The Middle Ages: 12th to 16th Centuries Soil fertility and soil amendment practices remained much the same as in the days of the Greeks and Romans, relying principally upon animal manures composts, sewage and other waste products; seas and, seaweed(海藻)and fish in coastal areas; bones; and liming materials, usually marl(泥灰)
The Middle Ages: 12th to 16th Centuries • Soil fertility and soil amendment practices remained much the same as in the days of the Greeks and Romans, relying principally upon animal manures; composts; sewage and other waste products; seas and, seaweed(海藻) and fish in coastal areas; bones; and liming materials, usually marl(泥灰)
What are plant nutrients? Greek guy from a long time past decides four elements are important ARISTOTLE (4 th century) had claimed that all matter was composed of the 4 basic elements earth. air. fire and water He considered the roots of plants to be the mouths" of the plant which absorbed the plant's food from(already made) soil
What are plant nutrients? • Greek guy from a long time past decides four elements are important • ARISTOTLE (4'th century) had claimed that all matter was composed of the 4 basic elements: earth, air, fire and water. • He considered the roots of plants to be the "mouths" of the plant which absorbed the plant's food from (already made) soil
What are plant nutrients? ·中国古代人认为植物养分就是地气、地 脉: 所有之田,岁岁种之,土敞气衰,生物 不遂;为农者必储朽以粪粪之,则收获 不减,地力长新 地力长新
• 中国古代人认为植物养分就是地气、地 脉： • 所有之田，岁岁种之，土敞气衰，生物 不遂；为农者必储朽以粪粪之，则收获 不减，地力长新。——地力长新 What are plant nutrients?
Chemical Discoveries In The 17th And 18th Centuries Gold, silver, copper, tin, iron, lead etc. were known at the time of the greek and roman civilizations Ammonium sulfate was discovered in the 1600s Potassium nitrate or saltpeter(6i)was known but not its composition, and phosphorus was identified in 1669 Nitrogen, oxygen, hydrogen, manganese and molybdenum were all discovered between the earl 1770s and 1782. Sulfur was classified as an element in 1777
Chemical Discoveries In The 17th And 18th Centuries • Gold, silver, copper, tin, iron, lead etc. were known at the time of the Greek and Roman civilizations. • Ammonium sulfate was discovered in the 1600s. • Potassium nitrate or saltpeter(硝石) was known but not its composition, and phosphorus was identified in 1669. • Nitrogen, oxygen, hydrogen, manganese and molybdenum were all discovered between the early 1770s and 1782. Sulfur was classified as an element in 1777
Chemical Discoveries In The 17th And 18th Centuries Ammonia was made for the first time in 1774 Urea was identified in 1773 and in 1775 the presence of large amounts of calcium Phosphate in bones was confirmed
• Ammonia was made for the first time in 1774 • Urea was identified in 1773 and in 1775 the presence of large amounts of calcium • Phosphate in bones was confirmed. Chemical Discoveries In The 17th And 18th Centuries