Asian Journal of Soil Science and Plant Nutrition

The most continuous farming practice is the yearly addition of phosphorus fertilizers to soils in arid and semi-arid regions that all suffer from shortages of phosphorus availability. A vital approach is rationalizing applied fertilizers and trying to benefit from their reservoir in yearly-fertilized old soils using an activated charcoal-fertilizer mixture. Thus, a field experiment was conducted at a private farm in Mushtuhur, Toukh, Qalyubia Governorate, Egypt. This trial was set up to study the effect of phosphorus (P) fertilizer sources (phosphoric acid Ph.A and super phosphate S.Ph), the P application rates (P₀=control, P₁=50%, P₂=75% and P₃=100% of P requirements), activated charcoal (A.Ch) rates (A.Ch₀=control, A.Ch₁=1, A.Ch₂=3 and A.Ch₃=5 g/hole, corresponding to 41, 124, and 207 kg ha^-1, respectively) and the interaction between them on promoting maize growth, production and its nutrient status. Generally, adding phosphorus improved plant height (m), dry grains (t ha^-1), and ash yield (t ha^-1) without a significant difference between all P rates. Phosphoric acid affects most studied parameters, mainly the biological, ear, and ash yield (t ha^-1); it was the best compared with superphosphate. Adding the 1^st rate of A.Ch improved the studied growth and yield parameters significantly compared with the control. Slight enhancement was induced by the 2^nd A.Ch dose, and there was no significant difference between the 3^rd and 4^th rates in most studied parameters. The heighest value of grain yield resulted from the third interaction between A. Ch₃ x P₀, followed by A. Ch₂ x P₀, and the next is Ph.A x A. Ch₂ x P₁ without significant difference among them. These results shed light on the fact that there is no need to add P fertilizers yearly, as described by the recommendations of the Ministry of Agriculture. Different materials can move the fixed P in old clayey soil, such as A.Ch.