Crop Diversification in the Asia-Pacific region - United Nations in ...

There are some advanced techniques used for increasing rice production, decreasingwater use and other material inputs, and making appropriate conditions for diversifyingcrops in rotation with rice, or feeding fish or ducks with insects that inhabit the rice fields.Some of these techniques are described as follows:An Improved Sowing Method for Rice in the Mekong DeltaOut of the 4 million hectares of rice grown, there are more than 3.5 million hectareswhere they apply the broadcasting method (the rest is transplanted) with a very high seedrate of 200-250 kg or even higher. These farmers are now using the row-seeding methodwith the improved IRRI Seeder to replace manual broadcasting. The results from tens ofthousands of hectares in all 12 provinces of the region show that application of the rowseedingmethod can save at least 100-150 kg rice seed/hectare, making better conditions forfeeding fish or ducks in rice fields, decreasing damage by rats and other pests, and with aconcomitant paddy yield increase of up to 20 percent.Use of Very Short Duration Rice Varieties to Reduce Rice Crop Duration in the FieldFrom 1985, the Cuulong Delta Rice Research Institute (CLRRI) has conducted abreeding programme for rice varieties named 'OMCS', which developed short duration typesof less than 90 days. Many such OMCS varieties have been released on a million hectares,not only in the Mekong Delta, but also in the South Central region, while some of them usedin the North are OMCS7 and OMCS96. The results from research and production on a largescale demonstrate that the very short duration rice varieties (80-90 days) can grow and yieldnormally. Many of them can yield nearly 7-8 t/ha with high grain quality and resistance toseveral pests and diseases. Although agro-techniques for these varieties are new to farmers,they prefer to use them to escape from floods in the wet season, from drought and salineintrusion in the dry season, and have the advantage of saving more cropping days for othercrops, or for crop intensification. Attempts are also being made to adopt the seedlingbroadcasting method from China (preparing seedlings for each hill in plastic plates withsmall holes). Adopting this method and using OMCS varieties, it is possible to shorten theduration of the rice crop in the field by 20-25 days.5. PROBLEMS, CONSTRAINTS AND FUTURE OUTLOOKIn each agro-climatic zone, there are certain physical constraints. Generally, themain constraints in mountainous, hilly, and middle elevation terraces are erosion, drought,temperature, and soil degradation. Typhoons, floods, low temperatures and pests; andfloods, drought and pest infestation are the main physical constraints in the North and Southdelta, respectively. However, socio-economic constraints are considered as the challengesfor the whole country. High inputs for crop production and low quality of crop products arethe main problems because of low technology levels applied by many farmers. Credit, postharvesttechnology and lack of proper infrastructure facilities are also constraints for cropdiversification for the development of sustainable agriculture.Viet Nam is trying to overcome the above mentioned constraints for agriculturaldevelopment as well as for crop diversification, in order to meet the requirements ofdomestic consumption and trade. There are long-term as well as short-term programmes inapplying new technologies to improve crop production. National programmes for the152