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91.
旨在维护国家稳定,为预判粮食生产前景、提高粮食生产效率、保障粮食安全提供理论依据。利用湖南省统计数据,运用灰色关联分析法筛选关联性较强的影响因素,并建立GM(1,N)预测模型预测粮食产量。2008—2017年与湖南省粮食产量关联度最大的影响因素是粮食作物播种面积和农业机械总动力;科技因素是影响2008—2017年湖南省粮食产量的主要因素,其次是自然因素,社会因素;2018—2027年湖南省粮食产量有较小波动,且农业机械总动力和财政农业支出影响较大;农业机械总动力在前后十年对粮食产量都有较重要的影响,越来越占据主导地位。粮食产量受国家政策的影响,受农业机械总动力影响最大,维持产量水平需高度重视农业机械化水平,稳步提高粮食作物播种面积。 相似文献
92.
基于改进GM(1,N)模型的我国大豆价格影响因素分析及预测研究 总被引:2,自引:0,他引:2
大豆是我国重要的粮食作物和油料作物,其价格对于国民经济尤其是农业经济的影响意义深远。大豆价格的稳定对于我国大豆市场的健康发展有着重要的现实意义。在灰色理论的基础上,提出了一种改进GM(1,N)大豆价格预测模型,首先运用灰色关联分析法对我国大豆价格的影响因素进行分析,选择主要的影响因素;再将这些影响因素作为模型的相关因素变量,构建GM(1,N)大豆价格预测模型。采用2010-2015年的大豆数据进行实证研究,模型选取国内大豆自给量、世界大豆产量、国民消费价格指数、消费者信心指数4个变量作为相关因素变量;模型预测误差为2.10%,预测精度较高,能够较好地掌握大豆价格的变化规律,可以为大豆价格市场预测及国家宏观政策的制定提供理论指导。 相似文献
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为选育出优良的毛薯种质,本研究以海南大学薯蓣种质资源圃里的80份毛薯为材料,以河南焦作温县的垆土铁棍山药为对照,采用苯酚硫酸法、考马斯亮蓝法以及蒽酮比色法对其干物质、粗多糖、蛋白、可溶性糖和淀粉含量进行测定和比较分析。结果表明:毛薯的干物质含量介于18.62%~38.88%,粗多糖含量介于2.88%~15.82%、蛋白含量介于5.14%~10.71%、可溶性糖含量介于0.1%~13.84%、淀粉含量介于11.94%~64.28%。与对照山药相比,Ds96所测品质均优于对照,可优先选择推广。此外,毛薯各营养品质之间存在着一定的相关性,干物质与糖类存在显著负相关,与蛋白和淀粉表现为正相关。通过对80份毛薯的营养品质进行聚类分析,在欧式距离为3.17时,可将其分为八类,按类群来看,类群Ⅳ各营养价值适中,其他类群在某些营养上比较优秀,可根据需要进行优良资源选择。 相似文献
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《农业科学学报》2019,18(10):2219-2229
Intercropping is used widely by smallholder farmers in developing countries to increase land productivity and profitability. We conducted a maize/peanut intercropping experiment in the 2015 and 2016 growing seasons in Shandong, China. Treatments included sole maize(SM), sole peanut(SP), and an intercrop consisting of four rows of maize and six rows of peanut(IM and IP). The results showed that the intercropping system had yield advantages based on the land equivalent ratio(LER) values of 1.15 and 1.16 in the two years, respectively. Averaged over the two years, the yield of maize in the intercropping was increased by 61.05% compared to that in SM, while the pod yield of peanut was decreased by 31.80% compared to SP. Maize was the superior competitor when intercropped with peanut, and its productivity dominated the yield of the intercropping system in our study. The increased yield was due to a higher kernel number per ear(KNE). Intercropping increased the light transmission ratio(LTR) of the ear layer in the maize canopy, the active photosynthetic duration(APD), and the harvest index(HI) compared to SM. In addition, intercropping promoted the ratio of dry matter accumulation after silking and the distribution of ~(13) C-photosynthates to grain compared to SM. In conclusion, maize/peanut intercropping demonstrated the potential to improve the light condition of maize, achieving enhanced photosynthetic characteristics that improved female spike differentiation, reduced barrenness, and increased KNE. Moreover, dry matter accumulation and ~(13) C-photosynthates distribution to grain of intercropped maize were improved, and a higher grain yield was ultimately obtained. 相似文献
98.
利用东北农作区58个气象站点1961—2010年的逐日气象数据,基于Simulation of Evapotranspiration of Applied Water(SIMETAW)模型分析气候变化背景下东北农作区春小麦生育期内作物需水量(Crop evapotranspiration,ETc)和灌溉需要量(Evapotranspiration of applied water,ETaw),以及典型站点春小麦的灌溉需求指数(Irrigation demand index,IDI)的时空变化特征。结果表明:近50年来,东北农作区日平均温度呈显著上升趋势,平均降水量下降趋势不明显,平均太阳辐射及作物蒸散量呈显著下降趋势。春小麦生育期作物需水量和灌溉需要量呈下降趋势,其分布均表现为西多东少。50年来春小麦作物生育期需水量下降主要集中于松辽及兴安岭南部地区,东部地区变化趋势不明显;生育期灌溉需要量下降集中于松辽及兴安岭地区,三江平原地区略有增加,长白山地区多年保持平稳。 相似文献
99.
ADELIJIANG Wusiman DELIBAIER NUERAILI Maitiniyazi BUHELIQIANMU Yiming SAIFUDING Abula 《中国畜牧兽医》2016,43(7):1869-1875
To research on polysaccharides from Lagenaria siceraria (Molina) Standl.against Newcastle disease virus (NDV).Total polysaccharide and four different solvent extractions of Lagenaria siceraria (Molina) Standl.were extracted by the methods of hot water extraction and ethanol precipition in this study.The content of polysaccharide was measured by phenol-sulfuric acid method and infrared spectroscopy method.The safe concentration and growth of chick embryo fibroblast (CEF) were assayed by MTT method,in order to facilitated the comparison under the same level,the safe concentration was united as 78.125 μg/mL.Under the safety range of concentration,detected the block-virus activity,anti-virus activity and virus-killing activity of polysaccharides through the ways of pre-adding polysaccharides,post-adding polysaccharides and adding polysaccharides with NDV.The results showed that the direct inactivation and propagation inhibition activity of total polysaccharide and four different solvent extractions were stronger than anti-absorption function.Anti-virus inhibition rate of 70%,80% gradient alcohol precipitation of polysaccharides from Lagenaria siceraria (Molina) Standl.(LSP70,LSP80) and total polysaccharide (LSPt)were 40.41%,44.54% and 61.85%,virus-killing inhibition rate were 44.74%,58.76% and 59.38%.LSP80 had the highest virus inhibition rate as 37.14% in the block-virus activity of those five polysaccharides.In summary,70%,80% gradient alcohol precipitation and total polysaccharide in polysaccharides possessed better activity and would be as the materials for further research. 相似文献
100.
Xiang-dong LUO Jian LIU Jun ZHAO Liang-fang DAI Ya-ling CHEN Ling ZHANG Fantao ZHANG Biao-lin HU Jian-kun XIE 《农业科学学报》2018,17(2):265-275
Cold stress is a major problem in rice production. To rapidly identify genes for cold tolerance in Dongxiang wild rice(DWR, Oryza rufipogon Griff.), sequencing-based bulked segregant analysis of QTL-seq method was used to resequence the extremely resistant(R) and susceptible(S) bulks of a backcross inbred lines(BILs) population(derived from Oryza sativa×O. rufipogon) and their parents. Single nucleotide polymorphisms(SNP)-index graphs and corresponding Δ(SNPindex) graphs(at 99 and 95% confidence levels) for R-and S-bulks detected a total of 2 609 candidate SNPs, including 58 candidate cold-tolerance genes. Quantitative real-time PCR analysis revealed that 5 out of the 58 candidate genes had significant differences in expression between O. sativa and O. rufipogon. Structural variation and functional annotations of the 5 candidate genes were also analyzed, and allowed us to identify 2 insertion-deletion(InDel) markers(12-7 and 12-16) that were linked with candidate genes on chromosome 12 in DWR. These results are helpful for cloning and using cold tolerance genes from common wild rice in cultivated rice. 相似文献