Nitrate leaching and nitrogen recovery following application of polyolefin-coated urea to potato.
High N fertilizer and irrigation amounts applied to potato (Solanum tuberosum L.) on coarse-textured soils often result in nitrate (NO3) leaching and low recovery of applied fertilizer N. This 3-yr study compared the effects of two rates (140 and 280 kg N ha(-1)) of a single polyolefin-coated urea (PCU) application versus split applications of urea on 'Russet Burbank' potato yield and on NO3 leaching and N recovery efficiency (RE) on a loamy sand. Standard irrigation was applied in all years and excessive irrigation was used in another experiment in the third year. At the recommended rate of 280 kg N ha(-1), NO3 leaching during the growing season was 34 to 49% lower with PCU than three applications of urea. Under standard irrigation in the third year, leaching from five applications of urea (280 kg N ha(-1)) was 38% higher than PCU. Under leaching conditions in the first year (> or = 25 mm drainage water in at least one 24-h period) and excessive irrigation in the third year, PCU at 280 kg N ha(-1) improved total and marketable tuber yields by 12 to 19% compared with three applications of urea. Fertilizer N RE estimated by the difference and 15N isotope methods at the 280 kg N ha(-1) rate was, on average, higher with PCU (mean 50%) than urea (mean 43%). Fertilizer N RE values estimated by the isotope method (mean 51%) were greater than those estimated by the difference method (mean 47%). Results from this study indicate that PCU can reduce leaching and improve N recovery and tuber yield during seasons with high leaching.
Zvomuya
Francis
F
Dep. of Soil. Water, and Climate, Univ. of Minnesota, St. Paul, MN 55108-6028, USA.
Rosen
Carl J
CJ
Russelle
Michael P
MP
Gupta
Satish C
SC
D005308:Fertilizers; D009566:Nitrates / Q000032:analysis*; D009584:Nitrogen / Q000032:analysis*; D011090:Polyenes / Q000737:chemistry; D012621:Seasons; D012989:Soil Pollutants / Q000032:analysis*; D011198:Solanum tuberosum; D014508:Urea / Q000737:chemistry*; D014873:Water Pollutants / Q000032:analysis*; D014881:Water Supply
D005308:Fertilizers; D009566:Nitrates; D011090:Polyenes; D012989:Soil Pollutants; D014873:Water Pollutants; C035051:PL 732; D014508:Urea; D009584:Nitrogen