Effect of Tilling and Seeding Methods on Seedling Emergence, Growth and Yield of Rice Direct-seeded in Well-drained Paddy Field

Abstract

This study was conducted to examine the effects of tilling and seeding methods on the growth of rice direct-seeded in well-drained paddy fi eld. The tilling methods used were plowing, non-tilling, and non-tilling-V-shape furrowing. The seeding methods used were dibbling at 1, 3 and 5 cm depth under the plowing condition, dibbling at 1 and 3 cm depth under non-tilling condition, and shallow and deep soil covering under the non-tilling-V-shape furrowing condition. Cultivar Koshihikari was used in this study. The percentage of emergence in most plots was higher than 70%, except for dibbling at 5 cm depth under plowing condition. Mesocotyl and the second internode elongated in some plots. In all plots, non-productive tillers rarely appeared. Many panicles differentiated on the tillers at nodal positions higher than the fourth node from the neck node of panicle, except for the plants seeded by dibbling at a 1 and 3 cm depth under a plowing condition. Dry matter weights of leaves and culms in direct-seeded plants were biased to the lower part of the plants compared with the transplanted plants. As a whole, the plants seeded by soil covering under non-tilling-V-shape furrowing condition showed the best growth, although there is a possibility of lodging in the fi eld. When seeded by dibbling at a 3 cm depth under a non-tilling condition, the emergence was good and the lodging was not observed, but the panicle number was somewhat low.

Rice Cultivation by Direct Seeding into Untilled Dry Paddy Stubble

“…4 Relationships between the average seedling number and the average productive panicle number (the upper panel), and between the average seedling number and the average winnowed paddy yield (the lower panel). Okabe et al (2003) reported that panicle number decreases with increasing seeding depth. In direct seeding to dry rice fields, the germination rate is very sensitive to meteorological factors.…”

Multiple Scattering Simulation of Ultrasonic Shear Wave in Unidirectional Carbon/Epoxy Composites

“…These quantities are given by the phase velocity c eff and the attenuation coefficient eff of the effective medium from eqs. (6) and (7). Eqs.…”

“…Eqs. (6) and (7) can be used to determine c eff and eff when the complex quantity T is given, provided that the parameters Fig. 4 Schematic illustration of the macroscopic one-dimensional model with the wave field representations, where the coefficients R, T, A and B are determined by the continuity conditions.…”

“…Namely, eqs. (6) and 7yield a set of nonlinear equations for c eff and eff , which can be solved numerically. In the present study, the complex transmission coefficient T was obtained from each multiple scattering simulation.…”

“…Ultrasonic nondestructive characterization of fiber-reinforced composite materials is becoming increasingly important [1][2][3][4][5][6] as these materials find yet wider applications owing to their high stiffness-to-weight and strength-to-weight ratios. In fiber-reinforced polymer-matrix composites, ultrasonic waves attenuate significantly due to the viscoelastic nature of the polymer matrix as well as the scattering by the reinforcing fibers.…”