PLANTING VINES FOR WINE BODEGAS URBINA
Planting vines is the action of firmly placing rootlings, grafted rootstocks, cuttings or canes (layering) in the soil with the intention of forming a vineyard and making wines with its grapes.
The decision of planting depends on natural variables (the soil and its composition, nutrients and aspect, climate, topography, etc.) and conditioned ones (variety selected, cultivation, wine type, choice of grafted rootstock as of training and pruning systems, etc.).
It is an operation carried out in winter or in spring and whose main objective is that the plants remain buried to an adequate height and roots are kept covered by loose and sufficiently humid land so they are able to nourish (avoiding air pockets, for which soil pressing needs to be performed).
In winter, buds or graft points are usually buried to protect them from frosts, the opposite to what is done in spring.
Different classes of planting are:
- Post hole augers: a hole of reduced dimensions is manually dug with the aid of a spade.
- Pit: a deeper and wider hole is dug using a special tractor implement.
- Furrowing: furrows are formed with the assistance of a plough.
- Employing a subsoiler: the most economical and modem method for planting in large estates, with laser-guided machines performing the entire cycle, from planting to soil pressing.
PLANTING GRAFTED ROOTSTOCK VINES
A grafted rootstock, is a rootstock which has been grafted for its planting. Its use is by far the most important form for asexual vine propagation, especially since phylloxera rampaged across European vineyards at the end of the 19th century.
The great majority of rootstocks used for grafting are either species of American Vitis on their own, or hybrids from them. They have important characteristics which will influence the vine’s growth, its yield, the quality of the fruit, its adaptability to weather conditions, as well as resistance to diseases and pests.
The selection of the grafted rootstock is often more relevant than the variety itself, for the latter may be limited by the appellation of origin or the legislation in force.
Its adoption on a given site is conditioned by the effect on the grafted cultivar (vigour, delayed or advanced ripeness, organoleptic properties of the wines, etc.), soil composition and fertility (especially its contents in lime and drainage), diseases and pests (nematodes and phylloxera) and climatic conditions (drought, frosts, etc.).
Although there are many, worthy of noting in Spain are 41B Millardet (a hybrid of Vitis vinifera chasselas and the American adapted to dry climates on
alkaline soils of the central plateau, 140 Ruggeri, 110 Richter and 1103 Paulsen (hybrids of the American berlandieri and rupestris), high productive in dry and cool climates on mountainous regions or in extremely dry conditions on the Spanish Mediterranean, or S04 (from riparia and berlandieri) in humid climates on poorly drained soils.
Among all recommended grafted rootstocks in Spain (Royal Decree 1244 /2008, of July 18th), only two have been developed in the country with the aid of the INIA (National Institute for Agrarian and Food Research): 13-5 EVE Jerez (direct progeny of berlandieri resseguier), quite resistant to drought and apt for soils rich in limestone; and 5A Martinez Zaporta (self-fertilization of 41B).
A rootstock is generally a not fully developed vine stock or vine, which has formed roots and is employed for asexual propagation of the plant (planting). The rootstock may be grown artificially (in a nursery) or naturally or, much more frequently, by mass or clonal selection as a clone, crossing or hybrid, and in the forms of either a cutting or a rootling.
When it originates from a grafted vine stock and a fructifying Vitis vinifera variety is grafted onto it, it is known as a grafted rootstock (or by extension, simply rootstock). Conversely, if it does not originate from a grafted vine stock and is planted on its own roots (without a scion), it would be an ungrafted rootstock (‘pie franco’ in Spanish).
The vast majority of rootstocks pertain to the first group, especially since phylloxera first made its way into Europe in the 19th century. They have important properties (i.e. resistance to extreme weather conditions or diseases and pests) which have a profound influence on the plant’s growth, as well as on ripening and quality of the fruit.
Hybrids are also known as direct producers. Varieties originated by hybridisation or crossing of cultivars from different species of Vitis (i.e. V. vinifera with any of the American ones, or American with each other) producing grapes adequate for vinification, not to be confused with the crossing of distinct varieties within the same species.
There are hundreds of them, which in general are divided into French (as Seyval Blanc, Baco I or Vidal) or American (Black Spanish, Alexander or Niagara), and may have emerged either naturally (especially in the United States by planting of European V. vinifera varieties) or promoted by man (the vast majority, which were provoked by the surge of phylloxera in Europe in the 19th century).
They are usually outlawed by the European Union, especially for the making of quality wines, though there are exceptions. The truth is that a significant part of the grafted rootstocks resistant to phylloxera are hybrids and clones from different species, mainly American as Vitis aestivalis, berlandieri, riparia and rupestris, which in a way bestows a hybrid character (though not productive) onto many traditional varieties of V. vinifera.
Crossing (or cross), in viticulture, is a new grape variety resulting from a natural (by crossing pollination) or artificial crossing of two different varieties of the species Vitis vinifera. In truth all grape varieties are crossing and to a large extent also hybrids, so the concept is increasingly applied to man made crossing such as that of Alicnate Bouschet (Garnacha Tintorera).
Grafting (or budding), is a asexual propagation of the vine consisting of the union of living tissues from two usually distinct plants so they grow as a single being, with the aim that the new plant improves its yield, quality of fruits or resistance to diseases and pests. Though it is a practice known since the most remote antiquity, it became practically indispensable at the end of the 19th century as phylloxera rampaged through European vineyards.
The louse was only controlled after grafting cuttings from traditional species of Vitis vinifera onto rootstocks of American species and their hybrids. The operation is carried out by joining the cambium (formed by enbroyonic cells) of both sides thus generating cellular proliferation at the union (known as callus), which shortly thereafter will regenerate by vascular connection.
The cutting must have at least one bud, from which the new vine will originate if temperature, humidity and affinity (tissues degree of contact and maturity levels) are adequate. The new sprouts will preserve all the genetic characteristics of the variety of the scion´s provenance. Grafting types are quite varied and may be classified depending on the location where they are grafted (field or bench budding), according to their shapes (with shaped cuttings or chip budding) or by placement and indentation type (top grafting or lateral grafting, cleft and notch grafting either on the head or at the sides of the rootstock).
Some of the more common forms are the simple top grafting and lateral types, as well as top grafting variants such as saw-toothed, omega and T shaped, and whip budding (by juxtaposition). The practice of grafting a new variety onto an already planted and grafted vine stock is called top working
Cutting (or budwood), is a cut from a shoot or cane of 30 to 50 cm. in length for asexual propagation of the vine, be it as a rootling or as a scion to be grafted onto a rootstock (a grafted rootsock). It must have at least one bud from which new sprouts will originate.
Scion (or graft), is a cutting used for grafting onto a rootstock or a vine. They usually come from clonal or mass selection of varieties with specific and differentiated characteristics.
Phylloxera, is an extremely important vine pest originating from the south-east of the United States (where it has existed from time immemorial), which practically devastated European vineyards at the end of the 19th century thus contributing to impel the new world production axes.
The plague, which rapidly spread around the globe, is caused by the hemiptera insect bearing the following equivalent Latin names Daktulosphaira vitifoliae fitch, Viteus vitifolii fitch, Phylloxera vastratix and Dactylosphaera vitifoliae shimer. It presents two dangerous life forms: one aerial (gall-form), which bites into the leafs causing galls or dents, and a root form (randiciola), which feeds on the roots thus making the vine lose its vitality and eventually die.
The insect exclusively lives on plants from the genus Vitis, affecting different species to a varying extent, and is very difficult to eradicate by traditional means. Fortunately it was noted that among them some had developed auto-defensive mechanisms, most specifically certain American vine species (not apt for quality wines).
This led to the grafting of V. vinifera varieties onto American vine species (not apt for quality wines). This led to the grafting of V. vinifera varieties onto American rootstocks, which eventually put under control the extreme threat the pest had posed. The so-called Ravaz scale measures the intrinsic resistance to phylloxera of the various Vitis species.
It varies from total resistance, marked by Vitis rotundifolia (20 points, though not valid as grafted rootstocks), to the null resistance of Vitis vinifera (0 points). American species Vitis aestivalis, berlandieri, riparia and rupestris or their hybrids, are the most widely employed grafted rootstocks. Curiosly enough specific soil types (e.g. sand) have kept the pest away from them, allowing for survival of undgrafted vines.
Any one of these, or any of the few pre-phylloxera vines remaining, is known as an ungrafted rootstock, which is supposedly held in grat esteem by winemakers given its pure and non adulterated character (as for instance in the Canary Islands, Yecla or Galicia).