Changes in soil characteristics as affected by different soil improvement techniques at Al-Fayoum Governorate [Egypt]

abonos npk contenido de agua en el suelo drainage systems egipto egypt engrais npk fertilidad del suelo labranza npk fertilizers red de drenaje rendement rendimiento soil chemicophysical properties soil fertility soil types soil water content teneur en eau du sol tillage tipos de suelos travail du sol type de sol yields