Nutrient and Heavy Metal Contents in Organic Fertilizers Produced in Fujian

  Objective  A survey was conducted to determine the quality of the commercial organic fertilizers produced in Fujian.

  Method  Fifty representative organic fertilizers were sampled in areas of Nanping, Zhangzhou, Longyan, Sanming, and Fuzhou during July to September 2019. Contents of nutrients and heavy metals of the specimens were determined.

  Result  According to the national standards for organic fertilizers in China NY 525—2012, 8% of the samples failed to meet the standard on pH, 10% on organic matters, 28% on total NPK, and 32% on moisture content. Heavy metals, including Pb, Cd, Cr, Hg, and As, were detected in all samples but did not exceed the safety limits. The organic fertilizers made of biomass were significantly higher on K and total nutrients (NPK) than other organic ingredients. Those of livestock manure-origins were higher on heavy metals, except Hg, than the others. The fertilizers made of pig manure were significantly higher in the contents of N, P and total nutrients than those made of chicken or sheep manure. Among the heavy metals, Cr was highest in the pig manure fertilizer, followed by the chicken and sheep manure fertilizers. And, Pb, Cd, Hg, and As were highest in the chicken manure fertilizer, which contained significantly more As than the sheep or pig counterparts.

  Conclusion  Heavy metals in the sampled organic fertilizers produced in the province did not exceed the national standards. However, the nutrient contents tended to be substandard, and the moisture content too high. The deficiency on NPK of these products was particularly alarming that proper measures should be implemented for adequate fertilization applications.