wrecfsanya

Review of SRI Presentations: 

Review of SRI Presentations Erick Fernandes Cornell University ecf3@cornell.edu Farmer’s SRI field, Madagascar. Yield 12.4 t/ha

Country Presentations: 

Country Presentations 17 Country presentations Africa: 3 Asia: 4 S.E. Asia: 7 Americas: 3 With the exception of Madagascar, all other country reports are based on less than 3 years of data

Elements of SRI: 

Elements of SRI Careful transplanting of young seedlings (8-15 days) 1 or 2 seedlings per hill Alternating flooding and drying during vegetative phase Weeding and aeration Compost application

Total Factor Productivity: 

Total Factor Productivity Yields Labor Soils & Roots Water Seeds Food quality Environmental benefits

Yields: 

Yields ¾ of studies confirm a significant yield advantage in SRI vs conventional rice For yields below 8 t/ha, yield increases due to SRI were between 10-50%. Madagascar reports “super yields” ranging from 17-23 t/ha relative to a national average of <2 t/ha Madagascar data show ~55% fertile tillers (~70% required for very high yields) Yield increases are most frequently observed on farmers’ fields rather than on station

Yields II: 

Yields II Although SRI results in increased yields for both traditional and improved varieties, several studies reported that some varieties respond better to SRI than others. 120-140 day varieties may respond best to SRI. Very short or long duration varieties appear to respond less. Although suggested spacings for SRI vary between 25x25 cm to 35x35 cm, high yields (~13 t/ha) have also been reported at 45x45 cm. There is most likely a significant interaction between variety and spacing.

Labor: 

Labor Most studies report that SRI is more labor demanding than conventional rice. (Three studies reported that SRI required less labor). Extra labor components: land preparation, careful planting of small seedlings, water and weed management)

Soils & Roots: 

Soils & Roots Effect of soil texture is still uncertain It is hypothesized that soil biological factors are very important for SRI synergy. Only 3 studies looked at root volume and root activity or soil microbial dynamics. Relatively little detailed soil data is available. Important for nutrient budgets as yields and nutrient harvests increases.

Compost Pits: 

Compost Pits End of cropping season Start of cropping season Crop residues Cattle manure + urine Legume prunings Grass clippings

Slide11: 

SRI Plants Traditional Rice

Water: 

Water Flooding and draining of water requires good access to and control of water A few studies carried out detailed measurements and report significant water savings relative to conventionally flooded rice. Weed pressure increases with draining and wide spacings. In one study, soil drying and cracking yielded less than continuously moist soil.

Seeds: 

Seeds Most studies reported a significant saving in the amount of seed used to establish the rice field.

Food & Environmental Impacts: 

Food & Environmental Impacts Fewer chemical and pesticide inputs can translate into healthier food Alternate flooding and draining can reduce CH4 emissions but result in significant increases in NOx emissions. The effect of nitrous oxide is ~35x greater than CH4.

Issues to Consider: 

Issues to Consider Better descriptions of the experiments Who is doing what? Metadata Where (georeferenced data sets) To tap into other databases (soils, vegetation) Replication of field trials (on farm, on station) to get a better handle of variability observed Socioeconomic studies to better characterize tradeoffs

Issues to Consider II: 

Issues to Consider II What is special about the sites where we observe SRI yields >10 t/ha? Soils, long-term management, soil biology? Should we have a standard experiment that is conducted at selected sites across the regions?