Effect of concenttration, physical and chemical forms of nitrogen fertilizers on qualitative characteristics of mulberry (Morus alba L.) leaf and silkworm performance

This experiment was conducted in order to investigation on the effect of different sources of nitrogen on the quality of mulberry leaves and silkworm cocoon yield based on a completely randomized design with thirteen treatments and three replicates for each treatment. Each replicate was included ten mulberry trees. Three factors included two fertilizer types as factor A (urea and ammonium sulfate)، each fertilizer as two physical forms as factor B (solid and liquid) and each item included three levels as factor C (12 treatment arrangments) with the control treatment (without fertilizer) were used in this experiment. Solid fertilizers were used forty days before the beggining of silkworm rearing، were mixed under 30 cm soil depth. As well as liquid fertilizer solution، 48 hours before the silkworm rearing was sprayed on the mulberry leaves. Each of the thirteen treated leaves was used for feeding of silkworm larvae. From obtained results it was showed that the concentration، the physical and chemical form of nitrogen fertilizer resources، improved the quality and nutritional characteristics of mulberry leaves; however، this effect was not significant (P≤0. 05). Leaf fertilization with urea solution with concentration of 5. 0 grams per liter، resulted to the highest nitrogen، protein، phosphorus، and potassium، and these the results were similar with obtained results of silkworm larvae fed with these treated mulberry leaves.