It might be very acid, or neutral, or very acid. So there must be enough water and enough oxygen for plants to grow successfully. Plants also need mineral salts like nitrates, sulphates, and phosphates. Plants remove these nutrients from the soil, and decomposers return them to the soil. Mineral salts are recycled in the ecosystem.
All food chains start with a producer.
They get their energy by eating other living things. Primary consumers eat plants, we also call them herbivores. Some herbivores graze on plants and others browse. Carnivores are secondary consumers, they eat other animals. A thrush eating a snail is an example of a carnivore, as is a lion eating a zebra.