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Trong vòng 50 năm SAU Thế chiến thứ hai, sản xuất nông nghiệp tăng lên rõ rệt. Ví dụ như thể hiện trong hình 5,1 cho ngô trong Mỹ và gạo tại Nhật Bản (Uchijima, 1990). Tại Mỹ, việc sử dụng ngô lai F1 vào những năm 1960 đã dẫn đến tăng nhanh chóng trong sản xuất trên một ha. Mặc dù sản xuất lúa ở Nhật Bản ĐÃ không có những bước tiến nhanh chóng như vậy là trong đó ngô Mỹ, sản xuất trên mỗi đơn vị diện tích đã tăng dần từ 1900 đến các mức độ rất cao hiện nay, đặc biệt. | 920103_CRC20_0904_CH05 1 13 01 10 48 AM Page 95 CHAPTER 5 Utilization of Biological Interactions and Matter Cycling in Agriculture Masae Shiyomi CONTENTS Introduction.95 From Agriculture Based on Fossil Energy to Agriculture Based on the Use of Complex Biological Interactions.97 Plant-Grasshopper-Mantis-Bird Model.98 Grasshopper-Mantis Model.99 The Importance of Matter Cycling in the New Agriculture.101 Grassland Ecosystems.102 Upland Crop Field Ecosystems.106 Paddy Field Ecosystems.107 Conclusions.108 References.110 INTRODUCTION For the 50 years following the Second World War agricultural production markedly increased. Examples are shown in Figure 5.1 for corn in the U.S. and rice in Japan Uchijima 1990 . In the U.S. the use of F1 hybrid corn in the 1960s led to a rapid increase in production per hectare. Although the production of rice in Japan has not made such rapid strides as that of corn in the U.S. the production per unit area has gradually increased from 1900 to the very high present level especially in the last 50 years. Modern agriculture which depends on the consumption of large quantities of fossil fuel is now being forced to change to an alternative system in 0-8493-0904-2 01 0.00 .50 2001 by CRC Press LLC 95 920103_CRC20_0904_CH05 1 13 01 10 48 AM Page 96 96 STRUCTURE AND FUNCTION IN AGROECOSYSTEMS DESIGN AND MANAGEMENT Figure 5.1 Corn and rice yields in the U.S. and Japan in the last 100 years Uchijima 1990 . which the interactions between organisms and environment and matter cycling in agricultural ecosystems are properly utilized Edwards et al. 1990 Shiyomi 1993 . First we discuss the problems everyone is presently facing. There are three reasons for making such a change. One reason is the depletion of readily available fossil fuel resources. According to the Tokyo newspaper Asahi-shinbun December 25 1994 Energy problem is serious. The Central Institute of Electric Power Industry Japan predicts that the annual energy demand in the world in 2050 .
