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1184-The Science behind SRI Practices

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Seminar by Amod K. Thakur (Borlaug Fellow at Cornell University and Senior Scientist at the Directorate of Water Management (ICAR) in Bhubaneswar, Odisha, India) presented at Cornell University on December 6, 2011. (Co-sponsored by the Dept. of Crop and Soil Sciences, International Programs and SRI-Rice)

Seminar by Amod K. Thakur (Borlaug Fellow at Cornell University and Senior Scientist at the Directorate of Water Management (ICAR) in Bhubaneswar, Odisha, India) presented at Cornell University on December 6, 2011. (Co-sponsored by the Dept. of Crop and Soil Sciences, International Programs and SRI-Rice)

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1184-The Science behind SRI Practices

  1. 1. Dr. Amod K. Thakur Directorate of Water Management (ICAR), Bhubaneswar Crop & Soil Sciences Dept. Seminar, Cornell University December 6, 2011r
  2. 2. Facts about Rice…… A Preface  Rice is main source of directly-consumed calories for about half of the world’s population  Rice provides 23% of all calories consumed by world’s population  Rice productivity has stagnated since the mid-80s  It is estimated that by the year 2025, the world’s farmers will need to produce about 60% more rice than at present to meet the food demands of the expected world population at that time (Fageria 2007).
  3. 3. Scarcity of water is acute in the world’s ‘rice bowls’ 1/3rd of the world’s population lives with water scarcity & this proportion will double by 2050
  4. 4. Dual challenges (a) Enhance Food Production (b) Under Water-Scarce Conditions Objective- “More Crop per Drop”
  5. 5. SRI System of Rice Intensification It involves the use of certain management practices which together provide better growing conditions for rice plants, particularly in their root zones, compared with those for plants grown under conventional practices It is a system rather than a technology because it is not a fixed set of practices. While a number of specific practices are basically associated with SRI, these should always be tested and adapted according to local conditions rather than simply adopted.
  6. 6. Practices  Transplanting young seedlings  Minimize time gap between uprooting & transplanting  Transplant seedlings singly rather than in clumps  Wider spacing in square pattern  Keep soil well drained (moist) rather than flooding  Weeding by mechanical weeder (aerate soil)  Organic inputs like compost or mulch (optional)
  7. 7. Impetus for this research: IRRI Rice Today, July-Sept, 2004 Energy for crop growth results from intercepted sunlight, and the amount of light intercepted translates directly into plant growth. High plant density enhances light interception, growth and yield. SRI suffers from poor light interception because of low plant densities, acc. to Sinclair.
  8. 8. Sheehy et al. 2004 FCR 88:1-8 SRI has no inherent advantage over the conventional system
  9. 9. But trials had excessive application of N-fertilizer (180-240 kg N ha-1), causing lodging in some SRI plants (uncommon) Herbicide was used-, so there was no active soil aeration as recommended in SRI practice Comparison was made of yield between 11 SRI plants/m2 (30 x30 cm spacing) with 25 plants/m2 (20 x 20 cm) If 16 or 25 SRI plants would have been used, maybe the results would have been different?
  10. 10. Research question: Whether SRI practices have any effect on the grain yield or not? If so, why? How do SRI practices affect rice plants’ morphology, their physiology, and what are their implications for crop performance?
  11. 11. Methodology Location: Deras Research Farm, Orissa, India DWM (ICAR), India Season: Dry (January-May) 2006, 2007 & 2008 Soil: Aeric Haplaquepts, sandy clay-loam in texture, pH 5.5. Design: RCBD - five replicates Plot sizes: 20 × 10 m2 Variety: Surendra Crop management systems: System of Rice Intensification (SRI) compared with Traditional flooding (TF) using Recommended management practices (RMP) proposed by Central Rice Research Institute
  12. 12. Management practices SRI TF/ RMP Seedling age 10-12 21-25 (in days) Plant spacing 20 x 20 cm 20 x10 cm DWM (ICAR), India and density One seedling /hill Three seedlings /hill Weed control 3 weedings with 3 manual cono-weeder @ 10, weedings @ 10, 20 and 30 DAT 20 and 30 DAT Water AWD after 3 DAD Flooding with 5-6 management during vegetative cm depth of stage water during the vegetative stage Nutrient Organic manure @ 5 t ha-1 management Chemical fertilizers: 80 kg N ha-1, (not a variable) 40 kg P2O5 ha-1, and 40 kg K2O ha-1
  13. 13. Directorate of Water Management, Bhubaneswar, INDIA Morphological Changes with SRI
  14. 14. Root Growth SRI hills had better root development (deeper roots, more dry weight, root volume and root RMP SRI length) than rice crop grown under RMP. Effects of rice management practices on root depth, root dry weight, root volume, and root length at early-ripening stage of development Management Root Root dry Root dry Root Root Root length Root practice depth weight weight volume volume (cm hill-1) density (cm) (g hill-1) (g m-2) (ml hill-1) (ml m-2) (cm-2) SRI 33.5 12.3 306.9 53.6 1340.0 9402.5 2.7 RMP 20.6 5.8 291.8 19.1 955.0 4111.9 1.2 LSD.05 3.5 1.3 NS 4.9 180.1 712.4 0.2
  15. 15. Tillering under SRI The number of tillers per hill significantly increased (by 2 times, up to 34 tillers) in SRI compared to RMP. But the number of tillers per unit area was found not to differ significantly in SRI vs. RMP. Effects of rice management practices on morphological characteristics at early-ripening stage of development Management Plant Culm height Ave. tiller Tiller number Ave. tiller practice height (cm) (cm) number (hill-1) (m-2) perimeter (cm) SRI 124.2 84.0 18.3 450.1 2.9 RMP 101.4 67.5 8.9 441.2 2.1 LSD.05 8.1 4.3 3.5 NS 0.3 Why?
  16. 16. SRI plants were able to complete more number of phyllochrons (completion of 10 phyllochrons in SRI plants and 8 phyllochrons in RMP) before the onset of reproductive stage of growth.
  17. 17. Phyllochrons 1st 2nd 3rd 4th 5th 6th 7th 8th 9th 10th 11th 12th New Tillers 1 0 0 1 1 2 3 5 8 12 20 31 Total tillers 1 1 1 2 3 5 8 13 21 33 53 84 Comparison between numbers of phyllochrons completed under SRI and RMP Prac- 12 DAG 30 DAG 40 DAG 50 DAG 60 DAG 70 DAG tice SRI TP < 4th 6th 7– 8th 8-9th 9th 10th phyllo- phyllo- phyllo- phyllo- phyllo- phyllo- chron chron chron chron chron chron RMP In Trans- 6th 7th 8th 8th mursery planting Phyllo- phyllo- phyllo- phyllo- shock chron chron chron chron
  18. 18.  The number of leaves/hill, leaf area/hill Leaf development and area of flag leaves significantly higher in SRI than RMP.  The size of individual leaf under SRI is more than leaves under RMP. Effects of rice management practices on morphological characteristics of leaves at flowering stage of development Management Leaf Leaf Ave. leaf Ave. leaf Ave. flag Ave. flag leaf practice number number length (cm) width (cm) leaf length width (cm) (hill-1) (m-2) (cm) SRI 79.8 1997.6 65.25 1.82 39.45 2.10 RMP 35.6 1766.5 48.14 1.34 30.27 1.66 LSD.05 15.8 229.4 6.09 0.21 4.49 0.31
  19. 19. Canopy structure SRI plants had higher LAI than RMP. Greater SLW of leaves under SRI shows greater thickness of leaf. SRI: Open-type canopy structure RMP: Closed-canopy structure Effects of rice management practices on LAI, SLW and canopy angle at flowering stage of development Manage- LAI SLW Canopy ment (mg cm-2) angle practice ( ) SRI 3.95 5.50 33.1 RMP 2.60 4.89 17.8 LSD.05 0.28 0.34 3.6
  20. 20. Comparison of leaf inclination at early-ripening stage under SRI and RMP Management 1st leaf 2nd leaf 3rd leaf 4th leaf 5th leaf practice (flag leaf)a SRI 7.5 4.9 7.5 10.7 15.9 RMP 9.2 7.3 9.9 13.7 19.9 LSD.05 0.8 0.6 0.8 1.3 1.8 a Angle between flag leaf and panicle axis
  21. 21. Directorate of Water Management, Bhubaneswar, INDIA Physiological Changes with SRI
  22. 22. Effects of rice management practices on xylem exudation rates at early-ripening stage of development Manage- Amount of Amount of Rate per hill Rate per area ment exudates per hill exudates per (g hill-1 h-1) (g m-2 h-1) practice (g hill-1) area (g m-2) SRI 7.61 190.25 0.32 7.93 RMP 2.46 122.95 0.10 5.12 LSD.05 1.45 39.72 0.06 1.66
  23. 23. 60 CGR (g m-2 day-1) 50 40 30 20 10 0 30-40 40-50 50-60 60-70 Period (Days after germination) Crop Growth Rate The increase in CGR in SRI crops was mainly due to maintenance of leaf area (lower leaf senescence). Lower rate of leaf senescence might be due to larger amounts of cytokinins (xylem exudates) transported from roots.
  24. 24. Light Interception SRI plants: intercept more light without shading RMP plants: in closed canopy, lower leaves experiences more shading 100 At PI stage: light Light Interception 80 interception reached 89% 60 in SRI canopies, while in (%) 40 RMP canopies this was 20 only 78% -- giving SRI 0 plants a 15% advantage 12 25 30 40 50 60 70 Days after seed germination
  25. 25. Changes in leaf chlorophyll content at different growth stages in SRI and RMP % 4 Flag SRI decrease 3.5 Flag TF from Chlorophyll content (mg g-1 3 Fourth SRI FL-LR Fourth TF 2.5 SRI-Flag 35.93 leaf 2 FW) 1.5 RMP- Flag 48.94 leaf 1 0.5 0 SRI-4th leaf 39.44 FL MR LR RMP- 4th 56.14 Stages leaf FL: Flowering stage; MR: Middle-ripening stage; LR: Late-ripening stage
  26. 26. Changes in chlorophyll fluorescence (Fv/Fm) at different growth stages in SRI and RMP 0.9 Flag SRI Flag TF % decrease 0.8 from Fourth SRI Fourth TF FL-LR 0.7 SRI-Flag leaf 22.77 RMP- Flag leaf 31.81 Fv/Fm 0.6 0.5 SRI-4th leaf 27.55 0.4 RMP- 4th leaf 31.88 0.3 FL MR LR Stages FL: Flowering stage; MR: Middle-ripening stage; LR: Late-ripening stage
  27. 27. Changes in chlorophyll fluorescence (Φ PS II) at different growth stages in SRI and RMP 0.650 Flag SRI Flag TF 0.600 Fourth SRI % Fourth TF 0.550 decrease from FL- 0.500 LR 0.450 SRI-Flag leaf Ф PS II 9.93 0.400 RMP- Flag leaf 21.62 0.350 0.300 0.250 SRI-4th leaf 15.31 0.200 RMP- 4th leaf 24.27 FL MR LR Stages FL: Flowering stage; MR: Middle-ripening stage; LR: Late-ripening stage
  28. 28. Changes in photosynthesis rate at different growth stages in SRI and RMP 30 Flag SRI Flag TF % decrease 25 Fourth SRI from 20 FL-LR Pn (µ mol m-2 s-1) SRI-Flag leaf 43.20 15 10 RMP- Flag leaf 51.09 5 0 SRI-4th leaf 52.98 FL MR LR Stages RMP- 4th leaf 59.02 FL: Flowering stage; MR: Middle-ripening stage; LR: Late-ripening stage
  29. 29. Directorate of Water Management, Bhubaneswar, INDIA Performance with SRI
  30. 30. Yield & yield-contributing SRI: Longer panicles, more Characteristics number of grains in spike (40%), higher 1000-grain weight, and more grain-ripening percent than the RMP crop, responsible for higher grain yield (42%) Parameters SRI RMP LSD0.50 Panicles / m2 439.5 421.2 ns Ave. panicle length (cm) 22.5 18.7 2.3 Spikelets / panicle 151.6 107.9 12.9 Filled spikelets (%) 89.6 79.3 5.1 1000-grain weight (g) 24.7 24.0 0.2 Grain yield (t/ha) 6.41 4.50 0.23 Harvest Index (HI) 0.47 0.32 0.04
  31. 31. Distribution of panicles according to their length under SRI and RMP 350 Panicle number/m2 300 SRI TP 250 200 150 100 50 0 Short Medium Long Extra long Category of panicles Short: >10 cm - 17 cm Medium: 17.1 cm - 20 cm Long: 20.1 cm - 24 cm Extra-long: 24.1 cm - <26 cm
  32. 32. Tiller number Panicle number Roots growth and activity Panicle length Canopy development Higher Yield Light utilization Grains per spike in SRI Grain filling
  33. 33. HIGHER GRAIN YIELD Increased effective tillers Enhanced panicle length, More grain number & grain filling Open hill structure Greater light interception More erect leaves Enhanced photosynthesis rate Higher LAI Higher leaf N-content, Increased leaf More chlorophyll content number & leaf size More Rubisco Delayed senescence More photosynthates to the roots Higher nutrient uptake CK Higher microbial activity Greater root growth and activity A schematic model showing factors that may be responsible for higher grain yield of rice plant grown under SRI management practices. (CK: Cytokinins; LAI: Leaf area index; Rubisco: Ribulose-1,5-bisphosphate carboxylase/ oxygenase)
  34. 34. Salient findings Significant changes were observed in the morphological and physiological characteristics of SRI plants: • Greater root growth & activity • Improved shoot growth • Greater LAI • Favourable canopy structure • Higher levels of leaf chlorophyll • Increasing fluorescence efficiency • Photosynthetic rate • Delayed senescence
  35. 35. These factors contributed to :  Larger panicles (more spikelets per panicle)  Better grain setting (higher % of filled grains)  Heavier individual grains (higher 1000- grain weight), and consequently  Higher grain yield
  36. 36. Take-home points Improvement in grain yield under SRI is attributable to improved morphology and physiological features of the rice plant both below and above ground (better and positive root-shoot interaction). SRI methods narrow the gap between genetic potential and in-field yield achievements through management practices.
  37. 37. Factors for giving super-high yield in super high-yielding rice Akenohoshi (a slowly-senescing and high- yielding cultivar) produces high dry matter production as a result of maintaining a high rate of photosynthesis, which is a consequence of the delayed senescence of its leaves, resulting from transport of large amounts of cytokinins from the roots to the shoots (Jiang et al. 1988, Soejima et al. 1995).
  38. 38. Variety: Xieyou 9308 Maintain higher root activity and cytokinin content Delayed senescence and highly efficient photosynthetic performance during grain- filling stage (Shu-Qing et al. 2004 JACS 190, 73-80) SRI plants had similar characteristics as that of the super high-yielding varieties- Xieyou 9308 and Akenohoshi – achieved through changes in management practices
  39. 39. SRI: Experience
  40. 40.  Varietal performance  Impact of spacing Objectives Effect of water management practices  Effect of different N-level  Evaluation of SRI components  Performance under Integrated SRI
  41. 41. Varietal performance
  42. 42. Khandagiri: Short-duration Surendra: Medium-duration CRHR-7: Hybrid Lalat: Medium-duration (popular variety) Savitri: Long-duration
  43. 43. • All the varieties performed better under SRI than conventional transplanted rice. • SRI showed 36-49% higher yield than TP • Short-duration variety (Khandagiri): 36%, • Medium-duration and hybrid varieties: 42-45 %, • Long-duration: 49% more yield than TP SRI: More panicle length, grains per spike and grain ripening percent are the major factors responsible for higher yield than TP.
  44. 44. Effect of spacing
  45. 45. Experiment 1 Grain yield (t/ha) under different spacing in SRI and TP Khandagiri Surendra Savitri Treatment Yield % Yield % Change Yield % (t/ha) Change (t/ha) in yield (t/ha) Change in yield in yield M1: 2.97c -1.65 2.94d -33.48 3.86d -19.79 30 x 30cm M2: 3.42b 13.12 4.26bc -3.58 6.31a 31.16 25 x 25cm M3: 4.44a 46.80 6.27a 41.89 6.06a 26.03 20 x 20cm M4: 3.01c -0.39 4.21bc -4.71 4.40c -8.53 15 x 15cm M5: 2.88c -4.80 4.16c -5.84 4.23c -12.10 10 x 10cm M6: TP 3.02c - 4.42b - 4.81b - (15x10 cm) Thakur, A. K.., S. K. Choudhari, R. Singh, and Ashwani Kumar. (2009). The Indian Journal of Agricultural Sciences 79 (6):443-447.
  46. 46. a.Short-duration variety (Khandagiri) 450 30 400 25 Panicle number/m2 Panicle length (cm) 350 300 20 250 15 200 150 10 100 5 50 0 0 M1 M2 M3 M4 M5 M6 Treatment Panicle number /m2 Panicle length (cm)
  47. 47. b. Medium-duration variety 450 (Surendra) 30 400 25 Panicle number/m2 Panicle length (cm) 350 300 20 250 15 200 150 10 100 5 50 0 0 M1 M2 M3 M4 M5 M6 Treatment Panicle number /m2 Panicle length (cm)
  48. 48. c. Long-duration variety (Savitri) 450 30 400 25 Panicle number/m2 Panicle length (cm) 350 300 20 250 15 200 150 10 100 5 50 0 0 M1 M2 M3 M4 M5 M6 Treatment Panicle number /m2 Panicle length (cm)
  49. 49. Salient Findings Optimum spacing: For short and medium-duration varieties for SRI, this was 20 cm x 20 cm (under the trial conditions) For long-duration varieties, it was 25 cm x 25 cm At wider spacing (more than optimum): Yield was reduced due to lesser panicle number/m2 At closer spacing (less than optimum) : Yield was reduced due to shorter panicles
  50. 50. Experiment 2 Variety: Surendra (medium-duration) Method: SRI and RMP Spacing: 5 spacings (30x30 cm; 25x25 cm; 20x20 cm; 15x15 cm; 10x10 cm)
  51. 51. Grain Yield Plant spacing Grain yield (g m-2) SRI RMP Mean 30x30 cm 295.4 247.0 271.2 25x25 cm 426.3 397.9 412.1 20x20 cm 627.7 448.1 537.9 15x15 cm 421.8 403.4 412.6 10x10 cm 388.2 342.9 365.6 Mean 431.9 367.9 Practice Spacing PxS LSD0.05 18.5 19.4 27.5 Grain yield was significantly larger in the SRI than in the RMP when plants with the same planting spacing were compared. Largest yield at 20x20 cm spacing; lowest at 30x30 cm.
  52. 52. LAI & Light Interceptio Flowering stage 5.00 100 4.50 90 Light interception (% ) 4.00 80 3.50 70 3.00 60 LAI 2.50 50 2.00 40 1.50 30 1.00 20 0.50 10 0.00 0 30x30 cm 25x25 cm 20x20 cm 15x15 cm 10x10 cm Plant spacing
  53. 53. Salient Findings At wider or closer than optimum, grain yield decreased in both practices. At wide spacing, yield reduction was due to the less number of hills/m2, and at closed spacing, yield reduction was due to shorter panicles with lower grain number. Chlorophyll content and photosynthetic rate of both flag leaf and 4th leaf was significantly higher in plants at wider spacing than in the closer-spaced plants. At all the spacings, these physiological parameters were greater in SRI compared to RMP. Performance of individual hills was significantly improved with wider spacing compared to closer-spaced hills. Both SRI and TP gave their highest grain yield with spacing of 20x20 cm in these trials. However, SRI yielded 40% more than the recommended practice. Lowest yield was recorded at 30x30 cm spacing under both practices, due to less plant population (11/m2), in spite of the improved hill performance.
  54. 54. Wide spacing beyond optimum plant density does not give higher grain yield on an area basis. For achieving this under SRI, a combination of improved hills with optimum plant population must be worked out under the specific soil and climatic conditions with the particular variety. In some locations, e.g., East Java, Indonesia, the optimum spacing has proved to be 30x30 cm
  55. 55. Effect of different N-level
  56. 56. Methods: SRI and conventional transplanting flooded practice of rice cultivation method (TF) N-doses: Four rates of N (0, 60, 90, and 120 kg N per ha)
  57. 57. Grain yield & HI Straw dry weight Grain yield Harvest Index N rate (t ha-1) (t ha-1) SRI TF Mean SRI TF Mea SRI TF Mean n N0 2.76 2.29 2.52 2.32 1.36 1.84 0.46 0.37 0.41 N60 5.77 4.55 5.16 4.27 2.75 3.51 0.43 0.38 0.40 N90 6.49 7.64 7.06 6.31 4.20 5.25 0.49 0.35 0.42 N120 7.55 7.25 7.40 6.07 4.37 5.22 0.45 0.38 0.41 Mean 5.64 5.43 4.74 3.17 0.46 0.37 LSD0.05 Cultivation ns 0.14 0.02 practice (CP) Nitrogen level 0.31 0.14 ns (N) CP x N 0.44 0.20 0.03 SRI increased yield by 49% compared to TF Yield enhancement was due to improvement in HI
  58. 58. N-uptake & use-efficien N rate N uptake (kg ha-1) ANUE (kg kg-1) PFP (kg kg-1) SRI TF Mean SRI TF Mean SRI TF Mean N0 27.38 24.17 25.78 - - - - - - N60 41.16 38.58 39.87 32.59 23.25 27.92 71.21 45.87 58.54 N90 58.32 54.30 56.31 44.32 31.55 37.94 70.07 46.62 58.35 N120 82.47 76.75 79.61 31.30 25.13 28.22 50.61 36.44 43.53 Mean 52.33 48.45 36.07 26.64 63.96 42.98 LSD0.05 Cultivation 2.49 3.10 1.89 practice (CP) Nitrogen level 1.89 2.00 1.65 (N) CP x N ns 2.84 2.34
  59. 59. Salient Findings Overall, grain yield increase with SRI practices was 49% N uptake, N use-efficiency, and partial factor productivity (PFP) from applied N was higher in SRI, which was attributable to the greater root development under SRI With SRI and TP management, one kg of added N produced 64 and 43 kg of grain, respectively Higher nitrogen and chlorophyll content - reflecting delayed senescence - contributed to an extension of photosynthetic processes, which translated into increased grain yield under SRI A.K. Thakur et al. (2011) Plant and Soil (under review)
  60. 60. Effect of different water level
  61. 61. 7 6 Grain yield (t/ha) 5 4 3 2 1 0 CF 1 3 5 7- CF 1 3 5 7 DAD DAD DAD DAD DAD DAD DAD DAD TP SRI Highest grain yield at 1 DAD under both cultivation methods
  62. 62. 20 10 % change over CF 0 CF DAD DAD DAD DAD CF DAD DAD DAD DAD 7- 1 3 5 1 3 5 7 -10 TP SRI -20 -30 -40 -50 As more water stress was imposed, grain yield reduced in both methods, but the reduction in grain yield was found to be greater in conventional TP than SRI. This might be due to deeper and greater root growth under SRI, which enables the plant to extract water from deeper soil zones
  63. 63. SRI components and their synergies
  64. 64. Grain Yield Treatments Grain yield (g/m2) AWD CF 25 × 25 cm 20 ×10 cm 25 × 25 cm 20 ×10 cm CW MW CW MW CW MW CW MW 1 Organic 522.3 501.7 468.3 458.4 468.2 416.3 417.9 427.0 14 seedling Org + 607.4 587.3 576.2 517.8 523.6 498.4 469.2 547.8 days Inorg 3 seed- Organic 428.7 416.3 478.7 476.8 398.7 387.6 447.7 397.6 lings Org + 475.4 412.7 376.9 397.4 368.9 447.1 311.9 377.6 Inorg 1 Organic 327.8 311.6 311.9 301.5 340.8 361.0 264.5 346.5 24 seedling Org + 359.7 427.2 368.9 407.3 284.2 335.0 326.9 278.4 days Inorg 3 seed- Organic 311.4 288.2 343.3 380.0 318.2 296.0 368.1 316.8 lings Org + 359.0 317.8 412.0 434.2 422.3 378.4 307.4 258.4 Inorg AWD: Alternate wetting and drying; CF: continuous flooding; CW: weeding by cono-weeder; MW: manual weeding by hand
  65. 65. In summary, the effect of various SRI components on grain yield area as follows- Grain yield (g/m2) Change in SRI SRI Conventional (in (in %) practices practices g/m2) No of seedlings 416.28 378.48 37.80 9.99 Seedling age 456.49 338.27 118.22 34.95 Fertilization 383.12 411.65 -28.53 -6.93 Spacing 403.10 391.67 11.43 2.92 Weeding method 397.70 397.07 0.63 0.16 Water management 417.63 377.14 40.49 10.74 Mean 412.39 382.38 30.01 7.85
  66. 66. Salient Findings Significantly higher number of tillers and panicles per hill was recorded due to SRI practices like wider spacing, younger seedling, intermittent irrigation, and mechanical weeding Grain yield was found significantly higher due to SRI practices like- single seedling, wider spacing, younger seedling, intermittent irrigation. and mechanical weeding Plots that received only organic (FYM) fertilization gave lower yield than mixed inorganic-organic fertilized plots Need more research
  67. 67. Performance evaluation of Integrated SRI
  68. 68. Treatments T1 Rice grown following conventional methods; all rainwater was harvested in the field with no supplementary irrigation T2 Rice grown following SRI methods; all rainwater was harvested in the field with no supplementary irrigation T3 Rice grown following SRI methods; no stagnant was kept in the field (excess water was drained) and 3 supplementary irrigations were provided during flowering and grain filling stages T4 Rice grown following SRI methods; no stagnant was kept in the field (excess water was stored for fish culture in the refuge) and 3 supplementary irrigations were provided during flowering and grain filling stages through stored water
  69. 69. Treat Grain Water Total Income Income Net Profit Net water Gross water - yield required expenditure from rice from fish (Rs./ha) Productivity Productivity ment (t/ha) (m3/ha) (Rs./ha) (Rs./ha) (Rs./ha) (Rs./m3 (Rs./m3 s water) water) T1 2.36 6509 16900 18880 - 1980 0.30 2.90 T2 4.21 6509 16500 33653 - 17153 2.64 5.17 T3 5.96 10009 17500 47653 - 30153 3.01 4.76 T4 6.22 6509 21500 36510 21360 36370 5.51 8.81
  70. 70. Estimated average productivity of inputs on SRI and RMP Units SRI RMP Seed Kg per kg seed 797.13 59.83 Fertilizer Kg per kg fertilizer 12.99 9.14 Labour Kg per man-days 35 23 Land Kg per ha land 6377 4487 Water Liter water per kg 1571 2801 SRI methods enhance paddy yields, increase returns, and save labour and water. They enhance productivity with respect to all of the key inputs in terms of paddy output per unit of seed, fertilizer, labour-days, and water
  71. 71. Directorate of Water Management, Bhubaneswar Sri Lanka Cambodia ‘Swarna’ in AP: Ave. yield: 6.5 t/ha SRI yield: 10.2 t/ha
  72. 72. SRI Crop at IARI, 2004 Directorate of Water Management, Bhubaneswar Madagascar SRI field, 2003 Cuba – Two plants of the same age (52 DAP) and same variety (VN 2084)
  73. 73. Directorate of Water Management, Bhubaneswar Eastern Indonesia - Nippon Koei Irrigation Project, 2004 Morang District, Nepal - 2005
  74. 74. Directorate of Water Management, Bhubaneswar Punjab WTCER, Bhubaneswar - 2007
  75. 75. Some of the reported effects of different SRI practices SRI Practices Effects Transplanting Greater root growth, more cytokinin flux towards single seedlings shoots, delayed senescence, higher with wide spacing photosynthesis (San-oh et al., 2004; 2006) Transplanting Early tillering, greater nutrient uptake (Mishra and young seedlings, Salokhe, 2008), greater yield (Pasuquin et al., 2008; quickly, carefully Menete et al. 2008) and at shallow depth Intermittent Water saving (Bouman et al., 2007; Satyanarayana irrigation /AWD et al., 2007; Zhao et al., 2009) Greater root growth (Satyanarayana et al., 2007) Improves ROA, cytokinin concentration in roots and shoots, leaf PS rate, and activities of key enzymes involved in sucrose-to-starch conversion in grains (Zhang et al., 2009)
  76. 76. Some of the reported effects of different SRI practices SRI Practices Effects Use of organic Root growth and nutrient uptake enhanced (Yang et manure al., 2004) Microbial biomass and activity increased (Gayatri, 2002) Compost application (@12 t/ha) increased the rice grain yield by 12-13.5% (Menete et al., 2008) Weeds controlling Aerobic soil condition improves root growth with mechanical (Satyanarayana et al., 2007) weeder
  77. 77. Future Research Needs Directorate of Water Management, Bhubaneswar Reason for the phenotypic alterations/tillering in SRI plants: what are the physiological, biochemical, hormonal, and genetic changes in plants responsible for these alterations Study grain-filling, source-sink relationships, and grain quality in rice grown through SRI methods There is considerable evidence for stimulating effects of soil aeration on N mineralization, like intermittent drainage favouring the accumulation of nitrate with subsequent denitrification. In view of current trends to minimize water use in rice cultivation, it is a challenging research issue to re-examine the quantity of N losses via nitrification-denitrification (nutrient budgeting).
  78. 78. Effects of fluctuating aerobic and anaerobic Directorate of Water Management, Bhubaneswar conditions on microbial populations, their activity, C and N dynamics, GHG emissions, and crop N supply. How do SRI practices affect diversity and functioning of soil microbial populations, what is effect of these populations in turn on crop performance, with consideration of the role of micronutrients? Roots are the key to a second green revolution Virginia Gewin (2010) ‘An underground revolution.’ Nature, 466, 29 July 2010 Need for breeding crop plants with deeper and bushier root ecosystems could simultaneously improve both the soil structure and its steady-state carbon, water, and nutrient retention, as well as sustainable plant yields. (Douglas Kell (2011) Annals of Botany)
  79. 79. Rice plant (cv. Ciherang) grown using System of Rice Intensification (SRI) methods in Indonesia, producing 223 tillers from a single seed, which means that it had reached into the 14th phyllochron of growth
  80. 80. SRI: Still has a long way to go…
  81. 81. Acknowledgement • USDA, CSS, Cornell University and ICAR • Norman Uphoff, Janice Thies, Francine, Harold, John Duxbury, KV Raman, Erika, Lucy • My friends at Cornell: Jin, Charles, Pulver, Lu, Shafiq, Aisha, Nicole, Rao, Vinod, Dr. Mehta All of You
  82. 82. Thanks Rice field art in Japan, just using plants
  83. 83. Discussion?

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