EFFECT OF SOME LEGUME COVER CROPS AND ORGANIC. FERTILIZER ON PETIOLE NUTRIENT CONTENT , PRODUCTIVITY AND FRUIT COMOSITION OF THOMPSON SEEDLESS GRAPEVINES.

This investigation was undertaken for three seasons 2003. 2004 and 2005
on seven years old Thompson seedless grapevines grown in a clay loam soil at EL—
Baramon Research station. Mansoura. Dakahlia Govemorate. Treatments included in
the experiment were : management of row middtes (cultivated vs. perennial legume
cover crops) and nitrogen fertilization (compost vs. mineral fertilizer). Leaf area. bud
fin‘lity. vine nutrititional status. yield. fruit composition weight of prunings were
monitored each season (2003 — 2005)
.Conventional cultural practices (cultivation and mineral fertilizer) produced
the highest yield, cluster weight .frult weight 8. diameter. TSS . TSSIacid ratio in the
first season .yet. the significant difference disappeared in the third season owing to
that the legume cover crop had become fully established
Cover crop with mineral fertilizer treatment increased leaf area . weight of
prunings and mineral content of leaf petioles in the first season whereas , cover crop +
compost treatment gave the highest values in the third season .
The highest nitrate and nitrite residues in the berries were observed in
mineral fertilization .whereas the lowest values were gained from compost with peas
or clover cover crop treatments.