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81.
Mustapha B Salawu Elizabeth H Warren Adegbola T Adesogan 《Journal of the science of food and agriculture》2001,81(13):1263-1268
This study evaluated the effects of two commonly used microbial inoculants (Lactobacillus buchneri (LB) and Lactobacillus plantarum (LP)), formic acid (FA) and quebracho tannins (QT) on the fermentation quality, aerobic stability and in situ rumen degradation of pea/wheat bi‐crop forages. Precision‐chopped spring pea (Pisum sativum, var Magnus) and wheat (Triticum aestivum, var Axona) bi‐crops (3:1 pea/wheat ratio) harvested at a combined dry matter (DM) content of 301 g kg?1 were used for the study. The bi‐crops were conserved without (Control) or with inoculants based on lactic acid bacteria (LB (105 CFU g?1 fresh weight (FW)) or LP (106 CFU g?1 FW)), QT (16 g kg?1 FW) or FA (2.5 g kg?1 FW) in laboratory silos of 1.5 kg capacity, with each treatment being replicated six times. The pH, chemical composition, aerobic stability and in situ rumen degradation of DM, nitrogen (N) and neutral detergent fibre (NDF) after 112 days of ensilage were measured. The average pH at silo opening was 4.0, suggesting that the silages were well fermented. There were no significant effects of additive treatment on water‐soluble carbohydrate, total N, soluble N, ammonia N and NDF. Lactic acid and acetic acid were the main fermentation products. High concentrations of acetic acid were found in all the treatments, indicating a heterofermentative pathway. Although FA treatment gave the most aerobically stable silage, the Control and QT‐treated silages did not heat up by more than 1 °C until after 6 days of exposure to air. There were no effects of additives on DM degradation characteristics. However, the inoculants increased the rate of N and NDF degradation in the rumen, and both FA and QT reduced the effective and potential degradation of N. © 2001 Society of Chemical Industry 相似文献
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为有效指导农业温室气体减排政策的制定,本研究分别采用CH4MOD模型和排放因子法估算了2018年长三角地区农作物甲烷(CH4)和氧化亚氮(N2O)排放,并分析其时空分布规律,最终建立了2018年长三角地区农作物1 km×1 km网格化温室气体排放清单.研究结果表明:长三角稻田CH4排放因子为348.54 kg/hm2,农作物N2O排放因子为0.95 kg/hm2,与前人研究结果具有一致性.长三角地区稻田CH4排放为176.9万t(折合约3 714.9万t CO2当量),最主要排放源为单季稻稻田;农作物N2O排放为15114.9 t(折合约450.4万t CO2当量),小麦是主要贡献源.CH4和N2O排放均主要来源于江苏省和安徽省,且集中在4—8月.建议加强对农业温室气体排放的管控,从源头上减少农田碳氮源的输入. 相似文献
84.
Michael S. Koch John M. DeSesso Amy Lavin Williams Suzanne Michalek Bruce Hammond 《Critical reviews in food science and nutrition》2016,56(3):512-526
To determine the reliability of food safety studies carried out in rodents with genetically modified (GM) crops, a Food Safety Study Reliability Tool (FSSRTool) was adapted from the European Centre for the Validation of Alternative Methods’ (ECVAM) ToxRTool. Reliability was defined as the inherent quality of the study with regard to use of standardized testing methodology, full documentation of experimental procedures and results, and the plausibility of the findings. Codex guidelines for GM crop safety evaluations indicate toxicology studies are not needed when comparability of the GM crop to its conventional counterpart has been demonstrated. This guidance notwithstanding, animal feeding studies have routinely been conducted with GM crops, but their conclusions on safety are not always consistent. To accurately evaluate potential risks from GM crops, risk assessors need clearly interpretable results from reliable studies. The development of the FSSRTool, which provides the user with a means of assessing the reliability of a toxicology study to inform risk assessment, is discussed. Its application to the body of literature on GM crop food safety studies demonstrates that reliable studies report no toxicologically relevant differences between rodents fed GM crops or their non-GM comparators. 相似文献
85.
This study compared the influence of different cover crops with clean tillage on wine aroma compounds of 5-year-old Cabernet Sauvignon vines. White clover, alfalfa, and tall fescue were used in the vineyard and compared with clean tillage. Aroma compounds of wine were analysed by solid-phase microextraction gas chromatography–mass spectrometry (SPME-GC/MS). Forty-seven volatile compounds were identified and quantified. Wines made from grapes grown with various cover crops had higher levels of aroma compounds. Ethyl acetate, isoamyl acetate, ethyl octanoate, ethyl hexanoate, phenylethyl acetate, isoamyl alcohol, linalool, citronellol, β-damascenone, α-ionone, and 5-amyl-dihydro-2(3H)-furan were the impact odorants of sample wines. Wines from cover crop also had higher contents of these impact odorants than the control. For different cover crops, alfalfa sward yielded the highest levels, followed by the tall fescue treatment. According to the data analysis of aroma compounds and sensory assess, permanent cover crop may have the potential to improve wine quality. 相似文献
86.
中国氮肥消费状况及其发展展望 总被引:10,自引:0,他引:10
中国氮肥的消费在经历了快速的波动性增长以后,近年来的增长趋势变慢。通过对全国农技中心2003年统计数据和2000年农户调查数据的分析,阐明了我国氮肥消费的空间分布、品种结构和农作物需求状况;并指出了农作物氮肥施用中存在传统施肥习惯影响氮肥消费结构,氮肥施用面积不足、适量和超量各占三分之一,施肥方式影响肥料利用率,氮肥价格的上涨也影响氮肥消费结构等问题。因此,中国氮肥总消费量增长的趋势并不明朗。目前开展的测土配方施肥行动和减少氮肥农田损失的措施都会不同程度地影响未来氮肥的消费结构。 相似文献
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88.
我国是农业大国,做好农作物新品选育及推广应用等工作,不仅关系到民生大计,也是我国农业发展转型的重要动力。文章主要研究农作物新品种选育及推广应用中存在的问题和应对策略。 相似文献
89.
Properties and Biotechnological Applications of Acyl‐CoA:diacylglycerol Acyltransferase and Phospholipid:diacylglycerol Acyltransferase from Terrestrial Plants and Microalgae 下载免费PDF全文
Yang Xu Kristian Mark P. Caldo Dipasmita Pal‐Nath Jocelyn Ozga M. Joanne Lemieux Randall J. Weselake Guanqun Chen 《Lipids》2018,53(7):663-688
Triacylglycerol (TAG) is the major storage lipid in most terrestrial plants and microalgae, and has great nutritional and industrial value. Since the demand for vegetable oil is consistently increasing, numerous studies have been focused on improving the TAG content and modifying the fatty‐acid compositions of plant seed oils. In addition, there is a strong research interest in establishing plant vegetative tissues and microalgae as platforms for lipid production. In higher plants and microalgae, TAG biosynthesis occurs via acyl‐CoA‐dependent or acyl‐CoA‐independent pathways. Diacylglycerol acyltransferase (DGAT) catalyzes the last and committed step in the acyl‐CoA‐dependent biosynthesis of TAG, which appears to represent a bottleneck in oil accumulation in some oilseed species. Membrane‐bound and soluble forms of DGAT have been identified with very different amino‐acid sequences and biochemical properties. Alternatively, TAG can be formed through acyl‐CoA‐independent pathways via the catalytic action of membrane‐bound phospholipid:diacylglycerol acyltransferase (PDAT). As the enzymes catalyzing the terminal steps of TAG formation, DGAT and PDAT play crucial roles in determining the flux of carbon into seed TAG and thus have been considered as the key targets for engineering oil production. Here, we summarize the most recent knowledge on DGAT and PDAT in higher plants and microalgae, with the emphasis on their physiological roles, structural features, and regulation. The development of various metabolic engineering strategies to enhance the TAG content and alter the fatty‐acid composition of TAG is also discussed. 相似文献
90.
Nitrogen use and losses in agriculture in subtropical Australia 总被引:3,自引:0,他引:3
K. L. Weier 《Nutrient Cycling in Agroecosystems》1994,39(3):245-257
This review examines the use of nitrogen (N) fertilizer on sugar-cane, summer and winter grain crops, cotton, tropical fruit crops and pastoral areas in the four subtropical zones in eastern Australia. The pathways for N loss from the various crops grown in these zones are also examined and estimates of N loss given.Sugar-cane is the most important crop grown in the subtropical humid northern and southern zones, using 77% of all N fertilizer applied in 1988–89. Urea is the most widely used form of N fertilizer with about 50% of the applied N often lost via ammonia volatilization, denitrification and leaching. Losses of N via ammonia volatilization can be reduced by either irrigating after application, applying urea in subsurface bands or delaying application until after canopy development. Denitrification losses of 20% of applied N have been measured on clay soils in sugar- cane areas while leaching losses may occur by movement of solutes down preferential pathways (e.g. soil fauna, root channels and structural weaknesses in the soil profile). Tropical fruit crops also make a significant contribution to the economy of the humid northern and southern zones. The livestock industry is well established in the subtropical northern zones, with beef and dairy production relying on leguminous as well as N fertilized pastures. Urea is again the most widely used form of N and is susceptible to large losses via ammonia volatilization. Over a 12 month period, losses of between 9% and 42% of the N applied were recorded from a subtropical pasture.Wheat is the major winter crop of the sub-humid northern and southern zones with grain sorghum the main summer crop. Urea is the principal form of N fertilizer applied to both crops and is essential for increasing or maintaining economic yields from both regions. This decrease in soil fertility in grain producing areas is due mainly to a decrease in the amount of soil organic matter available for mineralization. Cotton is another major crop of both areas and relies heavily on N fertilizer application. Nitrogen fertilizer losses have been recorded from all cropping areas, although nitrification inhibitors such as wax coated calcium carbide and 2-ethynylpyridine have reduced denitrification losses from soils growing wheat and cotton respectively.Subtropical agriculture relies heavily on N fertilizer, principally urea, to maintain and increase crop yields. Losses of N from soils sown to crops and from native and sown pasture occur although management practices are being developed to help minimize this loss. 相似文献