Effects of the nitrification inhibitor dicyandiamide on potassium, magnesium and calcium leaching in grazed grassland

• Published in: Soil use and management Vol. 20; no. 1; pp. 2 - 7
• Main Authors: Di, H.J, Cameron, K.C
• Format: Journal Article
• Language: English
• Published: Wallingford CAB International 01.03.2004
• Subjects: Agronomy. Soil science and plant productions; Biological and medical sciences; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; Soil-plant relationships. Soil fertility; Soil-plant relationships. Soil fertility. Fertilization. Amendments; Grassland; Agricultural chemical product; Calcium; Guanidine(1-cyano); Soil quality; Lysimetry; Nitrates; nitrate; SOIL CHEMISTRY; Inorganic element; Temperate zone; Ionic interaction; Antimicrobial agent; Field experiment; DAIRY FARMS; Inhibition; Magnesium; Grassland soil; Urine; cations; Substance loss; Nitrification inhibitor; Agricultural soil; Exchangeable cation; Grazing; Leaching; Soil management; Milk production; Inorganic cation; Urea; Nitrogen cycle; Inorganic nitrogen; Pasture; Chemical treatment; farm dairy effluent; Water pollution control; Nitrification; dicyandiamide; Potassium; Effluent; Cyanamides
• ISSN: 0266-0032; 1475-2743
• DOI: 10.1079/SUM2003205

Leaching of calcium (Ca), potassium (K) and magnesium (Mg) from urine patches in grazed grassland represents a significant loss of valuable nutrients. We studied the effect on cation loss of treating the soil with a nitrification inhibitor, dicyandiamide (DCD), which was used to reduce nitrate loss by leaching. The soil was a free-draining Lismore stony silt loam (Udic Haplustcpt loamy skeletal) and the pasture was a mixture of perennial ryegrass (Lolium perenne) and white clover (Trifolium repens). The treatment of the soil with DCD reduced Ca2+ leaching by the equivalent of 50%, from 213 to 107 kg Ca ha-1 yr-1 on a field scale. Potassium leaching was reduced by 65%, from 48 to 17 kg K ha-1 yr-1. Magnesium leaching was reduced by 52%, from 17 to 8 kg Mg ha-1 yr-1. We postulate that the reduced leaching loss of these cations was due to the decreased leaching loss of nitrate under the urine patches, and follows from their reduced requirement as counter ions in the drainage water. The treatment of grazed grassland with DCD thus not only decreases nitrate leaching and nitrous oxide emissions as reported previously, but also decreases the leaching loss of cation nutrients such as Ca2+, K+ and Mg2+.