Influence of Crop Establishment Techniques on Growth and Yield of Rice

Field experiments were conducted at

Rice is one of the most important cereal crops, which plays a key role for food security.In India, rice is cultivated in an area of 44.1 m ha with a production of 103.4 million tones (USDA, 2012).The country has to produce about 130 million tones of rice by 2025 to meet the food requirement of the ever growing population (Hugar et al., 2009).Meeting the targeted demands of rice is a challenging task.Increasing water scarcity is becoming real threat for rice cultivation.Hence water saving technology which also maintains soil health and sustainability and as well as economically beneficial needs to be developed (Uphoff and Erick Fernandes, 2002).Manual transplanting is the most common practice of rice cultivation in south and south-east Asia.In recent years water table is running down at a very rapid rate throughout the globe, thus sending an alarming threat and limiting the scope for cultivation of high water requiring crops very seriously.Rice being a crop having high water requirement, there is a need to search for alternative methods to reduce water requirement of rice without reduction in yield.Establishment techniques, plant density, nutrient requirement and management, water management etc., need to be standardized to achieve the reported yield potential of rice under different duration in various environments.Method of establishment is one of the cultural practices, which influences the rice crop through its effect on growth and development (Gopi et al., 2006).In recent years, the area under rice crop is decreasing year by year due to less profitability.Non availability of irrigation water and shortage of labour during peak periods, *Corresponding author increased labour wages make transplanting and manual weeding costly, invariably causing delays in farm operations.Because of the need to develop appropriate crop establishment methods to improve rice yield, this study was undertaken to assess the effect of different establishment methods on rice productivity.

Materials and Methods
Field experiments were conducted during kharif (June-Sep) and rabi (Oct-Mar) of 2011-12 at Agricultural Research Station, Thirupathisaram, Tamil Nadu with the aim of sustaining rice production under different crop establishment methods.The experiment was laid out in a randomized block design with four replications.The treatment structure comprised of wet seeding, drum seeding, random transplanting, line planting, SRI square planting and SRI machine planting.The variety ASD 16 and TPS 3 were used for kharif (May-Sep) and and rabi (Oct-Mar) seasons, respectively.Regarding drum seeding and wet seeding soaked seeds were used for sowing.With respect to random and line planting, 21-24 days old seedlings were used for transplanting.For SRI manual and machine planting, seedlings of 14 and 18 days raised under mat nursery were used for transplanting.The growth, yield characters, grain and straw yield were recorded and economics was worked out.

Growth characters
SRI system of planting influenced the plant height and number of tillers (Table 1).SRI machine planting  (Krishna et al., 2008) .The number of tillers per plant was significantly higher in SRI method of cultivation.Planting in square method with wider spacing might have resulted in profused tillering under SRI cultivation, which might have facilitated plants for better utilization of the resources.This advantage of SRI method in enhancing tiller numbers has been reported earlier by Udaykumar (2005).

Yield characters and Yield
SRI system of planting had significantly influenced the yield characters and yield (Table 2).SRI machine planting recorded significantly better yield characters and was on par with SRI square planting.Among the different methods of establishment, SRI machine planting recorded the maximum yield characters viz., number of panicles/ m2 (238.2 and 224.1), number of grains/panicle (218.6 and 204.0) and panicle length (26.1 and 27.0 cm) of ASD 16 and TPS 3 during kharif and rabi seasons, respectively followed by SRI square planting.The least yield characters viz., number of panicles/m2 (164.3 and 152.7), number of grains/ panicle (145.2 and 140.4) and panicle length (16.2 and 14.5 cm) were recorded in wet seeding method.SRI machine planting recorded higher grain yield during both kharif (5650 kg ha-1) and rabi (5520 kg ha-1) followed by SRI square planting (5520 and 5720 kg ha-1, respectively).The per cent increase in grain yield ha-1 under SRI machine planting was 9.25 per cent over random planting (traditional) method.Mahender Kumar (2012) obtained 7-20% more yields in SRI over normal method, irrespective of soils and locations across the years in the country.Bhowmick et al. (2013) obtained comparatively lower yields under normal transplanting due to gradual degeneration of rice roots with the progress of crop growth stages due to continuous submergence.SRI method provided better aeration, more spacing, and less competition, which enabled the plants to grow vigorously.The increase in the grain yield of SRI method was attributed to large root volume, profuse and strong tillers with big panicles, more and well filled spikelets with higher grain weight (Satyanarayana and Babu, 2004).Similar findings were recorded by Jayadeva et al. (2008).The lowest grain yield was noticed in case of wet seeding method (4710 and 4650 kg ha-1, respectively).Higher straw yield (5720 and 5725 kg ha-1) also showed the same trend like grain yield.

Economics
It is evident from the Table 3 that SRI machine planting proved to be the most profitable treatment in terms of highest gross income (Rs.62220 and 60925/ha), net income (Rs.40765and Rs.39473/ ha) and benefit cost ratio (2.90 and 2.84) during kharif and rabi, respectively.This might be due to lower cost of cultivation and owing to production of highest grain yield, the gross and net returns were found maximum under SRI machine planting.Higher gross returns were due to higher grain yield, consequently resulting better return for every rupee invested on cost of cultivation.The lowest returns were fetched from wet seeding which was the result of lowest grain yield under this treatment.From this study, it can be concluded that SRI system of planting was found to be superior in rice ASD 16 and TPS 3 during kharif and rabi, respectively.SRI machine planting resulted in better growth, yield characters, yield with additional gross, net returns and benefit cost ratio than that of random planting, line planting, drum and wet seeding.Hence, SRI machine planting is more promising establishment method of rice in enhancing higher productivity and economic returns.