Tantawy, Manal F. ; M. A. El-Sherif and M. A. H. Mohamad( 2013). Effect of gypsum and mineral nitrogen fertilization on nitrogen forms distribution through
agro-system and yield of potato grown on a clay soil under tile drainage system conditions
J. Soil Sci. and Agric. Eng., Mansoura Univ., Vol. 4 (8): 661 - 676, 2013
Abstract: A field experiment was carried out on an alluvial clay soil of a pilot field at Talla area, Minufiya Governorate , Egypt during two successive growth winter seasons 2011 / 2012 and 2012 / 2013 to study the effect of agricultural gypsum application and mineral -N fertilizer ( ammonium nitrate , 33 % N ) solely or in combination under different distances of tile drain on some soil properties and yield of potato plants (Solanum tuberosum L.) Scotland cv . Nieta. Agricultural gypsum was applied at rates of 0 and 3 ton/fed. as a protection dose. Nitrogen fertilizer was added at rates of 0 and 500 kg / fed. ( 165 kg N / fed. ) , which equals 100 % of the recommended dose. The field was provided by tile drains spaced at 30 m with 1.5 m depth. The content of nitrogen forms ( NH4-N and NO3-N ) distribution through different soil depths, ground and drainage waters in relation to time were studied. Water table depth after the first and second irrigations was measured above and midway of the laterals. Ground and drainage waters were analyzed. Tubers and shoots of potato contents of NH4-N and NO3-N were determined. The experiment was carried out in a split split - plot design with three replicates .The obtained data show that ground water depth was increased with increasing the period after irrigation especially after the first irrigation. The greatest increase of ground water depth was found above the laterals. Also , this depth was increased with gypsum application. After the first and second irrigation and harvesting stage, the soil content (mg/kg) from available NH4-N and NO¬3-N was decreased with the increase of soil depth. The greatest decrease of soil content of available N was found above the laterals in the soil treated by gypsum and unfertilized by N especially at harvesting stage. With the different treatments, the soil content of NH4-N was higher than of NO3-N. On the other hand, ground and drainage water content (mg/l) of NO3-N were higher than those of NH4-N with all treatments under study. Also , this content was increased with both gypsum and N fertilization applications. Soil salinity values were relatively affected by drain spacing treatments. In surface layer , the soil salinity value was 1.35 and 1.54 dSm-1 for above and midway (15 m) drain spacing. Results indicate that the highest tubers yield of potato plants was found in the soil treated by gypsum and fertilized by N above the laterals (16.39 ton / feddan). The highest content (%) of the two N forms in both shoots and tubers were found in the plants grown on above the laterals in the soil treated by gypsum and N fertilizer.
Keywords: (Agricultural gypsum , Tile drainage, Nitrogen fertilization, Potato plants , Chemical composition, Ground and drainage water. )
