Rayong, Thailand; stake position in wet and dry season; Average three years;171-11
Dak Nong, July 2007; serious erosion in cassava erosion control trial
Dong Rang, Luong Son, Hao Binh; after seven years, farmer practice vs. vetiver hedgerows, Aug 2001.
Session 4.1 Technologies and Issues in small-holder Cassava cultivation -form planting to harvesting by Howeler CIAT
Agronomic Practices for Smallholder Cassava Farmers Reinhardt Howeler and Tin Maung Aye Accra, October, 2010
Cassava yields can be increased by: <ul><li>Planting of new varieties with higher yield potential, higher dry matter content, and pest/disease resistance </li></ul><ul><li>Improved crop management, especially soil fertility management </li></ul>These two aspects are often of equal importance in increasing yields
Cassava yields in Thailand as affected by area under new varieties, fertilizer use and cassava root price 1990-2010 18.78 2,777 221 68.9 2010 22.68 1,668 229 70.3 2009 21.26 2,071 204 71.8 2008 22.92 1,753 197 79.9 94.6 2007 21.09 1,338 189 82.1 95.0 2006 19.30 1,061 172 56.2 97.9 2003 17.07 1,287 175 66.4 91.1 2002 16.86 850 91.1 2000 15.49 1,030 86.9 1999 14.93 1,780 80.8 1998 14.16 1,390 39.0 1996 13.02 1,620 23.8 1995 14.03 3.5 1992 13.91 1.1 1990 Average cassava yield (t/ha) Cassava root price (baht/t) Quantity of chem. fertil. applied (kg/ha) Cassava area receiving chem. fertilizers (%) Cassava area planted to new varieties (%) Year of harvest
Trend in the percent of the total cassava area planted to new varieties and the percent yield increase in Thailand from 1990 to 2010 (2003 = 100%)
How can farmers increase their cassava yields in a sustainable way?
To obtain high yields of cassava <ul><li>Plant high-yielding and well-adapted varieties </li></ul><ul><li>Use improved agronomic practices, such as: </li></ul><ul><li>Correct time of planting and harvesting </li></ul><ul><li>Use healthy and good-quality planting material </li></ul><ul><li>Plant at the most appropriate planting distance </li></ul><ul><li>Use adequate and well-balanced fertilization </li></ul><ul><li>Have adequate and timely weed control </li></ul><ul><li>Use effective erosion control practices (if needed) </li></ul><ul><li>Use integrated pest and disease management (if necessary) </li></ul>
What is the best time to plant and to harvest cassava?
Cassava root yield (t/ha) Effect of month of planting and age at harvest on root yields of cassava cultivars Rayong 2 and Rayong 3 planted at Rayong Field Crops Research Center in 1983-1985. Source: Field Crops Research Institute, Annual Report 1986. 12 months 10 months 8 months 6 months Age at harvest Rayong 2 (1984/85) 0 20 40 60 30 50 10 0 20 40 May June July Aug Sept Oct Rayong 3 (1983/84 and 1984/85) Month of planting 30 10
Response to N in Nanning, China ..to P and K in Xieng Khouang, Laos ..to K in Kampong Cham, Cambodia Adequate and well-balanced fertilization depends on the crop and the soil
Effect of annual applications of various levels of N, P and K on the root yield and starch content of two cassava varieties grown in Hung Loc Center in Vietnam in 2007/08 (18 th crop cycle)
After 31 years of continuous cropping in Khon Kaen, Thailand; without K in front, with well-balanced fertilizers in the back
In most soils in Asia, cassava needs Or, a fertilizer ratio of 10-5-15 - Potassium - Nitrogen - Phosphorus
Be aware! Cassava can cause serious soil erosion, even on gentle slopes….. … .if large amounts of run-off water accumulate in natural drainage ways
Soil loss by erosion can be a serious problem when the crop is planted on steep slopes
Fertilizer application improves canopy development and is therefore one of the most effective ways to reduce runoff and erosion
Months after planting Accumulative dry soil loss (t/ha) Effect of various soil/crop management practices on the accumulative dry soil loss by erosion at the Royal Project site in Pluak Daeng, Rayong, Thailand during a ten month growth cycle of cassava in 1990/91. 0 200 400 J J A S O N D J F M A M Rainfall (mm) 0 5 10 15 20 25 30 2 4 6 8 10 0 12 no fertilizers up-down ridging 1 plowing, 1 discing cassava harvester peanut intercrop closer spacing no tillage contour ridging
Contour hedgerows of vetiver grass (in back) are also very effective in reducing erosion
Trend in relative yield and relative soil loss by erosion when cassava was planted with contour hedgerows of vetiver grass, Leucaena leucocephala or Gliricidia sepium in comparison with the check without hedgerows during six consecutive years in Hung Loc Agric. Research Center in South Vietnam from 1997 to 2003. check without hedgerows Relative yield or soil loss (%) Year after planting hedgerows 0 20 40 60 80 100 120 140 160 180 200 1 2 3 4 5 6 7 Yield Soil loss Vetiver = Leucaena = Gliricidia =
Seven years after planting contour hedgerows of vetiver grass in Hoa Binh, these had caused the formation of natural terraces which markedly reduced erosion … .and after ten years in Khieu Thung, Phu Tho, Vietnam
Weed Control Cassava is a weak competitor, and its growth and yield are seriously reduced by weed competition Cassava fields need to be weeded at least 2-3 times during the crop cycle, usually at 1, 2 and 3 months after planting
<ul><li>Simple tools such as digging stick, hoe, or narrow spade </li></ul>Root harvest <ul><li>Simple harvesting tools </li></ul>
The accidental introduction of the mealybug Phenacoccus manihoti into Thailand in 2008 has had a devastating effect on the whole cassava sector … and a new witches broom-like disease in Vietnam
Integrated Pest and Disease Management in Cassava in Asia <ul><li>Plant pest and disease resistant varieties </li></ul><ul><li>Treat planting material with insecticides/fungicides before planting </li></ul><ul><li>Burn all pest or disease–infected crop residues after harvest </li></ul><ul><li>Do not spray pesticides on the crop, but let biological control agents, such as the mealybug parasitoid Anagyrus lopezi, control the pest </li></ul>Anagyrus lopezi
While many experiments have shown ways to increase yields, farmers seldom adopt improved agronomic practices, because: - they may not know the best and most efficient production practices - some recommended practices are not effective under the farmer’s particular conditions, or do not fit well in their farming systems - the recommended practices are too costly or too labor-intensive - they do not provide short-term economic benefits
To achieve impact through the adoption of improved practices <ul><li>Farmers must be directly involved in the development of new varieties and improved agronomic practices that are most suitable and cost-effective for their own conditions </li></ul><ul><li>Researchers and extensionists should help farmers to conduct simple Farmer Participatory Research (FPR) trials on their own fields </li></ul><ul><li>These FPR trials should expand rapidly to as many villages and involve as many farmers as possible </li></ul><ul><li>Farmers are most likely to adopt those practices that other farmers have already tested , selected and adopted, i.e. farmer-to-farmer extension is an effective tool to achieve widespread adoption </li></ul>
Farmer Participation and Decision Making Problem diagnosis with farmers Researchers show many technology options in FPR demonstration plots Feed back to research Adopt and disseminate Farmers adapt new practice and scale-up to production field Farmers retest and reselect Farmers select best options Farmers evaluate and select most suitable options/practices Farmers test options in FPR trials on their own fields Farmer Participatory Research (FPR) approach
Using RRAs, we l earn ed about farmers’ conditions, needs and concerns
We set out demonstration plots and let farmers evaluate the various options and select those that seem most promising
Farmers conduct FPR erosion control trials in their own fields
… .where they can clearly see that some simple practices can markedly reduce runoff and erosion
Farmers, researchers and extension workers evaluate the treatments in all the FPR trials conducted in the village Field day at time of harvest
After evaluating the trials in the field, farmers discuss the results together to select the best varieties and practices Field day at time of harvest
Thong Nhat commune in North Vietnam in 1998 Serious erosion problems and low yields of cassava and tea The Impact!!
Thong Nhat commune in North Vietnam in 2000 A farmer proudly shows off his “new cassava” field
Figure 1. Average cassava yields of farmers participating in the Nippon Foundation cassava project or of nearby but non-participating farmers, before the project started and at the end of the project. Data are from PRRA census forms collected from 439 households in Thailand and 393 household in Vietnam. For comparison the national average cassava yields in 1999 (before) and 2003 (after) are also shown = Project participants = Non - participants = All country (1999-2003) Before project Before project After project 0 5 10 15 20 25 30 After project 0 5 10 15 20 25 30 Thailand Vietnam Cassava yield (t/ha)
Figure 1. Trend of cassava yields in Africa, Latin America and Asia from 1961 to 2007. Year 20 1960 18 16 14 12 10 8 6 4 2 0 1970 1980 1990 2000 2010 Cassava yield (t/ha) Asia Americas Africa 20 18 16 14 12 10 8 6 4 2 0
Helping farmers to conduct simple FPR trials on their own fields is the best way to achieve adoption of improved varieties and agronomic practices that will increase cassava yields and farmer’s income
Is this going to be the future of our children?
…… .or c an we help cassava farmers improve their livel i hood by producing enough food AND feedstock for starch and biofuel?