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 [electronic resources].

Includes references.

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 N03-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.

Summary in Arabic.

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