Vegetables do well under trees. They can help smallholding farmers earn a good income and transform low-production farms into purposely managed, diversified and ecologically robust agroforestry systems.
The argument was made in a new book, Vegetable agroforestry systems in Indonesia, which details action research with farmers to develop sustainable tree and vegetable systems for steeply sloping hillsides.
According to James M. Roshetko, co-author of the book and a senior scientist with Winrock International and the World Agroforestry Centre, farmers in Nanggung, West Java, who traditionally grew vegetables in full sunlight, were delighted to find that they could successfully cultivate vegetables under a canopy of trees.
The seven vegetables he and his team tested did as well or better in medium shade than under full sunlight.
'In the understory of mixed trees with medium-light levels, the production per plant of amaranth, ‘kangkung’, eggplant, chili, tomato and "katuk" was around 100 to 300% superior to production under full sunlight. Even in understory with heavy shade, those seven vegetables produced up to 139% more than those in full sunlight”, he said
An array of vegetables was tested, including common ones like eggplant, chili, tomato, green bean and long bean, as well as indigenous Indonesian vegetables like amaranth (Amaranthus), ‘katuk’ (Sauropus androgynous), 'kangkung' (Ipomoea aquatica), 'kemangi' (Ocimum americanum), 'honje' (Etlingera giseke), 'kucai' (Allium tuberosum), 'legetan' (Spilanthes iabadicensis), 'pegagan' (Centella asiatica), 'beluntas' (Pluchea indica), 'kenikir' (Cosmos caudatus), 'sambung nyawa' (Gynura procumbens), and 'terubuk' (Saccharum edule).
The indigenous vegetables fetched higher prices in the market than the others. They were highly nutritious and many had medicinal or other valuable properties. For instance, katuk is used to improve the flow of milk in breastfeeding mothers, kenikir has beautiful flowers used for decoration, while the flowers of honje are edible.
However, the transformation of traditional, subsistence agriculture into market-oriented production is a formidable task, particularly if the benefits and risks are unclear.
In particular, the researchers found that farmers' weak links with traders and their post-harvest handling and processing were potential bottlenecks to increasing vegetable production.
For instance, a large and ready market for fresh katuk leaves existed in the cities of Jakarta and Tangerang, with daily demand from farmers in nearby Ciampea alone exceeding 15 tonne, worth US$2935 per day at a farmgate price of US$0.20 per kilogram.
Pharmaceutical companies were able to buy 5 tonnnes of dried katuk leaves from the farmers every day, at US$1.20 to 1.80 per kilogram. It took about 4 kilogram of fresh leaves to make 1 kilogram of dried.
So, economically, drying the leaves should have been attractive, increasing price margins several-fold. However, the researchers found that farmers often sold the leaves fresh because they lacked the experience, capital, technology and confidence to efficiently dry them.
'To capitalize on lucrative markets, farmers as well as traders needed to improve post-harvest handling and storage. Farmers, in particular, had to combine improved production and processing to increase the quantity and quality of yields. Once they achieved the standards needed for commercial orders, they could command premium prices in lucrative markets. Understory vegetable farming allowed them to intensify their farming by adding another, valuable "story" to their farms, without needing to expand their land area', said Roshetko.
Ujjwal Pradhan, the regional coordinator of the World Agroforestry Centre's Southeast Asia Program, said the research had helped improve farmers' incomes and also protect the environment.
'Because their land was under-productive, many local communities were forced to utilise the neighbouring Gunung Halimun National Park, a major watershed for Jakarta, leading to environmental degradation.
'Through intensifying vegetable production on the farmers’ own plots, without clearing any new land, benefits flowed not only to the farmers of Nanggung but downstream as well, in the form of improved water quality', Pradhan said.
The work in Indonesia was part of a research project called, 'Agroforestry and Sustainable Vegetable Production in Southeast Asian Watersheds', that took place between 2006 and 2010 in Indonesia, Vietnam and the Philippines. Companion volumes were published from research in each country. The program was led by the North Carolina Agricultural and Technical State University and funded by the United States Agency for International Development, with complementary support from partners. It brought together a team of 28 scientists from several prestigious US and Southeast Asian universities and research organizations, including Institut Pertanian Bogor, World Agroforestry Centre, World Vegetable Centre and Mars Incorporated.
Links to publications:
Understory Vegetable Production in Smallholder Agroforestry Systems of West Java – A Viable Option? James M Roshetko, Gerhard Manurung, Anas Susila, Denta Anggakusuma and Arif Rahmanulloh
Smallholder Cultivation of katuk (Sauropus andro gynous) and kucai (Allium odorum): Challenges in Sustaining Commercial Production and Market Linkage. James M. Roshetko, Iwan Kurniawan and Suseno Budidarsono