Importance of orchard floor management in organic fruit growing (nutritional aspects)

Preserving soil moisture as well as weed control are in focus of organic production all over the world. The practise of ground cover is suitable to solve these problems simultaneously. According to Libik & Wojtaszek (1973) the practise of mulching, well known to horticulture, is perhaps as old as agriculture itself. Mulching with organic materials is highly beneficial in many orchard crops because it is a traditional weed control method that offers important potential benefits by maintaining a high quality soil environment (Hogue & Neilsen, 1987, Holb, 2002, 2005, 2006). Moreover, mulching has used generally in organic fruit farming all over the world due to benefits of it (Skroch & Shribbs, 1986). Mulches are not only highly effective in checking evaporation and in preventing weed growth, but also have influence on several processes in the soil. The benefits are variously attributed to the suppression of weed growth, to the conservation of moisture by reducing evaporation and run off, to protection from erosion, to increased infiltration of water, to the increase or decrease of soil temperature fluctuations, to the enhancement of mineral nutrient availability, to the enhancement of nitrification, to additional nutrients and organic matter derived from a decomposing mulch, or to the preservation or improvement of soil structure (Merwin et al., 1994). Moreover, mulching has a positive effect on nutritional and biological factors as well (Faust, 1989). On the one hand mulching produces an increase in the nutrient content of the soil by leaching of nutrients from the mulch, but at the same time the entire condition of nutrient availability may be modified for better or worse by changes induced by the mulch in the moisture and temperature regimes of the soil. On the other hand applying mulches increases root length density and brought the roots closer to the surface (Merwin and Stiles, 1994). In a review of orchard floor management, Skroch and Shribbs (1986) provide some general guidelines for several aspects, including soil quality, water relations, and microclimate. They statement that the favourable effects on soil quality can be achieved in the following order: legumes > grass > mulch > bare ground > cultivation (Skroch and Shribbs, 1986).