Don't throw away rice hull or "ipa." Here are 5 practical uses.

Dr Abe V Rotor 

Living with Nature School on Blog

Paaralang Bayan sa Himpapawid (People's School-on-Air) with Ms Melly C Tenorio

738 DZRB AM Band, 8 to 9 evening class Monday to Friday

 Top: Cross-section of rice grain; closeup of grain.  Middle: Rice hull stove, building block of rice hull and clay. Bottom: rice hull as litter; newly built vegetable plots.  Acknowledgement: Google search, Wikipedia,  Internet  images
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Rice hull is the outer cover of the rice grain which comprises 25 percent of the total weight. The cover is made up of a pair of hull-shape structures - lemma and palea - which are tough and impregnated with silica and cellulose. Considered waste in rice producing areas, now there are uses which this article would like to share - and recommend.

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1. Rice hull ash protects mung-beans from bean weevil.

Burnt rice hull (ipa) contains silica crystals that are microscopic glass shards capable of penetrating into the conjunctiva of the bean weevil, Callosobruchus maculatus.  Once lodged, the crystal causes more damage as the insect moves and struggles, resulting in
infection and desiccation, and ultimately death.

This is the finding of Ethel Niña Catahan in her masteral thesis in biology at the University of Santo Tomas. Catahan tested two types of rice hull ash,  One is partly carbonized (black ash) and the other oven-burned (white ash).  Both were applied independently in very small amount as either mixed with the beans or as protectant placed at the mouth of the container. In both preparations and methods, mungbeans – and other beans and cereals, for that matter – can be stored for as long as six months without being destroyed by this Coleopterous insect. 

The bean weevil is a cosmopolitan insect whose grub lives inside the bean, eating the whole content and leaving only the seed cover at the end of its life cycle.  When it is about to emerge the female lays eggs for the next generation. Whole stocks of beans may be rendered unfit not only for human consumption, but for animal feeds as well.  It is because the insect leaves a characteristic odor that comes from the insect’s droppings and due to fungal growth that accompanies infestation

2. Preheated rice hull is used to incubate balot eggs.

Simulating the way the mother duck incubates its eggs old folks bury duck eggs in rice hull (ipa) heated under the sun until they become penoy (incipient embryo) or balot (full grown embryo). For commercial production the eggs are held in bundles made of simamay or fishnet), placed in large holding boxes filled with rice hull. They are harvested in batches to meet market schedules.    

3. Rice hull compost is good soil conditioner for the garden. 

Mix rice hull with other farm residues that are ordinarily used in making compost at varying proportions but not exceeding fifty percent of the total volume.  These include animal manure and chicken droppings, dried leaves, peanut "hay" or tops, scums (lumot, Azolla and Nostoc from ponds and rice fields). Add equal amount of top soil to the final product.  This is excellent medium for potted plants and for germinating seeds, bulbs, and cuttings. When buying commercial potted plants, examine the medium used; the rice hull is still partly visible.    

4. Rice hull as fuel 

There are stoves designed for rice hull as fuel. One has a continuous feeding system for commercial use, otherwise ipa is hand-fed for typical kitchen stoves. Rice hull has a high thermal value because it contains silica that increases temperature level. This means faster cooking. To make full use of this advantage, rice hull must first undergo thorough drying usually under the sun.  It is then stored in sack for ready use. With the spiraling cost of LPG and electricity - and the dwindling supply of firewood - rice hull as fuel  is the best alternative in rice-based areas. 

5. Rice hull as litter of livestock and poultry

To solve muddy animal sheds and corrals, spread rice hull for time to time. This is also good for range chicken, and holding pens of animals in the market. Rice hull binds the soil and other materials such as grass and rice hay. When the litter becomes thick and old, replace it with a fresh one. The old litter is a good fertilizer for the orchard and garden. ~