Effect of Furrowing Upon Transplanting on Plant Growth and Grain Yield of No-till Paddy Rice

Abstract

To achieve stable transplanting in no-till fields, add-on devices are designed for attachment to a commercially available rotary-type, ride-on transplanters for mat seedlings. Flat runners on the both sides of the transplanter were removed and furrowing discs were attached ahead of the tines to stabilize the plants. Commercially available circular saws were used as discs and set at an angle to the traveling direction to form V-shaped slits by rolling while cutting residues on the soil surface. No slit in the puddled soil as the control, in the no-till soil, the one or two discs（165 or 147 mm in diameter）and no the disc were set at each row of the transplanter. A pot seedling transplanter and a crank-type transplanter were also evaluated, with which no-till transplanting was physically feasible. Transplanting efficacy, plant growth, and grain yields were then measured in all the experimental plots. Transplanting in no-till soil without the slits resulted in lodging or floating, although these were avoided with the pot seedling transplanter and with the cranck-type transplanter, and generally in nearly half the grain yield compared with that（5.4 t/ha on the average, sieved brown rice）of the puddled soil. Furrowing with two 165 mm discs and adjusting the lowest position of the transplanting tines to the lowest depth of the slits yielded nearly the same grain as that of the puddled soil. Reducing the diameter or the number of the discs correspondingly reduced the grain yield down to 2/3 of that of the puddled soil. The reduced grain yield was attributed to the aberrant settlement of the plant roots, which affected the initial growth of the plants, resulting in the reduced number of panicles.