( 在 12 届全国农业生态学研讨会上的发言 )

1. 农业生态学教学的改革与思考 (在12届全国农业生态学研讨会上的发言) 山东农业大学 陈雨海 2005年5月●广州

2. 课程教学过程简介 课程教学改革情况 课程教学的思考

3. 课程教学过程简介 ※1982年开始设立农业生态学,农学专业，40 学时，必修课 ※ 1998年，增设选修课，面向全校非农学专业，全部36学时 ※ 2003年，列为全校重点建设课程，农学、植物科学与技术专业、种子专业的必修课，面向全校非农学专业，全部36学时

4. 课程教学改革情况 改革的趋动力 改革的基本内容 改革的效果

5. 改革的趋动力 ●社会需求 ●农业生态学的发展 ●教学对象 ●学时变化 ●教学条件改善 ●其他学科的发展 ●其它原因

6. 改革的基本内容 ●教学内容 ●教学手段 ●教学方法 国际化、现代化、 实用化、精品化

7. 国 际 化 ●双语教学 ●教师查阅大量英语文献 ●向学生提供国外原文 ●调动学生的积极性

8. 双语教学

9. "The supreme reality of our time is ...the vulnerability of our planet.. " - John F. Kennedy (1917-1963)Thirty-fifth U.S. President Speech 28, June 1963

10. "The Earth has an abundance of everything, but our share in it is only what we really need." -- - Satish Kumar Editor of Resurgence MagazineLeading figure in the spiritual and environmental fields in Britain

11. Ecologyis the study of organisms in relation to the surrounds in which they live. These surrounds are called the environment of organism. This environment is made up of many different components,include other living organisms and their effects,and purely physical features such as the climate and soil type. Ecologist, those who study ecology ,are always aiming to understand how an organism fits into its environment. Ecology principles and applications-----------------------J.L.Chapman and M.J.Reiss,Cambridge University Press,1999

12. Ecologycan be defined as the study of relationships between organisms and the environment. Humans have been students of ecology as long as we have existed as a species. Our survival has dependent upon how well we could observe variations in the environment and predict the responses of organism to the variations. Ecology: Concepts and Applications----------------------- Manuel C.Molles,Jr. McGraw-Hill Companies,Inc. 2000 Ecologyis the study of interactions between organisms and their environment. The ‘environment’ is a combination of the physical environment and any influences on an organismexerted by other organism-the biotic environments. Instant Notes in Ecology----A.Mackenzie, A.S.Ball and S.R.Virdee,BIO Scientific Publishers Limited,1998

13. The science of agroecology, which is defined as the application of ecological concepts and principles to the design and management of sustainable agroecosystems, provides a framework to assess the complexity of agroecosystems (Altieri 1995). The idea of agroecology is to go beyond the use of alternative practices and to develop agroecosystems with the minimal dependence on high agrochemical and energy inputs, emphasizing complex agricultural systems in which ecological interactions and synergisms between biological components provide the mechanisms for the systems to sponsor their own soil fertility, productivity and crop protection (Altieri and Rosset 1995).

14. Agroecology The application of ecological science to the design and management of sustainable agroecosystems. A holistic approach to agriculture and agricultural development based on traditional, alternative, and local small-scale agriculture. Linking ecology, socioeconomics and culture to sustain agricultural production, farming communities, and environmental health.

15. Comparison of Natural and Agroecosystems Gliessman, 1998

16. Agroecosystems About 40% of terrestrial NPP is directly or indirectly consumed by humans. Agroecosystems are ecosystems which are consciously controlled by humans for the purpose of extraction. They include managed forests, farms, rangelands, and aquaculture systems. While hunting-gathering is sustainable at very low human densities, it is extremely damaging at high densities, and cannot be sustained for long. Thus agroecosystems are absolutely necessary. However, most agroecosystems today are not sustainable (yields cannot be maintained indefinitely). Problems with contemporary agroecosystems:

17. PESTICIDES • ·Pests tend to be r-selected species with rapid growth rates. They therefore tend to evolve resistance very quickly. Most important insect pest species have evolved resistance to all major insecticides. The same has happened for weeds and herbicides. This leads to the "pesticide treadmill". (resistance is not the same as immunity) • Temporary solution: transfer genes from weeds to crops. This exacerbates the pesticide treadmill in the long run. • Predatory animals are more K-selected, and cannot evolve resistance to pesticides quickly enough. • Toxins accumulate at each level in the food chain, and thus have a large effect on predators. This is the reason for the decline of birds of prey. • Pesticides are present in rainfall samples wherever they have been measured. Pesticide in rain is a negligible direct health risk for humans, but the effects on the ecosystem are unknown. • There is great promise in controlling pests by biological and cultural (physical) controls. The problem is that such controls are more information-intensive. Agriculturalists must study the life histories of all beneficial and harmful species. Extension agents must know population biology and community ecology.

18. FERTILIZER • Because of this, humans control more than half of all nitrogen fixation. • Anthropogenic nitrogen fixation is extremely energy intensive, thus affecting the carbon cycle through fossil fuel use. • Nitrates escaping into groundwater have serious health effects (blue babies) • Nitrogen is the most limiting nutrient in most agroecosystems. • Runoff of N and P into streams causes eutrophication. • Fertilization by N, P, and K causes higher yields, but when plants are removed, many cations (esp. Ca and Mg) are removed. This increases the acidity of the soil (big problem in OK).

19. SOIL EROSION • Exposing bare soil to the elements and decreasing infiltration rates causes wind and water erosion. Conservation Reserve Programs, low-till techniques, increasing organic matter, and planting of hedgerows have decreased this problem.

20. MONOCULTURES • Planting crops in monocultures encourages pests, diseases, and crop failure.  Polycultures allow complementarity, and are making a comeback. GENETIC EROSION The genetic diversity of domestic animals and crop plants is becoming depleted. Genes for resistance to stress and disease are lost. ENERGETICS Most mechanized agriculture has more energy input than output.

21. The nitrogen cycle(1012g/a)

22. Rhizobium:根瘤菌 nitrosomonas:亚硝化菌nitrobacter:硝化菌 Pseudomonas:假单胞菌属,极毛杆菌属

23. Deforestation, and land clearance in general leads to substantial increases in nitrogen flux in streamflow and N2O losses to the atmosphere. The agricultural practice of planting legume crops, with their root nodules containing nitrogen-fixing bacteria, contributes further to nitrogen fixation. The production of nitrogenous fertilizers (more than 50×106 tons year-1) is of particular significance because an appreciable proportion of fertilizer added to land finds its way into streams and lakes, leading to eutrophication. The effects of agriculture on the nitrogen cycle

25. The phosphorus cycle(1012g/a)

26. More than 13×106 tons of phosphorus are dispersed annually over agricultural land as fertilizer and a further 2×106 tons as an additive to domestic detergents. In many lakes worldwide, the input of large quantities of phosphorus (and nitrogen) from agricultural run-off produce ideal conditions for high phytoplankton activity. In such cases of eutrophication (enrichment), the lake water becomes turbid because of dense populations of phytoplankton (often blue-green species) and large water plants are outcompeted. In addition, decomposition of the large phytoplankton biomass may lead to low oxygen concentrations which kill fish and invertebrates. Effects of fertilizer use on the phosphorus cycle

27. Water bodies in northern temperate regions of Europe and North America have suffered from acidification due to ‘acid rain’. Acid rain is a result of fossil fuel burning, which produces sulfur oxides (SOx) and nitric oxide (NO) which may combine with atmospheric water to form sulfuric acid (H2SO4) and nitric acid (HNO3), respectively. The term ‘acid deposition’ is more accurate as acid may also be deposited from the air in the form of snow, sleet and fog. Acid rain reduces the pH of soil and lakes, while acidification can also cause the death of trees and allow toxic metals (e.g. aluminium and mercury) to be leached from soils and sediments. Acid rain

28. Water pollution can be divided into one of four categories: (i) biological agents, (ii) dissolved chemicals, (iii) nondissolved chemicals, and (iv) heat. The eutrophication of aquatic ecosystems occurs due to an excess of inorganic nutrients. Organic matter in the water is broken down by microorganisms that deplete the oxygen levels, which may be quantified by the ‘biochemical oxygen demand’ (BOD). A particularly important class of organic water pollutants is the family of polychlorinated biphenyls (PCBs), a group of stable chlorinated compounds, that are highly toxic to vertebrates. Water pollutants

29. A range of chemical cause soil pollution problems, of which halogens (primarily solvents and pesticides) constitute the largest group. These chemicals are manufactured. The most complex group of compounds which are found polluting soils include polymers such as nylon, plastics and rubber. Bioremediation is a technique of utilizing microorganisms for the decontamination of polluted soils. Soil pollution

30. A further problem arises, particularly, in the use of chlorinated hydrocarbons, because of their susceptibility to biomagnification. Because these toxins cannot be metabolized or destroyed, they accumulate in the body of an individual. This results in an increasing concentration of insecticide in organisms at the higher trophic levels. These effects threaten natural predator populations and may pose a risk to the human food chain (especially if fish are affected). Biomagnification

31. 教师查阅大量英语文献 ●国外原版教材 ●国外文献 ●国外农业生态学网站

32. 向学生提供国外原文

33. 调动学生的积极性

37. 学生用网络发给老师的农业生态学作业

38. 现代化 • 利用信息技术，完善课程内容 • 强化多媒体教学，增加信息量 • 力所能及为学生提供各种学习途径

41. 学生用网络发给老师的农业生态学作业

42. 实用化 坚持理论与实践相结合，培养为农业可持续发展服务的人才

43. 理论与实践并重，强化实践教学 充分利用现代网络信息，获取大量的有关农业生态学应用性的素材，使授课生动有趣，内容贴近实践。采用理论教学、实践教学和科学研究三元结合的教学模式，强化创新能力培养，增强教学互动，增加教学环节中学生进行参与式和研究式学习的机会，使各种技能有机的结合起来。

44. 培养为农业可持续发展服务的人才 这是农业生态学课的一个重要目的。中共十六大提出全面建设小康社会宏伟目标，与之相伴随，各省也描绘了未来建设的美好画卷，如山东省在《山东生态省建设规划纲要》中提出：到2020年，全面增强经济和社会的可持续发展能力；社会发展的需要与农业生态学的内容完全吻合。坚持理论与实践并重，培养出更多、更优秀的生态学方面的人才，参与生态经济建设，使教学科研更紧密地与实现经济社会和人口、资源、环境协调发展的目标相结合。

46. 精品化

47. 改革的效果 ※开设专业增多 ※学生选修人数增多 ※开课班级增多 ※开课教师增多 ※学生考研增多

48. 课程教学的思考 体系优化 突出特色 强化实践 案例教学

49. 谢谢