Development of direct sowing culture of paddy rice [Oryza sativa] fields for high yield by dense and zigzag sowing

"We developed as follows after examined (Direct Sowing Culture of Paddy Rice Fields for High Yield by Dense and Zigzag Sowing) as technique of direct sowing culture which can get to brown rice yields more than 580kg per 10 a sa same as planting culture on paddy rice fields. This technique is as follows. (1) We improved on rice direct seeder combined paddy harrow of the seeded rice which can sow on high density of 28.3 hill per square m more than usual density of 22.2 hill and sow on zigzag hill in the place of row sowing. And we developed methods which can judge shooting disk revolutions by depth of golf bowl breaking into soils. (2) Yield component for gettng to brown rice yields 580 kg per 10a is 30,000-32,000 rice grains per square m, 22.0-22.2 g at thousand _ekernel-weight and 80__of ripened grains on the direct sowing cultures rice variety _gHAENUKI_h by improved direct seede. Best sowing time for high yields is the latter part of April and at heading time until 12 August as follows. And we developed standards of additional manure by stem numbers on the 5 leaves, of ear manuring by growth amounts (stem numbers*leaf colors) on the 10 leaves which can be stabilized growth after emergence and establishment of seedling. In addtion developed standards of lodging tolerance by growth amounts on 10 and 11 leaves. (3) We mede the follows clear about methods of maturing heading time at direct sowing culture as same as plantig culture. In case of ponding water release after seeding, the rate of establishment of seeding is large more than 70__on the condition of the dairy max temperature 19degC at term of 25 days after sowing. As a result, at the flat area in Yamagata prefecture we can seed directly on the rice fields from 25 April. (4) We made the follows clear about effective times of dusting herbicide for establishment of seeding retes more than 70__. 1 In case of sowing right or a day after puddling and leveling, we can dust herbicide from the eighth day after sowing to tenth on the condition of the daily mean temperature 14degC at term of 10 days on 1.0 leaves Japanese millet and on incomplete leaf rice. 2 On the low condition of the dairy mean temperature 12degC can dust herbicide from the twelfth day after sowing to fourteenth day on 1.5 leaves Japanese millet and on 1.0 leaves rice. (5) At the hill-seeded rice by improved direct seeder brown garin yields increeased more than 5-7__ as compared with usual hill-seeded rice. The reason is that the improved hill-seeded rice grow early and yield component of panicle and grain numbers increases comoared with the ususal. At the high density and zigzag hill-seeded rice, characteristics of dry matter production and ripenig are higher than the usual hill-seeded rice. Because of dry weight and carbohydrate metaborism during ripening period increase little compared with the usual. 6_jIn case of direct sowing culture getting to yields sa same as planting culture, profit on direct sowings increases to YEN3,000 per 10a or so as compared with plantings. Then we expect that technique of direct sowing culture change to the basic culture without making up for planting."