SOIL FERTILITY AND LIMITED NUTRIENT FACTORS OF INTENSIVE VEGETABLE ZONES IN THAI NGUYEN PROVINCE - Nghiên cứu phân bón

18
May

Nguyen Duc Dung, Tran Thi Hue, La Tuan Anh

Abstract

The assessing of soil situation and limiting factors is the basis for contributing to the appropriate nutrient management, improving the crop yield and quality towards to VietGAP standards and safe vegetable production. The study was carried out based on the survey, collection and analysis of soil of 90 points in major vegetables production of Pho Yen, Phu Binh districts and Thai Nguyen city, during 2017 – 2018. The results showed that the fertility of the soil was low and some chemical properties vary widely between study sites, pH ranges from 3.79 to 7.08; OC (organic carbon) from 0.53 to 3.13%, P₂O₅ available from 2.34 to 18.20 mg 100 g^-1 soil, K₂O exchangeable from 2.96 to 45.20 mg 100 g^-1 soil, Ca⁺⁺ exchangeable from 1.05 to 8.29 cmol kg^-1 soil, Mg⁺⁺ exchangeable from 0.15 to 6.7 cmol kg^-1 soil, Mn⁺⁺ exchangeable from 11.20 to 595.0 mg kg^-1 soil. With heavy metal content in soil: Arsenic from 1.57 to 11.60 mg kg^-1 soil, Cd from 0.02 to 0.5 mg kg^-1 soil and Pb from 16.80 to 46.50 mg 100 g^-1 soil. Heavy metal contents were within the permissible limits for agricultural soil production; however, some fields have arsenic levels close to the allowable limits of heavy metals in the soil.

Keywords: Heavy metal, intensive vegetable, organic carbon, pH_KCl, phosphorus available,  potassium available, soil fertility.