Nitrate Leaching Pattern from Slow Release Fertilizer under Polyethylene Film Mulching and Non-Mulching in Sesame (Sesamum indicum L.).
Dong-Wook Lee*, Ki-Do Park, Chang-young Park, Il-Soo Son, Ui-Gum Kang, and Sung-Tai Park. National Yeongnam Agricultural Research Institute, R.D.A, 1085 Naeidong, Milyang, South Korea
Nitrate (NO3-N) leaching from urea, cyclodiurea (CDU), and Latex-Coated Urea (LCU) was measured under Polyethylene Film Mulching (PFM) and Non-Mulching (NM) in Korean silty clay loam soils during sesame cultivation. The concentrations of NO3-N in soil solution at 21 days after urea treatment were 26mg L-1 in PFM and 83mg L-1 in NM, while those from CDU and LCU were 23mg L-1 and 14mg L-1 in PFM and 28mg L-1 and 18mg L-1 in NM, respectively. The NO3-N concentration of leachate at 44 days after urea application was 11 mg L-1 in PFM and 10mg L-1 in NM. On the other hand, the NO3-N concentration of leachate in CDU and LCU treatment was about 25% lower compared with that of urea treatment in PFM, while the NO3-N concentration of CDU and LCU treatment in NM did not change unlike that of urea. However, NO3-N concentration of leachate after 44 days was not significant in all treatments. The concentration of NO3-N in soil at 22 days after urea treatment in PFM was 130mg kg-1, while those of CDU and LCU treatment were 75mg kg-1 and 65mg kg-1, respectively. At the same time, concentration of urea-N in soil of urea treatment was 2 mg kg-1 in PFM compared with 5mg kg-1 and 7mg kg-1 in CDU and LCU treatments, respectively. NO3-N and urea-N contents in soil of urea treatment in NM were less than both CDU and LCU treatments. Consequently, nitrogen uptake efficiency of sesame plant, upon application of slow release fertilizers such as CDU and LCU, increased by 10%–25% in PFM and 3%–10% in NM compared with that of urea.