Evaluation of the versatile multi-crop planter for establishing sprouted direct-seeded rice

摘要

Wetland rice seeding is an increasingly common practice for irrigated and favourable rainfed lowlands. Most developed countries sow rice seed in saturated water to minimize cost and labour requirements (Smith and Show, 1996). Farmers in developing countries increasingly are adopting wet seeding because of the migration of farm labour to non-farm jobs and the consequent labour shortage and high costs for manual transplanting (Ho, 1995; Pandey, 1995; Pingali, 1994). Wet seeding in irrigated areas occurs into aerobic, anaerobic, and wet soils based on the level of oxygen in the vicinity of the germinating seed or the depth of flood water at seeding. Direct seeded rice either broadcasted or line sown gave significantly higher grain yield than transplanting under proper management (Elahi et al., 1997; Hussain et al., 2000). Santhi (1999) reported that the establishment of sprouted rice seed under broadcasted systems flowered 7.2 days earlier than transplanted rice seedling. The sprouted rice manually sown in lines had 7 days earlier flowering than transplanted rice in both dry and wet seasons. The delayed flowering in transplanted rice might be due to transplanting shock of the rice seedling. Islam (2008) observed that the radicle and plumule length was increased with the increase of incubation duration. Islam (2008) also reported that significantly higher grain yield was attained after 96 hours of rice seed incubation; however, using a drum seeder, no difference was observed among 24, 48 and 72 hours incubation. Very recently, CIMMYT has developed a 2-WT tractor-operated Versatile Multi-crop Planter (VMP) with the provision to use adjustable row spacing of crops for zero tillage, strip tillage, single pass shallow tillage, bed planting, and even conventional tillage (Islam et al 2010). The VMP has facilities to sow seed and place basal fertilizer simultaneously in a single pass operation under different tillage systems. To obtain the direct-seeded rice establishment benefits, the VMP was evaluated to assess the performance of sprouted rice seed sowing. A field study was undertaken to determine the establishment of sprouted rice seed and estimate the damage of radicle and plumule during mechanized sowing; and to determine the optimum time of rice seed incubation for grain yield.