Agricultural research is an essential component of any program to increase the sustainability of agriculture. Agricultural research is necessary to help farmers deal with diseases and pests. With the dramatic increases in travel and trade of the twentieth-century, even the traditional agricultural practices of relatively iso-lated  islands  in  the  Pacific  have  come  under  threat  from  introductions  of  exotic diseases  and  pests.  Agricultural  research  also  is  needed  to  develop  sustainable production practices and to adapt new technologies and cultivars to local conditions.  Many  of  the  traditional  agricultural  practices  used  in  the  tropical  Pacific become non-sustainable when they are intensified due to increases in population, or due to movement from subsistence to market production. Cultivars and practices  developed  elsewhere  may  not  be  suitable  for  the  climates  and  soils  of  the tropical  Pacific.  For  those  agricultural  products  that  are  produced  for  export markets, local research is necessary to adapt to the constantly changing demands of these markets. 

 

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The Portable Extension Office for Program Literature Exchange (PEOPLE) project aims to expand the sustainable agriculture information resources available to agriculture professionals and their clients in the islands of the Western Pacific. The project has identified, obtained, and disseminated literature, in digital format (web site and CDROM), through extension institutes and non government organizations (NGO) worldwide that relate to tropical sustainable agriculture issues and practices. At the participating project sites, staff skills have been updated to include use of various types of computer equipment, software, and information resources to enable the effective implementation of “print-on-demand” program literature exchanges. Issues identified in the project’s implementation and future efforts are presented.

In the 31 years of the Sulawesi transmigration program that ended in 1998, a strong correlation between population and food crops production was observed. As a product of the increasing numbers of people added each year, the Sulawesi population grew by 2.99% with food production increasing by 4.87%. This study indicates that it is feasible, using system dynamics, to simulate sustainable agriculture while concurrently estimating population increase and land availability. From 1998, the model used a time span of 50 years. Analysis shows that the agricultural land sector grew steeply from the 20th to 30th year, overshooting the population curve. From the 25th year on, nonagricultural land increased while agricultural labor decreased. Results likewise show that population/land and population/agricultural land declined until the 30th year, and growth was reduced by as much as 50%. Until the 27th year, the ratio of agricultural production to population had been adequate. All variables in the system have been equilibrium-seeking since the 30th year. The fundamental role of resource constraints in controlling growth and bringing about equilibrium is clearly observed in this model. This study also shows that agricultural land development precedes nonagricultural land development. Agricultural land decline is mainly due to nonagricultural land conversion, such as for public facilities, environmental purposes, and other construction. Deregulation in the form of a multiplier and an adaptive system construction is needed to sustain agriculture from the 30th year.

A concept test was conducted to assess local awareness of traditional root crops and to study the market potential for value-added products made from taro (Colocasia esculenta (L.) Schott), sweetpotato (Ipomoea batatas (L.) Lam). and cassava (Manihot esculenta Crantz). The test design was a self-evaluating survey that was used to explore (1) the level of consumption of chips and baked/fried foods, (2) the interest level of foods made from root crops, and (3) the level of interest of “Made in Guam” products. One hundred thirty respondents between the ages of 18–54 representing Guam’s consumer population were analyzed in a survey that was conducted from March to May 2000. The most popular type of value-added product was sweetpotato chips, followed by sweetpotato bread, cassava cake, cassava pudding and cassava tamales. Of the 130 persons surveyed, 72% had consumed sweetpotato within the past three months, while more than 60% had eaten cassava and 55% had eaten taro. Results suggest that there is a market potential for value-added foods made from these tropical root crops. The survey also shows that there is interest in “Made in Guam” foods.

Examples of aquaculture ventures in the Pacific Islands show that reasonable development has occurred. While some earlier and illplanned projects failed, recent initiatives have shown good results. Future prospects look good for pearl oyster, seaweed, marine and freshwater shrimps, and tilapia. A number of pitfalls must be avoided, however, for aquaculture to reach its potential for economic development in the islands.

Plant development of eight nitrogen fixing trees (NFTs) as potential hedgerow plants were evaluated on three soil regimes on Guam. Test plants included Acacia angustissima (Mill.) Kuntze, Cajanus cajan (L.) Millsp., Calliandra calothyrsus Meissner, Desmodium rensonii, Flemingia macrophylla (Willd.) Merr., Gliricidia sepium (Jacq.) Kunth ex Walp., Leucaena leucocephala (Lam.) de Wit cv. K636, and Sesbania sesban (L.) Merr. cv. Nubica. NFTs other than F. macrophylla and C. calothyrsus yielded more than 11 t ha–1 of biomass in the soil of Udic Haplustalfs at Barrigada, in central Guam. L. leucocephala cv. K636 produced the greatest biomass of 26.1 t ha–1 in the trial, followed by S. sesban cv. Nubica with 19.9 t ha–1. The average biomass of eight NFTs was 3.63 t ha–1 in very shallow Yigo soil classified as Lithic Ustorthents. L. leucocephala, yielding 12.3 t ha^–1, was the only promising NFT in this location. In the acidic Oxic Haplustalfs soil in Ija, in southern Guam, F. macrophylla, S. sesban, G. sepium, and D. rensonii produced about the same amount of biomass, ranging from 6.6 to 4.8 t ha^–1 while L. leucocephala, A. angustissima, and C. calothyrsus grew very poorly.

Four local cultivars of bananas (Musa spp.) in Kosrae, Federated States of Micronesia (FSM)—Kufwafwa, Lacatan (dessert bananas), Apat regular and Apat fissuse (cooking bananas)—were subjected to micropropagation experiments at the Micronesia Plant Propagation Research Center (MPPRC), Kosrae during 1999–2000. Protocols for efficient micropropagation of these varieties were developed during the study. Surface sterilization procedures were modified to attain acceptable numbers of aseptic stage I cultures. All varieties studied responded to modified MS medium. Plant growth regulator, 6–Benzylaminopurine (BAP, 3–7 mg L^–1) requirements for different varieties were substantially distinct in terms of optimal growth and multiplication. Multiplication rates varied considerably between 20–30 (Apat regular) and 2–3 (Kufwafwa). Longitudinal splitting of the shoot tips improved the multiplication rate in all the varieties.

Sunnhemp, Crotalaria juncea L. cv. Tropic Sun, was evaluated as a green manure crop in the vegetable production system in Pulantat soil (clayey, montmorillonitic, isohyperthermic, shallow Udic Haplustalf) during 1993 to 1996. A split plot design with four replications was used having an application of inorganic N urea fertilizers (224, 112, 56 and 0 kg ha–1) as a main plot and green manuring as a sub-plot. Sunnhemp was grown until the flowering stage and then incorporated into soil. Chinese cabbage, Brassica rapa L. var. chinensis L. cv. Speedy 602 was either directly sown in the field or transplanted. Sweet corn, Zea mays L. cv. Summer Sweet was planted after harvesting Chinese cabbage in 1995 and 1996 to examine plant response to residual soil nutrients. In 1994 Chinese cabbage yield was increased by N fertilizer application but not with green manuring. In both 1995 and 1996 the Chinese cabbage yield was increased by both green manuring and N-fertilizer application. Plant tissue analyses in 1995 showed that both green manuring and Nfertilizer application increased nitrate-N in petiole sap, and the total N in leaf tissues was increased as the amount of N application increased.

Vegetable soybean (Glycine max (L.) Merrill) accessions developed at the Asian Vegetable Research & Development Center (AVRDC) in Taiwan were evaluated in Guam cobbly clay soil during dry months of 1996 and 2000–01. In 1996 among five accessions, AGS190 (Veroy #4) and AGS335 (Ryokkoh x Mikawashima) were selected for their high yields. During 2000–01, eleven accessions including eight new germlines obtained from AVRDC were grown in order to identify accessions which produced two or more seeded-pods with good seed quality. AGS360 [Neu Ta Pien #2 x (PI 157424 x KS #8)] was our selection. Although its yield was lower than some other accessions, AGS360 had the largest green pods and seeds, which is a desirable trait for marketing. Further field experiments including on-farm trials should be conducted before local selections are released in Guam.

Pest management is a key factor in sustainable agriculture, particularly for an economy with limited land and natural resources. In view of the general recognition and acceptance of the importance of sustainable agriculture by the public, technologies of plant protection have been improved and measures disseminated to farmers in Taiwan during the past two decades. Presently, the most common non-chemical control methods of diseases and insect pests include uses of healthy seedlings, resistant varieties, cross protection, natural enemies, antagonistic microorganisms, non-pesticide pest-killing materials, sex pheromones, nutrient solution, high-molecular polymers, soil amendment and disinfections, and cultural practices such as crop rotation, net house cultivation, bagging and mulches. Integrated pest management (IPM), featuring pest identification, monitoring and management including timing application of insecticide, is recommended to farmers to prevent pest problems. The mark of Good Agricultural Products (GAP), issued to farmers under governmental guidance and inspection, has already gained the confidence of consumers in providing clean and highquality products. A biochemical method for the rapid bioassay of pesticide residue in vegetables and fruits has been developed and applied in both fields and wholesale markets for screening products and educating farmers. This technique has also been introduced to other Asian countries. In addition, the TARI web site, offering pest management information in sustainable agriculture is accessible through the internet.

Three common crop aphid pests on Guam, Aphis craccivora Koch, Aphis gossypii Glover, and Toxoptera citricida (Kirkaldy) were examined in laboratory dip test bioassays using three commonly used insecticides, dimethoate, diazinon, and malathion. The LD₅₀, LD₉₀, lethal dose ratios and 95% confidence limits were computed for each aphid-insecticide combination. The LD₅₀ and LD₉₀ for each aphid-insecticide combination were generally low, although there were differences in lethal doses among aphids collected at different sites on Guam. Analysis of the slopes and intercepts of the probit regressions suggests that different detoxification mechanisms or site-specific factors may be operating. Analysis of lethal dose ratios using the lowest lethal dose in an experiment as a baseline suggest that there is little to no detectable insecticide resistance in the aphid populations studied on Guam.

Pests and diseases, nearly all of which are exotic to the Marshall Islands, cause significant losses to agriculture. The most serious of these include insect pests such as the breadfruit mealybug, coconut scale and spiraling whitefly, which cause severe damage to many food crops and seriously affect crop productivity and overall food security. The number of insect pests and diseases has increased since 1975 as shown by insect survey done in islands of Ailinglaplap, Mejit, Lae, Jaluit, Likiep, Namu, Arno, Woja and Ailuk. Twenty-one new pest species were introduced to Jaluit and Majuro in 1975 of which twelve species were new to the country. Biological control methods have been conducted as an promote environment-friendly pest control method. A number of natural enemies and parasites, including Chilocorus nigritus and Pseudoscymnus anomalus for coconut scale, Rodolia limbata and R. pumila for breadfruit mealybug and Encarsia sp. for spiraling whitefly have successfully been introduced to some island groups. Rodolia limbata has contributed to a significant decline in breadfruit mealybug in the Majuro atoll, Arno atoll, Mejit Island and Ailinglaplap atoll. Pest density for spiraling whitefly and coconut scales are declining, but are, still present the atolls.

Research data indicates that sweet potato (Ipmoea batatas) is a natural health food given its high-energy yield, dietary fiber, and vitamin and mineral content. Sweet potato has many desirable qualities, including high productivity, high proportion of edible biomass, easy propagation, good nutritional value, ease of preparation, palatability, flexibility in use, human experience, storage stability, suitability for soilless culture, symbiotic requirements and restrictions, and a short growth cycle. Using some of the above-mentioned criteria to select crops appropriate for Controlled Environmental Life Support Systems (CELSS) on manned space missions, NASA selected the sweet potato as one of the crops in the carbohydrate accumulator group. Hydroponically grown sweet potatoes and field grown sweet potatoes possess similar nutritional content and quality. As a result of the diversified characteristics of sweet potatoes, the Center for Food and Environmental Systems for Human Exploration of Space (CRESH) at Tuskegee University has developed edible and non-edible products for utilization and consumption in space and on earth. Sweet potato syrup, drink, waffles, pancakes, muffins, bread rolls, tortillas, pasta, pound cake, biscuit mix, and leaf and root flour used to enhance other foods are among some of the many edible products developed. Paper made from the stem and leaves of the sweet potato has also been developed. Sensory evaluations of the products have been conducted (and are ongoing) by CFESH. Participating consumers from states including Alabama, Florida, Georgia, Tennessee, Washington, Maryland, Virginia, and Texas (Johnson Space Center in Houston) have thus far indicated high acceptability of the products. It is apparent that an increase in the development and production of valueadded sweet potato products will boost the economic value and marketability of sweet potatoes both locally and internationally.

The Natural Resources Conservation Service (NRCS) is an agency of the US Depart of Agriculture that provides technical assistance on a voluntary basis to private landowners and local governments to enable them to achieve the sustained use of natural resources. Technical assistance may include the development of resource conservations plans and design of structural and agronomic conservation practices for locations ranging from construction sites to farm fields. Project priorities are set by Soil and Water Conservation Districts that are composed of locally elected or appointed community members to assure that local needs are addressed.