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排序方式: 共有391条查询结果,搜索用时 15 毫秒
41.
Marlies M. Gerdemann Andrea Machmüller Emmanuel Frossard Michael Kreuzer 《植物养料与土壤学杂志》1999,162(4):401-408
The objective of this study was to evaluate the extent to which altering pig nutrition for environmental reasons could affect the N fertilizing value of slurry. This was assessed by studying the nitrification of NH4-N and the N use efficiency of slurries obtained from growing pigs offered feeds either with commonly applied contents of crude protein (CP) and bacterially fermentable substrates (BFS) or reduced CP levels and/or elevated BFS levels. Soil/slurry mixtures were incubated for 16 weeks at 20°C using 0.2 g total slurry N addition per kg soil. In a 15 weeks lasting pot experiment with Lolium multiflorum, N derived from the same slurries was applied at two N doses with overall either 0.4 or 0.8 g total slurry N/kg soil. In the pot experiment the effect of slurry on plant growth and N uptake was compared with a mineral N fertilizer (NH4NO3) treatment and a non-fertilized control. Slurries obtained from pigs fed at reduced CP content had lower pH, total N content and proportion of NH4-N than slurries obtained from pigs fed at higher CP. Accordingly incubation of soil/slurry mixtures using slurries obtained from low CP feeds resulted in lower NO3-N concentration in the soil. Furthermore, a lower proportion of the added NH4-N was nitrified in treatments involving slurries derived from low CP feeds. Modifying the BFS content in feeds had minor effects both on slurry characteristics and on slurry NH4-N nitrification in soil. Although reduced CP and, to a lesser extent, elevated BFS altered the N release pattern to plants, slurry N use efficiency during the four cuts following the first fertilization ranged at a similar level of 32 to 33% for all types of slurry. This apparent use was significantly lower than that of the mineral N fertilizer which amounted to 72 to 75% of the added N. Nitrogen balance showed that less than 22% of the added mineral N fertilizer was lost from the soil/plant systems while from 32 to 47% of the N added with the slurries was lost independently of the type of slurry. So overall N utilization by crop and rate of slurry N recovery did not significantly differ which indicates that the investigated modifications of pig feeding appear to have no short term negative effect on the N fertilizing value of slurries. 相似文献
42.
Yield stability studies of soybean (Glycine max (L.) Merrill) under rhizobia inoculation in the savanna region of Nigeria 下载免费PDF全文
Kehinde D. Tolorunse Andrew S. Gana Abdullahi Bala Emmanuel A. Sangodele 《Plant Breeding》2018,137(3):262-270
Soybean (Glycine max (L.) Merrill) production is expanding into temperate and tropical environments. Yield stability studies under rhizobia inoculation were investigated in 24 soybean genotypes over two successive growing seasons at three agro‐ecological zone of Nigeria, during the 2015–2016 rainy seasons. Treatments were arranged in a split‐plot design and replicated three times. Treatments were 24 soybean genotypes and three levels of rhizobia inoculation. Results indicated that the variation of genotypes and inoculation on percentage emergence, height, number of leaves, number of branches per plant, total biomass yield, above‐ground biomass and seed yield was significant (p = .05). The effects of genotypes (G), environment (E) and G × E interactions on seed yield were also significant. Two soybean genotypes (TGx 1989‐45F and TGx 1990‐110FN) were identified as the most promising in relation to yield stability. Of the three locations, Abuja produced the least interaction effects followed by Igabi and may be most appropriate environments for large‐scale soybean production. Appropriate inoculation of soybean with inoculants (LegumeFix and or NoduMax) should be encouraged in farmer's field. 相似文献
43.
Maximum germination distance(MGD) is an important component of Striga resistance in sorghum. The objective of this study was to determine gene action influencing MGD of Striga hermonthica and Striga asiatica among selected sorghum lines treated with a biocontrol agent, Fusarium oxysporum f. sp. strigae(FOS) for effective breeding with Striga resistance, and FOS compatibility. Twelve sorghum genotypes were selected based on their Striga resistance, FOS compatibility, and superior agronomic performance. Selected genotypes were crossed using a bi-parental mating design to generate six families for genetic analysis. Agar-gel assays were used to determine low haustorium initiation factor(LHF) using the 12 parental lines, their F_1 progenies, backcross derivatives, and F_2 segregants in two sets. One set had S. hermonthica seed and the other one had S. asiatica seed. Both were treated with and without FOS. Genotypes were evaluated using a split-plot design with three replications and MGD data were recorded followed by generation mean analysis. FOS reduced MGD by 1cm under both S. hermonthica and S. asiatica infestations. Additive, dominance, and epistatic gene actions were involved in the control of MGD of the two Striga species in the evaluated populations. On average, the relative contribution of additive, additive×additive and dominance×dominance genetic effects on the MGD of S. hermonthica and S. asiatica, with FOS, were 20, 33, and 36%; and 21, 32, and 35%, respectively. Breeding methods exploiting these genetic effects may provide enhanced response to selection for Striga resistance and FOS compatibility in integrated Striga management(ISM) programmes. 相似文献
44.
Effects of seasonal and environmental changes on aquaculture production in tropical Lake Volta,Ghana
Emmanuel T. D. Mensah Hederick R. Dankwa Lauridsen L. Torben Ruby Asmah Benjamin B. Campion Regina Edziyie 《Aquaculture International》2018,26(6):1387-1400
Globally, aquaculture production is faced with numerous challenges, notable among which is water quality. The study determined seasonal environmental changes in Lake Volta and its implications on cage production of Nile tilapia, Oreochromis niloticus in experimental and commercial farm (Sun Woo Farm) set-ups. For each set-up, three cages were used, each measuring 81 and 162.5 m3 for experimental and commercial, respectively. The cages were stocked with 22.5 g fingerlings at a rate of 40 and 80 m?3 in experimental and commercial cages, respectively, and fed commercial diet. The growth performance, yield, economics, and selected water quality parameters were monitored during the dry and wet seasons between November 2014 and July 2015. There were no differences in water quality parameters between dry and wet seasons (p?>?0.05). Water quality for both seasons remained within limits required for good Tilapia growth in both set-ups. There were minimal variations in growth characteristics between seasons which were not significant; however, final mean weight and yields were high in the dry seasons in both set-ups. The cost of feed and fingerling accounting for about 80% of total costs were the major components identified to affect cost of production. A higher profit index and returns on investment were observed in the dry season in both set-ups and was linked to higher survival rates in the season. Production of Nile tilapia in cages can be cultured throughout the year without any adverse effects as exhibited in similar production patterns in both experimental and commercial set-ups. 相似文献
45.
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47.
Emmanuel Senyael Swai A. Kapaga F. Kivaria D. Tinuga G. Joshua P. Sanka 《Veterinary research communications》2009,33(8):927-936
Despite the widespread prevalence of infection with Peste des petits ruminants virus (PPRV) in goats and sheep industry in
Asia and sub-Saharan Africa, there have been few, if any, structured population-based studies examining the epidemiology of
this infection in Tanzania. In this study, we investigated the seroprevalence, and risk factors, of Peste des petitis ruminants(PPR)
in sheep and goat flocks from seven different geographical administration authorities (Ngorongoro, Monduli, Longido, Karatu,
Mbulu, Siha and Simanjiro) located in Northern Tanzania. Serum samples from 657 and 892 sheep and goats, respectively, corresponding
to 91 sheep/goat flocks and 43 villages were collected. Competitive enzyme linked immunosorbent assay (c-ELISA) was used to
detect the presence of antibodies in the serum against PPRV. Chi-square analysis and multivariable logistic regression model
were used to identify risk factors for PPRV seropositivity. Findings suggested that the sero-positive cases were significantly
higher in goats than in sheep (49.5% versus 39.8%; P = 0.002). The overall seroprevalence of PPRV infection in small ruminants
was 45.8%. Highest seroprevalence (42.6–88.02%) was observed in Mbulu, Siha, Longido, Ngorongoro districts, while antibodies
less than 40% to none were found in serum from Monduli, Karatu and Simanjiro, respectively. These findings confirm natural
transmission of PPRV under field condition for the first time in Tanzania. Results may be correlated with variations in the
sheep and goat husbandry practices within different geographic localities, the uncontrolled movement of animals, the levels
of natural immunity and the sharing of grazing field amongst agro and pastoralists. 相似文献
48.
Emmanuel I. Unuabonah Bamidele I. Olu-Owolabi Abiola N. Oladoja Augustine E. Ofomaja Zhang L. Yang 《Journal of Soils and Sediments》2010,10(6):1103-1114
Purpose
Pollution of soils by heavy metal ions has attracted global concern because of the subsequent translocation into food chain which when taken up to a certain level can cause serious health problems. The influence of preadsorbed calcium by kaolinite clay modified with orthophosphate and tripolyphosphate reagents on the mobility of Pb2+ in kaolinitic soil system is studied. This is with the view to understand the fate of Pb2+ in phosphate-fertilized kaolinitic soils that are subsequently limed. 相似文献49.
The antiinflammatory effect of solasodine (50 mg/kg p.o.), of a purified component named sobatum (50 mg/kg p.o.) and of methanol extract of Solanum trilobatum (100 mg/kg p.o.) was evaluated. All the tested articles showed significant antiinflammatory activity. 相似文献
50.