On-going feasibility study of ‘System of Rice Intensification’ (SRI) in Bhutan Site I Site III Site II Figure 2 Figure 4 Figure 3 Lhendup, Karma, Lecturer, Sherubtse College, Royal University of Bhutan, Kanglung Results and Discussion Introduction
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On-going feasibility study of ‘System of Rice Intensification’ (SRI) in Bhutan
Lhendup, Karma, Lecturer, Sherubtse College, Royal University of Bhutan, Kanglung
Results and Discussion
The evaluation trials on SRI have been initiated this rice growing season in Bhutan and the final crop cut is yet to be done. Therefore, the actual performance of these trials cannot be reported. However, some of the yield contributing parameters on SRI trials (taken recently) as well as conventional method in three sites are reported (Table 1).
Rice is one of the important food crops for the people of Bhutan. Different varieties of rice, both local and introduced are grown in a wide range of elevation from subtropical lowlands (150 m) in the south up to elevations as high as 2600 masl in the north. The present productivity of rice of less than 3 ton/ha cultivated in 46,585 acres out of 69,414 acres of irrigated land has not been able to attain food sufficiency level in the country (MoA, 2004). For the first time in Bhutan, feasibility study through evaluation trials on System of Rice Intensification (SRI) has been initiated. This method is known to have advantages for small and marginal farmers in terms of economic and environmental benefits as compared to the conventional method. This presentation is focused on the preliminary results based on the contributing yield parameters from the on-going evaluation trials on SRI.
Table 1. Average of yield contributing parameters for 3 replicated SRI trials at three study sites
üTo carry out and promote SRI experiments with different cultivars with the involvement of farmers and extension workers.
A total of three on-going location specific SRI trials both on-farms (1600 & 1800 m) and on-station (2000 masl) using a simple randomized complete block design with 3 replications and five treatments has been started in Kanglung Geog (Fig.1). The treatments are planting spacing (20x20 cm, 25x25 cm) and seedling age (three and four leaf stage). The plot size is 5x4m2 and there are a total of 15 plots in each site. Each site is planted with a different variety of rice; Khangma map (Site I), Paropa (Site II) and Verna (Site III), which are all local varieties. Solarized bed was used to raise the nursery. Seed was soaked in water for 48hrs before sowing. For control plots, except for site I, 45-50 days old seedlings were planted at site II and III. After 3 to 4 days of transplanting, control plots were applied with pre-emergence herbicide (butachlor). No compost was applied but a little quantity of urea (46:0:0) @ of 160gm per plot was applied at about 50 days after transplantation due to yellowing of the tip of leaves.
T-1 (Treatment 1 with 20x20 cm spacing and 3 leaf seedling age for each site and so on. * Transplanted the seedling raised by farmers and at the time of their transplantation.
The best performance of SRI was observed at site I followed by Site II (Table 1). The reason can be due to the soil type as sandy loam has been found to be more suitable for SRI than clay soils (BRAC report 2002). The constant monitoring provided to the field can be another reason. Among the three sites, site III was farthest and frequent monitoring was difficult. Thus proper intermittent irrigation and weeding, which are necessary for SRI fields (Uphoff, 2005) failed sometimes. Further, the young transplanted seedlings at Site III were attacked by different types of grasshopper that fed on the leaves first and ultimately the stems. In all the three sites, treatment with wider spacing 25x25 cm and younger seedling 3 leaf stage (P-2) have shown better yield result(considering 1000 grains weighs 20 gm) with a maximum yield of 17.2, 14 and 7.7 tons/hac in site I, site II and site III respectively (Fig.2). The contributing yield parameters such as total number of fertile tillers, number of filled grains per square meter and the height of plant were more in treatment (P-2) as compared to P-4 (similar spacing but older seedling) and other treatments (P-1, P-3 & control). This indicates that maintaining wider spacing one plant per hill and transplanting younger seedling induces robust root growth, profuse tillering (Fig.3), longer panicles and consequently more grains per panicle (Fig.4) than smaller spacing and transplanting older seedlings. The yield performance of controls (traditional methods) in all the sites were lower, which is in agreement with the finding of Anthofer (2004) that SRI method had better yield performance. However, the yield is higher than the previously recorded productivity of 3.66 tons/hac (MoA, 2004) in Kanglung. This could be attributed to the frequent monitoring received.
Figure 1. Kanglung is one of the 16 sub districts of Trashigang District and falls under mid and high altitude rice growing zones. It has a total of 588.50 acres under paddy cultivation and the productivity is 408.28 MT (3.66 MT/ha) which is higher than the national average yield.
The findings based on the contributing yield parameters shows a positive trend towards the SRI performance observed in many countries. With more evaluations on SRI methods, it is expected that the findings would enable marginal farmers in Bhutan to enhance their rice productivity by many folds.Farmers in some of the regions worst hit by water scarcity
during paddy season would benefit the most by this method as it require lesser amount of water. The present trials have already sparked some interest to the farmers as well as others. In fact, farmers in Kanglung and other regions already practices one of the aspects of SRI i.e., transplanting of single seedlings but older seedlings and in narrow spaces. So, I feel and pray that it would not be difficult to help and inspire farmers to learn and experiment on the entire aspects of SRI.
I wish to acknowledge the help of Prof. Norman Uphoff, CIIFAD, Rajendra Uprety, Biratnagar, Nepal, Namgay Wangdi and his crew at the RNRRC Khangma and many others for providing valuable information for this work. I also thank my student researchers and farmers for allowing their plots to initiate such work. The financial support received from TRAID foundation with the initiatives of CIIFAD, Cornell University is gratefully acknowledged.
Agricultural Statistics 2004. Ministry of Agriculture, Royal Government of Bhutan, Thimphu. http://www.moa.gov.bt/a_statistics.php
Anthofer, J. 2004.The Potential of the System of Rice Intensification (SRI) for Poverty Reduction in Cambodia. In “International Agricultural Research for Development”. Berlin, October 5-7.
BRAC Centre 2002. Report of workshop on experiences with The System of Rice Intensification (SRI) in Bangladesh.
Uphoff, N. 2005. Features of the system of rice intensification (SRI) apart from increasing yield.