When is Cassava Poisonous?

There are two kinds of cassava: the sweet and the bitter kinds. The ordinary kind sold in the market is the sweet kind, and the one made into laundry starch is the bitter kind.

The manner of planting, whether horizontal or upside down has nothing to do with its poison. Cassava naturally contains hydrocyanic acid, which is poison to both man and animal. The bitter kind contains more of the poison, but both kinds have it.

In the sweet kind, the poison is concentrated on the bark or skin of the crop, not so much on the flesh or meat. In the bitter kind, the poison is spread out on whole crop.

Weather and environment also have something to do with the cassava's poison content. When there is much nitrogen in the soil, there is more poison in the cassava where potassium in the soil is high, the poison in the cassava is low.

A long dry season increases the cassava's poison content: wet soil as during the rainy season lowers its poison content. Because of this, it is said that cassava contains poison in Summer.

According to scientists, cassava's poison contains more or less 30-150 mg of hydrocyanic acid (a milligram is one part of a thousand grams). If the hydrocyanic acid content is less than 50 mg it will not be harmful to eat. If it will exceed 100 mg. the poison content could be dangerous.

In the ordinary way of cooking, the poison disappears in the sweet kind but in the bitter kind, about 20 mg per kilo remains in the fresh peeled cassava.

According to experts, the amount of hydrocyanic acid in cassava is poisonous from one-half mg (.5 mg) up to 3.5 mg per kilo of the person eating the cassava. Thus, a person who weighs 50 kilos will be poisoned if he consumes one and one-fourth (1 1/4) kilo of bitter cassava. When his stomach begins to ache and he starts vomiting, or his mind becomes confused after eating cassava, then he has been poisoned.

The poison in cassava disappears during cooking, so, cooking cassava as suman is a safe way of eating cassava. Besides, suman preparation entails removal of bark, grating, extracting the juice, before cooking. Grating and extracting the juice already removes the poison, and it is further evaporated during cooking.

Other ways of removing the poison in cassava are: chopping, soaking in water, heating up to 57°C, and exposing in the sun. It is best not just to steam it but to cook it well. Even the bitter kind loses its poison when cooked well.

But it is always better to buy the sweet kind. This is known if, upon removal of the bark, the flesh is sweet. The meat of the sweet cassava tastes sweet!

Source: Greenfields December 1980, photo courtesy of www.arafood.com

Radish Farming

Almost every part of the radish plant is useful. The leaves and roots may be eaten raw or cooked as vegetable, or cooked with meat or fish.

Besides its use as food, radish is also used in many other ways its oil doesn't dry up like ordinary oil. This is used in soapmaking the meat after juice extraction is used as fertilizer. Radish is also medicine for diseases of the liver and spleen.

There are two kinds of radish. One is planted for its crop and the other for its leaves and roots. The different varieties we have are:

Japanese radish -- big and long, late harvested

Chinese radish -- fine, smooth and white, productive and has moderate length of time for harvest

White icicle -- early harvest, rounded, long with small roots.

Bombay, 60 Days and others -- can harvest within 100 days from planting, and mature 30 days from germination.

Land Preparation

1. Plow and harrow the field lengthwise and crosswise, and leave it for seven days to allow the uprooted weeds to rot and their seeds to grow.
2. Plow and harrow as before, repeat a third time but deeper.
3. Make elevated beds about one-half meter away from each other.
4. Put fertilizer where plants will be grown mix this with the soil by means of a rake.

Planting

A hectare of land would accommodate about 100 grams of seeds. Apply a kerosene can of compost before planting (see no. 8)

1. Treat the seeds first in growth regulator like "Seet Treat."
2. Mix one teaspoon Orthocide 50 WP per kilo of seeds to check whatever diseases they may have.
3. Prepare the planting of the seeds. To make them evenly apart, use a string attached to both ends -- one at 10 cm, a second at 40 cm, etc.
4. With the aid of a pointed stick, make a hole one and a half (1½) cm deep and 10 cm apart,following the distance of the string.
5. Drop two seeds in each hole and cover with fine soil. Water with fine spray so as not to dislodge the seeds or remove the top soil.
6. Cover with straw about 5-10 cm thick between the rows of plants, with space of about 5 cm from the plant. Don't cover the seed especially if it has not germinated. Keep away chicken from scratching the seeds away. The straw or dried leaves serve to protect the plants from strong rain or intense heat, and from growing weeds.
7. Water morning and afternoon in the first three (3) days after planting don't allow them to get dry. When the seeds germinate, water only in the morning. Ten days after all have germinated, water only in the afternoon when the ground is dry.
8. Dig a canal around the plot about 30 cm wide and 40 cm deep to where the water will run in case of heavy rain.
9. Before planting, mix a can of compost to every 2 sq. meters of plot. If animal manure will be used, apply this after the first plowing: one can per sq. meter. If chemical fertilizer will be used, have the soil analyzed first at the Bureau of Soils Laboratory. If not, the National Food and Agricultural Council recommends 8 bags of ammonium sulfate for every hectare of radish plants.

Maintenance

When the soil around the plant becomes compact, loosen it especially when the roots are beginning to grow. Be careful not to hurt the roots. If in spite of putting straw or dried leaves, weeds continue to grow, remove them manually.

Pests

To control insect pests, spray any of the following: Orthene 75 SP, SD, Tamaron 600 EC, Phosdrin 1.5 Ec, Hostathion 40 EC, or Vegetox, following instructions on the label, at an interval of 7 days. Trapping by means of light helps to control insect pests.

Diseases

A soil-borne or seed borne disease of radish attacks the new plant when the soil is very wet. As mentioned earlier, treat the seeds with orthocide or Spergon Fermate or Zerlate -- one-half teaspoon per gallon water. The black rot disease has a V-shape on the leaves. The leaves turn yellow then fall off. There is a black ring around the body when the leaf is removed.

Harvesting

Different varieties have different times of maturity, from 30 days from germination to 100 days after planting. Thus, it is good to know the variety to be planted, or try ten plants first. When overmature, radish is fibrous, porous and doesn't taste good. Pull up the crop when harvesting in early morning or late afternoon. Don't harvest when the sun is hot because it will wilt immediately. Wash, bundle and bring to market first hour in the morning. Don't pile them too high so as not bruise the crops, and to avoid heating for the crops under the pile.

Seeding

Get seeds only from healthy plants. Let these flower and bear seeds. Apply 2 grams ammonium sulfate, and water daily. Maintain with care until the fruits turn yellow. Select good seeds from good plants. When the pods are over mature, these will burst open. Dry the seeds in the sun to kill pests or disease. Before storing them, mix a little DDT or Orthocide 50 WP before packing. Put in a jar with fine charcoal at the bottom and over it a piece of cardboard with holes. Label jar. Seal the cover with masking tape until the next planting season.

Source: Greenfields November 1992, photo courtesy of www.nandyala.org, and www.greenharvest.com.au