This work was carried out during the two autumn seasons of 2015 and 2016 at
Ghazala Experimental Farm, Fac. Agric., Zagazig University to study the effect of mineral nitrogen
fertilizer levels (15, 25 and 35 kgN/fad.) and lithovit levels (0, 2, 4 and 6 g/l) as well as the interaction
between them on growth, seed yield and anatomical traits of cowpea plants grown in clay soil.
Fertilizing cowpea plants with mineral N at 35 kg/fad., increased plant height and number of both
leaves and branches/plant, total dry weight/plant, as well as seed yield/fad., and N, P, K, total
carbohydrates and total protein in seeds. Whereas N at 25 kg/fad., increased dry weight of leaves and
branches/plant as well as N,P and K uptake in leaves and branches compated with low used level of 15
kg N/ faddan. Spraying cowpea plants with lithovit at 6g/l induced all previous characters as well as
N, P and K uptake in leaves and branches. The interaction between N at 25 kg/fad., and lithovit at 6 g/l
increased plant height, number of both leaves and branches/plant, total dry weight/plant, N,P and K
uptake by leaves and branches, seed yield/fad., and N, P, K total protein in seeds. As for the effect of
N levels and foliar application with lithovit on anatomical structure of vegetative organs of cowpea, it
could be stated that 25 kg mineral nitrogen appeared a decrease in the main stem diameter, thickness
of cortex, fiber, phloem, xylem and pith diameter, number of vascular bundle and diameter of vessel
compared with high level of 35 kg N/fad., whereas the same level of N and lithovit at 6 g/l showed an
increase in all previous characters except fiber thickness. Application of 25 kg mineral N/fad., caused
in reduction in midvein, lamina of leaflet blades, palisade and spongy tissue thickness and dimensions
of midvein bundle compared with high level of 35 kg N/fad., but the same level of N and lithovit
reflected an increase in thickness of midvein region, width of midvein bundle, number of vessels/
midvein bundle and average diameter of vessel, but decreased the thickness of leaf lamina.