|What are the differences in how fertilizers, mulch and soil amendments are used?|
|I'm not sure I understand your question, but I'll try to define each of the things you've mentioned. Fertilizers provide the nutrients necessary for plant growth. They can be either liquid or granular in formulation and some of the granular formulations are coated with a clay material and called slow-release. Fertilizers are typically used in the spring or early summer when plants are most actively growing and most are broadcast onto the soil over the root system - or if liquid, sprayed onto the foliage and around the surface of the soil covering the root system.
Soil amendments are generally incorporated into the soil prior to planting. These amendments are usually organic in nature and as such can release small amounts of nutrients into the soil as they decompose, but are often used solely to help loosen the soil and improve drainage. Soil amendments might also be organically derived fertilizers such as bone meal, blood meal, etc.
Mulch materials can be either organic, such as compost, aged manure, peat moss, straw and shredded bark, or inorganic materials such as rock chips. The purpose of mulching bare soil or soil beneath and around plants is to help suppress weeds, moderate soil temperatures, and slow water evaporation. One advantage to using organic mulch materials is that they eventually decompose and you can dig them into the soil so they can enrich the soil both with bulk and with nutrients as they continue to decompose.
Great garden soil takes years to develop but once you've turned your garden soil into rich loam though the use of organic amendments and mulch, you'll have a much healthier and better producing garden.
Hope this answers your question~