NITRATE TRANSPORT IN CLAY SOILS AND ITS LOSSES INTO FIELD DRAINS TILES FROM UREA APPLIED FOR SUGAR BEET | ||||
| Journal of Soil Sciences and Agricultural Engineering | ||||
| Article 5, Volume 32, Issue 6, June 2007, Page 4987-4998 PDF (662.41 K) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/jssae.2007.201300 | ||||
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| Author | ||||
| A. S. Antar | ||||
| Soil, Water and Environment Res. Inst., Agric. Res. Center Egypt. | ||||
| Abstract | ||||
| Two field experiments were carried out at Fuwwa district, Kafr El-Sheikh Governorate (North Nile Delta), during the two growing seasons 2005/2006 and 2006/2007 to find out the impact of tile drainage system with two spacings of 30-m and 60-m on nitrate losses. N-fertilizer in the form of urea was added in two doses before the first and second irrigation. Results indicated that, water table levels increased with time after irrigation. The drop was faster with 30 m spacing than 60 m one. Drain discharge were higher for 30 m spacing (0.09 – 9.15 mm/day) than 60 m one (0.34-7.48 mm/day). NO3- content of the soil was decreased with the increasing of soil depth. The highest contents of NO3- were found after fertilizer application, and ranged from 29.4 to 61.5 ppm. These contents were reduced at the end of seasons. After fertilizer application, NO3- content was lower to some degree in 30 m spacing than 60 m spacing. At the end of seasons, NO3- content was increased under 60 m spacing than 30 m by about 26.3% and 24.9% for the first and second seasons, respectively. Nitrate concentration in drainage water during the two growing seasons was reduced with the time and it ranged from 11 to 18.5 ppm. The concentration of NO3- was higher under 30 m spacing than 60 m spacing. The average of NO3- concentrations for 30 m and 60 m spacings in the first season were 12.9 and 11.9 ppm, respectively. The estimated loss of NO3- was 16.7 kg/fed for 30 m drain spacing and 11.7 kg/fed for 60 m. Also, in the second season the estimated loss of NO3- was 16.8 kg/fed for 30 m drain spacing and 11.8 kg/fed for 60 m one. NO3- concentration in the groundwaterranged from 12.4 to 20.1 ppm and reduced at the end of seasons. The concentration of n in groundwater was higher with 30 m spacing than 60 m one. Root, shoot and gross sugar yield of sugar beet was higher under 30 m spacing than 60 m one. N-uptake by root and shoot was paralleled to the yield results, whereas, N-uptake of root and shoot was higher with 30 m spacing than 60 m spacing, in both seasons. Nitrogen application efficiency (%) was higher in 30 m spacing than 60 m for both seasons. Research should be focused on designing practical strategies to minimize the preferential flow during the first few irrigations after fertilizers application and consequently nitrate loss. Continued research is also needed on ways to better predict and apply N to more closely match the needs of the crop during the growing season. | ||||
| Keywords | ||||
| Drain spacing; discharge rate; nitrate transport; N-uptake; sugar beet | ||||
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