Performance of an Optimized Nutrient Management Approach for Tomato in Central Sri Lanka

Abstract

A systematic approach of fertilizer recommendation for tomato was evaluated in central Sri Lanka. An optimum (OPT) treatment was formulated based on soil analysis for available nutrients and nutrient-fixation capacities and tested with sorghum (Sorghum vulgaris L.) in a greenhouse and with tomato (Lycopersicon eculentum L.) in the field for four seasons. Soil analysis revealed deficient levels of nitrogen (N), phosphorus (P), potassium (K), sulfur (S), boron (B), and zinc (Zn) with high fixing capacities for P, K, S, and B. Greenhouse survey confirmed nutrient deficiencies except for Zn. A field study with 17 treatments including OPT showed significant main effects and interaction of fertilizer treatment and season for tomato yields and profit. The OPT providing 220 kg N, 160 kg P, 250 kg K, 50 kg S, and 1 kg B per ha often gave greater yields and profits than treatments with lower nutrient rates, but treatment providing N, P, and K at 150% of optimum was superior.

Keywords:

• Micronutrients
• soil fertility
• tomato

Acknowledgment

The authors greatly acknowledge the International Plant Nutrition Institute for the financial support. The advice and suggestions from Sam Portch (formerly with the Potash and Phosphate Institute, China Program), T. N. Rao (formerly with the Potash and Phosphate Institute, India Program), and A. H. Hunter (Agro Services International Laboratory, USA) are greatly acknowledged.