免费国产自久久久久三四区久久_久久99性xxx老妇胖精品_欧美女女_老司机深夜福利网站_91影视免费版在线看_91九色porny首页最多播放

position: EnglishChannel  > InnovationChina> Plowing a Place in History

Plowing a Place in History

Source: Science and Technology Daily | 2023-09-04 17:03:11 | Author: BI Weizi


Quyuan plow. (PHOTO:VCG)

By BI Weizi

Chinese people have long known how to use oxen and horses to pull carts, with cattle being the main draft animal. However, it was after Spring and Autumn Period (770 BC-476 BC), that animal husbandry was rapidly popularized throughout the country, and the frame structure of the plow was basically established in the Han Dynasty (202 BC-220) and continuously improved with the needs of production.

In the Tang Dynasty (618-907), the curved-shaft plow, later called the Quyuan plow, was invented on the basis of two oxen pulling the plow. It needed only one ox to pull it and had a perfect structure that was light, flexible and could adjust the digging depth.

Compared with previous plows, the Quyuan plow had two main features: first, the straight and long shaft was changed into a curved and short one, and a shaft head was invented and installed so that it could rotate freely. The plow disc not only makes the plow frame smaller and lighter, but also facilitates flexible operation, thus saving manpower and animal power.

Second, the plow blade and plow arrows are added. When the plow blade is pushed forward, the plow arrows can be moved downward. When the blade is pushed forward, the plowshare penetrates deep into the soil. Moreover, the earth could be turned away from the blade because the arms were also curved, which both reduced friction and more effectively plowed the soil.

The organic combination of arrows and plowshares adapted to the different requirements of deep and shallow plowing and facilitated intensive farming.

The invention of the Quyuan plow, which had been used for more than a thousand years, is a milestone in the country's history of agricultural development.

Editor:龍云

Top News

Forging a Resilient Economy with Sci-tech Power

Tiangong Ultra, developed by the Beijing Humanoid Robot Innovation Center, won the world's first half-marathon for humanoid robots in Beijing on April 19, demonstrating the prospects of China's humanoid robot industry and the epitome of the country's strategic emerging industries and future industries. These industries are surging ahead, facilitating the construction of a resilient economy with sci-tech force.

抱歉,您使用的瀏覽器版本過低或開啟了瀏覽器兼容模式,這會影響您正常瀏覽本網頁

您可以進行以下操作:

1.將瀏覽器切換回極速模式

2.點擊下面圖標升級或更換您的瀏覽器

3.暫不升級,繼續瀏覽

繼續瀏覽
主站蜘蛛池模板: 波多野结衣一区二区三区高清 | 亚洲午夜理论片精品无码推荐 | 无码人妻一区二区三区精品视频 | 91精品久久久久久久久久久久久久久 | 中文字幕亚洲视频 | 五月婷激情 | 69夜色精品国产69乱 | 久久久精品欧美一区二区免费 | 青青青草伊人 | 国产欧美网站 | 91精品免费久久久 | 久久久全国免费视频 | 国产一区二区h | 欧美二三区 | 呦女网站www哟女 | 亚洲av午夜福利精品一区 | 日韩激情一级毛片久久久 | 亚洲图片偷拍自拍 | 黄片在线免费观看精品巨 | 国产精品亚洲专区无码影院 | 中国内地毛片免费高清 | 国产日本亚洲手机在线 | 一区二区三区国产最好的精华液色 | 毛片一 | 久久99精品久久久久久6194 | h漫在线观看 | 欧美一级久久久久久久大片 | 精品视频久久久 | 成年人免费小视频 | AV成人午夜无码一区二区 | 91在线伊人观看视频 | 人人天天色 | 一级黄色片a | 黑人巨大欧美一区二区视频 | 久久精品久久99 | 国产一级一级理论片一区二区 | 成人日韩av| 99视频导航 | 国产亚洲精品无码成人蜜臀 | 免费观看一级 | 伦理天堂eeuss |