400克/升氯氟醚菌唑悬浮剂对香蕉叶斑病的防治效果

通过大田试验研究了400克/升氯氟醚菌唑悬浮剂防治香蕉叶斑病效果及其对香蕉产量的影响。研究结果表明,分别以20毫升、13.3毫升、10毫升400克/升氯氟醚菌唑悬浮剂兑水60公斤分3次喷雾施药,第二次施药后14d后对香蕉叶斑病防治效果在60.43-66.52%,第三次施药后14d后对香蕉叶斑病防治效果在75.72-80.72%,并对香蕉的单株产量有明显增产效果。其中尤以20毫升400克/升氯氟醚菌唑悬浮剂兑水60公斤剂量喷雾处理的效果最好。     

Performance and uncertainty analysis of a short-term climate reconstruction based on multi-source data in the Tianshan Mountains region,China

Short-term climate reconstruction, i.e., the reproduction of short-term(several decades) historical climatic time series based on the relationship between observed data and available longer-term reference data in a certain area, can extend the length of climatic time series and offset the shortage of observations. This can be used to assess regional climate change over a much longer time scale. Based on monthly grid climate data from a Coupled Model Inter-comparison Project phase 5(CMIP5) dataset for the period of 1850–2000, the Climatic Research Unit(CRU) dataset for the period of 1901–2000 and the observed data from 53 meteorological stations located in the Tianshan Mountains region(TMR) of China during the period of 1961–2011, we calibrated and validated monthly average temperature(MAT) and monthly accumulated precipitation(MAP) in the TMR using the delta, physical scaling(SP) and artificial neural network(ANN) methods. Performance and uncertainty during the calibration(1971–1999) and verification(1961–1970) periods were assessed and compared using traditional performance indices and a revised set pair analysis(RSPA) method. The calibration and verification processes were subjected to various sources of uncertainty due to the influence of different reconstructed variables, different data sources, and/or different methods used. According to traditional performance indices, both the CRU and CMIP5 datasets resulted in satisfactory calibrated and verified MAT time series at 53 meteorological stations and MAP time series at 20 meteorological stations using the delta and SP methods for the period of 1961–1999. However, the results differed from those obtained by the RSPA method. This showed that the CRU dataset produced a low degree of uncertainty(positive connection degree) during the calibration and verification of MAT using the delta and SP methods compared to the CMIP5 dataset. Overall, the calibrated and verified MAP had a high degree of uncertainty(negative connection degree) regardless of the dataset or reconstruction method used. Therefore, the reconstructed time series of MAT for the period of 1850(or 1901)–1960 based on the CRU and CMIP5 datasets using the delta and SP methods could be used for further study. The results of this study will be useful for short-term(several decades) regional climate reconstruction and longer-term(100 a or more) assessments of regional climate change.     

China's alfalfa market and imports: Development,trends, and potential impacts of the U.S.–China trade dispute and retaliations

This study examines the development and trends of China's alfalfa market and imports, identifies key factors for the rapid increase in China's alfalfa imports, and discusses potential impacts of the U.S.–China trade dispute and retaliations on the alfalfa markets and trade in both nations. China's rapid transition toward larger-scale commercial dairy production, with enhanced feed and cost management as well as quality and safety control, and its limited resources for high-quality alfalfa production are key factors for the dramatic increase in its alfalfa imports, from 19 601 metric tons in 2008 to 1.38 million metric tons (mmt) in 2018. While the United States dominated China's alfalfa imports with an average share of 97.01% from 2007 to 2017, the share dropped to 83.76% in 2018 and 63.28% in January 2019 due to the trade dispute and retaliations started in 2018. China will likely remain a large importer of alfalfa because of both its growing demand and the comparative advantages of imported alfalfa in quality and price, but the imports from the United States will be highly affected by the ongoing trade dispute and negotiations. China is also expected to make more efforts to reduce its dependence on U.S. alfalfa through increased investment in domestic alfalfa production and identification of alternative sources of alfalfa and other hay imports.     

山西省襄垣县有机旱作农业发展研究

襄垣县是山西省有机旱作试点县,根据其自然条件,通过总结该县有机旱作发展现状、制约因素及潜力分析,提出适宜的对策措施,为今后有机旱农业的发展提供一定的参考。     

环境对西府海棠锈病发生的影响与病害防治技术

西府海棠锈病是危害西府海棠的最重要病害,造成叶片枯黄、早落,影响次年的开花与结果。本研究,分析了近年来病害严重发生的环境影响因素,并提出防治技术方案。     

“虚拟仿真”背景下畜牧兽医研究生实践教学改革探索研究

研究生教育位于国民教育体系的顶端，是国家高等教育发展水平的重要标志。为培养 既具有责任担当精神，又具有宽厚的专业知识和创新能力，还具有较高的英语水平和较强的计算机网络应用能力的高层次畜牧兽医人才，本研究对我校畜牧兽医专业研究生的培养现状进行了分析总结，提出了基于“虚拟仿真”背景下人才培养的新模式，总结了虚拟仿真研究生科研平台建设的优势和使用效果，为其它专业研究生的培养提出参考。     

阿拉善右旗近50年气温变化特征分析

本文通过整理右旗1969—2018年气温逐年气象观测资料，对右旗近50a平均气温年际变动、季节性变化趋势、突变特点展开研究。得出结论：50a来右旗温度呈0.39℃/10a的速度增加，在20世纪九十年代之后増温明显，且有显著的阶段性波动特点。季节性气温都是以不同速度在增加，春季平均气温增加发展趋势在四季中极为明显。由最高气温季节平均值可知，春季最大，其次秋季夏季冬季，由此可知，最低温度季节性均值是春季最大，其次夏季秋季冬季。年和四季平均最低气温的增加波动,使得平均气温日较差呈减小态势。     

氮磷钾配比对长优2号产量和经济性状的影响

采用“3414”方案设计试验,研究氮磷钾不同配比施肥对长优2号产量及经济性状的影响,结果表明,氮、磷、钾对长优2号都有一定的增产效应,其中以氮的增产效应最为显著,磷与钾次之。初步得出本次试验最佳施肥量为“N”16.23㎏/667㎡、“P2O5”8.46㎏/667㎡、“K2O”16.06㎏/667㎡,NPK比接近“1：0.5：1”水平。     

“一带一路”背景下农业类本科生外语素养的培养研究——基于项目式学习理论

随着“一带一路”倡议的不断推进,农学人才在逐渐加深的中国与沿线国家农业合作中的重要性日渐凸显。在此背景下,国家对农业类人才的要求也越来越高,仅掌握农业类专业技术的人才已不能很好地适应新时代的农业发展要求,英语素养成为农学人才的必备的语言能力。本文从提升农学本科生英语素养的重要性出发,分析目前农学本科生外语教学现状,并结合项目式学习理论探索提升农学本科生外语素养的途径,旨在为培养具有较高外语素养的应用型农学人才提供可行建议。