ESTABLISHMENT OF LOW COST NO-TILLAGE CULTIVATIONS AND INVENTION OF NEW CONTROLLED AVAILABILITY FERTILIZERS FOR THEM WITH SPECIAL REFERENCE TO ENVIRONMENTAL PROBLEMS

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No-tillage (NT) cultivation of both rice and corn were conducted using controlled availability fertilizer (CAF) to reduce both labor costs and environmental degradation while maintaining high yields.Innovative rice cultivation methods was developed by using sigmoid type of CAF (POCUs-100 ; 100-days release duration-polyolefin coated urea) as a single basal application of total nitrogen in nursery box for the NT transplanting system. Brown rice yields of NT system with POCUs-100 in nursery box were statistically the same or grater than those of conventional tillage (CT) system with readily available fertilizer (RAF). Recoveries of basal POCUs-100-N of rice plants (73-83%) were much higher than those of RAF (20-39%) and thus reduced greatly environmental degradation caused from fertilizer. Further more, no-tilled direct seeding of rice without soil cover were developed using Y-shape furrow and CAF considering the dominant presence of poor drained paddy soils in north eastern Japan. Seedling establishment of rice was improved by using both Y-shape furrow and CAF in combination with POCUs-100 and Long 40 containing nitrate and ammonia.In dent corn cultivation, Co-situs application of CAF (POCU-30+POCU-70) and corn seeds in no-tillage system was studied in comparison with that of RAF and corn seeds. Emergence rate of corn seedling was more than 90% in CAF plot while that in RAF plot was less than 40% because of burning problem. The dry matter production of corn in NT with CAF was the same or greater than that in CT system applied both basal and top-dressed RAF.Therefore, it was concluded that NT with CAF in both rice and corn cultivation is innovative feasible method to reduce both labor and environmental degradation while maintaining high yield.