Role of Nitrification Inhibitor Combined with Different Nitrogen Sources in Decreasing Injurious Components in Spinach

Abstract

Vegetables spinach (Spinaciaoleracea L.), represents good sources of vitamins B and C as well as minerals such as iron, calcium and magnesium, besides the dietary fibers, nitrate and oxalate, which usually affected by both N rate and form. Therefore, pot experiments were carried out in green house of Agriculture and Veterinary Medicine Experiment Station, Qassim University to find ways to prevent undesirably high nitrate and oxalate contents. However, increasing useful compounds such as vitamins and minerals were also considered. The treatments included two nitrogen sources viz., recommended dose (100%) of nitrate (NO 3 -) and ammonia (NH 4 +), 50% of each sole or in combination with or without nitrification inhibitor (2-chloro-6-trichloro-methyl-pyridine-nitrapyrin). Results were noticed that nitrate and oxalate concentrations in spinach leaves were reduced by application 50% /50% N mixture compared with higher rates of each. Noticeable, additional reduction caused in nitrate concentrations, soluble and insoluble oxalates, highest concentrations of vitamins C and B9 as well as minerals contents (Ca, K and Fe) in leaves by conjunction mixture with nitrification inhibitor (nitrapyrin). Although highlight results obtained herein, more studies are needed to find out the recommendation can followed by farmers.