A project of Volunteers in Asia ironical Vesetables by G.J.A. Terra Publishnd by: The Royal Tropical Institute Amsterdam THE NETHERLANDS Available from: Swiss Center for Appropriate Technology (SKAT) Varnbuelstrasse 14 CH-(3000 St. Gall SWITZERLAND Reproduced by permission. Reproduction of this microfiche document in any form is subject to the same restrictions as those of the original document. T ICA EGETA VEGETABLE GROWING IN THE TROPTCS AND SUBTROPICS ESPECIALLY OF INDIGENOUS VEGETABLES PROF. IR. G. J. A. TERRA DIRECTOR NEDERF COMMUNICATION No. 54e OF THE DEPARTMENT OF AGRICULTURAL RESEARCH PUBLISHED JOINTLY WITH THE FOUNDATION “NETHERLANDS ORGANIZATION FOR INTERNATIONAL ASSIFi-ANCE” (NO\ LB) KONINKLIJK INSTITUUT VOOR DE TROPEN, AMSTdRDAM Q u66 Koninkfijk Mituar voor de Tropen, Amsterdam No part of this book may be reprnluced in any form, by print, photoprint, microfilm, or any other mrans without written permission from the publisher Second i%iion 1973 Index udded Prinred in the Netherhds Sel in Monotype Spectrum Printed by Koninkl$e drukkerij v. d. Garde NV., Zaltbommel CONTENTS Foreword VII I. Introduction I II. The culture A. Commercial cultures and separate cultures for home con- sumption Choice of site Tillage and manuring Seedbeds Maintenance Choice of plants B. Mixed gardens or compounds or hcme gardens 5 7 8 9 12 r3 If I4 III. Enumeration of vegetables 18 A. The principal cultivated or much used tropical vegetables 18 B. Other plants producing edible young leaves or shoots 86 C. Palms for palm cabbages 101 D. Ferns and related plants 103 References 105 LIST OF ILLUSTRATIONS I. ,QR fnwsclrrrs mmihat Med. 2, Aiacusia niacrorrhizu Schott., Xmthownu violarem Schott., escrrlentuSchott., Colocasia &untea Hooh. f. (tubers). 3. Alocasla macrorrhm Schott., Xunthasoriiu violucem Schott., escirlenta S.:hott. Colocasiu gigunttu Hook. f., (leaves). 4. Arwunthrrs hybridus L. 5. hsellu rlrbta ‘,. 0. Corchorru oiitorius L. 7. Eqhorbia p&herrimr; Willd. 8. C;r‘etrrm gnemon L. g. Mibiscus esculenttls L. 10. Ip3riaeu repms Poir. II. Leucuenu gluucu Benth. 12. Munihot rrtilissimu Pohl. 13. Momordicu churuntia L. 14, Moringa oleifku Lam. 15. Psopbocurpus tetrupolobus A. DC 16. Suurqm androgynlrs Merr. 17. Sechium edde SW. 18. Tulinum triungu~ure Willd. rg. Viflnu unguiculutu Walp. page I7 Colocasia 21 Colocasia 22 24 28 40 47 48 51 53 55 58 60 62 69 ?2 74 78 81 The numbers I, 5,7, 8, g are from OCHSE, J. J.: Indische Groenten; 4, IO, II, 12, 12, 14, 15, 16, 17, 18 from OCHSE, J. J.: Tropische Groenten; z and 3 from SOEP.,RM!., S. : Indonesische Groenten; 6 from Bars, D. : Les plantes alimen- taires chez tous lrs peuples; Ig from HE RKLOTS, C. A. C. : Vegetable culti- vation in Hongkong. NOTE: Nomenclature is used to the best of our knowledge withont extensive botanical verification. VI FGREWORD It gives me great pieasure to introduce our communication no. 54e on tropical vegetables, which is published by the Department of Agricultural Research of the Royal Tropical Institute jointly with the Foundation “Netherlands Organization for International Assistance” (NOVIB). This co-operation is d natural one: both our organizations have a common interest in the contents of this volume, which indicates a practical remedy against a dangerous situation existing in many tropical countries, a situ- ation which too often is not yet understood by the local population. itself. The volume does this by presenting numerous data on locally available’ sources for improving the diet and by recommending and describing methods that are not beyond the capacity of the rural population. This publication in English will be followed by a French (and possibly also a Spanish) version. The importance of green vegetables in the diet for vitamin supply, especially of vitamin A, is well-known, particularly for the arid regions. Nowadays, their imrsrtance for improving the protein content of the diet also deserves great consideration. In most publications of this type the imported temperate vegetables dominate. Here, on the contrary, it is tried to stress information on original vegetables of equatorial and subtropical regions. These are more adapted to local soil and climate: leached soils, humidity, temperature, daylength, etc., and therefore they can be grown more eas,lv and more cheaply. Moreover, propagation is fairly easy. They offer vast resources for further selection, which has been insufficient until ROW. Many of tbem are only found in the wild or half-wild state. They are only locally grown or even locally known as vegetables, and sources of information are few and far t *:*ween. The author, Professor Ir. G. J. A. TERRA, is an expert in tropical horti- culture. After twenty years of experience as a Head of Horticulture in pre- war Indonesia he gathered data and experience in several other tropical regions, lately as the Director of the “Netherlands Foundation for de- signing and executing the Home Gardens Project” (NEDERF), operating VII in Western Africa and fostered by NOVIB aiid FAO/Freedom from Hunger Campaign. It stands to reason that this volume is not meant to serve as reading matter for entertainment. But it does furnish much valuable information ni a concise and surveyable way, thus al1o-A ‘::& for quick application. It is an example of what was meant in the introduction to one of our former publications by pointing out that not only ultra-modern sophisticated western scientific methods and equipment would have the monopoly for solving the problems at hand: “A wealth of experience, both old and new, is readily available for application in vast areas which both figuratively and literally still lie fallow”. We assume that this publication will be a valuable guide to extension workers in the field of practical horticulture and nutrition, and in this way play its modest role in tackling the urgent task of our present days: Narrow- ing the existing gap between knowledge and its application in developing countries. DR. R. BRINK Director, Department of Agricultural Research, Royal Tropical Institute Amsterdam, October 1966 VIII I. INTRODUCTION Vegetables and fruits are those fresh and juicy parts of plants, which are eaten as a supplementary food, as a side dish or simply by themselves. Fruits may be distinguished, since they are real botanical fruits, eaten as such, as well as prepared and preserved, mostly in their mature stage, for their agreeable, sweet, acid or aromatic flavour. They may include various nuts, which are not juicy. Vegetables are the other components of this group, mostly eaten prepared in some way or other, but sometimes used as such in the fresh, raw state, particularly leaves. Vegetables are specially important as a supplementary nutrition, in addition to the main food. The latter, which usually consists of cereals, farinaceous foods or tubers, must furnish the necessary energy (calories) and also the proteins, inasmuch as these are not obtained from meat, fish, eggs, milk or cheese. The vegetables then supply a large part of the necessary vitamins and minerals and often supplementary proteins as well. Usually, the vitamins and minerals are the most important contri- bution from the vegetables, but where the main food has a poor protein content e.g. if it consists of tubers without meat, fish etc., the protein supply from vegetables can be considerable. In regions, where the principal food consists of cereals, the protein content of the vegetables may be less important. There is no general agreement as to what is meant by vegetables. We may distinguish: I. Leaf vegetables e.g. spinach, cabbage, corchorus, purslane. 2. Pulse vegetables such as young pulses of beans and other leguminous plants. 3. Fruit vegetables, young or ripe fruits such as pumpkin, gourd and egg plant. 4. Seed vegetables such as young seeds of peas, beans etc. 5. Tuber vegetables e.g. roots, tubers and rhizomes of carrots, sweet potato, beet, radish, turnips, ginger etc. 6. Other vegetables e.g. young flowers, stalks etc. of cauliflower, asparagus, onion and other bulbs. Vegetables, especially the leaf an d pulse varieties, are particulariy im- I portbnt for the s*upply of vitamins. A’bove all, they furnish vitamin C and carotene (provitamin A), as well as considerable quantities of the various B vitamins and minerals. On the whole we may say: a. Fresh vegetables, fruits and tubers supply vitamin C and minerals. Vitamin C is not proof against long boiling, i.e. against high tempera- tures. It is soluble in water. A shortage of it is noxious for everybody (scurvy). b. Greens, especially leaf and pulse vegetables, supply important quantities of carotene (provitamin A). Often yellow, orange- and red-coloured vegetables, tubers and fruits contain important quantities of it, but a red or blue colour (as in beet, red cabbage) need not indicate carotene. Blanched vegetables always contain less carotene than green ones. Carotene can stand high temperatures reasonably well, vitamin A cannot. Both are soiuble in fat (red palm oil e.g.). A shortage of this vitamin may cause night-blindness and, particularly in children, blindness (xerophtalmy, keratomalacy). c. Vegetables, especially those of the pulse, leaf and <both ripe and young) seed varieties supply large quantities of the various B vitamins. They are proof against boiling, but B2 cannot stand direct sunlight. They are solub!e in water. A shortage of them causes a.o. beri-beri (Bi) and pellagra (B complex). Moreover, many vegetables e.g. young leaves of cassava and of trees and shrubs such as Poinsettia, Gnetum and Moringa, and also pulses and their young seeds, contain from 4 to IO% of protein of the f. re h weight. These vegetables s are of pa.rticclar ir,lportance for the supplementary supply of proteins. Ordinary leaf vegetables mostly have only ~2% of proteins, just like many tubers and usually the protein content of fruits is still lower. Shor- tage of protein may cause kwashiorkor in young children and death may follow soon. Most vegetables are annual plants. But in the tropics, young leaves, shoots, pods and other fruits are often harvested from shrubs and trees. Their great advantage is the fact that they often continue to grow and yield in the dry period, when the growing of annual vegetables meets with difficulties. In addition to greens, also fruits and tubers are desirable. Fruits contain minerals and vitamin C, and the coloured ones often carotene. They offer an agreeable change from the normal food and stimulate the appetite by their various vegetable acids and aromatic components. Most of the tubers contain mainly starch; in the first place, they supply energy (calo- ries), but they may also have many vitamins (carotene and minerals). They offer a suitable alternative for cereals and other starchy foods, which are mostly poor in minerals. An idea of the greater value which greens, young pulses and young 2 seeds iiac;o for our diet than any other vegetabieq, tubers and fruits, is given by the follo\j.ing table. All data refer to 101, grams of fresh weight. Vegetables Cal. Protein Vitamin \‘ltamin Vitamin Nia-in Vitamin in g A In 1U HI in mg BZ in mg in mg C in mg l.tflWS Cassava leaf Tropical spinach Kankong * Green vegetables (av.) Yellow vegetables (av.) Pods and seeds Beans ipods) Asparagus bean (pods) Peas (seeds) Young fruits Cucumber Okra or go-nbo Tomato Tubers Cassava (fresh) Sweet potato (fresh) Coca-yam (fresh) Fruits Banana Papaw Orange Mango Water melon Avocado 5.3 7 44 4 17 3 22 2.4 18 1.5 33 2.2 18 2 48 3.4 10 .6 29 1.8 18 1 131 .7 121 1.5-2 88 1.5-2 103 1 38 .6 43 .8 ;: :: 210 2 lU,OOO 13,000 4,000 5,000 500 200 1,200 1,500 200 1,000 1,200 0 O-5000 40 100-350 2,500 250 1,000 500 200 Especially dark green tropical vegetables are rich in proteins and vitamins, also the young pulses and seeds. Fruit vegetables, tubers and fruits are much less important in this respect. The avocado is also rich in vitamins, but when these contents are calculated per IOO calories, they will be seen not to exceed those of other fruits. An adult person needs tooo to 3000 calories a day. If one gets these from cheap food, rich in calories but poor in proteins etc., then the supplemen- tary food must consist of products, rich in protein and vitamins e.g. meat and fish. Now this purpose may also be served by those parts of plants which are rich in protein and vitamins, as calculated per IOO calories, e.g. beans and greens. This supplementary food is particularly important for the young and the sick, who cannot ingest large quantities of food. Of course, the need for vegetables depends on the composition of the staple food. If this contains suffici.ent proteins, the quantities of fresh green vegetables needed per capita may be put at a minimum of 0.1 kg per day, because then the total supply of vitamin C and carotene can be considered safe. Should the vegetables have to take over part of the protein supply, * = Ipomoea reptans = I. aquatica (swamp cabbage or water spinach) 3 .14 .26 .15 .25 .1.5 .2 .07 .15 .04 .06 .08 .lO .lO .lO .28 .12 .04 .05 .? .l :, ‘5 .04 -02 .l .l .06 .05 .06 .05 .06 -02 .02 .08 .03 .06 .05 .05 .07 .l .15 1.5 300 .85 100 1.6 140 .6 55 .13 31 .6 13 1.1 20 2.0 10 .I6 10 .7 25 .7 25 .6 30 .7 20 .4 6 .5 .l tci .2 25 .2 30 .05 6 .l 20 then a quantity up to 0.5 kg may be desirable *. These quantities are not excessive, for them a&e regions where more than 0.5 kg of vegetables a day are eaten. Calculated per annum, this need for vegetables amounts to respectively 40 and 200 kg per head, which means 200 or 1000 kg a year per family. As we shall see later, from I to 5 ares will have to be planted for this purpose f#>r each family. Mefhds ofpreparation. Though this is not the place to enter into the exact preparation of vegetables, a general description may be very useful. In Indonesia and also in other tropical countries, it is still customary to collect various wild growing vegetables (young leaves, shoots) and to eat them raw, sometimes with a sauce. This so-called “lalab” can also be used after having been dipped into boiling water for 5-10 minutes. In this manner, the vegetables become softer without losing their consistency. They are then often eaten with a I;eanut sauce (gado-gado or petjel, Indonesia) or with coconut milk. h/lastly people use locally grown vege- tables: cabbage, swamp cabbage or water spinach, bean sprouts, asparagus bean, four-angled bean, etc. In western. countries as well, some vegetables are eaten raw, sometimes with a sauce: lettuce, endive, cabbage, radish, cucumber, tomato. Some- times boiling water is first poured over them (cabbage) for softening. in primitive regions vegetables are wrapped in banana leaves etc. and baked in hot ashes or between hot stones (Polynesia, New Guinea). The normal western manner is + x .ti boil vegetables in water; often thei are then further stewed with fat, milk, flour etc.; mostly they lose their consistency and often also some of their flavour. The Chinese kitchen stews or fries vegetables with fat; they keep their consistency and are not boiled out. In Africa vegetables often are stewed with palmoil, e.g. young cassavp leaves, and used after passing through a sieve, as infant food. In many countries vegetables are mixed with the main food and boiled together; hotchpotch, rice with vegetables (riz a la creole), Irish stew etc. Also thick vegetable soups are much in use; they are eaten separately (minestrone e.g.) or with the main dish (sayor in Indonesia and Thailand) rumasava (Madagascar), the sauce eaten with the couscous (North-Africa). Sometimes a thick soup with rice is used as infant food (nasi tim, Indonesia). In Africa, especially along the Guinea Coast, it is customary to cook * In general, proteins of vegetable origin contain less of the important, sulphur containing rmino acids cystine and methioni:e than animal proteins. Moreover, methionine can be transformed by the human body into cystine but not the reverse. Therefore, each time a vegetable is known to have a higher content of methionine than normal, this will be indicated in the text, according to the data contained in the work of BUSSON and in FAO “Amino acid content of foods”. This applies to contents above z g of methionine per 16 g N (which corresponds with IOO g protein). The standard FAO content is 2.2 g per 16 g N. 4 vegetables a long time into a thick, sticky sauce: palaver sauce, eaten with the main dish fufu. The sauce should be thick, viscous and slimy, since the fufu is dipped into it; normally, it is bitter, salty or hot (chillies). Often people use a powder obtained from dried leaves. Another way of preparing vegetables is to boil or stew them with chillies (sambalan, Indonesia) or curry (India). Sometimes the vegetables are snredded and fried (India). Generally, boiling for a long time diminishes the vitamin C content; the influence on the vitamin A and carotene contents is still somewhat un- certain; on the other hand, it may destroy poisonous substances. It is a fact that by boiling in much water and throwing away the superfluous water, part of the water-soluble vitamins (e.g. B and C) disappear. How digest- ibility is affected by eating vegetables raw or boiled for a short time, is not certain. In general the digestibility of young leaves is estimated at about 80%. Drying in the sun and above a fire impairs vitamin C and Ba contents. More serious is the fact that the proteins and their digestibility may be atfected. This may depend for a large part on the temperature during the drying process, which should not be higher than 6o’C. The situation is not clear: proteins may be affected chemically, the process may have to do with sugar caramelization u hich starts above 60% and which could promote the formation of inactive protein compounds, or irreversible drying out of the vegetable matter could affect digestibility. It should be stressed that many tropical vegetables cannot be eaten raw, since they ar e then irritatine or even poisonous e.g. leaves of Poinsettia (E ph b’ p I1 II OT la II c rerrinra), young leives and shoots of maniac (Manihot utilissima). II. THE CULTURE Vegetables may be grown for the market or for home consumption. When the r are 1 grown for home consumption, this may still be done in any of three different ways, viz. planted in well cared-for and manured beds, as is usual for the commercial cultures, or as an intercrop between agricultur- al crops, or seemingly running wild around the house, without much care or manure. Which manner of growing should be preferred, depends on the circumstances. z. Ve~etabies &r the market. These are often grown in accordance with the demand from the well-to-do public for European vegetables such a: cauliflower, beans, lettuce and radishes, which do not grow naturally in the tropics. Therefore, they need very intensive care but, owing to the high prices they can command, the culture is still paying. Most of the time they are too expensive for ordinary people. Moreover, the seed of many of them cannot be grown in the tropics. 5 Commercial growing of real tropical vegetables is very rare outside India and Sout-East-Asia. ‘They are then found in special small farms or in crop rotation with agricultural plants, mcxtly for the city markets. 2. Mensive crrltfrre of vefletablP5 fir hnrrfe