Manual of techniques for sustainable mountain viticulture Josep Lluís Pérez Verdú

The dendrometer data is extremely useful because it provides information on the hydrous state of the

plant a long time before the effects of a possible imbalance are visible (excessive growth, grape dehy-

dration, leaf wilting, etc.). Bear in mind that it may be several weeks before the visible consequences

of hydrous imbalances can be seen.

3.3.4 Irrigation application and control

The need for precise irrigation that maintains the appropriate soil moisture at all times without wasting

water led Mas Martinet to experiment with the installation of an underground drip irrigation system.

Thus, the water reaches the roots more directly without getting lost on the soil surface where it is not

required. To do so, a specially-prepared piping system was used so that the roots did not put pressu-

re on or obstruct it. It contains water outlet emitters every 40 cm and is 40 cm underground. 

In conventional drip irrigation, the water piping system is placed above ground level. For the water to

reach the roots, it is first necessary to saturate the top part of the soil, which leads to an unnecessary

waste of water, made even worse by surface evaporation that may become quite severe. 

With underground irrigation, a moist area is created around the roots. 

However, the first year of irrigation must be above the surface because the roots have not yet fully

developed. From the second year, irrigation can be placed 40 cm underground. 

Precise irrigation requires sufficiently precise knowledge of the amount of water to be given to the soil

during each session, i.e. when irrigation must be stopped, without waiting for the response from the

plant through the dendrometer readings. 

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Conventional “drip” irrigation

Irrigation with underground piping

Conventional

“drip” irrigation

pipe

Underground

irrigation

pipe

Section of roots at

the same level as

the irrigation piping

30

40

50

Moisture sensors

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To do so, moisture sensors were fitted in the soil at three depths: 30 cm, 50 cm and 70 cm, providing

the necessary information, e.g. 

•

When the soil moisture on the roots is low and the plant begins to have problems to extract the

necessary water.

•

When the field capacity is being reached and irrigation must be stopped so as not to saturate lower

levels.

The data from the moisture sensors are radio transmitted to the control office where it is processed

and the appropriate decisions made at all times. Irrigation can be started from that same office and

can even be automatically programmed. 

Figure 3.9 gives a guideline as to how the soil moisture levels must be kept during the vegetative cycle.

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Sensors for measuring soil moistu-

re at three depths: 35 cm, 50 cm

and 70 cm

Figure 3.9 Relative soil moisture levels that must be kept during the vegetative cycle (illustrative in Priorat

“Licorella” slate soil) 

Field capacity

(17%)

(10-12%)

(7%)

(15%)

Apr

May

June

July

Aug

Sept

Oct

Wilting point

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The episodes of rain keep the soil moist and the den-

drometer graph remains balanced

The dendrometer indicates a risk of hydric stress during

August. Irrigation and rainfall balance the situation

The drip irrigation installation must also be precise, i.e. when irrigation is stopped then dripping onto

the roots must quickly stop. It must be taken into account that irrigation is installed on a terraced esta-

te with steep slopes and that the water in the upper pipes tends to accumulate on lower levels due to

gravity. Hence, the emitter system must ensure irrigation can be controlled at every height of the vine-

yard. The stock at lower altitudes must not receive more irrigation than those situations at higher

levels. This strict control is not as necessary during the growth period of the plant because excess

water will not cause significant problems, although it is essential as of June. 

The experiments carried out by Mas Martinet within regards to applying precise irrigation and its con-

trol using dendrometers and moisture sensors were carried out in collaboration with two supplier com-

panies: 

•

Netafim, Irriwise system (supplied in Spain by Regaber): drip irrigation including the applications

for automatic irrigation, dendrometers and soil moisture sensors. 

•

Adcon (represented in Spain by Verdtech): dendrometers and soil moisture sensors.

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3.4. Plantation framework

As indicated in Section 3.3.2, a shorter distance between rows of stock reduces the plantation frame-

work (PF) without altering the effective leaf area (ELA) of the stock, thus increasing the ELA/RSV ratio.

A high ELA/RSV ratio makes all vine growing control processes easier, although particularly that of

ripening. 

The distance between stock on the same row completes the definition of the plantation framework.

This distance has no impact on the ELA/RSV ratio, although it does play a decisive role in the speed

with which the plant’s architecture is formed: 

•

All foreseen shoots with their optimal dimensions (1.2 m in length, 45-55 g in weight and 6 to 8

mm in thickness).

•

The effective leaf area (an average of 0.14 m

2

on each shoot) so that the plant synthesises the

amount of sugar it needs during its vegetative cycle. 

The sooner the foreseen architecture is formed, the sooner target production with the required quality

will be obtained. The Mas Martinet experiments showed that if the stock on the same row are placed

closer together, the production branch is formed more quickly (Chart 3.1). It was also seen that stock

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Irrigation: comparison between quality drip emitters and irregularly working emitters 

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