稻米：一百年,一千年,一万年

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。     

Impact of climate change on maize yield in China from 1979 to 2016

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.     

休闲农园节约建设规划设计的探索与实践

休闲农业是乡村经济发展的重要途径,也是乡村振兴的有力推手.休闲农园是实现农业多功能、三产融合、增产增收的重要载体.目前,资金短缺成为休闲农园发展的桎梏,研究其低成本打造及管理意义重大.从规划设计角度出发,结合多年规划设计实践经验,对休闲农园的低成本投入、低成本管理、集约高效生产、节约型景观美化提升以及绿色生态可持续发展等方面做了有益探索,以期为乡村振兴添砖加瓦.     

Effects of Large Saddle Panels on the Biomechanics of the Equine Back During Rising Trot: Preliminary Results

The saddle panels, directly in contact with the horse's back, are likely an important element to optimize the fitting of the saddle, the comfort of the horse, and subsequently, the pain management in dorsalgic horses. The aim of this study was to better understand the effect of the saddle panels on the horse's back, by evaluating a prototype saddle (comfort panels: CP) compared to a standard saddle (STD). The horse's back movements were measured using inertial measurement units (IMUs) fixed at the levels of thoracic vertebrae T6, T12, T16 (under the saddle) and lumbar vertebrae L2 and L5. The centers of mass (COMs) of the horse and the rider and limb's protraction-retraction angles, pressure between saddle and horse's back, and force on the stirrups were measured using respectively 2D motion capture, pressure mat and force sensors in the stirrup leather. Three horses were trotted at the rising trot (sitting: left diagonal-rider seated; standing: right diagonal-rider standing) by the same rider. To compare saddles, linear mixed-effects regression models were used. The estimated means (SE) were calculated. During sitting phase, pressure in the cranial and middle areas of the saddle significantly increased for CP compared to STD (+0.9 (0.2) kPa and +1.0 (0.1) kPa, respectively) whereas caudal pressure decreased (−1.8 (0.4) kPa). Concurrently, the range of motion of angles T12-T16 and T16-L2 under the saddle significantly increased (+1.8 (0.2)° and +2.3 (0.3)°, respectively). The results showed that modifications of the panels' shape not only affect the pressure distribution but also the kinematics of the thoracic and lumbar regions of the equine back.     

京津冀一次区域性暴雨特征分析

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。     

云南野生食用菌生态休闲观光旅游探索

得天独厚的地理环境和悠久的野生食用菌历史,奠定了云南野生食用菌的重要地位与属性,云南也逐渐将野生食用菌资源纳入到生态休闲观光旅游的范畴,并成为云南旅游经济新的增长点。结合云南的野生食用菌栽培及旅游模式开发的现状,发现云南在野生食用菌生态休闲观光旅游探索上存在的问题,通过对问题的分析与解决,对云南野生食用菌的生态休闲观光旅游建设具有一定的指导意义。     

我国农业区域开发简史及历史经验

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。     

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

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     

南方山区草地资源的类型及开发利用途径

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。     

中国大陆环境污染聚类分区及林业对策

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。