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Oryza sativa L.

Common rice

Source: James A. Duke. 1983. Handbook of Energy Crops. unpublished.

  1. Uses
  2. Folk Medicine
  3. Chemistry
  4. Description
  5. Germplasm
  6. Distribution
  7. Ecology
  8. Cultivation
  9. Harvesting
  10. Yields and Economics
  11. Energy
  12. Biotic Factors
  13. Chemical Analysis of Biomass Fuels
  14. References


Rice is cultivated primarily for the grain which forms an important part of the diet in many countries, especially in Asia. Grains are quite nutritious when not polished. In the US, 60% of domestic rice consumption went into direct food use, 11% into processed food, and 29% into beer production around 1975 (Rutger, 1981). US per capita consumption is between 3 and 4 kg/yr, up from 2.7 a few years ago (cf >50 kg in portions of Latin America). Common or starchy types are used in various dishes, cakes, soups, pastries, breakfast foods, and starch pastes; glutinous types, containing a sugary material instead of starch, are used in the Orient for special purposes as sweetmeats. Rice bran contains 15–17% oil, and is a source of vitamin B, used as a preventative and cure of beriberi. Grain is also used to make rice wine, Saki, much consumed in Japan. Fermented or Sierra rice is consumed in the Andean highlands and is used exclusively there in the preparation of dry rice. Rice hulls are sometimes used in the production of purified alpha cellulose and furfural. Rice straw is used as roofing and packing material, feed, fertilizer, and fuel.

Folk Medicine

According to Hartwell (1967–1971), the seeds are used in folk medicine for breast cancers, stomach indurations, other tumors, and warts. Reported to be antidotal, aperitif, astringent, demulcent, diuretic, excipient, larvicidal, refrigerant, stomachic, tonic, and vermifuge, rice is a folk remedy for abdominal ailments, beriberi, bowels, burns, diarrhea, dysentery, dyspepsia, epistaxis, fever, filariasis, flux, hematemesis, inflammations, jaundice, nausea, ophthalmia, paralysis, piles, psoriasis, skin ailments, sores, splenosis, stomach ailments, and swellings (Duke and Wain, 1981). According to Duke and Ayensu (1984), the flowers are dried as cosmetic and dentifrice in China, awns are used for jaundice in China. The stem is used for bilious conditions; ash for discharges and wounds, sapraemia in Malaya; infusion of straw for dysentery, gout, and rheumatism. The husk is used for dysentery and considered tonic in China. In China, rice cakes are fried in camel's fat for hemorrhoids; rice water is used for fluxes and ulcers and applied externally for gout with pepper in Malaya. Boiled rice is used for carbuncles in Malaya and poulticed onto purulent tumors in the East Indies. The root is considered astringent, anhidrotic, and is decocted for anuria. Sprouts are used for poor appetite, dyspepsia, fullness of abdomen and chest, and weak spleen and stomach in China. The lye of charred stems (merang, Indonesia) is used as a hair wash and used internally as an abortifacient. In the Philippine Islands, an extract (tikitiki), rich in antineuritic B1 vitamin, made of rice polishings, is used in treatment of infantile beriberi and for malnutrition in adults. In Java, the vitamins are extracted and supplied as lozenges (Reed, 1976).


The nutritional value of rice and its milling products is shown in Rutgers Table 3. Brown rice protein contains in g/16g N: 4.6 g isoleucine, 7.9 g leucine, 3.6 g lysine, 5.1 g phenylalanine, 4.7 g tyrosine, 5.3 g total sulfur amino acids, 2.8 g methionine, 3.6 g threonine, 1.4 g tryptophane, and 6.4 g valine (Rutger, 1981). Based on 68–84 analyses, Miller (1958) reports that the straw contains 88.0–93.4% DM (mean 91.5) and, on a zero moisture basis 2.8–6.2% CP (mean 4–2), 0.7–2.3% EE (mean 1.4), 27.6–38.3% CF (mean 35.1), 14.0–20.1% ash (mean 16.9), and 36.6–48.1% NFE (mean 42.4). Han and Anderson's analyses (1974) are similar, 0.19 mcal/100 g, 4.5% CP, 1.5% EE, 35% CF, 4.5% lignin, 34.0% cellulose, 42.0% NFE, 16.5% ash, 14.0% silica, 0.19% Ca, 1.2% K, 0.4% Mg, 0.10% P, and 0.10% S.


Erect annual grass, to 1.2 m tall; culms angled, smooth, nearly enclosed in glabrous, strongly-nerved leaf-sheaths; leaf-blades long, flat, 1.2 cm broad, more or less scabrous; panicle terminal, narrow, curved or nodding to one side, 15–30 cm long, with many long, ascending branches; spikelets strongly flattened sidewise, perfect, ribbed pubescent, awned or awnless; palea with 2 nerves near margin; kernel free-threshing, oblong, flattened on the sides, with long hilum, straw-colored or yellow, from 28,000 to 44,000 per kg, depending on the variety (Reed, 1976).


Reported from the China-Japan, Indochina-Indonesia, and Hindustani Centers of Diversity, rice, or cvs thereof, is reported to tolerate aluminum, disease, drought, fungi, high pH, laterite, low pH, sodium, nematodes, photoperiod, slope, smut, virus, weeds, and waterlogging (Duke, 1978). Several thousand cvs are known, many well studied with genetic maps, disease-resistance and yield data. Cvs are divided into short-, medium-, and long-grained types. Long grains have the highest market value. Upland rice is grown without submersion, usually on terraced hillsides; lowland rice is grown in flooded beds through much of the growing season. (2n = 24, 48)


Native to the tropics and subtropics of Southeast Asia, rice is now cultivated in many localities throughout the world with favorable climatic conditions. More than 90% of the world rice production is in Asia; China and India being the largest producers (Reed, 1976).


Ranging from Cool Temperate Steppe to Wet through Tropical Very Dry to Wet Forest Life Zones, rice is reported to tolerate annual precipitation of 4.2 to 42.9 dm (mean of 85 cases = 15.2), annual temperature of 8.4 to 27.8°C (mean of 85 cases = 23.0), and pH of 4.3 to 8.7 (mean of 72 cases = 6.3) (Duke, 1978, 1979). According to Rutger (1981), fertile soils are desired, with pH between 5 and 7.5. Rice is a tropical, subtropical and warm temperate crop, growing best where summer temperatures of 24–25°C prevail and in full sun. Rice grows as far north in Japan as 42°N and as far south in Queensland as 23°S. On the south side of the Himalayas rice is grown to 2,400 m. Rice mostly cultured on the humid coastal lowlands and deltas of the world. Growth arrested below 10°C; rice exhibits little or no frost tolerance. Temperatures of 0.5 to 5°C are lethal after 24 hours. Aquatic rice may require a dependable supply of fresh, slowly moving water, at temperature of 21–29°C. If rainfall is less than 125 cm annually, irrigation is used to make up deficit. Rice is said to require the equivalent of 8–10 dm during its growing period. Crop is salt tolerant at some stages of growth; during germination but not seedling stages rice has even been grown to reclaim salty soils. Terrain should be level enough to permit flooding, yet sloped enough to drain readily. Soil should be of a fine texture that holds water or should have a subsoil which holds water with little seepage. Friable loam overlying heavy clay, as in many coastal and delta areas, is ideal (Reed, 1976). Although most rice cvs are shortday, there are photosensitive and long day cvs.


Rice should be planted on a smooth seedbed. In United States rice is seeded in spring at rate of 101–123 kg/ha when drilled and 130–225 kg/ha when broadcast; on virgin land, 140–145 kg/ha. This will give 80–300 plants/m2 0.1 sq. m. Cover seed 3.7–5 cm, or broadcast in water with airplane. In some countries (as India, Malaya, Philippines, China, Japan, and Spain), rice is transplanted into fields when 25 cm high, spaced 10–20 cm apart in 20–30 cm rows. Thirty-five laborers can plant 1 ha/day. Plant in very low water and then increase depth. Transplanting makes better use of limited land areas. Tipar (Upland) culture is still found in Sumatra, Thailand, Borneo, and the Philippines. It represents a primitive kind of culture and is of slight overall importance. Rice is sown 3–4 cm deep in holes 15 cm apart on hillsides where no irrigation is possible. Fields are worked as corn fields; crop rotation is practiced with bananas or sugar cane; yields are small. Continuous rice culture depletes soil nutrition and lowers yield. Rotations with soybeans, grain sorghums or small grains, vetch, safflower, field beans, burclover, horsebeans, bananas, sugarcane, cotton, lespedeza, or corn, have been used. Nitrogen to 90 kg/ha was found to increase yields; beyond that no further increase. Potash and phosphorus are used only on the basis of soil tests. All phosphorus and potassium and some nitrogen should be applied at time of seeding; the rest of the nitrogen at mid growing season as a top-dressing. Flood soon afterwards to eliminate weeds. Other fertilizers which are used; as rice straw, rice ash, stable manure, buffalo dung, green manure, fish guano, fish meal, natural manure, and human feces (Reed, 1976).


From planting to harvest varies: 4 months in Italy, 6 months in monsoon regions of Asia, and 135 days for some cvs in the US. In the US, rice is harvested directly with self-propelled combines and dried artificially before storing or milling. If rice is cut, swathed and threshed from windrow, the harvesting should be done when the seed moisture is 12% or less. In unmechanized societies, the panicles of rice seed are harvested with knives or scythes. Sheaths are dried in the sun, and threshing is done with horses, in wooden troughs or with flails.

Yields and Economics

The world low production yield figure for rice in 1979 was 500 kg/ha in French Guiana, the international production was 2,615 kg/ha, and the world high production yield was 7,000 kg/ha in Gabon (FAO, 1980a). Highest experimental yields of rice exceed 12 MT. Rice straw is usually calculated as about equal production in dwarf varieties, two times production in conventional varieties. Rice chaff is figured at 0.25 times production. The highest phytomass figure I have to date for rice is 40 MT/ha/yr, which assumes 365 days a year of rice production (Duke, 1982a). Yields vary widely: United States average 4 MT/ha; India, Indochina, Malaya, Philippines, 1–1.5 MT/ha; Java, Thailand, Madagascar, 1.5–2.5 MT/ha; Egypt, Brazil, China, Japan, 2.5–3.5 MT/ha; Spain, Italy, 3.5–4.5 MT/ha. CIAT (1978) has reported yields exceeding 10 MT/ha. World production of rice was 197 million MT, excluding Communist Asia. Producers in order are: China, Indian Union, Pakistan, Japan, Thailand, Indochina, Java, and Burma. Ninety-five percent of the world's rice production is in the Orient, where per capita consumption is 100–200 kg annually. From 1970–1977, US farmers received 11.37 to 30.35 per quintal (100 kg) of paddy, prices highly dependent on Asian production. Farm value of the US crop has averaged $1 billion annually for this period (Rutger, 1981). Rice is grown on ca 1 million ha per year with yields ca 5 MT/ha, more than double the world average yield of 2.4 MT/ha (Rutger and Grant, 1980).


According to the phytomass files (Duke, 1981b), annual productivity ranges up to 40 MT/ha. Energy output/input ratios for US rice range from 1.03 to 1.76, compared to 3.36 or higher for developing countries. Energy return per human labor hour is high in the US, ranging from 1,600,000 to 3,200,000 Btu/hr compared to 48,000–60,000 Btu/hr in the Philippines. Irrigation at 20–40% of total energy input is the largest single production in US rice production (Rutger, 1981). Rice residues are often viewed for their energy potential. Rice yields break down as follows: 20% hulls, 10% bran, 3% polishings, 1.17% broken rice, and 50–66% polished rice. Nutritional values of all these can be found in Gohl (1981). Yoshida (1977, in Ecophysiology of Tropical Crops, Academic Press) presents data suggesting roughly that where one crop of rice is grown a year (temperate regions), annual productivity is about 7 MT/ha, but closer to 11 for two crops, 16 for 3 crops, and 24 for 4 crops (tropical Philippines). Yields under various configurations are cited by Yoshida. Duke et al. (1975) give the high energetic value to the rice straw of 400,000,000 BTU/ha, equivalent to ca 67 barrels of oil per hectare. Rice has a relatively low annual productivity. Highest yields are close to 13 MT paddy/ha in Australia. The maximum yield reported from Northern Australia is equivalent to 21 MT organic matter/ha/yr. The average for New South Wales is equivalent to 15 MT/ha/yr. Westlake (1963) explained that high figures of 41 MT/ha/yr in the Belgian Congo reflected the total plant, continuous cultivation, and 4.1 harvests/yr. The actual organic production of one harvest was equivalent to 9.9 MT/ha. It must be remembered that Westlake's figures usually include below-ground corrections also. Usually, there are two types of rice residue considered in biomass budgets, the rice straw, usually left in the field or even burned, and the chaff, usually generating waste disposal problems at the rice mill. Rice straw is usually estimated at two times yield figures. Han and Anderson (1974) gave figures indicating that for the nearly 200,000,000 MT rice paddy produced in 1970 in the world, there were nearly 400,000,000 MT straw. Studies in Colombia (CIAT, 1978) showed that 42.1% of the dry matter was containe in the grain in 'IR22', 50% in 'CICA 8'. The ratio of grain for 'CICA 8' was 0.96, for lR22, 0.72. Thus, for the highly derived dwarf varieties, a harvest ratio of 1:1 grain:straw seems to prevail, but with land races the ratio is closer to 1:2. NAS (1977a) gives the residue coefficient of paddy as 0.38–1.25. (Residue coefficient is the ratio of the weight of DM of residue to recorded harvested weight at field moisture. Rice chaff is usually figured at about 10–20% of production, but NAS (1977a) states that rice hulls amount to 20–30% of total residue, which would convert to 20–60% of production. I am more comfortable with the 20% conversion factor (Duke, 1982a). The harvest index (HI) of cereals in general is ca 0.36, meaning that 64% of total above ground crop production is residues at least 1/3 of which should be left in the field. The HI of 'Prior' barley ranged from 0.48 to 0.41 with increasing N fertilizer levels. Wheat HI usually runs ca 0.30 to 0.35. Rice often has a high HI, while grain sorghum generally has a low HI. The "Green Revolution" cereals with short straw and high grain yields have relatively high HI. The estimated cost of ethanol and reethanol from cereal grains is $0.35 and $0.16 per liter; the overall energy efficiency, i.e. the ratio of the energy value of the gross liquid fuel output to the total energy inputs including feedstocks is 0.34 for ethanol and 0.40 for reethanol. For each ton of ethanol produced from distiller's residue, valued in the US as animal feed (Stewart et al, 1979). Han and Anderson (1974) show data suggesting that the straw to grain ratio is 1:2, for each kg grain there should be 2 kg straw. They cite Asian production of rice at ca 175 million MT, straw at ca 350 million MT in 1970. US rice production is highly mechanized, with ca 20 man-hours labor/ha compared to ca 800 man-hours in LDC'S. The energy return is 400,000–800,000 kcal/hr in the US, ca 12,000–15,000 kcal/hr in the Philippines. Under the LDC conditions energy output/input ratios are quite high, perhaps 3–17. In the US, the ratios reported by Rutger and Grant run closer to 1, rice being an energy intensive crop in the US, highly mechanized, fertilized, and irrigated. For example, Arkansas rice yields of 4,742 kg/ha, energetically equivalent to ca 14,000,000 kcal/ha required ca 12,500,000 kcal/ha for production, roughly 700,000 for machinery, 900,000 for gasoline, 2,300,000 for diesel, 85,000 for electricity, 2,000,000 for N, 50,000 for K2O, 20,000 for Zn, 450,000 for propanil, 290,000 for molinate, 110,000 for 2,4,5T, 95,000 for insecticide, 625,000 for seed, 3,800,000 for irrigation, 1,000,000 for drying, 110,000 for transportation. Rutger and Grant (1980) give more details for Louisiana yields of 4,114 kg/ha, Mississippi delta yields of 4,484, and Texas Gulf Coast yields of 5,235 kg/ha (output/input ratio only 1.17).

Biotic Factors

Rice is self-pollinating with some cross-pollination. Rice is attacked by a great number of fungal diseases, especially since it is grown in wet or very humid conditions, near very wet soil. Some of the fungi include: Achlya americana, A. flagellata, A. prolifera, Acrocylindrium oryzae, Alternaria oryzae, A. tenuis, Ascochtya leptospora, A. oryzae, Aspergillus niger, A. oryzae, A. tamarii, Balansia oryzae, Brachysporium oryzae, Cephalosporium oryzae, Cercospora oryzae, Chaetomium bostrychodes, C. brasiliensis, C. indicum, Chaetophoma oryzae, Cladosporium herbarum, C. miyakei, C. spaerospermum, Cochliobolus heterostrophus, C. miyabeanus, C. stenophilus, Coniothyrium oryzae, Corticium centrifugum, C. sasakii, C. solani, Curvularia affinis, C. fallax, C. geniculata, C. inaequalis, C. lunata, C. pallenscens, C. penniseti, C. spicifera, C. tuberculata, C. verruculosa, Dactylaria oryzae, Dinemasporium oryzae, Diplodiella oryzae, Ectostroma oryzae, Entyloma oryzae, Ephelis oryzae, E. pallida, Epicoccum hyalodes, E. neglectum, Fusarium annulatum, F. arthrosporioides, F. decemcellulare, F. equiseti, F. fujikuroi, F. graminearum, F. heterosporum, F. kuhnii, F. moniliforme, F. reticulatum, F. scirpi, F. semitectum, Geotrichum candidum, Gibberella fujikuroi,G. moniliformis, G. saubinetti, G. zeae, Graphium stilboideum, Haplographium chlorocephalum, Helicoceras nymphaerum, H. oryzae, Helminthosporium avenae, H. hawaiiense, H. oryzae, H. rostratum, H. sigmoideum, H. tetramerum, H. turcicum, Hendersonia oryzae, Heterosporium avenae, H. echinulatum, Hypochnus centrifugus, H. sasakii, Koorchaloma madreeya, K. lomella var. oryzae, Leptosphaeria culmicola, L. culmifraga, L. iwamotii, L. michotii, L. oryzina, L. salvinii, Linocarpon cariglumarum, Melanospora zamiae, Metasphaeria albescens, M. cattanei, M. oryzae, M. oryzae-sativae, Microspire dasulfuricans, Monascus purpureus, Mucor varians, Mycosphaerella danubialis, M. malinverniana, M. oryzae, M. shimadae, M. shirsiana, M. tulasnei, Myrothecium indicum, M. oryzae, M. striatisporum, M. verrucaria, Nectria bolbophyllii, N. zeae, Neovassia barclayana, N. horrida, Nigrospora oidium, N. oryzae,,N. padwickii, N. sphaerica, Ophiobolus graminis, O. herpotrichus, O. miyabeanus, O. oryzae, O. oryzinus, Pellicularia sasakii, Penicillium citreoviride, P. vermiculatum, Periconia byssoides, P. digitata, P. minutissima, P. pulla, Pestalotiopsis disseminata, Pestalozzia oryzae, Phaeoseptoria oryzae, Phaeosphaeria oryzae, Phitomyces chartarum, Phoma glumarum, P. glumicola., P. necatrix, P. oryzae, Phyllosticta glumarum, P. japonica, P. miurai, P. oryzae, P. oryzina, Phytophthora macrospora, Piptocephalis cylindrospora, Pleosphaerulina oryzae, Pleospora herbarum, Protoascus colorans, Pyricularia grisea, P. oryzae, Puccinia graminis, Pyrenochaeta nipponica, P. oryzae, Pythium aphanidermatium, P. arrhenomanes, P. debaryanum, P. dissotocum, P. echinocarpum, P. gracile, P. graminicola, P. hemmianum, P. monospermum, P. nagaii, P. oryzae, P. rostratum, P. ultimum, Ramularia oryzae, Rhizoctonia batataicola, R. microsclerotia, R. oryzae, R. solani, Rhizopus nigricans, Rhynchosporium oryzae, Saprolegnia diclina, Sclerophthora macrospora, S. oryzae, Sclerotinia oryzae-sativae, S. sclerotiorum, Sclerotium funigatum, S. hydrophilum, S. oryzae, S. oryzae-sativae, S. rolfsii, S. sphaeroides, Septoria oryzae, S. poae, Spegazzinia tessatthra, Sphaeronema oryzae, Sphaeropsis oryzae, S. vaginarum, Sphaerulina oryzina, Sporidesmium bakeri, Sporotrichum angulatum, Stagonospora oryzae, Stauronema sacchari, Syncephalastrium racemosum, Syncephalis cornus, Teichosporella oryzae, Thielavia angulata, Tilletia horrida, Trematosphaerella oryzae, Trichoconia caudata, T, indica, T. padwicki, Trichoderma viride, Trichonis padwicki, Trichothecium roseum, Ustilaginoidea oryzae, U. virens, Ustilago avenae, Vermicularia oryzae. Rice is also attacked by the algal weed Chara, and by the parasitic flowering plants of Striga asiatica, S. euphrasioides, S. hermonthica, S. lutea, and S. senegalensis. Following bacteria have been isolated from rice: Bacillus prodigiosus, Bacterium oryzae, Pseudomonas oryzae, Xanthomonas itoana, X. oryzae, X. oryzicola, X. translucens. Several virus infections cause serious damage to rice: Hoia blanca (very serious), Leaf-gall virus, Stripe virus, Tungro virus, Yellow dwarf virus. Also, since rice grows in wet soil, it is afflicted with a great many nematodes. The following is a world list: Aphelenchoides besseyi, A. bicaudatus, A. parietinus, A. oryzae, Boleodoroides oryzae, Chronogaster typicus, Criconemella onoensis, C. curvata, C. rustica, Ditylenchus angustus, D. intermedius, Dorylaimellus virginianus, Dolichodorus sp., Galophinema lenorum, Helicotylenchus cavenessi, H. multicinctus, H. nannus, H. pesudorobustus, H. retusus, Hemicriconemoides cocophillus, Hemicycliophora paradoxa, Heterodera elachista, H. oryzicola, H. oryzae, H. schachtii, Hirschmanniella nana, H. oryzae, H. spinicaudata, Hoplalaimus galeatus, Lenochium oryzae, Meloidogyne exigua, M. arenaria, M. graminicola, M. incognita, M. incognita acrita, M. javanica, Paralongidorus beryllus, Paraphelenchus pseudoparietinus, Peltamigratus nigeriensis, Pratylenchus brachyurus, P. coffeae, P. goodevi, P. neglectus, P. penetrans, P. pratensis, P. thornei, P. zeae, Psilenchus hilarulus, Pterygorhabditis pakistanensis, Radopholus lavaberi, R. mucronatus, R. oryzae, Scutellonema clathricaudatum, Tylenchorhynchus annulatus, T. clavicaudatus, T. elegans, Xiphinema campinense, X. ifacola, X. indicum, X. parasetariae. The major seed-borne fungal diseases are Black smut or bunt (Neovossia horrida), False or green smut (Ustilaginoides virens), Minute leaf and foot rot (Nigrospora), scab (Gibberella zeae), and Bakanie disease and foot rot (G. fujikuroi). The insects which are known to be pests to rice are: Acrida turrita, Acrotylus insubricus, Chilo suppressalis, Cofana spectra, Cyrtacanthacris tatarica, Diacrysia obliqua, Dicladispa armigera, Echinocnemus oryzae, Hydrelia griseola (Rice leaf miner), Locusta migratoria, Macrosiphum avenae (M. granarium), Nizaga simplex, Nymphula depunctalis, Oxya velox, Pelopidas mathias, P. thrax, Pseudauletes sp., Rhopalosiphum rufiabdominalis mauritia, Trigonotylus ruficornis, and Tryporyza incertulas. Rice weevil (Sitophilus oryzae) attacks seed in storage. IRRI reports that "natural enemies control most rice insect pests. For every 200 eggs a brown planthopper lays in a field of susceptible rice variety, only five hoppers survive to reproduce as adults. For green leafhoppers, only eight reach adulthood. Predators, parasites, and pathogens normally kill 95–99% of the potential hoppers—in the absence of insecticides." (IRRI reporter 1/82 Mar 1982). Martinez and Catling (1980) identified 7 N-fixing algae on leaves and/or nodal roots or Oryza glaberrima in water 1.6 m deep; Anabaena torulosa, A. vaginicola, Cylindrospermum licheniforme, Gloeocapsa quaternata, Gloeotrichia natans, Hapalosiphon stuhlmanii, and Nostoc sp.

Chemical Analysis of Biomass Fuels

Analysing 62 kinds of biomass for heating value, Jenkins and Ebeling (1985) reported a spread of 16.14 to 15.27MJ/kg, compared to 13.76 for weathered rice straw to 23.28 MJ/kg for prune pits. On a % DM basis, the hulls contained 65.47% volatiles, 17.86 % ash, 16.67% fixed carbon, 40.96% C, 4.30% H, 35.86% O, 0.40% N, 0.02% S, 0.12% Cl, and undetermined residue.

Analysing 62 kinds of biomass for heating value, Jenkins and Ebeling (1985) reported a spread of 14.56 to 13.76 MJ/kg, compared to 13.76 for weathered rice straw to 23.28 MJ/kg for prune pits. On a % DM basis, the straw (weathered) contain 62.31% volatiles, 24.36% ash, 13.33% fixed carbon, 34.60% C, 3.93% H, 35.38% O, 0.93% N, 0.16% S, and undetermined residue.

Analysing 62 kinds of biomass for heating value, Jenkins and Ebeling (1985) reported a spread of 16.28 to 15.34 MJ/kg, compared to 13.76 for weathered rice straw to 23.28 MJ/kg for prune pits. On a % DM basis, the straw (fall), contained 69.33% volatiles, 13.42% ash, 17.25% fixed carbon, 41.78% C, 4.63% H, 36.57% O, 0.70% N, 0.08% S, 0.34% Cl, and undetermined residue.


Complete list of references for Duke, Handbook of Energy Crops
Last update Wednesday, January 7, 1998 by aw