Effect of continuous application of inorganic nitrogen fertilizer on selenium concentration in vegetables grown in the Taihu Lake region of China

• Published in: Plant and soil 2015-08, Vol.393 (1-2), p.351-360
• Main Authors: Li, Sumei, Bañuelos, Gary S, Min, Ju, Shi, Weiming
• Format: Article
• Language: English
• Subjects: Agrochemicals; Biomedical and Life Sciences; Crop production; Ecology; Fertilizer application; Fertilizers; field experimentation; Greenhouses; Health aspects; Lakes; Life Sciences; Mineral fertilizers; nitrate nitrogen; Nitrates; Nitrogen; Nitrogen fertilizers; phosphorus; Plant Physiology; Plant Sciences; Regular Article; Selenium; Selenium (Nutrient); selenium fertilizers; soil; Soil fertility; Soil Science & Conservation; Soils; vegetable growing; Vegetables
• ISSN: 0032-079X; 1573-5036
• DOI: 10.1007/s11104-015-2496-3

BACKGROUND AND AIMS: Vegetables provide an important source of selenium (Se) for many regions of China. Excess nitrogen (N) fertilizers are commonly used for vegetable production. In this regard, the effect of inorganic N-fertilizer application on the Se content in soils and plants was evaluated in vegetables produced in a polytunnel greenhouse vegetable system. METHODS: Vegetables were continuously cultivated for 6 years in a microplot field experiment and treated annually with conventional N fertilizer (870 kg ha⁻¹ inorganic fertilizer) and 0 kg N ha⁻¹ as control treatment in polytunnel greenhouse vegetable system in the Taihu Lake region of China. Both treatments included 234 kg ha⁻¹ N provided by manure. After each harvest, soil and vegetable samples were collected, and analyzed for soil NO₃-N, Olsen-P, Se, phosphate extractable S and Se and vegetable Se. RESULTS: Six years of continuous application of inorganic N-fertilizer resulted in a significant accumulation of NO₃-N, Olsen-P and extractable S in the soil over the course of the experiment. Soil NO₃-N concentration accumulated up to 600 mg kg⁻¹ with application of inorganic N-fertilizer, while soil phosphate extractable Se and vegetables Se concentration were significantly lower than that those grown in control treatments. The negative effect of continuous application of inorganic N-fertilizer on vegetable Se concentration may be a consequent of excessive accumulated soil NO₃-N. When NO₃-N concentration was greater than 300 mg kg⁻¹, vegetable Se concentration was negatively correlated with soil NO₃-N. CONCLUSIONS: The negative effect of continuous application of inorganic N-fertilizer on vegetable Se concentrations was likely the result of soil nitrate’s competitive or antagonistic effect on Se uptake by vegetables grown in an intensive polytunnel vegetable cultivation system.