Ho Ando

Comparison of growth and 15nitrogen recovery between direct seeded flooded and transplanted rice at early growth stage under conventional and delayed planting

Abstract In the tropics, broadcast seeded flooded rice (BSFR) was found to show a higher 15N recovery than transplanted rice (TPR) under the same fertilizer N management conditions mainly due to the higher initial growth rate at early stages as a result of the lack of transplanting shock. This study was conducted to compare the growth characteristics and 15N recovery at early growth stages between BSFR and TPR under conventional and delayed (low and high temperatures) planting environment in Japan. Under both planting environments, BSFR produced a larger number of tillers m-2 (600-700) than TPR (420-450) at the middle growth stage (89 d after seeding, DAS). However, TPR showed a larger crop dry weight accumulation at either planting time resulting in a higher total plant N uptake. Irrespective of the cropping method and time, dry weight was exponentially correlated with the plant uptake while 15N recovery showed a curvilinear relation to the N uptake. Under conventional planting, TPR showed a higher basal...