Determination of Suitable Planting Date and Nitrogen Rate Hybrid Maize in Vientiane Plain

Abstract

The optimum sowing date for hybrid maize (cv. LVN-10 and LVN-61) in summer - autumn and autumn - winter season was investigated and determined by experiments conducted at the National Center for Research on Crop Varieties (Naphok). In both years 2006 and 2007 three sowing dates were practiced: 28 April, 8 May and 18 May in 2006; 18 October, 28 October, and 7 November in 2007. In each season, a constant dose of 10 tones manure, 60 kg P₂O₅ and 60 kg K₂O per hectare was applied.  The nitrogen rates, however, varied and included following rates 0 kg, 60 kg, 90 kg,  120 kg, and 150 kg per hectare. The experiments were arranged in a RCBD with 3 replications and plot size of  21 m².  The results indicated that the most suitable sowing date in summer - autumn season for corn in Vientiane Plain ranged from 20 April to 15 May, in autumn - winter from 30 October to 15 November. The optimum nitrogen dose for LVN-10 variety in both autumn - winter and summer - autumn season is 150 kg and for LVN-61 variety is 120 k