Sorption water potential of different soils as influenced by nitrogen and potassium fertilizers additions [electronic resource].

Includes references.

Laboratory experiment was carried out during three month at 2006-2007 in Soils Dept., Faculty of Agric., Mansoura Univ., Egypt, to study the effect of adding two type of nitrogen fertilizers, ammonium sulfate and ammonium nitrate both of rates (0, 100, 150 and 200 kg N fed⁻¹) and potassium fertilizer (Le. 0, 80, 120 and 160 kg K₂O fed⁻¹ ) on soil water potential under different solis. The results of sorption curves illustrated that the most effective treatment on increase maximum hygroscopic water (M.H.W) was the third one of any fertilizer used in this study (200 kg N fed⁻¹ or 160 kg K₂O fed⁻¹). Furthermore the most affected fertilizer in clayey soil was potassium sulfate then ammonium Nitrate, but in loamy soil it was potassium sulfate then ammonium sulfate at relative humidity (R.H) 93%. In sandy soil potassium sulfate was the affected one then ammonium sulfate at R.H 100%. Based on the results, adding chemical fertilizers had obvious effect on the increase of (M.H.W) in all studied soils. Whereas they considered salts and may be have ability to absorb high amounts of water especially potassium sulfate and ammonium sulfate fertilizers. In addition they increase soluble salts in all studied soils. E.C values of adding 160 kg K₂O fed⁻¹in clayey, loamy and sandy soils were 3.4, 3.0 and 1.9 dS m⁻¹, respectively. While E.C values of adding 200 kg N fed⁻¹in clayey, loamy and sandy soils were 3.0, 2.8 and 1.4 dS m⁻¹ respectively at R.H 93%. Also, clayey soil was higher in its adsorption water content comparing with loamy and sandy soils. This illustrates the effect of both soil texture and the chemical fertilizers in soil water retention and accordingly its availability in soils.

Summary in Arabic.

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