Chemical fertilisers can lead to soil degradation. Guano contains a living microbial flora which enhances organic matter, encouraging microbial activity which improves nutrient uptake, plant health and soil moisture levels.
The second most deficient soil nutrient (second only to calcium). Phosphate is necessary for proper plant metabolism (energy transfer), blooming and possibly somewhat earlier maturity. Phosphorus is important in cell division and the development of new tissue. Plants deficient in P have stunted growth.
Calcium is important for soil pH, soil health and cell wall development in plants. Calcium also reduces the toxic effect from sodium and from soil borne fungi such as root rot and phytophthora.