Mulching tomatoes is a very useful technique to promote plant growth and soil conservation. It consists of covering the ground around the plant with a layer of natural material or artificially produced in imitation of what commonly occurs in nature: when the leaves and dry branches fall from the trees they form a protective covering of the soil, which decomposes slowly and enriches it with substances nutrients. Despite the benefits it brings, mulching in Italy, unlike in other European countries, continues to be little used in the industrial production of tomatoes. The plastic sheets used for this technique in fact involve problems in the harvesting phase of the machines used. This problem can actually be easily overcome by using biodegradable sheets that eliminate the risk of blocking the machinery.
The benefits of mulching
The mulching technique provides several benefits to tomato plants and the soil on which they are only grown. This is in fact protected from the erosion of atmospheric agents, remains moist longer, allowing savings on the use of water for irrigation. If the mulching layer is placed in spring, the soil will remain fresh during the summer season. If instead it is spread during the summer, it will allow the substrate to retain the stored heat, protecting the roots of the plants from the cold of the cold months. The use of organic materials for mulching also enriches the soil with nutrients through the slow decomposition of the mulching layer itself. Finally, the material spread on the ground, which must widen on a surface wider than about 30 cm compared to the roots of the plant, suffocates the development of weeds that can disturb tomato growth.
Natural materials for mulching
There are different natural materials for mulching and the choice depends on several factors: the cost and availability of the material, the effect that their decomposition has on the chemical balance of the soil, their reaction to atmospheric agents. Green lawn clippings, for example, should not be used alone as they tend to compact and produce a large amount of heat that would disturb plant roots. Otherwise, the bark has longer decomposition times, does not subtract nitrogen from the soil and therefore does not interfere with the growth of the plant, making it more suitable to be used even alone. Moss and peat, if used alone, could form an impermeable layer that would prevent the plant from watering. Instead, straw and hay are light, retain moisture well and have a neutral ph; however they are potentially flammable and may contain weed seeds.
Tomato mulching: The artificial materials for mulching
Man-made materials for mulching can be organic and inorganic. Cardboard and newspapers are generally used in combination with heavier elements that prevent them from being removed by the wind; they must obviously be free of inks and toxic components. The most used materials for the industrial production of tomatoes are the synthetic sheets, which are laid on the ground before the planting of the tomatoes and drilled in the points where the plants will be inserted. The advantages of using synthetic sheets are their durability, the suffocation of weeds and the protection of the soil from nitrate run-off, which reduces the use of fertilizers. There are also sheets produced with biodegradable organic materials, such as Mater-Bi, which last for 9-18 months. They have all the advantages of synthetic sheets and do not create problems for the machinery during the collection phase, also eliminating the problem of disposal.