Survey of taro varieties and their use in selected areas of Cambodia

Taro seed bank

The farmers always keep the small tubers (corm) for the next growing season, and the techniques for storing the tubers vary from farmer to farmer according to their experience. Around 54 % of farmers keep the small tubers under their house under a layer of rice straw for the next season's planting. An alternative technique is to keep the roots in the field so that they can germinate after the first rain of the season. Another method involves placing the tubers near a water source in sandy soil (Table 5).

Seeds for planting

Two common methods that farmers are using are direct and indirect planting. For the direct method, farmers plant tuber seeds directly in the field and the indirect method involves taking the tubers to a nursery and then transplanting the young plant in the plots. Most farmers (89%) preferred indirect planting, as the survival rate is much higher, while 11% of the farmers practiced direct planting because it requires less labour.

Soil preparation and planting

 

The soil is generally plowed twice then harrowed once. After the first plowing, fertilizer is applied and the ploughed soil left to sun-dry for one week before the second ploughing. Cultivation starts in the late dry season and early rainy season, during April to July. The small plants from the nursery at an age of 15 days are planted with a distance of 40-54cm (Figure 6) between rows. The tuber should be completely covered and water supplied at this stage. However, the distance between rows can be smaller or bigger according to the variety of the taro and experience of farmers in their location.

Management and fertilization

Taro cannot grow fast unless water supply is optimum, because taro needs a lot of water. One month after planting, the farmers pump water to swamp the taro field so that the soil is always wet. During the first 2-3 months, farmers water 2 or 3 times per day. Fertilizer is used during the soil preparation, and more is applied after planting. The use of fertilizer was dependent on the soil fertility and the management. In Takeo Province 48% of the farmers applied fertilizers and the 52% who did not believe that as taro is planted in low-lying soils or on the bottom of canals or ponds, organic materials are available to plants through rain wash. In Pursat 67% of farmers used fertilizer in order to increase yields (Table 6). Beside watering and fertilizing, taro was weeded and the soil around the plant loosened at the age of 1.5 months.

Harvesting

Taro is harvested between December and January. The tuber yield was different between locations due to the different management and fertilization practices. The average tuber yield was 4.5-6 tonnes ha^-1 for all interviewed sites (Figure 7). The average of petiole and leaf reported by interviewed farmers was 5-8.5 tons ha^-1 (Figure 7). The price of root was 600 - 1000 Riel (0.15-0.25 $) per kg depending on the quality of the tubers and season. The petioles are rarely sold, but the price is around 100-200 Riel (0.025-0.049$) per kg. Generally, leaves are thrown away or sometimes fed to pigs, and on a few occasions sold at a price of 100 Riel per kg.

Uses of taro for humans and animals

The tubers of taro are used for human food, particularly during the period when there is a shortage of rice, and they are not generally used as animal feed. However, some farmers do feed poor quality tubers to pigs. Leaves have been used for human food and feeding to pigs, but are never used for poultry. Furthermore, petioles are fed to pigs after boiling with broken rice or rice bran, but are also discarded at harvesting time. Some farmers use the tubers as a vegetable by cooking with fish or snail to produce a soup.

Twenty two % of the interviewed farmers in Takeo fed taro to their pigs while 78% did not use it. In Pursat 63 % used taro for their pigs while 37% did not use it. This could indicate that taro has been used for pigs for generations, although there is no data to show the potential or benefit of feeding taro to growing pigs. Interviewed farmers reported on their experiences of using taro for pigs; one observation reported was that their pigs prefer taro after boiling with rice bran or broken rice and they also commented on the availability of taro on their farms. Generally the farmers believe that taro has good nutrient properties for animals and also can reduce the amount of broken rice or rice bran in pig diets.

Reasons for not using taro stems and leaves for pig feed

Most of the interviewed farmers did not use taro petiole and leaf for their pigs (Table 9), and the reasons given were that they cause itching (31%), lack of knowledge (30.5%) and that they had never tried them (20.7 %) (Table 10). The use of taro for pigs is not widespread because farmers lack the knowledge for the use and processing of taro and the potential benefits of feeding it to pigs.

Problems of oxalate and itching in taro

In practice, some farmers feed taro to their pigs after boiling with broken rice. Sometimes they observed that pigs still have a problem with itching, but not as much as when consuming the fresh material. Around 44.4 % of farmers thought that there was no danger with feeding taro, while 55.6 % observed that their pigs seemed to have itching, but this did not affect their health. It may be that there are lower intakes when pigs seem to suffer from itching.

The whole taro plant contains oxalic acid that can result in itching, but the amount may depend on the parts of the plant, and 77.4 % of the interviewed farmers mentioned that the petioles have highest potential to cause itching, followed by the leaves and then the tubers (Table 11). However, their assessment was based on their previous experience of holding different parts of the plant.

Local methods for reducing oxalate or itching

As many as 96% the interviewed farmers boiled taro before feeding it to their pigs. Seventeen % of the farmers used sugar palm syrup to reduce itching after boiling, while 2% used salt, frying or sun drying. The most common method to reduce the oxalate or itching is thus boiling, but this takes time and firewood.

Locally available resources for pigs

In Cambodia, farmers in rural areas raise pigs as a source of savings and for ceremonial purposes. Pigs are fed on rice bran, broken rice, kitchen waste, water spinach, water hyacinth and some vegetables. However, some farmers used concentrate feed as supplement. Almost all (90.8%) of the interviewed farmers use rice bran as basal feed for their pigs, 50% fed kitchen waste and 72% fed water spinach as supplement (Table 13). However few farmers used concentrate for their pig due to the poor accessibility, but did not provide data on profits because they do not keep records.

Discussion

Taro is a wet land crop that is cultivated in most regions in Cambodia. There are two kinds of taro, the water taro and land taro. This survey is agreement with Florida ID: (899) that reported that Taro falls into two main groups: Wetland taros and upland taros. Taro is a tropical plant grown primarily as a vegetable food for its edible corm, and secondarily as a leaf vegetable. Its flowers are also eaten. The Chouk and Sla taro varieties can be considered as "taro cocoyam" or "old cocoyam". Its scientific name is "Colocasia esculenta" and the binomial name is "Colocasia esculenta (L) Schott" (Wikipedia 2006).

The Chouk and Sla taro varieties are quite similar in DM and CP (Table 4), but these values are higher than the values of FAO (1993) for Colocasia esculenta, and also higher than the values for Xanthosoma reported by Baruah (2002), Leterme et al (2005), Agwunobi et al (2004) and Rodriguez et al (2006). However, these differences can be the result of differences in fertilizer application, age of plant, and sampling procedure.

The two varieties are short term varieties (6-8 months), which are suited to the climate of Cambodia, with two main seasons, a six months dry and six months rainy season. Farmers can start planting in the late dry season and early rainy season, from April to July and can harvest from December to January. During harvesting, which is in the dry season, farmers stop applying water and then collect the tubers for sale and home consumption. The tuber yield was found to be different between locations due to differences in the management and fertilization. The average tuber yield was 4.5-6 tons ha^-1 for all sites, which is lower than the results of Salam et al (2003), who reported that the highest biomass yield of corms was 7.20 tons ha^-1, while Susan et al (2003) reported that the total biomass yield of corms ranged from 7.64 to 9.25 tons ha^-1. The average yield of stem and leaf reported by the interviewed farmers was 5.0-8.5 tons ha^-1. The low yield of stem and leaf may be an effect of the way of estimating yield, because farmers weighed only 1m² of stem and leaf, and then using this value calculated yield for the whole area of their lands. However, it was not only very difficult to separate petiole and leaf yields but also very difficult to get reliable whole petiole and leaves yield, because it would be affected by harvesting method.

The use of taro for pigs is not widespread, because farmers lack the knowledge of how to use and process of taro, and also of the benefits of taro for pigs. However, 96% of farmers fed taro to their pigs after boiling with broken rice. Sometimes they observed that the pigs still had a problem with itching, but not as severe as after feeding fresh taro. This point was also made by Miller (1929), who said that the stems are peeled and boiled before being fed to livestock, particularly pigs. Boiling is the most suitable method for the farmers in Cambodia, because in practice they always boil all feeds before giving them to their pigs, and also because they are worried about itching. However the growth performance of pig that fed the boiled petiole and leaves with broken rice are seemed to be better, but there are no data on this. Agwunobi et al (2002) reported that boiling reduced (p<0.05) the amounts of the antinutritional factors in taro cocoyam cormels, and that feed intake, weight gain and feed efficiency for the diets containing boiled taro cocoyam cormels were better than for non-boiling and sun-drying.

Conclusions

• Two varieties of taro, Chouk and Sla, are commonly cultivated, and Trav Prey (wild taro) grows naturally in Pursat and Takeo provinces. Chouk and Sla taro are short-term varieties and can be harvested 5-8 months after planting. Taro is considered to be a good vegetable crop that is planted nearby the houses in the two selected provinces of Cambodia.

• Tubers of taro are used for human consumption, while stems and leaves are not widely used for animal feeding. The main reasons for not using them are itching, and lack of knowledge.

• The average tuber yield was 4.5-6 tons ha^-1 for all sites, and the average petiole and leaf yield reported by interviewed farmers was 5.0-8.5 tons ha^-1

• Farmers considered stems to be most likely to cause itching, followed by leaves then root. However the effect can be reduced by boiling, frying, ensiling and sun-drying. Both salt and sugar palm syrup can be used for ensiling.

Acknowledgments

The present survey is part of a study on ensiled taro (Colocasia esculenta) leaves in diets of local crossbred pigs in Cambodia, supported by the MEKARN project, financed by Sida-SAREC. The authors express their gratitude to the PRA team of CelAgrid for help in collecting the data, and also thank the authorities and farmers in Pursat and Takeo provinces who spent time with the team during the interviews.

References

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Salam MA, Patwary M M A, Rahman MM, Hossain MD and Saifullah M 2003.Profitability of Mukhi kchu (Colocasia esculenta) production as influenced by different doses and time of application of urea and muriate of potash. Asian Journal of Plant Sciences 2 (2): 233-236. ISSN 1682-3947.

Susan C, Miyasaka R M, Ogoshi GY, Tsuji L and Kodani S 2003. Site and planting date effects on Taro growth: comparison with Ariod model prediction. Agron. J. 95:545-557.

Wikipedia, 2006. Taro, the free encyclopedia. http://en.wikipedia.org/wiki/Taro

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