THE ESTABLISHMENT OF A SUSTAINABLE AGRICULTURAL SYSTEM IN

Paul M.H. Sun and S.C. Hsieh*

Department of Agriculture and Forestry Taiwan Provincial Government Chung-Hsing New Villa, Nantou Taiwan, ROC

* District Agricultural Improvement Station 200, Lane 361, Section 1, Chiatung Road 51501 Tatsuen Hsiang, Changhua, Taiwan

ABSTRACT

Modern agriculture, based on the monoculture of cash crop varieties that require high inputs, depends on heavy applications of inorganic fertilizers and on chemical pesticides for pest control. The sustainability of modern agriculture has become a subject of great concern to policy makers, researchers and farmers in Taiwan. Research into sustainable agricultural systems has been conducted by various research institutes in Taiwan. The problems encountered in implementing sustainable are discussed, based on the results of experimen- tal data, with regard to the following factors: (1) nutrient management, (2) applications of organic matter to soil, (3) crop rotation and interplanting, (4) minimum tillage, (5) integrated pest management, (6) non-chemical pesticides and (7) weed management. Current government policies are discussed, and methods of organic farming practiced by farmers in Taiwan are also described.

INTRODUCTION an urgent need to establish a feasible sustainable agricultural system in Taiwan, which was officially Taiwan is located in the subtropical zone, recognized in 1986 when the , where a warm climate, fertile and ample rainfall Executive Yuan, held a meeting to evaluate the make it possible to grow crops throughout the year. possibility of adopting an organic farming system in The people living on the island thus enjoy an abun- Taiwan. In 1988, all aspects of the problems in- dant food supply, as well as the island’s natural volved were discussed thoroughly at a Symposium beauty which has given it the historical name of on Organic Farming held in Changhua, and several “Formosa”, meaning ‘beautiful’. research programs dealing with organic farming The island now is less beautiful than it was, were then begun at a number of agricultural insti- because of environmental pollution caused by indus- tutes, including a three-hectare organic farm in trial activity, as well as by the excessive use of Taichung District Agricultural Improvement Sta- chemical fertilizers and pesticides in agriculture. As tion. in other developed countries, modern agricultural According to Lockeretz (1988), sustain- practices in Taiwan have greatly increased agricul- able agriculture is a loosely defined term that encom- tural production, but their impact on the ecological passes a range of strategies for addressing a number and economic systems has not always been positive. of problems, including loss of soil productivity from In some cases, it has even led to reduced farm profits. erosion and related nutrient losses, the pollution of The sustainability of modern agriculture has thus surface water and groundwater from pesticides and become a subject of great concern to the policy fertilizers, and low farm incomes as a result of makers, researchers and farmers of Taiwan. There is reduced commodity prices and high production costs.

Keywords: Sustainable agriculture, cropping systems, organic fertilizer, crop rotation, pest 1 management, sex pheromones, sticky plates, bagging, bottle traps, natural pesticides The present paper describes the strategies calcium superphosphate, potassium chloride etc. for establishing a sustainable agricultural system in were increasingly used, reaching a peak of 140,000 Taiwan based on the results of current research on mt in 1974 (Fig. 2). Insecticide use also increased, organic fertilizer applications, crop rotation, inte- to reach a peak of 23,000 mt in 1984. The use of grated pest management, weed management etc. herbicides and fungicides showed a corresponding The extension of sustainable agriculture to farmers increase: on average, 1,500-1,700 mt of herbicides in Taiwan is also discussed. and 200-500 mt of fungicides have been used each year from 1978 up to the present (Fig. 3). The heavy USE OF CHEMICALS IN use of chemical products in agricultural production TAIWAN’S AGRICULTURE over the past 30 years in Taiwan has resulted in an increased level of environmental pollution. Prior to 1950, chemical fertilizers and pes- ticides were not widely used by farmers in Taiwan. APPLICATION OF ORGANIC MATTER Crop production at that time depended mainly on green manures and compost made of straw, Source of Organic Materials leaves, and cattle and hog wastes. Farm- ers sometimes mixed bonemeal, or soybean cake and The organic matter (OM) content of the other plant products, into compost to increase its soil is often used as an index of soil fertility. Gener- nutrient value (Fig. 1). The natural ecology was ally, organic matter influences the soils in three ways, fairly well balanced at that time. by altering the physical, the chemical, and the bio- After 1960, chemical fertilizers such as logical properties. The term “soil organic matter” ammonium sulfate, urea, calcium ammonium nitrate, covers all kinds of plant tissues and animal residues

Fig. 1. Consumption of (non­commercial) organic fertilizers in Taiwan, 1940­1990

Includes green manures, cattle and other wastes, bonemeal, soybean cake, wood ash etc.

2 Fig. 2. Consumption of chemical fertilizers in Taiwan

Includes ammonium sulfate, urea, calcium ammonium nitrate, calcium super- phos- phate, potassium chloride, potassium sulfate, compound fertilizers etc. (Ammonium phosphate before 1970, calcium cyanamide before 1972)

in the soil. Soil organic matter may turn into humus izers varies greatly according to the type of organic after decomposition and become an active compo- material, while the nutrient requirements of different nent of the soil. Organic matter used for agriculture crops also vary, the type of organic fertilizer should in Taiwan may be classified into the following cat- be selected to meet the requirements of the particular egories: crop residues, green manure, common com- crop. Generally, leafy require more nitro- post, mushroom compost, cattle manure, hog ma- gen for better vegetative growth, while fruit trees nure, manure, municipal refuse, wastes from and fruiting vegetables require less nitrogen and the extraction of oil, and residues from more phosphorus and potassium for better - processing animal products (Hsieh and Hsieh 1989). ing. Therefore, for a crop like spinach, the farmer Organic materials should be composted before they should apply poultry manure or some other manure are applied to the soil. A suitable method of with a high nitrogen content, or mix a substantial composting has been described by Hsieh and Hsieh amount of high-nitrogen manure into the composting (1990). material to get better results. For fruiting vegetables such as , common compost or other low- Application Rate of Organic Matter nitrogen materials such as rice bran can be used, or a low proportion of high-nitrogen manure in the The application rate of organic matter is composting material. The application rates gener- determined mainly by soil fertility, the nutrient con- ally used for common organic fertilizer in Taiwan is tent of the organic material concerned, and the shown in Table 1. nutrient requirements of the crop. However, less than 2% organic matter in the soil is generally Effect of Green Manure on Crop Yield considered to be “insufficient”, 2.5% is “fair”, and more than 5% is “plenty”. An experiment was carried out to study the Since the nutrient content of organic fertil- effect of Berseem clover, milk vetch, and rape, used

3 Fig. 3. The consumption of pesticides in Taiwan

as a green manure, on the grain yield of sorghum ha) were applied to the conventional farming plot. (Tsai, Huang and Lay 1989). After only one crop of Five treatments were applied to the organic plots. green manure had been plowed under, the soil or- On three of these (treatments 2,3,4) the composted ganic matter content increased slightly (Fig. 4) while manure of hogs, cattle and chickens, respectively, the grain yield of sorghum increased proportionally was applied at a rate of 25 mt/ha. A mixture of one with the amount of green manure (Berseem clover) half chicken manure and one half cattle manure was applied. Fig. 5 shows that the grain yield of sorghum applied to the plot with treatment 5, and a mixture of increased about 20% when 20 mt of Berseem clover one half chicken manure and one half hog manure to was applied, and by 45% when 30 mt/ha of clover the plot with treatment 6. Bacillus thuringiensis, was applied. and extracts of hot pepper and tobacco leaves, were used to control pests (Hsieh et al. 1992). Effect of Different Livestock Manures The results, shown in Table 2, indicated that the fresh ear yield of sweet corn harvested from Several experiments have been carried out the organic plots was equivalent to that of corn given to compare the effects of organic and chemical chemical fertilizer, except for the plot with cattle fertilizers on the yield and quality of sweet corn and manure which gave a lower corn yield. This was in vegetable soybean. In the corn experiments, chemi- spite of the fact that the incidence of corn borer was cal fertilizers (N-P2O5-K2O at a rate of 200-60-60 kg/ significantly lower in the plot fertilized with cattle 4 Table 1. Application rates for organic fertilizers in general use in Taiwan

Fig. 4. Effect of green manure on soil organic matter content after harvest A: Control B: Milk vetch C: Berseem clover D: Rape Source: Tsai et al. 1989

manure than in the plot with chemical fertilizer. The improved soil conditions after organic fertilization nitrogen and magnesium content of the corn grain offered a better soil environment in which the roots were significantly higher in corn from the plot with of the leguminous soybean could grow. chemical fertilizer, while the phosphorus and potas- sium content was slightly higher in the organic plots Crop Performance in an Organic than in the chemical one. Farming System A similar study of vegetable soybean showed a marked difference in pod yield, according to whether In order to evaluate the feasibility of or- the plot was fertilized with organic compost or ganic farming in Taiwan, experiments were carried chemical fertilizer. All types of organic fertilizer out to compare rice yields from conventional (chemi- except hog manure gave a higher pod yield than cal) farming with those from organic farming, as well chemical fertilizer (Table 3) possibly because the as an intermediate system (a mixture of chemical and

5 Fig. 5. Relationship between the fresh weight of Berseem clover and the grain yield indices of spring sorghum Source: Tsai et al. 1989

Table 2. Effect of chemical fertilizer and composted livestock manure on the yield of sweetcorn

organic fertilizers). A high-quality rice variety, Composted hog manure (13.3 mt/ha) was applied as Taichung 189, was planted at a spacing of 25 cm x 21 a basal fertilizer. 4. Organic farming (B): Composted cm under the following fertilizer treatments: 1. Con- chicken manure (6.6 mt/ha) was applied as a basal ventional farming: Chemical fertilizer at a rate of N- fertilizer.

P2O5-K2O: 160-60-60 kg/ha was applied. 2. Inter- A sugar–vinegar microbic solution, together mediate type of farming: Half the fertilizer applied with other natural pesticides, were used for pest was chemical, (80 kg N, 30 kg P2O5, 30 kg K2O) and control during the experiment. half was organic compost (6.6 mt/ha). The latter was The results, shown in Table 4, indicate that applied as a basal fertilizer. 3. Organic farming (A): the application of composted chicken manure gave

6 Table 3. The effects of chemical fertilizers and composted livestock manure on the yield of vegetable soybean

as good a grain yield (7.43 mt/ha) as that from diseases, while another benefit common to all types conventional farming which depended solely on of rotation is the improved control of weeds (Stinner chemical fertilizer. and Blair 1990). An experiment was carried out at Taichung, CROP ROTATION central Taiwan, to evaluate the economic returns from a rotation of sorghum, corn, peanut, Job’s Crop rotations and biological diversity have tears, soybean, green manure and rice. The yield of long been utilized very successfully in traditional each crop varied in different types of cropping sys- agricultural production systems. It is important to tem, but the net profit per year was 3.7-60% higher explore the potential of the effect of crop rotation than the traditional rice-rice cropping pattern (Table when it is used in a sustainable agricultural produc- 5). tion system. Since an appropriate rotation of differ- ent crops may help control pests, rotation is an MINIMUM TILLAGE important component in integrated pest manage- ment systems. Minimum or conservation tillage is a crop planting system that may leave 30% or more of the Effect of Rotation on Crops residues of the preceding crop lying untouched on the soil surface. This system can reduce production Legumes contribute nitrogen to the suc- costs as well as runoff and soil erosion, and can also ceeding crop, and proper utilization of legumes as a conserve soil organic matter and increase soil mois- green manure may help improve soil fertility for ture retention. This is partly because the higher better crop production. Annual legumes are useful moisture content under no-tillage offers better con- as rotation crops with common annual crops, veg- ditions for phosphorus diffusion. Minimum tillage etables, and . Annual legumes can also systems also tend to have a more abundant microbial improve the production of perennial forage crops, if soil community, as a result of the reduced frequency they are properly utilized. Francis and Clegg (1989, and intensity of soil disturbance, and a more stable 1990) concluded that rotation effects were primarily soil biomass (Heuse and Stinner et al. 1984). Corn due to the increased nitrogen made available to crops planted in the field without tillage thus often gives a grown after soybean, peanut and other legume crops. higher yield than when it is grown with tillage (Table Other effects of rotation include increased soil mois- 6) (Lian and Wong 1988). No-tillage is worth ture. It is generally agreed, however, that the most recommending for sustainable farming systems, in important benefit of rotation is control of insects and view of its lower production costs.

7 PEST MANAGEMENT biological, cultural, as well as chemical controls can be combined in an ecologically and economically Pest control should be based on a thorough sound integrated pest management (IPM) strategy. understanding of the habitat, food preferences and The aim of IPM is to maximize natural and cultural other behavior of the pest, so that the most effective controls, and use pesticides only as a last resort.

Table 4. Performance of Taichung 189 rice under different cultural systems

Table 5. Yield of, and net profits from, crops grown in different cropping systems in central Taiwan

8 Cultural Control (Spodoptera exigua (Hübner)) the western corn rootworm, (Diabrotica virgifera Leconte), the white- Cultural control reduces pest damage fringed beetle (Graphognathus leugoloma Boh), through manipulation of the environment. Cultural and the rice stem borer (Scirpophaga incertulas control is often associated with mechanical opera- (Walker)). tions such as tillage, interplanting, crop rotation, and adjusting the time of planting and harvesting. Al- The Use of Sex Pheromones to Control though cultural practices alone may not give satis- Insect Pests factory pest control, they are important in minimiz- ing pest injury. There has been rapid progress in the use of sex pheromones as an attractant to control insect Crop Rotation and Inter-Planting pests in the field. Sex pheromones of many different insects are now being chemically synthesized and are Crop rotation systems offer many advan- available on the market. Since sex pheromones are tages in terms of improved soil structure and fertility, not sprayed directly onto the crop, there is no and control of erosion as well as various pest species. pollution problem. Sex pheromones are basically The value of crop rotation is limited where the used to attract and trap insect pests so as to reduce control of highly mobile insects, pathogen spores, or the insect population. airborne weed seeds is concerned, all of which move The results of experiments in Taichung by readily from field to field (Francis and Cregg 1990). Cheng (1989) indicated that sex pheromone traps at However, some soilborne diseases such as Fusarium a rate of three traps per 0.1 ha (30 traps/ha) were able may be reduced by proper rotation or intercropping to control more than 90% of beet armyworm in a with leek and green , and nematodes can be field of green onion (Table 7). The efficiency of sex partially controlled through crop rotation or by pheromone traps for rice borer was 7.3 times higher intercropping with marigold or Cassia tora*. The (3635.2 vs. 496) than that of ordinary illumination results of experiments conducted in Taichung indi- traps. (T.S. Liu, personal communication). cated that the rotation of rice with corn, or of rice with peanut, reduced the incidence of rice diseases Use of Yellow Sticky Plates to Control (leaf blast, bacterial leaf blight, Helminthosporium Insects leaf spot and sheath blight) to 1.6-3.4%, and insect pests (rice borer, brown plant hopper) to only 0.1- Different species of insect are attracted by 3%. Crop rotation is useful for the control of many different colors. Experiments were carried out in other insect pests, including beet armyworm Taichung to explore the possibility of catching and

Table 6. Yields of corn grown under tillage compared to no­tillage, southern Taiwan

9 killing insects in the field with colored sticky plates Use of Soil Amendment to Control coated with insecticide (Omethoate). The results Soilborne Diseases indicated that yellow plastic plates coated with in- secticide were effective in controlling leaf miner The low organic matter content and high (Table 8). This method avoids environmental pollu- soil acidity of subtropical soils promote outbreaks of tion since the insecticide is not sprayed directly onto serious soilborne diseases such as crucifer club root; the crop. Different insects may be attracted by Fusarium wilt of watermelon, cantaloupe, and ; different colors, so that similar experiments using Fusarium yellows of radish and mustard; and other colors may indicate what other insect species phytophthora blight of cucumber. These diseases can be controlled by this method. cannot be controlled by fungicides. Sun (1989) and Huang (1992) indicated Bagging Fruit to Control Melon Fly that amending the soil with S-H mixture (Table 10), at a rate of 1-1.5 mt/ha, effectively controls all these The melon fly, Dacus cucurbitae Coquillett, diseases, plus bacterial wilt of tomato (Table 11). is an important insect pest of sponge gourd and bitter Soil texture and soil vitality are greatly improved by gourd in tropical countries. According to Fang organic amendments (Sun 1989, Huang 1992). (1989), wrapping the young fruit in paper bags immediately after the petal wilting stage is a good The Use of Natural Pesticides in Sus- way of protecting the fruit from melon fly damage tainable Agriculture (Table 9). Bagging the fruits of other crops also reduces damage by melon fly (Kawasaki et al. 1991). As natural pesticides are prepared from natural products, application of these materials has a Use of Plastic Bottle Traps to Control less unfavorable impact on the environment than Flat Snail chemicals. They are now used widely in sustainable agriculture for the control of diseases and insects in The flat snail (Bradybaena similaris , the , and many other countries. (Férussac)) is widely distributed in Taiwan, Main- According to our preliminary studies, tobacco leaf land , Japan, India and the islands of the extract solution is effective in controlling aphids, Pacific. It is the most important pest of , and is snails and leaf rollers, and has the same effect on also found on many commercial and ornamental some other insect pests. Extract of hot pepper can be plants and trees in Taiwan. The snail hatches in the used to control aphids, leaf mites, ants, and some soil and moves up into the grape vine, and grape virus diseases transmitted by aphids. oil can growers generally scatter metaldehyde granules over be used to control aphids, leaf mites, powdery mil- the ground to control it. However, this method has dew, rust, and many other insects and diseases. several disadvantages. It is effective for only a short Spraying vinegar can control powdery mildew dis- period, it is costly, and it leaves toxic residues. ease, while combining vinegar with fermented sugar Recently, a method has been developed of control- and effective microorganisms gives more effective ling the snail by the use of disposable plastic soda control of both insects and diseases. bottles made into traps. These prevent the snails As Tables 12 and 13 show, natural pesti- from climbing up into the grapevine. The traps are cides cannot give complete control of peanut thrips made by cutting off both ends of the bottle and and sweetcorn borer, but they do lower the rate of splitting one side of the body longitudinally to allow infestation. However, in our preliminary studies the it to be sleeved around the stem of the grapevine control effect of natural pesticides is far from satis- (Plates 1, 2). The bottles are then stapled firmly factory. Further studies should be made, using a around the stem at a height of 1 m above the ground. wider range of natural pesticides. Even if more Since the bottles are tightly fixed around effective natural pesticides are identified, they will the grape stem, the snails cannot pas through the probably be best used as one measure in an IPM neck to infest the vines. Unable to descend, all the system. snails trapped in the bottle soon die of starvation. These traps give a control rate of more than 94.8% Integrated Weed Management (Chang 1988). This is a very cheap and effective method of controlling flat snail, and is no threat to the Integrated weed management relies heavily environment. It can thus be widely recommended to on cultural practices such as mulching or mechanical grape farmers. tillage during the first four to eight weeks of crop growth. This allows the crop to become well-grown 10 Table 7. Control of beet armyworm by sex pheromone traps, Taiwan

Source: Cheng 1989

Flat snails eating grape

Use of plastic bottle trap to control flat snail on grape vines 11 Table 8. Control of chrysanthemum leaf miners by yellow sticky plates

Source: T.S. Liu (Unpublished data)

Table 9. Effect of bagging gourds on infestation by melon fly

Source: Fang 1989

before the emergence of weeds, and allows crops to in 18 counties and cities took part in this demonstra- compete effectively with weeds by shading them. tion program. As a result of these field demonstra- Mechanical control of weeds by tillage operations tions, farmers began to apply more organic matter to includes primary tillage, secondary tillage, hand their farms, particularly to orchard crops such as weeding and tillage during the fallow period. Cover grape, pear, apple, peach, , citrus, starfruit, crops and mulches are also a good way of managing , and guava. Application of organic matter weeds. Small hand-operated weeding machines can to upland crops and rice is still rather limited, be- easily control weeds in paddy fields. cause of the lower value of these crops. In 1989, an integrated organic demonstra- EXTENSION OF SUSTAINABLE AGRICULTURE tion farm was set up to grow sponge gourd and IN TAIWAN in central Taiwan, in which 11 farms participated. Another three-hectare organic demonstration farm In 1986, various small demonstration or- in which 11 farms participated was established nearby ganic plots were set up around the island to demon- to produce green onion, cucumber, phaseolus bean strate the usefulness of organic fertilizers to farmers. and . At the same time, green manure demonstration plots Neither of these two organic farms was were also set up in farmers’ fields, with the support very successful, because those operating them lacked of a government subsidy. Altogether 211 townships experience in non-chemical methods of pest control.

12 Table 10. Components of the S­H soil amendment

Table 11. Control of soilborne vegetable crop diseases by S­H mixture in Taiwan 1983­1988

Table 12. Effect of natural pesticide on corn borer

However in 1990 a government-sponsored organic was a 25% increase in the yield of high-quality farm was established to produce sponge gourd. sponge gourd. This farm can therefore be consid- Green manure crops were grown on two-thirds of ered to represent a successful organic farming sys- the land to increase the N source, while the remaining tem. In the same year, a 10-ha citrus farm based on land received 2 mt/ha of cattle compost and soybean organic methods was established, and it too has been meal, plus slag as a basal fertilizer. No chemical very successful, with regard not only to production pesticides were applied, and pests were controlled by but also to marketing. available non-chemical IPM methods. The result

13 Table 13. Effectiveness of natural pesticides in controlling peanut thrips and corn borer

CONCLUSION chemical methods the insects and diseases which are particularly serious in the hot, humid climate of Modern agriculture, based on the monocul- Taiwan. Much more research is needed on this ture of cash crop varieties that require high inputs, problem. needs heavy applications of inorganic fertilizers, and To feed more than 20 million people from a of synthetic chemicals for pest control. Intensive total of only 900,000 ha of is a great production has tended to accelerate wind and water challenge to Taiwan’s agriculturalists. A new Re- erosion of soils, and to contaminate surface water gional Agricultural Development Program, launched and groundwater (Lockeretz 1988). by the government in July 1991, has as its main There is a growing awareness of the need to objectives the development of new production sys- adopt more sustainable and integrated systems of tems which focus on efficient use and regeneration of agricultural production, that depend less on chemi- resources. Particular attention will be given to cals and other energy-based inputs (Sun 1992). Such recycling resources such as livestock manure, mak- systems can often maintain good yields, and at the ing efficient use of water and fertilizers, and the same time lower the cost of inputs, increase farm biological control of pests (Sun 1992). In addition, profits and solve ecological problems. Some coun- large quantities of various kinds of green manure are tries which have adopted intensive farming have now being grown between cropping seasons and on found that, although yields are high, they are now fallow land. Education and extension programs are experiencing greater problems of pests, diseases, being conducted for consumers as well as for farm- and weeds, and increased environmental stress. ers. It is only when consumers can accept the Hence, there is an urgent need to develop and extend concept of sustainable agriculture, that there will be to farmers sustainable farming systems that can an incentive for farmers to practice it. More research maintain productivity and farm profits without en- is needed, not only on new technology for sustain- dangering resources and polluting the environment. able agriculture, but on marketing strategies to en- The concept of sustainable agriculture has sure a profitable return for the farmer. become important in Taiwan in recent years, and emphasizes the integration of agricultural systems and ecological processes to maintain profitable pro- REFERENCES duction with reduced environment pollution. A sustainable system must be both economically prof- Chang, C.P. 1988. The occurrence and con- itable and environmentally sound (Hsieh 1992). trol of Bradybaena similaris (Ferussac). However the most difficult problem in sustainable Bulletin of the Taichung District Agricul- agriculture in Taiwan is how to control by non- tural Improvement Station, Taiwan ROC,

14 21: 1-2. (In Chinese). Cheng, Y. 1989. A study of sex pheromone Hsieh, S.C. 1992. Agricultural environment for the control of insect pests in the and establishment of a sustainable agricul- field. In: Organic Farming, S.C. Hsieh tural system in Taiwan. Agricultural Ex- and C.F. Hsieh (eds.). Special Publication tension: News in Brief from the Taichung No. 16 of the Taichung District Agricul- District Agricultural Improvement Station, tural Improvement Station, Taiwan ROC, Taiwan ROC 14,1: 4-8. (In Chinese). pp. 57-181. (In Chinese) Hsieh, S.C. 1992. Present status of sustain- Fang, M.N. 1989. Studies on using different able agriculture research at the Taichung materials for controlling melon fly on bit- Agricultural Improvement Station. Agri- ter gourd and sponge gourd. Bulletin of cultural Extension: News in Brief from the Taichung District Agricultural Im- the Taichung District Agricultural Im- provement Station, Taiwan ROC, 25: 3- provement Station. 14,1: 16-21. (in Chi- 12. nese). Francis, C.A. and M.D. Clegg. 1990. Crop Kawasaki, K., O. Iwahashi and K.Y. rotations in sustainable production system. Kaneshiro (eds.). Proceedings of the In- In: Sustainable Agricultural Systems, C.A. ternational Symposium on the Biology and Edwards, R. Lal, P. Madden, R.H. Miller Control of Fruit Flies. Food and Fertil- and G. House (eds.). Soil and Water izer Technology Center for the ASPAC Conservation Society, U.S.A., pp. 107- Region, , Taiwan ROC. 122. Lockeretz, W. 1988. Open questions in sus- Francis, C.A. and M.D. Clegg. 1989. Alter- tainable agriculture. American Journal of natives to Monoculture: Sustainable Sys- Alternative Agriculture 3,4: 134-181. tems for U.S. Crop Production. Exten- Lian, S. and C.H. Wang. 1988. Effect of sion Bulletin No. 301, Food and Fertilizer interseasonal cropping of sesbania and till- Technology Center for the ASPAC Re- age on corn production under a rice-corn gion, Taipei, Taiwan ROC. system. Jour. Agric. Res. China 37,4: Ileuse, G.J., B.R. Blimet, D.A. Crusseley Jr., 416-423. (In Chinese). and E.P. Odum. 1984. Nitrogen cycling Stinner, B.R. and J.M. Blair. 1990. Ecologi- in conventional and no-tillage cal and agronomic characteristics of inno- agroecosystems: Analysis of pathways and vative cropping systems. In: Sustainable processes. Jour. of Applied Ecology 21: Agricultural Systems, A. Edwards, R. Lal, 991-1012. P. Madden, R.H. Miller, and G. House Hsieh, S.C. and C.F. Hsieh (eds.). 1989. (eds.). Soil and Water Conservation So- Organic Farming. Special Publication ciety, U.S.A., pp. 123-139. No. 16 of the Taichung District Agricul- Sun, S.K. and J.W. Huang. 1985. Formu- tural Improvement Station, Taiwan ROC. lated soil amendment for controlling pp. 307. (In Chinese). Fusarium wilt and other soilborne diseases. Hsieh, S.C. and C.F. Hsieh. 1990. The Use Plant Disease 69,11: 917-920. of Organic Matter in Crop Production. Sun, S.K. 1989. Use of soil amendments Extension Bulletin No. 315, Food and for the control of soilborne diseases In: Fertilizer Technology Center for the Organic Farming, S.C. Hsieh and C.F. ASPAC Region, Taipei, Taiwan ROC, pp. Hsieh (eds.). Special Publication of the 1-19. Taichung District Agricultural Improvement Hsieh, S.C. 1992. Concept and practice of Station No. 16, pp. 141-155. (In Chi- natural farming in the subtropics. Paper nese). presented at the International Seminar on Sun, Paul M.H. 1992. Taiwan’s agriculture, Natural Farming, held in Bangkok, Thai- from the perspective of sustainability. land, January. 18-25, 1992. Natural Farming 5: 45-46. Natural Hsieh, S.C., C.F. Hsieh, C.H. Lin, and K.N. Beauty Education and Ecology Foundation, Hsu. 1992. Effect of long-term applica- Taipei, Taiwan ROC. tions of animal and poultry waste com- Tsai, Y.F., S.C. Huang, and W.L. Lay. posts on soils and crops. Proceedings of 1989. Effects of green manure on the the Workshop on the Effects of Agricul- growth of spring sorghum. Bulletin of tural Resources and Materials on the En- the Taichung District Agricultural Im- vironment. Taiwan ROC, pp. 179-194. provement Station 23: 11-20. 15 DISCUSSION

In the discussion, Dr. Sri Adiningsih was interested in the income from organic farming, and whether this was sustainable. She was also concerned at the very high level of organic matter applied in the experiments discussed by Dr. Hsieh, and questioned whether farmers would be able to apply such large amounts, particularly in view of the labor cost. Dr. Hsieh replied that modern organic farming has only been practiced recently in Taiwan (traditional farming is of course entirely organic). For this reason, there is not yet a marketing structure to handle organic products, although this will be developed in the future. He felt that Taiwan had an abundance of organic materials, especially since its warm climate makes possible the production of crops all year round. In the past many farmers used to burn their rice straw, but they are now prohibited from doing this, and must use the straw as a raw material. Taiwan also produces more than 10 million head of hogs a year, with a consequent huge volume of livestock manure which is now being used to make organic fertilizer, as is cattle and poultry manure. He said that there are two types of organic fertilizer used in Taiwan: one is the farmer’s own compost made from farm by-products, and the other is the commercial compost made by Taiwan’s 120 compost companies, most of which is sold to farmers. It is bulky and costly to transport to the farm, but machinery is now available to broadcast organic materials which helps reduce application costs.

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