燕麦农艺性状与产量多元回归分析          下载免费PDF全文

梁万鹏  窦晓利  韩庆辉  张金霞 《中国牛业科学》2023,49(5):12-17

为了筛选出适应旱作农业区推广的燕麦(Avena sativa L.)品种,对引进的3个燕麦品种进行生产能力测定。对影响燕麦产量的指标间采用多元线性回归分析法建立多元线性回归方程。结果表明,燕麦产量的最优回归方程为：y=17.923+247.222x1+8.274x3+127.316x7-12.463x10,从相关系数大小得知,影响大小次序为：品种>株高>茎节数>小穗数。最优回归方程表明：燕麦的产量与其株高(x3)、茎节数(x7)、品种(x1)、小穗数(x10)密切相关。  相似文献   

寒地粳稻碾磨品质和食味品质相关性状的综合分析     

王荣升  牟凤臣  李坤  张微  刘会  丁国华  杨光  王南博  张国民  刘玉明  陶永庆 《作物杂志》2023,39(2):115-554

为阐明寒地粳稻碾磨品质和食味品质性状间的相互关系，以337份高世代纯合品系材料为对象，对其11个品质指标进行相关、主成分和聚类分析，构建准确可行的稻米品质评价回归方程。结果表明，糙米率、精米率和整精米率间呈显著正相关，食味评分与蛋白质和直链淀粉含量均存在相关关系。在主成分分析中，累计方差贡献率80%以上的主成分共4个，综合得分排名前5的水稻品系分别为J139、J201、J141、J204和J138。以食味评分为因变量，糙米率、精米率、蛋白质含量、含水量和直链淀粉含量为自变量得到回归方程。这些研究手段及回归方程可用于快速、准确分析新品系稻米品质，比较品系间差异。  相似文献   

水体理化因子对感染WSSV凡纳滨对虾存活时间的综合影响          下载免费PDF全文

黄海洪  曾丽娟  李朝云  刘小林  张运生  类延菊  杨品红  罗玉双 《西北农业学报》2017,26(8):1123-1129

对文献报道的单因子试验数据进行挖掘,收集盐度、NH_4~+-N和NO_2~--N、pH、WSSV注射量等5个因子对凡纳滨对虾(Litopenaeus vannamei)发病后存活时间影响的独立试验数据,重新整理后进行多因素方差分析和多元回归分析。结果显示,盐度、pH和WSSV注射量对凡纳滨对虾存活时间的影响极显著,NH_4~+-N和NO_2~--N的影响不明显,与文献报道的单因子试验结果一致。多元回归分析结果显示,pH和WSSV注射量与凡纳滨对虾存活时间的相关性极显著,回归方程为"Y(存活时间)=827.6-57.5 X_1(pH)-0.045 X_2(WSSV注射量)",R=0.820,其他3个因子的影响与凡纳滨对虾存活时间的线性关系均不明显。利用单因子数据综合分析的结果与文献报道的多因素试验结果一致,表明对文献数据进行综合分析的方法可行,为凡纳滨对虾疾病综合防控研究提供新的思路。  相似文献   

Refining the accessibility evaluation of urban green spaces with multiple sources of mobility data: A case study in Shenzhen,China     

《Urban Forestry & Urban Greening》2022

Urban green space (UGS) is an important component of urban resources which contributes to human physical and mental health. Studies on the accessibility of UGS under the two-step floating catchment (2SFCA) framework have recently received much attention. However, the effects of people’s actual mobility patterns have not been fully considered in current studies. Proposed in this study is an improved accessibility model called AM-Ga2SFCA, which refines the traditional Gaussian 2SFCA method with the actual mobility information extracted from mobile phone big data and online map. A new attractiveness index of UGS is implemented by combining the popularity evaluated by the PageRank algorithm and the actual utilisation based on buffer analysis. In addition, realistic travel time between each demand point and UGS is retrieved from the online map, which is further introduced into AM-Ga2SFCA as the travel cost. A case study is conducted in Shenzhen, China to validate the proposed model. Results show that the accessibility of UGS is strongly correlated with regional urbanization level, for example, higher accessibility generally occurred in the region with developed transportation and rich green resources. From the perspective of age groups and travel modes, we found that the environmental justice issue had already occurred in Shenzhen especially for the non-elderly: under the walk mode, nearly 80% of the non-elderly only shared 20% of UGS whilst approximately 80% of the elderly shared 30% of UGS. However, taxi or private vehicles can effectively alleviate the aforementioned phenomenon by reducing the Gini index to less than 0.5. The proposed model is expected to advance the understanding of UGS accessibility and facilitate effective planning to reduce environmental justice.  相似文献   

北疆地区粮食作物熟制问题研究          下载免费PDF全文

季良  季方 《西北农业学报》1998,7(3):88-89

对北疆地区粮食作物熟制的研究表明，在露地栽培、８０％保证率下有效积温达３６００℃和３４５０℃，无霜期１７ｄ和１６９ｄ的区域可在早熟小麦后复种特早熟玉米和特早熟大豆，北疆地区发展粮食作物复种的潜力有限，粮食作物种植制度的发展应以一年一熟为主，一年二熟或二年三熟为辅，间，混，套作和复种等多种形式并存。  相似文献   

Review on the multi-scale interactions of urban forests and atmospheric particles: Affecting factors are scale-dependent among tree,stand and region     

《Urban Forestry & Urban Greening》2022

Increasing studies worldwide have examined the impacts of urban forests on mitigating atmospheric particulate matter (PM) over the past decades. These scattered studies revealed the aerodynamics of atmospheric PM deposited on urban forests, as well as the various factors influencing the PM capture and removal by urban forests. However, these evidences are varying and even contradictory, and the affecting factors do not follow a universal pattern. In addition, these studies generally have been conducted in a specific scale such as leaf, stand and city without considering the multi-scale associations and incorporations. This literature review tried to address the associations of urban forest and PM removal across single tree, stand and regional scales, and summarized the confounding factors for PM capture and removal within each scale. Particle size and local meteorology have significant impacts across scales. For an individual tree, PM capture and removal capacity are largely determined by the leaf morphology and epidermal structures, but at the stand scale, the biophysical characteristics and configurational designs of urban forests are the essential factors. At the city and regional scale, the determinants are the fraction of forest coverage, as well as background pollution levels. The literature collation emphasizes the necessity of concerning the appropriate factors responding to the specific scale when quantifying and evaluating PM capture and removal by urban forests, and warrants a multi-scale research paradigm and inclusive modeling evaluation incorporating the confounding factors from multiple scales for PM capture and removal by urban forests.  相似文献   

关于国内“资本下乡”的研究综述          下载免费PDF全文

熊立芳 《现代农业科技》2022,(7)

长期以来，优质非农资源要素流向农村十分困难。而随着国家对乡村发展的大力扶持，资本下乡成为一股热潮，资本下乡的现象也得到了学术界的广泛关注。资本下乡为乡村带来了发展机遇的同时，也对乡村带来了一系列负面影响。本文首先对关于“资本下乡”的国内研究概况进行介绍。随后从资本下乡的阶段划分以及目前学术界对资本下乡所研究的不同聚焦点两方面对“资本下乡”的相关文献进行了综述，最后对其进行总结。  相似文献   

陇东旱塬区复种马铃薯田蛴螬及金针虫防治药剂筛选试验          下载免费PDF全文

梁宏杰  吕和平  张文伟  高彦萍  吴雁斌  王芳芳  杨昕宇  黄伟  张武 《寒旱农业科学》2023,(10):922-926

陇东旱塬区种植冬油菜和冬小麦后，土地闲置期可复种马铃薯，但蛴螬、金针虫等地下害虫对马铃薯为害严重，科学合理防治蛴螬、金针虫对保证马铃薯产量非常重要。为筛选出陇东旱塬区复种马铃薯田防治蛴螬、金针虫危害的低毒高效的适宜药剂，以马铃薯品种陇薯7号为指示品种，蛴螬、金针虫为防治对象，选用3种高效低毒杀虫剂对各药剂的拌种或喷沟处理进行田间防效试验，调查各处理蛴螬、金针虫虫口基数，出苗期的出苗率、受害率、安全性和成熟期的受害率、安全性。结果表明，35%噻虫嗪种衣剂、60%帮巧时种衣剂防效均达85%以上，且拌种处理和喷沟处理无显著差异。60%帮巧时悬浮种衣剂拌种和喷沟防效均好，分别为88.44%、90.36%；折合产量高，分别为16 407.41、17 066.14 kg/hm2，较空白对照分别增产16.71%、21.40%，较常规药剂对照分别增产12.07%、16.57%；保产效果好，分别为95.39%、96.20%。见于此，60%帮巧时悬浮种衣剂可作为陇东旱塬区复种马铃薯田蛴螬、金针虫防治的候选杀虫剂；并建议用48.00 mL的药量稀释10倍液后拌种薯100 kg，将525.00 mL的药量稀释250倍液，按225 L/hm2喷沟。  相似文献   

山东省农业现代化建设现状及发展建议——基于农业劳动力数量          下载免费PDF全文

刘欣怡  李梅芳 《农业工程》2022,12(8)

基于2008-2019年山东省农业就业人口数量,运用Stata软件对影响山东省农业就业人口的因素进行OLS多元线性回归分析。研究结论：化肥使用量、有效耕作面积、农民实际可支配收入三个变量对山东省农业劳动力数量影响最显著,扩大有效耕作面积对山东省吸引农业劳动力起正向影响,而限制化肥使用与农民实际可支配收入增加对山东省农业劳动力增长起反向影响。据此,在山东省提升机械化程度,提高农业就业质量；优化农业空间布局,实施新型城镇化战略；健全惠农强农体系,为农业就业者提供保障等方面实行切实有效的措施,从而推进山东省农业现代化建设。  相似文献   

多元资本介入下乡村运营现状调研及问题思考——以南京市江宁区观音殿村为例          下载免费PDF全文

熊立芳  姜雨嫣  鞠秋宇  张文成  徐菊芬 《现代农业科技》2022,(13)

本调研从乡村运营的角度出发，探究多元资本介入对乡村发展的影响，通过对南京市江宁区观音殿村的物质空间与社会空间两个层面的调查研究，深入挖掘此乡村的物质空间建设、资本运营情况、经营主体构成、乡村运营模式等现状问题，从而分析观音殿村的现存问题。并结合观音殿村内部不同群体需求，对其进行总体评价，总结政府主导下的开发模式给乡村运营带来的影响，并进一步提出问题与反思。  相似文献