Before you do anything else, research the state/condition of your backyard/farm and plan the essential adjustment you need to make so as to make the garden vegetative for constant planting without forfeiting its fertility standing.
Maintaining soil fertility constantly is a bit tedious as you are going to be making some changes merely to maintain fertility. You can also visit https://biosoilsolutions.com.au/ to know various methods and techniques to improve the fertility of the soil.
You may want the plant to remain healthy and grow vigorously. So, they are able to grow properly and have vegetables, fruits, and flowers continuously without damaging the soil.
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When challenges arise, you will have to find natural organic products for use. Beneath the soil, there are a few organisms such as earthworms that assist you to supply organic matter by using their excreta in order to add fertility to the soil.
To carry on the soil fertility, add organic fertilizer, and water the plants. You can also utilize some organic mulch when you have planted your plant, use organic mulching materials to keep soil moisture.
The gardener may also continue to keep the soil covered with brown and green mulches that keep the soil cool and can also provide optimal habitat for soil micro-organisms.