SRI TECHNOLOGY (SYSTEM OF RICE INTENSIFICATION)
I. INTRODUCTION: SYSTEM OF RICE INTENSIFICATION (SRI):
The SRI methodology was developed by Fr. Henri de Laulanie, a French Jesuit who assembled the set of simple, but synergetic practices that now constitute SRI.
II. OBJECTIVES OF SRI:
To increase the rice production.
To reduce the water consumption by efficient water management.
To reduce cost of cultivation.
To increase the profitability.
Different experimental trials were conducted worldwide including Tamil Nadu. Different steps for SRI methodology were finalized based on the outcome of the experimental trials conducted.
III. WORLD RICE SCENARIO:
Rice is grown in 114 countries over 171 million hectares (mha).
Nearly 90% of worlds’ rice is produced and consumed in Asia and is the staple food for more than half of the worlds’ population. Rice is indeed a global food grain. Per capita consumption of milled rice has increased 40% in the last 30 years from 61.5 kg to about 85.9 kg per annum. In particular about 55% of total rice area is under irrigation. SRI GENESIS – TAMILNADU AGRICULTURAL UNIVERSITY
TKM 6 RICE VARIETY MONUMENT
Global rice production has to be increased manifold in a sustainable fashion to match the ever increasing population. Globally the present day rice production faces serious problems including depleted (or) depleting water resources, short supply of labour and inefficient or inappropriate institutional support. Potential to increase the production of rice is not only the scarcity of land for cultivation, but also water shortages. Scarcity of water is triggered in areas where the conventional water intensive method of irrigated rice cultivation through inundation is followed.
About 70-80% of global fresh water withdrawals are for the agricultural sector particularly irrigation and rice accounts for about 85% of this, mainly due to inundated production.
In Asia bout 84% of water withdrawal is for agriculture, used mostly in flooded rice irrigation. Rice cropping today has lion’s share about 45% of irrigated areas.
Particulars US Europe South Asia India Tamil Nadu Per Capita water resource (in cubic metres) 9535 1112 1255 1167 750 Water utilized for agriculture (in %) 6.8 4.43 46.62 44.03 86.76
ENTRANCE OF RICE RESEARCH STATION, TIRUR
PLATINUM JUBILEE MONUMENT
Given these constraints, the conventional method of rice cultivation will obviously become expensive, primarily in terms of water resources.
For most rice rich and rice dependent nations, there is an increasing demand to adopt alternative eco-friendly and people oriented production methods. Many of the countries have started to realized that employing rice cultivation methods that use water judiciously like the SRI (System of Rice Intensification) method has lot of potential. IV. INDIAN RICE YIELD SCENARIO:
Rice plays a pivotal role in Indian Economy as it is the staple food for two thirds of the populations. Globally, India ranks first in area (42.4 million hectares).
In India, rice is being cultivated in 534 districts outs of 607 districts. But productivity levels in 20% of the districts with an area of 6.9 million hectares are deplorably low i.e. less than one ton per hectare.
Productivity level in another 40% of districts is in the range of one to two tonnes per hectare.
In the state of Tamil Nadu water is a scarce resource. Rice cultivation consumes 70% of the water available for agriculture and hence economizing water use in rice production is very important. The Fig 1 Grain yield (kg ha-1) using different crop establishment and plant densities (EXPT 1)
Fig 4 Development of root volume in conventional (24 days old) and young (14 days old) seedlings (EXPT2)
System of Rice Intensification (SRI) offers scope to achieve water savings. A systematic approach to understand and evaluate SRI through field experiments showed that SRI principles of using young seedlings, wide spacing, mechanical weeding and shallow irrigation had positive effects on crop growth and grain yield besides 30-50% savings in irrigation water. A modified SRI package comprising of nursery management, transplanting, weeder use and limited irrigation was developed and tested under experimental conditions and subsequently verified in farmers’ fields. Evaluation in farmers’ fields showed an average yield increase of 1.6 tonnes per hectare and higher net profits. Savings in irrigation water were recognized by farmers. The first experimental trials results show that grain yields were low using plant density of 16 m-2 or less suggesting that such a wide spacing is not suitable but a plant density of 32 m-2 could result in yields equal to conventional (20 X 10 cm) spacing (Fig 1). It also showed that the alternately submerged-non-submerged flooding did not reduce yields. However, the irrigation method was difficult to apply as it required more labour due to the irrigation in the evening and draining in the morning. In depth exploration of SRI principles (EXPT 2 and EXPT 3) Only four factors of SRI were considered in experiment 2 (EXPT 2) i.e. seedling age, water management weed management and green manure
Fig 2 Rice yields as affected by different management factors (EXPT 2)
application while other factors such as plant spacing (20 X 20 cm) and number of seedlings (single seedling per hill ) were kept the same. This showed significant yield increase due to the use of a rotary weeder (Table 1) and non-significant effects for differences in seedling age, water management and green manure application (Fig 2). The interaction between seedling age, weed management and nutrient management was significant. Green manure application combined with young seedlings significantly increased yields using a rotary weeder, but decreased yields under manual weeding. Grain yields of 14 day old seedlings, green manure and manual weeding were lowest under both 5 cm (5893 kg ha-1) and 2 cm (5059 kg ha-1) irrigation. However, with rotary weeder use, grain yields were dramatically increased by 1.7 t ha-1(5 cm irrigation) and 2.0 t ha-1(2 cm irrigation). This suggests that the use of a rotary weeder and green manure has synergistic effect. Grain yields using water layers of 2 cm were similar to yields realized with conventional irrigation (5 cm water layer) while on average 53% less irrigation water was used. Savings of 25 to 50% irrigation water by alternately submerged-non-submerged conditions have been reported by Ramamoorthy et al (1993) and Jeyaraman (1992) observed that partial submergence of rice fields at critical stages of growth gave similar yields as continuous submergence. The major advantage of flooding rice fields is the case of weed control. Here the use of rotary weeder was convenient and resulted in a yield increase. Dinesh Chandra and Manna (1990) showed that a Japanese rotary weeder was twice as effective in controlling weeds than a water layer while the weeder increased grain yields by 30%. Fig 3 Rice yields as affected by different management factors (EXPT 3)
Table 1. Rice yields as affected by seedling age, method of weeding and green manure application (EXPT 2)
Particulars
Fertilizers 24 days old seedlings 14 days old seedlings
5 cm irrigation 2 cm irrigation 5 cm irrigation 2 cm irrigation
Manual weeding NPK 6151 6199 6841 6268 NPK + GM 6000 6195 5893 5059
Weeder use NPK 6008 6908 6838 6707 NPK + GM 6343 6349 7612 7126
NPK: Nitrogen, Phosphorus & Potassium GM : Green Manure The significant findings from the EXPT2 were that (i) weeder use increased yields and (ii) grain yields were not affected by shallow irrigation up to flowering. In EXPT 3, modifications were made in crop establishment and water management. Instead of young seedlings, direct seeding followed by thinning to maintain a single plant per hill was adopted. Alternately submerged-non-submerged irrigation was continued up to maturity. Results of ExPT 3 showed no interaction between the factors but confirmed the statistically significant yield increase due to weeder use (Fig 3). Direct seeding resulted in significantly higher yields. Continuation of alternately submerged-non-submerged irrigation up to maturity significantly reduced the yield indicating that water was limiting production during the grain filling period. The number of filled grains per panicle was significantly
reduced with shallow irrigation (82 panicle-1) compared to conventional irrigation (96 panicle-1). The negative interaction of green manure with young seedlings and manual weeding observed in EXPT2 was not observed with direct seeding in EXPT3. The fourth experiment (EXPT 4) and the last experiment (EXPT 5) was the Adaptive Research Trial (ART) carried out in 100 selected farmers’ fields in different parts of the Thamirabarani river basins of Tirunelveli and Thoothukudi districts, Tamil Nadu during the wet season. Before taking up the ART’s farmers’ awareness was raised through field demonstrations, theoretical explanations and discussions. The ART consisted of comparing SRI with conventional cultivation in plots of 1000 m-2 which each participating farmer made available. The highest water productivity (kg m-3) was obtained with 24 days old seedlings and alternately submerged-non-submerged irrigation in both EXPT2 (0.732) and EXPT3 (0.871). In these treatments, water productivity increased by 84 and 96% respectively compared to conventional flooded irrigation (Table 4). Water saved with alternately submerged-non-submerged irrigation was higher in EXPT 3 than EXPT 2. As a consequent of the longer growing period after transplanting, the use of young seedlings / direct seeding resulted in lower water savings than old seedlings. Improvement of soil aeration and root pruning due to the use of rotary weeder has been reported by Misra and Sahoo (1971) and Shad (1986). In both reports, the number of productive tillers was significantly higher with young seedlings and direct seeded plants than with conventional seedlings.
Use of young seedlings resulted in higher root volume throughout the crop growth period (Fig. 4) and alternately submerged-non-submerged irrigation resulted in higher leaf area index during the grain filling period (Fig.5). Patel et al (1983) and Hoshikawa (1992) reported higher yie0lds using young seedlings. Higher uptake of N, P and K by the SRI crop (green manure application, young seedling, alternately submerged-non-submerged irrigation and rotary weeder use) was also observed in EXPT 2 and EXPT3. Verifying SRI Package (EXPT 4) EXPT 4 showed that yields with alternately submerged-non-submerged irrigation, wider spacing and rotary weeding could be equal to that of conventional cultivation with considerable savings in irrigation water (Table 5). The observations in crop growth showed the influence of the management practices adopted in SRI. Since seeds were not equally spaced, it was not possible to use the rotary weeder across the rows. On the basis of the results obtained in these experiments, farmer recommendations for SRI cultivation were formulated. The recommended SRI package as compared to conventional cultivation.
THICKNESS OF ROOT & BIOMASS UNDER SRI
TPR- Transplanted rice WSR- Wet Seeded rice SRI- System of Rice Intensification DSR- Direct Seeded Rice FB- Flat Bed RB-Raised Bed CROP GROWTH AT FLOWERING, GRAIN YIELD & WATER USE IN EXPT 4
Parameters Conventional(23 d old seedlings;2-3 seedlings per hill, hand weeding and 5cm irrigation SRI package(14 d old seedlings; single seedling per hill, rotary weeding in both directions and 2cm irrigation
Panicles m-2 500 475
Leaves hill-1 47 62
Root volume hill-1 34 53
Filled grains panicle-1 96 114
Grain yield (kg ha-1) 6701 7139
Water use
Number of irrigations 21 18
Irrigation water(m3ha-1) 11813 3480
Rainfall (mm) 246 246
Total water used(m3ha-1) 14274 5941
Water productivity(kg m3) 0.469 1.232
LEAF AREA INDEX IN SRI
On-Farm evaluation of SRI (EXPT 5)
The grain yields recorded under SRI and conventional cultivation ranged from 4214 to 10655 kg ha-1 and 3887 to 8730 kg ha-1 respectively. The mean grain yield was 7227 and 5657 kg ha-1 respectively showing an average yield advantage of 1570 kg ha-1 under SRI. Nearly 31 farmers recorded yields of more than 8 t ha-1 under SRI against three farmers using conventional cultivation. The maximum yield advantage recorded for SRI was 4036 kg ha-1 (70%).
Details on the costs of cultivation are given in Table 7. Costs for the nursery and weeding under SRI were lower while costs for transplanting wer higher compared to conventional cultivation. Overall cost savings in SRI were 11%. Despite a 50% reduction in the number of seedlings in SRI, costs for transplanting are higher which is cused by the mandatory line planting slowing down the planting process and leading to higher labor requirements. Net returns were Rs.11149 and 23868 ha-1 for conventional and SRI cultivation respectively.
The yield increase under SRI was due to increased number of panicles m-2 and increased number of grains panicle-1. The farmers used 10 different varieties and one of these varieties was known for shy tillering but produced more tillers under SRI. Many farmers require less labour in SRI cultivation. Considering the high N uptake of the SRI crops, the farmers have been advised to use leaf colour chart for N management to avoid excess application of N.
RRS SCIENTISTS FIELD INSPECTION OF ADAPTIVE RESEARCH TRIAL
DATA COLLECTION OF MATURED PANICLES BY TEAM OF SCIENTISTS
TABLE 6: DIFFERENCES BETWEEN CONVENTIONAL AND SRI METHOD OF CULTIVATION
Practices Component Conventional SRI Nursery (to plant 1 ha) Area Seed rate (kg ha-1) 800 m2 Recommended : 60 100 m2 7.5 kg ha-1 Farmer’s practice: 125 – 150 Planting Seedling age 21+ 14
Number of seedlings hill-1 2 – 3 + 1
Style Recommended :
Rectangular
Square
Farmer’s practice:
Random
Spacing Recommended :
15 x 10 cm
(105 – 115 d crop)
20 x 10 cm
(135 – 155 d crop)
25 x 25 cm
Farmer’s practice :
Variable
No. of hills m-2 66 / 50 / + 16
Irrigation Recommended
Irrigate to 5cm depth one day after the disappearance of ponded water Irrigate to 2.5 cm depth (after hairline crack formation up to panicle initiation and after disappearance of ponded water
Farmer’s practice Flooding (variable depths)
Weeding Recommended Pre-emergence herbicide + hand weeding at 30 DAT (or) hand weeding at 15, 30 DAT Using rotary / cono weeder in between rows in both directions at 10,20, 30 and 40 Days after transplantin and hand removal of left out weeds
SRI IN RICE AT ARJUNANADHI SUB BASIN
SRI IN RICE AT PAMBAR SUB BASIN
V. CRITICAL STEPS IN SRI: The success of SRI entirely depends on the adoption of critical management steps. They are (i) Seedling Age (ii) Number of Seedlings per hill (iii) Square planting (iv) Water Management (v) Mechanical (Cono) Weeder usage
- SEEDLING AGE: Young seedlings if carefully planted into an aerobic soil environment, not submerged in hypoxic soil (oxygen less soil), have more vitality and resilience and more growth potential as can be explained in terms of the research analysis. So young seedling of two weeks duration is recommended. Recommended seed rate for one hectare is just 7.5 kg. Nursery area is reduced to 100 square metres. Form raised beds @ 1 X 5 m and 20 beds are required for one hectare. Spread polythene sheets over the beds evenly. Old poly sacks can also be used. Fill soil evenly over the sheets upto 4 cm. Seed treatment and fertilizers can be used but judiciously.
SRI FIELD EXPLANATION GIVEN BY THE STAFF
FIELD PREPARATION FOR SRI CULTIVATION
Uniformly spread 375 g of seeds in each 5 square metre nursery bed. Watering through flowerpot advisable. Cover the seed bed using locally available mulching materials like coconut fronds/straw.
- NUMBER OF SEEDLINGS PER HILL This intuitive notion is contradicted by the known fact that when any plant is crowded together, the root growth is inhibited, something that applied to rice as much as any other plant species. Hence, planting of single seedling should be adopted.
- SQUARE PLANTING High density among plants inhibits their growth and performance, although spacing is a parameter to be optimized rather than maximized so as to get the greatest number of large and fertile panicles per unit area. Square planting with 25 cm X 25 cm ensures optimum space for efficient utilization of resources. Besides it eases operation of cono weeder usage. SRI is entirely new concept and certain critical elements are new to the farmers who are in conventional mode. Square planting is one such element.
Rolling marker a unique tool easing the square planting.
Reduces the drudgery in transplanting. IRRIGATION FOR SRI CULTIVATION
NURSERY FOR SRI CULTIVATION
Eases the labour and the process gets simplified. Square impressions laid in the field and single seedlings are planted.
- WATER MANAGEMENT
Hypoxic conditions cause rice plant roots to degenerate. Continuous flooding early in the growth cycle will diminish the size and health of plants root systems, making them less able to tolerate water stress later in the cycle. Plants with truncated roots cannot access the residual soil moisture in lower horizons that is accessible to plants which have large and functioning roots systems to maintain their growth and productivity. Hence, alternate wetting and drying is advocated. 4.1 RECOMMENDED WATER MANAGEMENT FOR SRI In Tamil Nadu, 3 million wells, heavily utilize the available surface water (17.5 BCM) and groundwater (15.3 BCM). Hence, there is a need for water conservation. Agriculture is the single largest consumer of water in the state using 75% of the state’s water and rice is the principal food crop or the state and majority of area is under irrigation. It has been found that in the most intensively cropped areas under rice, where groundwater is often used for irrigation, water tables have been falling at the alarming rate of one meter per year or more! DEMONSTRATION OF SRI NURSERY
TRANSPLANTING OF SEEDLINGS OF SRI
Water management is one of the critical steps in SRI and provision of aerobic environment in rice fields is the core point in SRI. Irrigate to 2.5 cm depth (after hairline crack formation up to panicle initiation and after the disappearance of ponded water). 40 to 50% water saving from planting to harvest.
- MECHANICAL (CONO) WEEDER USAGE Square planting eases the cono /rotary weeder operation in two directions and thereby weed management could be effected efficiently. The greatest part of the space between plants is cleaned by the “teeth” on the small rotating wheels of such weeder and weeds germinating near plants will be covered by the churned-up mud, which will give the rice enough time to grow in advance of the weeds. Hence ,mechanical weeding is recommended four times from 10 days after planting at weekly intervals. Usage of weeder is one of the critical step in SRI weeders should be used at 10 days interval from the transplanting day. Three labourers are enough to weed one acre. Weeds are trampled and on decay the nutrients are ploughed back to the soil. Soil is frequently disturbed which has beneficial physic chemical-biological results in soil. SQUARE PLANTING UNDER FIELD CONDITION
CONO WEEDER FOR SRI
Root pruning triggers the tillering that results in bursting out of tillers. Water lever should be properly monitored for usage of weeders. The leftout weeds should be handweeded. IRRIGATION 25 -50% water saving from planting to harvest. CROP RESPONSE Higher root growth Higher tillering of even shy tillering genotypes Higher plant height Increase in number of productive panicles m-2 Higher number of grains panicle-1 Higher percentage of filled grains per panicle Lodging resistance Leaves remain green up to harvest Resistance to adverse effects of drought Higher nutrient use efficiency Higher biochemical activities Higher grain and straw yield PROFITABILITY Higher outturn of milled rice Higher net profit
USAGE OF CONO WEEDER FOR WEEDING IN SRI
FIELD DEMONSTRATION OF CONO WEEDER
OTHER BENEFITS All genotypes (high yielding varieties, hybrids, land races) respond well ADVANTAGES OF SRI NURSERY Reduction in nursery area from 800 m2 to 100 m2 (to plant 1 hectare) Drastic reduction in seed rate from about 60 kg ha-1 to 7.5 kg ha-1 Lesser pest problems in the nursery. Reduction in nursery duration from 21 -30 days to 14 days. TRANSPLANTING Square planting to enable the crisscross use of weeder. Reduction in planting density from 50-66 hills m2 (15 cm x 10 cm or 20 cm x 10 cm) to 16 hills m2 (25 cm x 25 cm) Reduction in number of seedlings per hill from 2-3 + to 1. WEEDING No requirement of herbicide One labourer with a rotary weeder can cover an area of about 0.13 ha in a day. Reduction in labour requirement for weeding from 30-60 ha-1 to 25 ha-1.
Multiple benefits of using weeder (weed control; less labour for weeding; incorporation top dressed fertilizer; disturbance to the soil; pruning of older roots increased crop growth). Timely removal of weeds facilitating latter absorption of applied nutrients. Small farmers can do the weeding by themselves.
CONVENTIONAL Vs SRI METHOD OF CULTIVATION
CULTIVATION EXPENSES
Sl.No.
Details Total Expenditure
(Rs./ ha)
Conventional SRI
1
2
3
4
5
6
7
8 Nursery
Main field preparations
Manures & fertilizers
Transplanting
Weeding
Irrigation
Plant Protection
Harvest 2110
2005
7254
2400
3200
300
660
3500 681
2005
7254
3200
1520
240
660
3500
Total 21419 19060
PANICLE INITIATION STAGE IN SRI
HARVESTING STAGE UNDER SRI
ECONOMIC BENEFITS
Sl.No. Details Conventional SRI 1
2
3
4
5
6 Revenue from grain yield @ Rs. 7 / Kg
Revenue from straw yield @ 0.25 Re / Kg
Total revenue (in Rs./Ha)
Total Expenditure (in Rs./Ha)
Net Profit (in Rs./Ha)
Cost Benefit Ratio
42441
2263
44704
21429
11149
2.08 56014
2918
58932
19060
23868
3.09
AZOLLA BIO-FERTILERS FOR RICE PRODUCTION IN SRI
STAFF OF RICE RESEARCH STATION
Built With
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