THE EFFECT OF PLANTING DATE ON THE GROWTH AND YIELD OF PEANUT LV20 VARIETY IN THE AUTUMN - WINTER CROP IN SOME NORTHERN PROVINCES OF VIETNAM

Abstract

The study was conducted to evaluate the effect of sowing time on the growth and yield of the groundnut variety LV20 in Hanoi city, Thai Nguyen province and Nghe An province during the Autumn - Winter season of 2023. The experiment was arranged in a Randomized Complete Block (RCB) design with three replications. The experimental plot size was 6 m² (5 × 1.2 m). The fertilizer background applied per hectare was 30 kg N, 90 kg P₂O₅, 60 kg K₂O, 500 kg lime powder and 1 ton of Song Gianh organic microbial fertilizer. The planting density was 40 plants/m² (25 cm times 20 cm times 2 seeds/hill) with five treatments corresponding to five sowing dates: August 28, September 4, September 11, September 18 and September 25 (in Thai Nguyen province and Nghe An province) and August 21, August 28, September 4, September 11 and September 18 (in Nghe An province). Results indicated that the most appropriate sowing time for the LV20 groundnut variety in the Autumn - Winter season ranged from August 18 to September 4 (in Hanoi City and Thai Nguyen province) and from August 21 to August 28 (in Nghe An province). Groundnut plants under these conditions exhibited optimal growth and development, resulting in superior values for number of sound pods per plant, 100-pod weight, 100-kernel weight, and shelling percentage. The actual yield recorded at these two optimal sowing times was the highest and significantly different from the remaining sowing dates at the 95% probability level; 3.53 - 3.60 tons per hectare in Nghe An province; 3.66 - 3.72 tons per hectare in Hanoi city and 3.46 - 3.73 tons per hectare in Thai Nguyen province, respectively.