Anan Polthanee and Vidhaya Tre-loges

pp. 197 - 207

Abstract

The experiment was conducted in a farmer’s field in Ban Fang District, Khon Kaen Province in 1999-
2000. The objective of this study was to investigate the effect of soaking seed in water or not soaking before
seeding, and fertilizer placement (surface broadcast at seeding, banding below the seed at seeding and banding beside the plant row 10 days after seeding) on growth and yield of soybean grown after rice in the postmonsoon season. The results showed that soaking seed before seeding had no significant effect on leaf area
per plant, total top dry weight, root length density, pod number per plant, seed number per pod, 100-seed
weight and seed yield of soybean. However, soybean growth, yield components and seed yields tended to be
higher with no soaking. Therefore, soaking seeds in water before seeding had no advantage over no soaking
in terms of early emergence and early maturity before the plant was subjected to water stress at grain filling
phase. Fertilizer placement had a significant effect on growth and yield of soybean. Banding application gave
higher leaf area per plant, total top dry weight, root length density, pod number per plant and seed yield than
those of broadcast application. Banding generally increased leaf N, P and K concentration. There was no
significant difference in seed yield between belowband and sideband application. Belowband application
tended to produce higher seed yield than that of sideband application. Belowband application at planting saved labour as compared with sideband application. To obtain a satisfactory yield of soybean grown following rice in the post-monsoon season during the rainless period, however, shallow depth of groundwater table
to provide upward movement of water to the root zone should be considered.