Chapter 4

4. Comprehensive sustainable mountain viticulture management

The integration of terracing techniques into those of vigour control allow for sustainable mountain viticulture to be developed from an environment, economic and social viewpoint based on two mainstays:

• In eco-designed terraces, the two types of new vine training are used for optimum soil use, which is essential for increasing the productivity of the remaining production factors. Depending on the topographic profile of the natural land, planting takes place on both slopes and on the terraces themselves to obtain the best results.
• Once planting is complete, all the necessary information is obtained and prepared regarding the condition of the soil, the plant and the environment for easier decision-making as to the application of the remaining vigour control techniques.

With this in mind, comprehensive vineyard control is implemented. One of the main characteristics of this viticulture is controlling the even ripeness of the grape berries with very low dependence on the weather

4.1. Soil productivity: planting on terraces or on slopes

As indicated in Section Section 2.2.1, one of the basic design conditions of terraces is to limit the slope height to ensure it blends in with the surroundings. Once fixed, this height must be constantly maintained along the entire length of the terraces. This ensures that the terraces have a uniform gradient of 3% in order to control the runoff of rainwater to avoid erosion.

Moreover, the gradient of the slope on terraces cannot exceed a maximum as of which the risk of instability is significant. This theoretic maximum, which can be estimated using sufficiently representative soil cutting tests, must also involve a safety factor. As already said, the extensive experience of Mas Martinet in the building of terraces in the Priorat region proves that slopes with a gradient of up to 65º are safe¹, provided that the construction technique described in Section 2.2.3 is applied.

Given that terraces must have a constant, minimum width for machinery to pass (1.3 m), the greatest difficulty in maintaining the height of the slope below 1.5 m without its gradient being over 65º arises in the area of the estate where the natural gradient is at its maximum. If, in other areas of the estate, the natural gradient decreases, the height of the slope can be maintained by reducing its gradient.

Therefore, the construction of terraces must begin in the area of the estate where the natural gradient is at a maximum. At this point, a decision must be made as to whether the vineyard is to be planted on the terrace or on the slope, as this decision will determine the height of the slope and, given that this height must remain constant, it will also determine planting on terraces or slopes if the natural gradient drops along the terraces.

To make this basic decision, the design conditions of the terrace must initially be established. As explained in Section 2.2, Mas Martinet applies the following design conditions at the current stage of the experiments:

• Maximum slope height: 1.5 m (2 m if planting on the slope).
• Terrace width: 1.3 m.
• Maximum slope gradient: 65º.
• Maximum slope length for gentle gradients (as a guideline <25%): 11 m.
• Maximum slope length for gradients > 25%: 6 m.
• Vine training type: double vine training when planting on the slope and circular training when planting on the terrace (double vine training can also be used, particularly if the terraces have a relatively straight layout).

Once these conditions have been established, two causes can be presented in relation to the natural gradient of the land:

• The natural gradient remains significantly constant along the entire length of the terrace (although it may vary sideways in peak-valley direction).
• The natural gradient decreases significantly along the terraces.

In the first case, the best solution is to plant on the terrace, whatever the natural gradient (Chart 4.1).

Chart 4.1 Comparison between slope and terrace planting with constant natural gradient
	Natural slope (%)	20	30	40	50	60
Plantación en la terraza con círculos	Terrace width (m)	1,3	1,3	1,3	1,3	1,3
	Slope gradient (º)	32	43	51	58	62
	Slope height (m)	0,38	0,57	0,77	0,95	1,15
	Slope lenght (m)	0,7	0,8	1,0	1,1	1,3
	Nº of terraces per ha	52	52	52	52	52
	Theoretic ELA (m2/ha)(1)	24.504	24.504	24.504	24.504	24.504
Plantación en el talud con doble emparrado	Terrace width (m)	1,3	1,3	1,3	1,3	1,3
	Slope gradient (º)	14	22	32	42	52
	Slope height (m)	1,31	1,51	1,44	1,46	1,47
	Slope length (m)	5,4	4,0	2,7	2,2	1,9
	Nº of terraces per ha	15	19	27	34	40
	Theoretic ELA (m2/ha)(2)	18.371	17.796	16.774	16.605	16.920
	Theoretic ELA (slope height < 2m)	19.757	19.036	18.629	18.680	18.856
	Theoretic ELA: effective leaf area of all stock planted in 1 ha; calculated for shoots of 0.14 m2 of ELA with an average space between shoots of 7 cm. (1) The limiting factor is the horizontal ledge of the slope (parameter p in Figure 2.2), which must be over 0.6 m so that the ring of the upper terrace does not interfere with passing along the lower terrace (with a sufficient gap). This prevents the use of slopes with a higher gradient. (2) The limiting factor is the height of the slope (maximum 1.5 m), which prevents more gentle gradient slopes from being used. Where the height of the slope is limited to 2 m, the resulting ELA increases to the values of the lower row.

 If the gradient decreases along the terraces then the slope gradient will also have to decrease to keep the height constant. Therefore, the horizontal ledge of the slope (distance between two consecutive terraces) will increase. With this new geometry, it may be of interest to continue planting on the terrace or change from the terrace to the slope. Depending on the natural gradient and on the extent of the lengthways variations of the slope, the optimum will be different. To obtain a precise result, a 3D model must be prepared to introduce the topography of the land and the design conditions of the terraces. However, certain illustrative criteria can be established based on a 2D model:

• If the average gradient of the land is only slightly less than the maximum (e.g. up to 33% less), all the vineyard should be planted on the terrace.
• If the average gradient of the land is much less than the maximum (e.g. up to 66% less), all the vineyard should be planted on the slope.
• In intermediate cases, planting should be started on the terrace and the slope then used at the point where the vineyard develops, which will depend on the average gradient: the further away the average gradient from the maximum, the earlier planting should be changed to the slope.

In all cases, planting on slopes makes viticulture work more difficult:

• Precise irrigation of intermediate stock (that is not on the terrace but on the slope) is more complicated because it is on a gradient.
• Access to intermediate stock may require climbing the slope on foot. Where the slope gradient exceeds 30-35%, steps must be installed.

It also has advantages, however:

• The height of the slopes is greater and, therefore, fewer terraces are required.
• Double vine training is cheaper than ring vine training.

In general, it is only wise to plant on slopes when the ELA gain is significant (e.g. over 15%), although this will depend on the criteria of each vine grower.

One way of making slope growing easier is to plant only the end two stocks on the terraces and leave the liana plant to develop its production branch along the slope with no intermediate stock. To do so, Mas Martinet is carrying out experiments in order to answer two questions:

• Is it possible to accelerate plant growth to form the entire production branch in fewer years through
  irrigation?
• How does the grape quality vary as the shoots grow further away from the stock?

The results of these experiments are not yet available.

To show the increase in productivity achieved by combining the terracing techniques with those of vigour control, Chart 4.2 compares the soil area required to produce 10,000 kg of grapes (equivalent to around 8,600 bottles of wine) for three forms of cultivation:

• Conventional terraces with the following characteristics:
  • Terrace width: 2.3 m (2 rows of stock on each terrace).
  • Slope gradient: 45º (100%).
  • Formation: cordon royat.
• Mas Martinet terraces and ring vine training on the terrace.
• Mas Martinet terraces and double vine training on the slope.

In al cases, the natural gradient of the land remained constant at 40%.

As shown by experience, the real ELA is seen to be 65% its theoretic value (see Section 3.4). This also occurs in conventional plantations, given that some stock is not feasible and other does not reach the expected ELA.

In line with Chart 4.1, ring vine training provides the best results. Somewhat more than 1 ha of land is required to produce 10,000 kg of quality grapes. Conventional planting has a lower productivity and requires more than 3 ha of land.

Note that, if 6,000 kg/ha are collected in a conventional plantation like the one considered, the resulting production per m2 of ELA is 1.3 kg, which is very high for preparing a quality wine that can withstanding a good ageing process. The significant parameter is not production per ha, as regulations are often limited to, but production per m2 of ELA truly developed on productive stock.

In other words, for each plot, variety and weather, etc. the optimum ratio between ELA and the production of a quality grape can be assessed, although there is no optimum ratio per ha. As explained in the previous sections, it is worth noting that production is not linked to the number of shoots but to the ELA. The number of shoots depends on the vigour of the stock in order to obtain grapes with the appropriate morphology for their quality.

Chart 4.2 Comparison of the productivity of different mountain vineyard designs (natural land gradient: 40%)
Terraces		Conventional	Mas Martinet
Vine training		Cordon Royat	Double traininf vine on slope																Círcles on terrace
Slope gradient	º	45	32																55
Terrace width	m	2,3	1,3																2,3
Nº of terrace	Ud./ha	26	27																52
Slope height	m	1,5	1,4																0,7
Production branch lenght per ha.	m/ha	5.200	8.180																12.252
Nº of stocks	ud/ha	4.333	8.180																6.500
Theoretic nº of shoots	ud/ha	52.000	116.862																175.032
ELA per shoot	m2/ud	0,14	0,14																0,14
Theoretic ELA per ha.	m2/ud	7.280	16.361																24.504
Real ELA per ha. (65%)	m2/ud	4.732	10.634																15.928
Real quality production (first wine)(1)	kg/m2	0,6	0,6																0,6
Real quality production (first wine)	kg/ha	2.839	6.381																9.557
Area required to produce 10.000 Kg. per year	ha	3,5	1,6																1,1
(1) See section 3.5

4.2. Comprehensive vineyard control

	Once planting has been developed, the crop must be managed every year: Adjust the vigour of the stock required for the formation of the plant’s architecture regarding vigour control techniques. Decide on the time and the duration of irrigation. Apply the necessary treatments for the control of disease and blight. In order to collect and prepare the necessary information at all times for decision-making regarding crop management, the vineyard is divided into plots that can behave in a similar way in terms of vigour and their response to irrigation:  Soil conditions (fertility, porosity, etc.). Stock variety. Underground or surface irrigation.
Dendrómetro y sensor de humedad del suelo
	The resulting plots will cover a variable area depending on each case (e.g. from 0.5 ha to several ha). The following method is used to adjust the stock vigour each year during winter pruning: 30 to 35 sample stocks are selected from each plot. The shoots from each sample stock are classified according to their size and are weighed to obtain the vigour. Depending on the results, the irrigation guidelines (ferti-irrigation) are decided on and the production targets of the plot determined for the following year. As already indicated, reaching a production close to the target value may require several years, once the stock has developed its entire production branch.
Transmisor de datos de la viña a la oficina central

To obtain the supporting information for irrigation decision-making, the following is installed on each plot:

• 2 dendrometers on two representative stocks.
• 2 soil moisture sensors next to the dendrometers.
• 1 radio transmitter: this sends the readings of the dendrometers and the sensors to the central computer where estate operations are controlled.

A weather station is also installed on the vineyard (valid for all plots), which is equipped to measure the following parameters:

• Ambient temperature.
• Soil temperature.
• Rainfall.
• Relative humidity.
• Wind speed and direction.
• Vine leaf moisture.
• Solar radiation.

The weather station² has several functions:

• To add to the information from the dendrometers and sensors for irrigation management.
• To obtain weather forecasts useful for planning viticulture work.
• To provide the data required for the control of disease and blight.

The information measured by the equipment installed on the vineyard is transmitted to the central computer where it is stored and processed for real-time decision-making. In turn, the irrigation orders for each plot can be run from the central control, acting o the solenoid valves that open o close the run of water at the different levels of the estate. The system records the start time and the duration of irrigation at each level and on each plot, as well as the flow of water used.

Figure 4.1 Information technologies applied to viticulture

All the information generated either through automatic devices (e.g. irrigation flow or dendrometer variations) or manually prepared (shoot size, pesticide applications, etc.) must be recorded and subjected to analytical accounting, given that what is not measured cannot be managed. It is ultimately a question of ensuring the traceability of the quality of each batch of grapes and wine with the crop management decisions.

Hence, through the experience accumulated and the assistant of the relational and data interpretation models, productivity, quality, resource savings and environmental protection can be continuously improved.

These techniques are particularly appropriate for mountain plantations, which are often small (from only a few hectares to several dozen hectares). The application potential for large operations of hundreds or thousands of hectares is smaller, as business criteria regarding process standardisation that are easily systematically repeatable are normally introduced.

4.3. Eco-efficient mountain viticulture

Mas Martinet techniques provide eco-efficient viticulture, i.e. the added economic value is increased while environmental impact is decreased, by reducing the use of natural resources and preventing their degradation or pollution (providing more with less).

For example, a winery can obtain its wine bottle production decided upon based on business and market considerations, occupying must less land than if conventional techniques are used. The efficient use of land has extremely important environmental consequences in the form of preserving the landscape, reducing erosion and saving water and fertilisers, etc. Likewise, the grape quality increases its value and this is achieved with a low dependence on the weather conditions.

4.3.1 Environmental sustainability

The integration of terrace design and construction and vigour control techniques together with the addition plant cover and disease prediction techniques provides for the development of environmentally sustainable mountain viticulture.

Chart 4.3 shows the environmental benefits explained in detail throughout the Manual.
Benefits/techniques		Optimised terrace design	Vigour control  and precise ferti-irrigation	Plant cover on terraces and slopes	Disease forecasting model
Landscape preservation	Blending in of terraces. Use of mosaic terroir without vine monopolisation	x	x
Preservation of soil and its fertility	Prevention of erosion, compacting and loss of organic matter	x		x
Prevention of pollution	Minimisation of run-off and polluting leaching (nutrients, toxics)		x	x	x
Greater resource productivity	More and better (grape) production with less materials (soil, water, fertilisers, pesticides)	x		x

 4.3.2 Economic and social sustainability

The financial feasibility of the techniques for environmental sustainability has been assessed in two cases: 

• Small vineyard (2 ha) belonging to one self-employed farmer who works his own vineyard and sells the grapes to a wine producer. He has one small tractor. The winery supplies him with the basic information on disease prevention and irrigation guidelines.
• 15 ha vineyard belonging to a wine producing company. It appoints staff for cultivation work. It has its own machinery and central office to prepare information and make decision.

The vineyard is planted on land with a natural gradient of 40% using terraces measuring 1.3 m wide and ring vine training with terrace planting. In both cases, Mas Martinet comprehensive management techniques are applied. The real target production per ha is set at 9,500 kg/a (see Chart 4.2). The hypothesis is established that grape production evolves as follows: 

• Year 1: 0% of real target production.
• Year 2: 30%.
• Year 3: 80%.
• Year 4: 100%.

The production targets are summarised in Chart 4.4.

4.4 Production hypothesis for financial assessment (vigour control)
Type of operation	Vineyard		Real production
	ha	Nº of plots	Kg/a
Self-employed farmer	2	1	19.000
Wine producing company	15	8	142.500

Chart 4.6 shows the annual investment and operating costs in the two cases given.

The following hypothesis is used to calculate the financial results:

• Constant inflation of 2.5% per year.
• The farmer invests using all his own capital.
• The company finances 40% of the investment at a nominal interest rate of 5%, with quarterly settlements (5.1% APR) and 0.25% opening commission.
• The sale price or value of the grape is 1.4 Euros/kg.

The financial results are summarised in Chart 4.5.

Chart 4.5 Financial feasibility of the vineyard using Mas Martinet techniques
		Farmer	Company
Project IRR at 20 years	%	9,6	0,24
Financial IRR (leveraged)	%	0	0,35
Investment return period	years	11	20
Pre-tax profits, once target production is reached	euros (euro 2007)	20.000	50.000

The annual profits for the farmer can be considered sufficient. The company has a low IRR, given that its main business is the sale of wine.

As well as the added environmental and economic value, both direct and indirect, the Mas Martinet techniques help towards social sustainability with two specific contributions being particularly noteworthy:

• The quantity and quality of the grape harvest is independent to the weather conditions to a great extent. This fact, together with the high productivity of resources, provides strong financial feasibility under good conditions to withstand the ups and downs of the market. This leads to increased job stability.
• The use of information technologies, analytical and environmental accounting systems and crop management based on relational and data interpretation models requires significant intellectual work that may be adapted and is continuously improving. As a result, more skilled jobs are created with greater possibilities of continuous training in a wide range of subjects and, therefore, more attractive to youngsters and, most particularly, more accessible to women.

Moreover, the terrace access and phytosanitary control techniques lead to improved occupational safety for workers.

Chart 4.6 Investments and operating costs for the financial assessment of Mas Martinet techniques Natural slope: 40%. Terraces: slope gradient: 52º, terrace width: 1.3 m, 5,200 lm of terrace/ha Vine training: rings with a diameter of 0.6 m every 0.8 m, production branch for one ring = 1.88 m, ELA = 3.6 m2/ring, no. of shoots = 26 shoots/stock Number of rings/stock per ha = 6,500 (5,200/0.8); theoretic ELA = 24,500 m2/ha; 9,500 kg/ha 2 ha vineyard: 1 plot. Farmed by one self-employed farmer who sells the grape to a wine producer 15 ha vineyard: 8 plots. Farmed by a wine producing company.
Investment		Amortisation(a)	Depreciation(a)	2 ha	15 ha
Terracing (including tree and shrub clearing, removal of rots and stone crushing)	30.000 euros/ha	20		60.000	450.000
Stock	1 euro/stock	20		13.000	97.500
Vine training	5 euros/stock		10	65.000	487.500
Machinery	tractor, trailer, pesticides		10	9.000	30.000
Boxes and other tools		20		4.000	8.000
Irrigation pond			15	24.000	54.000
Irrigation installation (including hut, fertiliser storage tanks, pumps, programmer, etc.)	12.000 euros/ha		15	24.000	180.000
Weather station + blight forecasting contract			10	0	6.000
Soil moisture sensors + dendrometer + data recording and transmission (datalogger)	2 measuring points x plot			3.000	24.000
Total investment				202.000	1.337.000
Operating costs
Staff				0	90.000
Phytosanitary products				1.200	9.000
Machinery maintenance				450	1.500
Disease forecast and equipment maintenance				0	3.000
Various (insurance, consumables, etc.)				500	5.000
Total costs				2.150	108.500

1 In some vineyard, 70º has been used with good results
2 The Mas Martinet experiments regarding weather stations were carried out in collaboration with Adcon (represented in Spain by Verdtech)