稻米：一百年,一千年,一万年     

曾雄生 《中国稻米》2021,27(4):127-132

大致说来,一万年前是中国稻作的起源时期,一千年前则是中国稻作传统的形成时期,而最近一百年则是中国稻作发展最快的时期。用一百年、一千年、一万年这三个大致的时间节点,全景展示中国稻米的历史、稻米对于国计民生的重要性、千百年来中国人民为解决吃饭问题所做的努力、近百年来中国稻作科技的发展与进步,展望未来稻米所可能遇到的挑战和前景。  相似文献   

Impact of climate change on maize yield in China from 1979 to 2016          下载免费PDF全文

Jian-zhai WU  Jing ZHANG  Zhang-ming GE  Li-wei XING  Shu-qing HAN  Chen SHEN  Fan-tao KONG 《农业科学学报》2021,20(1):289-299

Climate change severely impacts agricultural production, which jeopardizes food security. China is the second largest maize producer in the world and also the largest consumer of maize. Analyzing the impact of climate change on maize yields can provide effective guidance to national and international economics and politics. Panel models are unable to determine the group-wise heteroscedasticity, cross-sectional correlation and autocorrelation of datasets, therefore we adopted the feasible generalized least square(FGLS) model to evaluate the impact of climate change on maize yields in China from 1979–2016 and got the following results:(1) During the 1979–2016 period, increases in temperature negatively impacted the maize yield of China. For every 1°C increase in temperature, the maize yield was reduced by 5.19 kg 667 m–2(1.7%). Precipitation increased only marginally during this time, and therefore its impact on the maize yield was negligible. For every 1 mm increase in precipitation, the maize yield increased by an insignificant amount of 0.043 kg 667 m–2(0.014%).(2) The impacts of climate change on maize yield differ spatially, with more significant impacts experienced in southern China. In this region, a 1°C increase in temperature resulted in a 7.49 kg 667 m–2 decrease in the maize yield, while the impact of temperature on the maize yield in northern China was insignificant. For every 1 mm increase in precipitation, the maize yield increased by 0.013 kg 667 m–2 in southern China and 0.066 kg 667 m–2 in northern China.(3) The resilience of the maize crop to climate change is strong. The marginal effect of temperature in both southern and northern China during the 1990–2016 period was smaller than that for the 1979–2016 period.  相似文献   

京津冀一次区域性暴雨特征分析     

李美琪  贾小卫  郭蕊  吴丹  刘浩 《绿色科技》2020,(6):34-37,42

利用FNL再分析资料、卫星资料和自动站资料对2019年7月22~23日京津冀一次区域性暴雨过程进行了环流形势、卫星云图、动热力结构的分析。结果表明:此次暴雨发生在500hPa两槽一脊、副热带高压北抬、低空急流的大尺度环流背景下。西南方向的水汽输送和黄渤海的补充水汽为暴雨提供了良好的水汽条件,在河北中部的水汽辐合抬升则为暴雨提供了抬升条件。此次暴雨的产生受中尺度对流云团的连续生成合并影响,降水效率高。在暴雨中心整层表现为低层辐合、高层辐散,上升速度中心明显,使得高层的抽吸作用更强,更有利于上升运动的维持与发展,为降水强度增大提供了有力的动力条件,高空弱冷空气的入侵对能量锋区不稳定能量的释放起到了触发作用。  相似文献   

我国农业区域开发简史及历史经验     

王缨 《湖北农学院学报》1990,(3)

本文讨论了中国农区开发之始、几个主要农区的深开发、黄淮江湖的连片开发、海河流域的开发、其它农区的开发和农区开发的历史经验与教训。完好的灌溉系统、导致深开发的人工运河和农业技术是开发成功的要素。  相似文献   

Study on Cultural Technologies and Salt-resistance of Nitraria sibirica in Coastal Areas with Serious Salt-affected Soil     

ZHANG Jianfeng XING Shangjun SUN Qixiang XI Jinbiao SONG Yumin Research Institute of Forestry  CAF  Silvicultural laboratory of Forestry  SFA  Beijing  P.R.China Shandong Academy of Forestry  Jinan  P.R.China 《中国林业科技(英文版)》2004,3(4):12-16

In this research, five Nitraria sibirica provenances such as Dayilu were selected to do experiment of salt-resistance, combining fixed plots test with typical plot investigation, measuring survival rate and growth as main indicators. The experiments of main cultural technology were done on Nitraria sibirica in 4 types of site preparation, 3 types of planting, 3 designs for planting density. The Nitraria sibirica experiments for the effects of curbing salt and improving soil were done by testing soil nutrients, salt content, soil physical properties as focal points in typical site of 3-4 years woods. The experiment results showed that the Nitraria sibirica could survive well with soil salt content of 0.6%, and that survival rate declined distinctively as soil salt content exceeded 0.8%. However, high soil salt content did not influence growth in the year of planting. There were obvious differences in salt-tolerance among Nitraria sibirica provenances; Dayilu was the best on salt-tolerance, the other 4 pro  相似文献   

南方山区草地资源的类型及开发利用途径   总被引：4，自引：1，他引：3  

高永革  樊江文 《四川草原》1997,(3):1-3

根据生态学的基本原理，对我国南方山区草地资源的特点进行了分析，从生态学类型上对该地区草地进行了划分，进而提出了南方山区草地开发利用的途径。  相似文献   

中国大陆环境污染聚类分区及林业对策   总被引：1，自引：0，他引：1  

袁嘉祖  谷建才  陆贵巧  宋珍 《河北林果研究》1996,(1)

根据我国大陆２９省（市、区）的土地资源、地形、水文、气候、生物、能源消耗、国民生产总值、人口密度和环境质量现状等资料，应用等级系统聚类分析法，将全国分为９个分区，其中：东北、黄土高原和四川为风沙、侵蚀、酸雨严重污染区；黄淮海平原和云贵高原为盐碱、酸雨重度污染区；东南部平原丘陵山区８省为侵蚀、盐碱、酸雨中度污染区；青藏高原、新疆和海南为高寒、干旱、风暴潮轻度污染区，并以此为根据，提出了相应的林业对策，从而为生态环境的综合治理和林业建设提供了决策依据。  相似文献   

我国饲料工业发展概况     

张建云  阎贵龙  靳玲品  李秀花 《河北北方学院学报(自然科学版)》1995,(4)

本文对我国饲料工业发展现状、存在问题、措施及对策三个方面进行了综述。  相似文献   

略论西北地区渔业发展现状及对策     

王立新  周继术  苏建国 《畜牧兽医杂志》2004,23(5):13-15

通过对西北地区渔业现状的分析，从中挖掘出西北地区渔业落后的社会经济原因，并结合当前的社会经济状况和渔业发展形势，总结了西北地区渔业发展的优势所在，以此为基础提出了加强市场宣传和资源开发、引进资金和技术以及政策引导等发展西北渔业的几点建议。  相似文献   

华北山区草地资源及其生产力的研究     

姚彦臣 《四川草原》1997,(4):1-6

华北山区位于温带——暖温带，东经１０７°～１２３°，北纬３５°～４３°。包括山东丘陵区，太行山区，冀北辽西山地区，阴山山地区四部分。该区属于农牧业交错区，农业、牧业（农区牧业和草地牧业）、林业十分发达，并且在迅速发展。华北山区是我国小麦、玉米和杂粮的主要产区。草地类型多样，饲草料丰富，又是养牛业、养羊业、养猪业相当发达的地区。经统计，华北山区总人口为５６２９万，总土地面积３５４５万ｈａ，天然草地总面积为１５８８．９１万ｈａ，占土地总面积的４４．８２％，人均草地０．２８２３ｈａ。各个区的草地类型不同，生产力差异显著（ｐ＜０．０１）。  相似文献