This study included two experiments; the 1" was conducted in the laboratory to find out the optimum conditions to prepare a natural organic foliar fertilizer (containing N. P, K, Fe, Mn and Zn) using corn starch as a caMer after certain modifications in starch properties and en-riching it with the above-mentioned elements. The 2nd experiment was carried out in the greenhouse (pot experiment) to evaluate this foliar fertilizer at two levels (which referred as blends A and B) on tho growth. yield and mineral content of sorghum plants, using alluvial, calcareous and sandy soils.
The obtained results revealed that : 1. The optimum laboratory conditions to reach the desired properties of the foliar fertilizer (containing appreciable amounts of total N and P in addition to the highest solubility percent in water) were when 100 g of corn starch was heated at 150°C for two hrs, with 5 ml., conc. phosphoric acid + 7.5 g urea. 2. Any deviation from the above-mentioned conditions led to a low wa-ter solubility of the foliar fertilizer (this property is considered one of the main properties of any foliar fertilizer). 3. Both of the two tested levels of this foliar fertilizer namely; blend A and blend B. (whereas blend B is two folds of the micronutrients con-tent) recorded pronounced increases in dry weight., macro and micro-nutrients contents of sorghum plants in the three different soils over the control treatment.
4. The highest positive effects on growth, dry weight, along with macro and micronutrients contents were obtained in case of the interaction between alluvial soil and the highest level of this fertilizer (blend B). 5. The favorable effects of the treatments were in the order: blend B> blend A> control, whereas the sequence of soils was alluvial> calcare-ous> sandy. The study alluded to the importance of using natural fertilizers as could as possible, considering human health must be in the first class.