improving adaptation to these stresses include the development of varieties with early maturity and enhanced abiotic stress tolerance. Several varieties with improved drought tolerance have been developed by selecting for grain yield under moisture stress conditions. Similarly, selection for pod set in the crop subjected to heat stress during reproductive stage has helped in the development of heat‐tolerant varieties. A genomic region, called QTL‐hotspot, controlling several drought tolerance‐related traits has been introgressed into several popular cultivars using marker‐assisted backcrossing (MABC), and introgression lines giving significantly higher yield than the popular cultivars have been identified. Multiparent advanced generation intercross (MAGIC) approach has been found promising in enhancing genetic recombination and developing lines with enhanced tolerance to terminal drought and heat stresses.  相似文献   
6.
Abstract

The experiment was conducted at Kulumsa, South East Ethiopia, using four levels of nitrogen (N) (0, 50,100 and 150?kg N ha?1) and four levels of phosphorus (P) (0, 35, 70 and 105?kg P2O5 ha?1) fertilizers arranged in 4?×?4 factorial arrangements in randomized complete block design with three replications. The available P was increased after harvest due to the application of N and P fertilizer at the rates of 100 or 150?kg N ha?1 and 70 or 105?kg P2O5 ha?1. More specifically, nutrients concentration and nutrient uptake were significantly (p?<?.01) varied among treatment combinations and nutrient use efficiency was declined by increasing N and P after optimum rates. The higher physiological efficiency of N (53.47?kg kg?1) and P (580.41?kg kg?1) and the highest apparent recovery of N (19.62%) and P (2.47%) was recorded from application of 50?kg N ha?1 and P at 70?kg P2O5 ha?1 and the highest agronomic efficiency of N (10.78?kg kg?1) and P (15.25?kg kg?1) was recorded from N at the rate of 50?kg N ha?1 and P at 35?kg P2O5 ha?1, respectively. The combination of N at 100?kg N ha?1 and P at 70?kg P2O5 ha?1 was promising combination that generated highest net benefit 488,878.5 ETB (Ethiopian birr) ha?1 with the highest marginal rate of return (36638%) and gave the highest seed yield (1858.82?kg ha?1) with yield increment of about 57.72% over the control.  相似文献   
7.
A cross sectional sero-prevalence study was conducted on 1,595 cattle in Jimma zone, Ethiopia to investigate the status of bovine brucellosis and identify potential risk factors. Sera samples were analyzed using Rose Bengal Plate Test (RBPT) and Complement Fixation Test (CFT). The overall individual and herd level sero-prevalences were 3.1% (n = 1,595) and 15.0% (n = 227), respectively. The sero-prevalence of bovine brucellosis at individual animal level was significantly higher in non-pregnant (11.18%) than pregnant (2.77%) and lactating (22.35%) than non-lactating animals (2.46%). Moreover, significantly higher sero-prevalence was observed in herds of larger sizes. Individual animal sero-prevalence was also positively associated with the occurrence of abortion (26.98 and 1.54% in those with and without previous history of abortion, respectively). Generally, the sero-prevalence of bovine brucellosis found in Jimma area was not high and the sero-prevalence was closely associated with some of the risk factors considered at individual animal and herd level.  相似文献   
8.
There are several hurdles to ensure sustainable seed production and consistent flow of improved legume varieties in sub‐Saharan Africa (SSA) and South Asia (SA). The unreliable demand, autogamous nature of most of the grain legumes, and slow variety replacement rate by smallholder farmers do not provide strong incentive for private seed companies to invest in legume seed business. Unless a well thought‐out and comprehensive approach to legume seed delivery is developed, current seed shortages will continue, eroding emerging market opportunities. The experiences reported here are collated through a 10‐year partnership project, the Tropical Legumes in SSA and SA. It fostered innovative public–private partnerships in joint testing of innovative market‐led seed systems, skills and knowledge enhancement, de‐risking private sector initiatives that introduced in new approaches and previously overlooked entities in technology delivery. As new public and private seed companies, individual seed entrepreneurs and farmer organizations emerged, the existing ones enhanced their capacities. This resulted in significant rise in production, availability and accessibility of various seed grades of newly improved and farmer demanded legume varieties in the target countries.  相似文献   
9.
Journal of Crop Science and Biotechnology - Chickpea (Cicer arietinum L.) is one of the most important food legumes in the world. However, Fusarium wilt is one of the major yield limiting factors...  相似文献   
10.
This study was carried out to evaluate the reproductive performance and calves survival rate of Holstein–Friesian (HF) herd in Holeta, central highland of Ethiopia. A retrospective analysis of 26 years data was carried out, from which records of 724 age at first calving (AFC), 2,022 calving intervals (CI), 2,971 breeding efficiencies (BE), 260 abortions, 111 stillbirths were derived from 795 cows. Moreover, 738 female calves’ records were also included for survival rate study. The overall least squares means of AFC, CI, and BE were 40.9 ± 0.33 months, 475 ± 2.84 days, 81.9 ± 0.26%, respectively, while the incidence rates of abortion, stillbirth, and female calves survival rate for this herd were 8.0%, 3.4%, and 77.5%, respectively. The effects of parity number and year of birth/calving on CI and BE were significant (P < 0.001). Moreover, birth year had significant (P < 0.001) effect on AFC and calves survival rate, while calving season had significant effect on BE. The reproductive performance found in this study was lower than the performance reported in many tropical regions and the genetic potential of HF breed in their origins. Moreover, higher loss due to calf mortality was observed. Thus, the centre should consider appropriate measures to improve its herd reproductive performance and calves survival rate for attaining its aspired objectives.  相似文献   
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