Soil preparation in an orchard depends on several factors; the varieties planted, the age of the plantations, the irrigation system, the type of soil, the environment, the ecosystem...
To be brief and knowing Paul's orchard, located in the Gard, in clay-limestone soil and without a watering system, which represents a large number of amateur orchards, I will focus my answer on two themes:tillage and fertilization
The various tests carried out on bare soil and grassy soil show that the latter are very favorable to animal and microbial life of the soil with yields equal or even superior to orchards on bare soil. Grass can be natural or sown; in the latter case, a mixture of grasses and legumes (fabaceae) is chosen. In any case, the grass is mowed quite often, to avoid too much competition with the trees, at 6 - 8 cm high. Then several possibilities:either we work the soil over the entire row, over a width of 3 meters, or we work the soil just under the crown of the tree, but superficially so as not to damage the roots. For my part, I greatly prefer grassy soils. Any overturning of the soil, even superficial, causes disturbances in the life of the latter.
On this bare soil, we sow green manure which will be mowed in the spring. In the case of Paul's orchard, bare ground is preferable because the hens will find some of their food there. You just have to scrape the surface of the soil to loosen it, the gallinaceae will be delighted
It also depends on the type of soil and the varieties planted. As a general rule, in autumn, if there is no green manure, the fertilization will be organic , or organo-mineral, basic fertilizer type, (low in nitrogen and richer in phosphoric acid and potash) to be buried by scratching in the first cm of the soil. A mature compost is also a good fall fertilization.
There is also the spreading of RCW, ramial fragmented wood, which provides a large amount of carbon. The results are surprising. Straw manure can also be added in the fall, under the crown of the trees.
Working the soil, taking the opportunity to pick up the mummified fruits remaining on or under the tree. They are carriers of pathogenic germs.
Tillage and fertilization will be done between October and November.
