Cam Sanh - a special kind of orange is cultivated in all parts of Vietnam. This kind of fruit has been cultivated by People in Ham Yen district of Tuyen Quang province for a long time with rich experiences. However, extensive farming is a very popular method of cultivation. The application of integrated technique management with appropriate level of nitrate to cultivate "Cam Sanh" in Ham Yen has released some conclusions as following: - Integrated technique management methodologies play an important role to the development, quantity and quality of "Cam Sanh". - If the level of used fertilizer is low and technical methodologies (formula I) are not applied, "Cam Sanh" trees' development and efficiency is not as good as other formulas
- In the same condition of experiment (from formula 3 to formula 6), different levels of phosphate influence "Cam Sanh" trees' development at different levels. This influence tends to increase when the amount of phosphate is used increasingly. - To sum up the results of monitoring on the growth, development and yield of the experimental formulas, the formula 6 contributes the highest efficiency, but formula 5 has the most significant effect on the general evaluation of the effectiveness of biomass and economic efficiency.