Fertility Management of the Soil-Rhizosphere System for Efficient Fertilizer Use in Vegetable Production
Ma Chin-hua and Manuel C. Palada AVRDC — the World Vegetable Center P.O. Box 42, Shanhua, Tainan, Taiwan 74199, October 2006

Abstract
Extensive researches on soil-rhizosphere processes have shown that a very small proportion of rhizosphere soil is of critical importance for plant growth and health. The soil-rhizosphere zones occupied less than 5-7% volume of the upper 15 cm surface soil in a vegetable field. Designing sustainable management practices that focus on rhizosphere soil is more efficient and cost-effective for improving crop productivity with fewer agrochemical inputs. The innovative Starter Solution Technology (SSTi) for applying nutrients directly to the soil-rhizosphere system is proposed in this paper. The SST reduces fertilizer application, increases vegetable yields, decreases fertilizer residues in the soil and is simple to apply. Other practices for managing the fertility of rhizosphere soil, such as supplying nutrients through drip irrigation, applying organic fertilizers and biocharcoals to increase soil-buffering capacity and localized amendment as strategies for problem soils are also discussed. All of the proposed management practices can be easily adopted by Asian farmers.

Key words: Soil-rhizosphere system, Starter Solution Technology, Drip irrigation, Localized
amendment, Biocharcoal application

International Workshop on Sustained Management of the Soil-Rhizospherei System for Efficient Crop Production and Fertilizer Use 16 – 20 October 2006 Land Development Department, Bangkok 10900 Thailand