Ở các nước Đông Nam Á, bắp là cây lương thực quan trọng đứng thứ hai sau lúa. Các ghi nhận gần đây cho thấy năng suất bắp trung bình so với tiềm năng suất của một giống trong điều kiện khí hậu nhất định có cơ hội gia tăng hơn nữa bằng biện pháp quản lí cây trồng và dinh dưỡng tổng hợp | Omonrice 16: 88-92 (2008) IMPROVING OF MAIZE YIELD AND PROFITABILITY THROUGH SITE-SPECIFIC NUTRIENT MANAGEMENT (SSNM) AND PLANTING DENSITY Trinh Quang Khuong1, Pham Sy Tan 1 and Christian Witt2 1 Agronomy Department, Cuu Long Rice Research Institute, Cantho City, Vietnam Email: trinhquang_khuong@ 2 International Plant Nutrition Institute (IPNI), Southeast Asia Program, Singapore ABSTRACT Maize is the second most important cereal crop after rice in Southeast Asian countries. Currently, recorded average maize yields as compared to the yield potential for a given variety and climate indicate significant opportunities to further increase maize productivity through site-specific, integrated nutrient and crop management. The on-farm experiments were conducted at Tan Chau district, An giang Province, Vietnam in 2006 dry season and 2006 wet season on maize-maize-rice cropping system. The 10 treatments were the combination of planting densities: regular density 67,000 plants ha-1 (75x20cm), and improved planting density (iPD) 50x30cm, and ICM with high plant density 74,000 plants ha-1 (75x18cm), and fertilizer application methods: FFP (fertilizer farmer practices), SSNM and the omission plots of N, P and K on five farmer fields in a randomized completed block design. The results revealed that maize yields of 8-10 t ha-1 can be achieved in Tan chau, An giang. The highest yield was recorded at t ha-1 on alluvium soil in dry season and t ha-1 in wet season. Yields increased of about t ha-1 by increasing plant density. At planting density of 67,000 plants ha-1, improved plant density (50x30 cm) gave a better grain yield as compared to farmer’s planting density (75x20 cm). Improved planting density with higher NPK rate of SSNM got higher grain yield by t ha-1 and higher net benefit by 833 thousand VND ha-1 and 786 thousand VND ha-1 in 2006 DS and 2006 WS, respectively. Keywords: fertilizer farmer practices (FFP), grain yield (GY), improved planting
