Drip irrigation in the vine
We analyzed how to calculate the water needs of a drip irrigation system in a vineyard, taking into account the contributions of rain and other factors to obtain an optimal harvest.
What are the water needs of a vineyard?
Vine cultivation is one of the least water requirements . A vine would survive with about 300 mm of water throughout its vegetative cycle, either provided with rainwater or by some external irrigation system.
The amount of water a vineyard needs depends on a number of factors:
- Grape variety
- Soil Type: a clay soil stores more water than a sandy one.
- Evaporation and perspiration: The key points here are the temperature, light, soil type and layout of the plant.
- Planting density: Depending on the amount of land available for each plant, it will have a quantity of water from the ground.
- Fertilization: The lack of mineral nutrients limits in some cases the hydric conductivity to the roots.
- Vineyard Conduction System: They increase their demands if the vineyard is under an extended and very productive driving system.
The distribution of water needs varies over the course of the Vine, and is not evenly distributed throughout its vegetative cycle.
Percentageally, the two largest water items are produced between the fall of the leaf, and the curd and the Envero, approximately a 44 for each of these stages. To a lesser extent, it consumes a 10 in sprouting and curdling, and a 2 during the winter rest.
What are the effects of water stress on the vine?
Irrigation contributes to avoid the effects caused by the absence of water and the lack of fertilizer. The main effect of irrigation is the increase in production, which affects the quality of the wines.
It is necessary to be careful with the moment of irrigation because it is not always good, for example during the phase of Envero to harvest.
When the water supply of rain is not enough it is when it should be supported in external irrigations that guarantee, at least, the survival of the plant. If the plant suffers stress in any of its phases its external manifestations are different, affecting the production and quality of the wine.
The effects of water stress are different according to the stages of growth:
- Sprouting: in the bud, an irregular sprouting with few flowers and short branches is achieved.
- Flowering: A lack of water in flowering causes a decrease in curdling, with small berries.
- Curdling: after flowering the lack of water causes a scarce development in the foliage and in harvesting; If the stress is severe it can even cause a delay in maturation. It is important that there is no water deficit at this stage, because if it exists it will considerably reduce the harvest and leaf area.
- Envero: If the leaf area is reduced, it causes a decrease in the development and quality of the berries, as well as in the acclimatization of the vine, which causes an increase in the susceptibility to the autumn frosts and low temperatures of the winter.
- Grape Harvest: A lack of water in the harvest causes the senescence and premature fall of the leaves, and an advancement in the agostamiento of the stems. After the harvest the water shortage can lead to the reduction of carbohydrate and nitrogen reserves in the perennial parts.
What are the effects of excess water on the vine?
Just as the lack of water in the vine can produce harmful effects, excessive irrigation or rainfall also has consequences:
- At the time of the sprouting, there may be a lack of oxygen due to the flooding, exteriorized in short shoots, yellowed leaves and even the death of the outbreak.
- In the long term, it ends up delaying both the Envero and the onset of maturation. Excess moisture at the time of flowering causes excess vigor in the branches causing deficiencies in the curd and causing the bleed.
- After the Envero, excess moisture increases the size of the grape, but with a lower sugar concentration and higher acid.
From Prakor we offer agricultural tools for the installation and automation of drip irrigation systems in vineyards, thus avoiding the harmful effects of lack or excess irrigation. One of the machines is the Perforator-Bee Connector, the fastest and most accurate way to place drippers of any brand and model in polyethylene hoses.
Calculation for drip irrigation system in vineyards
The drip irrigation allows for proper adjustment of the quantities of water and fertilizers to crop needs, these needs are detected by technicians based on “The calculation of water needs of the vine”. This is the method proposed by the United Nations Food and Agriculture Organization (FAO), which is based on the publication Evapotranspiration of the crop.
The procedure estimates water requirements depending on:
- The climatological variables that determine the demand for reference Evapotranspiration (ETo).
- A factor linked to the crop, called the crop coefficient (Kc).
In this way, the water needs or evapotranspiration of the crop (ETc) are calculated as:
ETc = ETo * Kc
In the previous expression, consider:
- The effect of the rain, if it occurs.
- The amount of rainfall that is actually exploited by a crop although it is a very difficult value to parameterize.
It has been taken into account, therefore, simple models of estimation of Effective precipitation (Pef) for calculating the needs of net irrigation.
NRN = ETc – Pef
From here, the crude Irrigation needs are obtained taking into Account the efficiency of the installation and, where Appropriate, the washing fraction when it is necessary to compensate with the irrigation management.
The ETo and precipitation are obtained from the information provided by the meteorological stations integrated in the SIAR network.
As for the Kc, the coefficients of the most representative crops have been compiled and incorporated into the water needs calculation module. These coefficients are the result of works published by different national agrarian research centres or result from experimental plans developed in the IVIAduring the last years.
In this way, this methodology allows to obtain a fairly precise estimation of the irrigation needs of the majority of species cultivated in our territory.
