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4.1 Introduction

Global warming is a direct or indirect result of human activities (burning fossil fuels, changing land use, energy consumption, etc.) with an impact on the atmospheric composition (Carlton et al. 2015). At the 19th International Wine and Spirit Exhibition “Vinexpo Bordeaux”, organized during 18–21 June 2017, viticulturists addressed different possibilities to save their vineyards and made a call for general mobilization to fight against global warming. Climate change will definitely affect the vine-growing boundaries. High temperatures in the wine-growing area will increase sugar and alcohol rate and decrease acidity, which affect the wine flavour and taste. The result will be a reduction in vineyards in warm areas, while new areas will appear in places that were previously too cold for the vine growing. Fires, late frosts, prolonged drought, diseases and pests, hail and storms are events that will worsen in the future, as warned by John P. Holdren (Harvard Physicist, International Expert in Climate Change and Energy—Holdren 2018).

For greenhouse gas emissions’ mitigation, viticulturists and winemakers try new working methods for their own and global benefit. Some successful practices have been proven to be: growing of drought-resistant rootstocks varieties, cover crops, grazing middle rows or straw mulch, expanding vineyards in colder climates, reducing the amount or total abandonment of the use of pesticides and herbicides, improving fertilizer application and irrigation, using green fertilizers, nitrification inhibitors and wastewater treatment, biochar incorporation in soil (not only reduces GHG emissions but also contributes to increased productivity and soil quality). Undoubtedly, interactions of the environment, climate and soil conditions with grape variety needs, floor management are the agricultural practices that can control N2O and CO2 release from vineyards.

4.2 Viticulture in Romania

GHG emissions from Romanian agriculture (the equivalent of Mt CO2 to 1,000 € gross added value in agriculture) are among the lowest in the EU 28. Within the EU 28, Romania ranks fifth among the lowest share of greenhouse gas emissions from agricultural production and for the main components—nitrous oxide (N2O), carbon dioxide (CO2) and methane (CH4). Therefore, in many small family farms without financial possibility to buy machinery and chemical fertilizers, GHG emissions are low. The total concentration of all GHG emissions had reached 441 ppm CO2 equivalent in 2014, which is an increase of about 3 ppm compared with 2013 and 34 ppm compared with data from 2004. Experts believe that even small increases in global warming will reduce crop yields and will increase yield variability in low latitude regions (Scrucca et al. 2018).

4.2.1 Romanian Vineyards

The soils and the climate in Romanian vineyards are diverse. Therefore, different varieties can be grown for table wines or for high-quality wines. Vineyards are planted from 25 m altitudes (Dobrogea area—Black Sea), up to 600–700 m in piedmont areas in Transylvanian Hillsides. Soil type varies from sandy or light soils to clayey or limestone (Toti et al. 2015).

During 2000–2016, world area under vineyards decreased from 7.8 to 7.5 Mha in 2016. Five countries hold 50% of the world vineyards; Spain ranks the first with 14%, followed by China (11%), France (10%), Italy (9%) and Turkey (75); Romania ranks 10th with 191 Kha in 2016. Currently, it has an area of 243,000 ha of vineyards (242,000 ha older and 1,000 ha newly planted vineyards). The wine grapes represent 82% of the total vineyards area with wine production reaching 5–6 million hl/per year (Tamas 2017).

In Romania, grapevine growing is an ancient tradition. During the Roman Empire with the conquests in Dacia (the present territory of Romania), it is certainly known that the grapevine was cultivated in large areas. Romans brought new grape varieties, new winemaking and pruning methods. Even in the years with poor wine production or when the vineyards were affected by the invasion of phylloxera, varieties from the Drăgăşani, Odobeşti, Cotnari or Tarnavele vineyards and the Romanian wines such as Grasa de Cotnari, Tămâioasa, Busuioaca or Black/White Feteasca were appreciated in international markets (Bărbulescu 2017).

Vineyards in Romania (about 37) are grouped into eight viticultural regions, the most extensive of which is Moldavian Hills, which covers almost 70,000 ha. Relief differences (altitude, slope and sun exposure), soil and climate influence the ripening period from one region to another for the same variety. A variety grown in eastern Romania matures earlier by about 1 month than in north-west of the country, and therefore, different wine grape varietals cover each region (Irimia et al. 2017) (Fig. 4.1).

Fig. 4.1
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Romanian vineyards and wine regions (WRs)

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In 2016, vineyard area in Romania was 258 860.83 ha (1.79% of agricultural land), with 8432.39 ha (3.26%) on soil of the first-class quality, 65016.23 ha (25.12%) on soil of the second-class quality, 80346.63 ha (31.04%) on soil of the third-class quality, 79242.80 ha (30.61%) on soils of the fourth-class quality and 25822.78 ha (9.98%) on soil of the fifth-class quality.

Transylvania Plateau vine-growing region (I) includes five vineyards (Tarnave, Alba, Sebes-Apold, Aiud and Lechinta) with 17 vineyards. Main production is white wine (Protected Denomination of Origin (PDO) and Protected Geographical Indication (PGI)), semi-sweet, sweet and sparkling wines.

Moldavia Hills vine-growing region (II) is the largest and includes 12 vineyards (Cotnari, Odobesti, Panciu, Dealul Bujorului, Iași, Cotești, Huși, Covurlui, Colinele Tutovei, Ivești, Nicorești, Zeletin). Most wines are white (PDO or PGI) and sweet. Cotnari wines are included in the catalogue of the best wines in the world. Dry wine can be found in Odobesti, Panciu and Cotesti vineyards. Red wines are produced in small quantities.

Oltenia and Muntenia hills’ vine-growing region (III) includes eight vineyards (Dealu Mare, Sâmburești, Dealurile Buzăului, Ștefanești, Dealurile Craiovei, Plaiurile Drancei, Drăgășani and Severin). In Samburesti are produced mainly red wines, while in the other vineyards, white and red wines labelled PDO or PGI from several varieties are produced.

In Banat Hills’ vine-growing region (IV), and those two main vineyards (Recas, Buzias-Silagiu), are cultivated not only wine varieties but also table grapes (such as Chasselas, Black Hamburg, Muscat d’Adda or Victoria). White and red wines are labelled PDO (49%) or PGI (3%).

Crişana and Maramureş hills’ vine-growing region (V) cultivates both white and red grapevine varieties, in Minis-Maderat, Valea lui Mihai, Diosig and Silvania vineyards for PDO (10%) and PGI (0.5%) wines and small quantities of sparkling wines.

Dobrogea hills’ wine-growing region (VI) is located in the East of Romania near Black Sea and is well known from ancient times. Murfatlar, Istria-Babadag and Sarică-Niculițel vineyards have around 17 342.70 ha, cultivated with table grapes and red/white wine varieties labelled as PDO (51%) and PGI (15%).

Danube Terrace wine growing (VII), can be found along the Danube on sandy soils and includes two main vineyards (Greaca and Ostrov—11 305.34 ha). The main production is table grapes and white wine varieties (PGI 3%).

Sands and other lands from South favourable wine region (VIII) include three vineyards (Calafat, Dacilor, Sadova-Corabia) on 13 029.40 ha cultivated with wine grape varieties labelled PGI (4%) and on small area with table grapes.

In Romania, vineyards cultivated with DOC wine varieties represents 15.1% from total vineyards area; PGI wine varieties from all vineyards hold 84.9%. In 2015, Romania ranks first in the European Union by the number of vineyard owners (855.000 or 36% from total UE), but Romanian’s owners hold the lowest average vineyards area (0.2 ha compared with French owners with 10.5 ha, or Austria—3.2 ha). The share of the vineyards area for table wines was 72.1% in Romania, followed by Bulgaria (38.4%) and Italy (26.2%).

Regardless of the global region that cultivates grapevine, global warming affects the growing area. As in other regions of the world, it is expected that in Romania and South-East Europe as well, climate change will have a major impact on the wine industry (Irimia et al. 2017). In order to cope with these changes, it is necessary to adopt new, adequate technologies that will contribute to the greenhouse gas emissions (GHG) mitigation. Viticulture, although less polluting than other agricultural sectors, has its contribution through fossil fuel consumption for maintenance or transport and energy related mainly to winemaking (Goode and Harrop 2011).

4.3 Greenhouse Gas Emissions in Viticulture

Grapevine, as a perennial plant with large canopy, is able to sequester much more CO2 than annual crops. Unlike other industries, viticulture is not as polluting, but it is quite difficult to assess the level of greenhouse gas emissions (GHG), taking into account CO2 emissions from the various management methods and technologies used in winemaking to the transport and distribution to the consumers (Brunori et al. 2016).

Organic soil matter from vineyards includes essential nutrients for plant nutrition and soil health, including carbon and nitrogen which are incorporated into the plant roots, microorganisms, dead tissue from plants or animals. Organic matter plays a major role in ensuring the physical, chemical and biological properties of the soil. The amount of carbon and nitrous oxide emissions from the soil is influenced by soil type, management, temperature, rainfall, vegetation (Suddick et al. 2010). Soil texture influences the carbon cycle; clay-rich soil retains organic matter between the particles and is hardly accessible to microorganisms (Krull et al. 2001).

Vineyard floor management influences the carbon and nitrous oxide loss from the soil and has major contribution in organic matter decomposition. In vineyards, greenhouse gas emissions (GHG—N2O, CO2, CH4) result directly at the farm scale through soil tillage, indirect due to inputs (machines, seeds, fertilizers, pesticides, irrigation), or from grape juice fermentation, electrical power, gas and fuel consumption throughout the year, bottling and transport of wine to the consumers (Colman and Päster 2007).

Manure and compost, chopped and buried pruning debris, improve the carbon level in the soil. However, fertilizers applied in excess, on wrong place or very wet periods, lead to high GHG emissions (Toscano et al. 2013). Less herbicide applied in the vineyard increases plant biodiversity, the amount of carbon in soil and less CO2 release to the atmosphere (Ball et al. 2014).

Vineyard irrigation contributes to N2O and CO2 emissions. Nitrous oxide (N2O) is 300 times more dangerous for global warming than CO2. High moisture content in the soil is equal with more N2O emissions which are generated by microorganisms and organic matter decomposing. However, enough water in soil stimulates canopy growth and more carbon sequestration in plants (Robertson 1993).

4.3.1 Vineyard Carbon Dioxide Emissions and Potential Carbon Sequestration

Carbon atom is found in all organic plant or animals. Unfortunately, according to the latest statistics, Earth has passed the threshold of 400 ppm (parts per million) of carbon dioxide in the atmosphere, and there is very little chance that this limit will ever be lowered. By photosynthesis, plants convert CO2 and H2O into oxygen and carbohydrates. At night, photosynthesis stops, but the vine continues to respire. However, the amount of CO2 released at night is lower compared to O2 released or CO2 sequestered over a day (Fraga et al. 2012). Simultaneously with surface photosynthesis, organic matter is decomposed in the soil; organic exudates from the roots, crops debris or the fall leaves are decomposed by the microorganisms and contribute to the soil fertility. Soils in general are a huge organic carbon pool (SOC), which is estimated to be 1 500–2 000 Pg C (1 Pg = 1015 g) till a depth of 1 m and at 2450 Pg till 2 m deep into the soil (about 2/3 from terrestrial carbon). In the same soil layers, inorganic carbon is stored up to 750 Pg (Carlier et al. 2009). It has been estimated that soil can be seized up to 20 Pg in 25 years (Zomer et al. 2017). The carbon stock in the vineyards remains constant without soil and other inputs in the soil (FAO 2017).

According to recent studies concerning winemaking and its life-cycle assessment (LCA) from the Oregon Region, viticultural practices contribute about 24%, winemaking with about 11% and packaging with 23% to the carbon footprint in wine life cycle. Distribution and transport rate of carbon footprint are around 13% but are greatly influenced by distances, type and models of bottling and packaging. Storage, consumption and refrigeration have 18% contribution to carbon footprint (CF), while disposal of wastes and packaging contributes with about 11% (Bonamente et al. 2016; Iannone et al. 2016; Benedetto 2013).

4.3.1.1 Direct and Indirect GHG Emissions

In vineyards and winemaking, there are the activities that result in greenhouse gases emissions and CO2 sequestration. According to the Kyoto Protocol, OIV covers four greenhouse gases (CO2, CH4, N2O, SF6) and other two groups of hydrofluorocarbons (HFCs) and perfluorocarbons (PFCs). Direct gas emission starts with the change of land use from previously forest or pasture ecosystems in vineyards (Suddick et al. 2010). By turning grassland into arable soil, around half of the carbon sink is lost in the early years (Johnston et al. 2017). The reverse process of C sequestration lasts up to 50 years for permanent grassland to accumulate the lost carbon stock. Researches by Garwood et al. (1977) have shown that grassland contains in the first 10 cm of soil a double amount of C compared to tillage soil from vineyards.

Vineyards “produce” CO2 through vine respiration, soil tillage and fossil fuel, but “consume” CO2 by photosynthesis. Nearly insignificant in vineyards, methane is released from anaerobic degradation process of organic matter, while nitrous oxide (N2O) results from nitrogen fertilizers and transformations in the soil (Fraga et al. 2012). In the winemaking sector, refrigerant fluids release gases like hydrofluorocarbons (HFC), PFCs and SF6; cold extraction and maceration, grape juice refrigeration, debourbage in white wines, pellicular maceration in red winemaking, controlled fermentations, cold storage of finished wines, amicrobic, colloidal and tartaric stabilization or ageing in oak require optimum temperatures (Bernard 1999).

4.3.1.2 N2O Emissions

The most noxious gas in the vineyards is N2O, considering the high greenhouse potential of this gas. It contributes to the depletion of the ozone layer in the stratosphere (Portmann et al. 2012). Research results estimate that about 50% of the vineyard pollution is generated by this gas (Wine Institute 2014). Nitrous oxide (N2O) results naturally by nitrification/denitrification of organic fertilizers and especially synthetic nitrogen application. Ammonia by biological oxidation is transformed into nitrite (nitrification) followed by next step of nitrogen cycle, conversion of nitrite into nitrate. Nitrate ion is one of the most soluble anions in water. All these transformations are strongly influenced by temperature, humidity, pH and carbon amount in soil (Fan and Li 2010). Nitrous oxide (N2O) release from the soil is influenced by the unstable carbon stock due to the incorporation of green fertilizer, weeds or stubble into the soil and more nitrates combined with soil moisture. A higher amount of labile C and NO3 from soil leads to a higher amount of N2O emission in the atmosphere (Butterbach-Bahl and Dannenmann 2011).

On the other hand, the nitrogen application as fertilizer increases the amount of sequestered carbon in the canopy and vine wood, which through leaves and pruning wood is added into soil year after year (Bouwman et al. 2002). The largest amount of nitrogen (nearly 75%) is stored in vine roots, trunks and canes (Bates et al. 2002).

In order to decrease nitrogen emissions, it is necessary to apply fertilizers in the optimum quantity during the active growth of the roots (before bud break and after harvest, respectively) correlated with the optimum temperature and humidity in the soil. Opinions concerning the contribution of soils to N2O emissions are divided. On the one hand, soil tillage increased emissions as a result of intensive denitrification process (higher NO3 accumulation), and on the other, cover crops increase emissions after extraction of larger amounts of nitrogen from the soil that is no longer decomposed by microbial biomass (Suddick et al. 2011). Relative equilibrium was found by Garland et al. (2011) in Mediterranean vineyards between soil emissions and no-tillage system.

4.3.1.2.1 CO2 Emissions

Soil carbon is related to soil quality and is strongly linked to the nitrogen cycle, both being components of organic matter in the soil. It has been found that carbon stocks increase with depth due to the addition of organic matter in the deeper soil layers during soil tillage (Suddick et al. 2010). Soil organic carbon ensures fertility and soil health (Smith et al. 2008). As more CO2 is stored in the soil as biomass or organic matter, lower the concentration of this gas in the atmosphere (Alvaro-Fuentes et al. 2008). The carbon stock in the soil depends on the climate, soil texture, land use and vegetation. Soil covered with natural vegetation accumulates a higher amount of carbon compared to those in which frequent and deep tillage are performed (Krull et al. 2001); CO2 is released from the soil when organic matter is decomposed and taken up by plants. Direct emissions of GHG are produced mainly from field tractors and equipment, in wineries by diggers, forklifts, water heaters, bottling halls, etc., and electric power consumption. Grapevine is one of the perennial crops that are preserved for decades and can act as a carbon sink through the wood that grows continuously and through the pruning debris which can remain on the ground. Debris and leaves from soil help to increase the carbon stock for a long period of time (Johnston et al. 2017).

Grapevine maintenance and cover crops can increase the amount of organic matter in the soil. Biomass from cover crops or other sources decomposes over time with the release of CO2. Carbon sequestration in soil is a long process. Climate and soil play a major role in storing carbon in the soil. More carbon amount in the soil is correlated with less N2O emissions (Garland et al. 2011).

Data on GHG and carbon sequestration in vineyards are scarce, as research requires long time (3–5 years for N2O and CH4 and 10–20 years for C sequestration—Carlisle et al. 2010). The accuracy of the research data is relative. For example, Rugani et al. (2013) reported 22% CO2 emission for the vegetation and packaging cycle, while Bosco et al. (2011) found 7% carbon emissions for planting stage in Italy, with many tractors passes for tillage and planting with a lot of fossil fuel consumption. More conclusively, Marras et al. (2015) specified CO2 emission of 0.39 kg/1 kg of grapes in South Sardinia (Italy) vineyard.

The amount of carbon sequestered in the soil can be increased by using green fertilizers grown between rows, cover crops or pruning debris. This type of floor management is, however, unclear because plants are competing for nutrients and especially for water with grapevine. Very well-developed root system also leads to an increase of carbon sequestered in the soil. To limit the temperature increase in soil and decomposition of organic matter, resulting in CO2 emissions decreases and alley-row mulch can be used. Grape berries contain great amount of carbon during fruit set and growing season. Powlson et al. (2011) specify that: “in a temperate environment, organic matter from soil, after one year sequesters only 1/3 carbon from the initial content and the remaining is released in the atmosphere”.

4.3.1.2.2 Emissions from Wine Closures

Cork closures have a minor impact on carbon emissions (4%), being environmentally friendly and wine consumers’ favourites. Some researchers even argue that these corks contribute to GHG mitigation as they are a bio-based product. Cork trees are even considered as an important reservoir for carbon storage in the soil as a result of the conversion of CO2 into O2 during photosynthesis and organic matter in cellulose.

According to Pereira et al. (2007) studies in cork forest near Evora from Portugal, 179 g C cm−2 are sequestrated annually. In Portugal, 4.8 million tonnes per year or 5% from the entire emissions of CO2 in the country can be absorbed by the cork forests. The 1-year absorption of these greenhouse gases is equal to total emissions of 490,000 cars (Pereira et al. 2007). The accumulated thickness of all layers of cork removed from a cork tree throughout its life (about 200 years) is 3–4 times larger than a tree from which it has never been harvested. Using aluminium caps involves emission of larger amount of greenhouse gases, followed by plastic closures (10% emissions) that are made usually from recyclable plastic (Marin et al. 2007).

4.3.1.2.3 Winery Emissions

In Romania, there are more than 250 wine cellars. From those, 140 produce and sell bottled wine. Wineries are generating greenhouse gases during various activities. To produce the wine, energy is needed for crushing and pressing the grapes, filtering the must, for cooling or heating the fermentation tanks and finally for bottling, storing and transporting the wine (Niccolucci et al. 2008).

In wineries, part of the energy consumption (electric, fossil fuels) can be replaced to a certain extent by solar energy or other renewable sources, for increasing efficiency and mitigation of GHG emissions from lighting, fermentation tanks and filtration, of refrigerators, etc. Night-time cooling tanks, windows and large doors, for shorter gap in temperature reduction, help to reduce energy consumption by up to 15% (case study in Recas vineyards). For barrel wine maturing and sensor quality pattern, most wineries in Romania have built underground cellars that keep constant temperature throughout the year without energy consumption (Șerbulea and Antoce 2016).

Hot water used to wash bottles can be reused for washing other equipment. Recycling of wastewater from wineries can be used to irrigate vineyards with a significant reduction in energy consumption for pumping and bringing water from longer distances. Comandaru et al. (2012) studied wine life-cycle assessment (LCA) in wine production from north-east of Romania (Iasi County) facility (75,000 hl/year wine production) to set the impact on environment of one white wine bottle. Production stages, energy and transport had significant impact on wine LCA. Winemaking has the major contribution on water consumption due to the large volume of wastewater during wine production. A lot of energy is necessary for removing from wastewater the pollutants until normal limits.

An option for GHG mitigation in wineries is to generate own electricity. For example, Carastelec winery from Salaj County (north-west of Romania) works with green energy: heating and cooling are done with heat pumps, and energy consumption is provided by solar panels; each year (without climate or pest damages), the winery produces 200,000 wine bottles from grapes harvested on 22 ha vineyard.

Stefanesti winery (Arges County, South of Romania) has 25 ha vineyards and is the only one cellar with completely energy autonomy in Romania. Each year, the winery produces 40,000 wine bottles. Electricity is provided by the 102 solar panels installed on the roof with a total of 25 kw (Fig. 4.2). The wine cellar also has a geothermal heat pump, powered by three drillings with 120 m deep. For the water required for the wine cellar, drills were made at 200 metres deep (Grigorescu 2018).

Fig. 4.2
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(Source Denis Grigorescu)

Stefanesti winery with 102 solar panels on the roof

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Colman and Päster (2009) calculate the carbon footprint taking into account the agrochemicals, mechanization, water for one tonne of grapes, electricity, natural gas, bottling, transport of bottled wine, etc., for the 2001 wine world production (2,668,300,000 l), and the result was 0.08% of whole GHG emissions. The amount generally not considered impressive is however equal to the emissions of about 1 million cars during 1 year (Colman and Päster 2009).

Transportation is one of the major sources of GHG in wine industry. In the recent year’s flex tanks of 25,000 l, bottling and packaging near the market destination are viable alternatives, especially for table wines. Biofuel engine, electric engines for tractors, fewer passes by tractor, two tools attached to tractor (one rear, one front for two treatments/operations in the same time) reduce the time for tractors use and are options for the future.

4.3.1.2.4 Bottling

For bottling the quality wine, energy is consumed for the bottles and boxes production necessary for packaging. To decrease the carbon footprint, there is an alternative to bottling in light bottles. If the weight of a classic bottle of 0.75 cL is currently around 500 g, one lightweight glass is only 300 g (Forsyth et al. 2008).

“Lightweight” glass, as it is called by manufacturers, is made by reducing the thickness of the wall and removing that thick part that is naturally found in the bottom of the glass. Reducing the raw materials such as quartz sand and sodium carbonate led to an overall cost savings of 10%. Manufacturers of such bottles are also advised to use a larger amount of recycled glass, such as glass pellets. In 2003, a Hopland-based wine factory in California decided that their wine would be bottled in over 23 million of such bottles. Thanks to this choice, the amount of greenhouse gases in the USA decreased by more than 14%, more precisely by 2985 tonnes of CO2 in 2003 from this factory. This greenhouse gas reduction was equivalent to planting over 70,000 trees and raising them for 10 years (Associated Press 2008).

Bag-in-box is an organic way to pack and transport wine with reduced carbon footprint (it was invented in the 1950s in the USA). This type of packaging reduces carbon footprint by 40%. Another advantage is that they are easy to handle and do not break easily. The disadvantage is short shelf-life (up to 9 months), and metallic polyester can crack. Bag-in-box or boxed wines that first appeared on the market in 1960 used for bulk wines were considered cheap at the time. This type of bag has one or more layers of cardboard, flexible and high strength (Yam 2009). Girboiu, Ostrov Domains, Budureasca, Oprisor Wine Cellars, Recas Wine Cellars, Odovidis-Jaristea or Vinarte are just some of the Romanian wineries selling PGI wines and table wines (white, rose and red), dry, semi-dry or semi-sweet, “bottled” in PET or a 3, 10 or 20 l bag-in-box.

Times have changed, and today, this type of packaging is mainly for certain varieties of young white wine. Manufacturers claim that this packaging presents the easiest way to open, compared to all currently available containers on the market. In spite of the efforts being made for global spread, this type of packaging still has the disadvantage of wine oxidation even when it is not opened. Thus, it cannot be used on an industrial scale for the long-term preservation or ageing the wines.

In conclusion, choosing the wine according to the bottling type remains to the consumer. However, it should be known that if wine will be consumed in a year or two, alternative packaging should be used while wine for ageing and storage should be bottled in glass containers (Penela et al. 2009).

In recent years, for cheaper table wine, bottling in plastic (PET) bottles from recyclable material (from 0.25 to 1.5 l) has been tried, to replace the glass bottles and make the transport easier and safer. PET helps to protect against colour oxidation over long periods of time and minimize temperature differences. They are 100% recyclable and 90% lighter than a traditional bottle, and they reduce transport costs and the amount of fuel used by trucks to deliver. However, consumers do not appreciate plastic packaging primarily for environmental reasons, but also the quality of wine that oxidizes much faster than in glass bottles (Imkamp 2000).

One of the most viable alternatives for wine bottling is Tetrapackaging. Tetra pack containers are from paper and weigh 40 grams compared to glass bottles weighing up to 700 grams. The production of these packages is done with about 92% less raw materials and 54% less energy. This means 80% less greenhouse gas emissions and 60% less solid waste. Additionally, these containers can be easily stacked and are resistant to transport and storage because they do not break (Borg 2013).

Unfortunately wines bottled in Tetra Pak, “lightweight” bottles, etc., are for retail selling because the consumer has the impression that the wine is of poor quality and does not realize that the price is lower due to the low cost of the packaging. The bag-in-box has 80% less carbon footprint than glass packaging (the entire production chain from vineyard to the wine bottle). Because producers want to sell their wine, packaging decision is determined by the market and consumer preferences rather than by the winemakers (Colman and Päster 2007).

Globally, 2.7 billion people are affected by water scarcity for at least 1 month each year (Degefu et al. 2018). Water footprint in food is high (e.g. 1 kg of beef requires around 15 thousand litres of water, Gerbens-Leenes et al. 2013). Winemaking industry is not an exception. Ene et al. (2013) evaluated the water footprint of a 750 cl bottle of wine produced in a medium-sized wine cellar in Romania, based on the production chain diagram representing current emissions and environmental impacts. The results of this study indicated that nearly 99% of the total water footprint is related to the use of water in the supply chain. The three water footprints are: green—water from precipitation stored in the root zone and is incorporated by plants, evaporated or transpired; blue—comes from groundwater or surface resources and is incorporated in products or evaporated; grey—is fresh water necessary to assimilate pollutants for meeting water quality standards (Bonamente et al. 2016). GHG emissions decreasing by water, raw materials or energy savings in the winemaking industry from Romania are an actual goal. Several practices are already applied in recent years (vineyards floor management, pest control by novel technologies, wineries waste treatment and monitoring, or increase water resources use efficiency).

4.3.1.3 Ageing Wine in Barrels

Wood barrel will never go out of winemaking. Maturing wine in barriques (225 l barrels, equivalent to 300 bottles of 0.75 l) is very popular in wine cellars that want to market the highest quality wines. The barrels of oak and acacia (for white wines) have been used since ancient times for flavour and preserving the wine quality. About three and five barrels can be manufactured from one oak tree (depending on size). An oak tree of 100 years old and 20 m height has leaves that cover 1,600 m2 area, and produces 12.8 kg/day or 4.672 kg/year of O2 that is necessary for 11 peoples and absorb about 2,265 kg of CO2 (del Alamo-Sanza and Nevares 2015).

The wine ages in oak barrels for approximately 3 months to 2 years, depending on the wine and the number of barrel use. A barrel can be used 3–4 times. Subsequently, the wood tannins will be exhausted and the pores of the wood get clogged. Between the uses, the barrel is hygienized by repeated rinsing with hot water and sulfation. An interesting observation has been made that Romanian wines improve their aroma and taste qualities in American or French oak barrels, while South African wines are improved in Romanian oak barriques.

4.3.1.3.1 Wine Distribution

Wine is produced usually in specific viticultural regions and must be transported to the warehouses, markets and wine drinkers. The transport chain depends on distance (trucks, rails and ship or air cargo) and can thus have a large carbon footprint. Air cargo has the bigger impact concerning carbon emissions (11 times more than 460 shipping, followed by trucking 5 times), according to the research results of Colman and Päster (2007).

4.4 Vineyard Floor Management

Grapevine grows on the same land for at least 30–35 years, and it is an intensive labour crop and over the year requires significant soil tillage. Therefore, vineyard soils are generally anthropic soils, poorly structured, low in humus and capillary porosity, with severe erosion on sloping lands, reduction of soil organic matter; soil compaction after repeated tractor and equipment passing in wet periods; imbalance of mineral nutrition, which generates a high sensitivity to pathogens (diseases, pests, frost, drought, etc.). Correct tillage in the best moment is very important for humus preservation, nutrients accessibility, weed control, chemical and biological activity (Duda et al. 2014). Nearly 60% of the vineyard area is covered by middle rows, an unproductive field but with major impact on grapevine yield and quality. Vineyard floor can be managed by tillage (bare soil), herbicides, cover crops, green manure, mulch, etc. (Dobrei et al. 2014). To avoid soil structure degradation, tractor and additional equipment should be used such that several different management activities are carried out simultaneously. Alleyways with cover crops as buffer between tractors tires and soil, mulching, green manure are only few possibilities to reach higher yield and production and to have a healthy soil.

4.4.1 Bare Soil Tillage

Cover crops are used in vineyards since ancient times, but few data are available about their influence on soil carbon cycle. Until the early 1980s, bare soil was the traditional floor management in viticulture (Pool et al. 1991). Bare soil advantages are more efficiency of water in the soil, increasing the amount of nitrogen, mobile phosphorus and potassium in the soil and enhancing the photosynthesis process in the vine leaves (Murisier 1981). Disadvantages include the acceleration of the humus degradation; destruction of soil structural aggregates as a result of four to five tractor passes per year; increasing soil erosion process; large volume of dust that favours mite development and air pollution; high fuel consumption and expenditure for tillage works (Martinson 2006).

Different floor managements in Burgundy vineyards from the West of Romania, including bare soil under-vines and middle rows or cover crops between rows, confirm other research results concerning cover crops influence on chemical and physical soil traits, vine vigour or crop load and weed control improvement (Dobrei et al. 2015). Nitrogen infiltrates more slowly in the soil with real effect on canopy and grape yield. Soil organic matter is a major component of soil, with extremely important contribution of water and nutrients for plant nutrition and for soil carbon sequestration. Minimum tillage on several soil types (phaeozem, haplic luvisols, chernozem and molic fluvisol) from north-west of Romania increased the organic matter from 0.8 to 22.1% and water stability of soil aggregates (WSA) up to 13.6 from 1.3% in the first 30 cm of soil, compared with bare soil system (Moraru and Rusu 2010).

Extending these results to 50% of the Romanian arable land, it was estimated that 6.9 million tonnes/year of carbon could be stored if minimum tillage is performed. Furthermore, no-tillage or moderate tillage on argic–stagnic faeoziom soil (north-west of Romania) influences the time and the amount of carbon sequestration. Results after 3 years of observations show the effect of soil tillage on daily average soil respiration as follows: no-tillage had the lowest influence (315–1914 mmoli m−2 s−1) and 318–2395 mmol m−2 s−1 for moderate tillage system, respectively, compared with conventional tillage (321–2480 mmol m−2 s−1) (Moraru and Rusu 2013). Tractors and equipment used for minimum tillage on argic–stagnic faeoziom in Jucu Experimental Station (north-west of Romania) increased the GHG emission twice compared with no-tillage soils. The smallest rate of CO2 emission in minimum soil tillage was 1929 ppm, and the highest rate was 8901 ppm. When no-tillage was adopted, the CO2 concentrations registered were between 1443 ppm and 4880 ppm/day (Marian et al. 2013).

Relation between soil, climate, grapevine and variety influence on wine character is different in each viticultural region. Management of vineyard floor is particularly important in the wine production chain. Soil moisture has a strong impact on grape yield and quality during growing season. In Valea Călugărească vineyards, Fetească regală grapevine located on mollic reddish-brown soil, floor management was evaluated during 2012–2013. Soil moisture was measured, and comparisons among bare soil, straw mulch across vine rows and alleyways (10 cm layer), mulching with pomace compost alleyways (10 cm layer) and minimum tillage were made. During both years of experiment, soil moisture in the first 60 cm was normal and quite equal in the early growing season (April–May), but in summer and autumn time, mulching system plots had positive influence on water evaporation and soil moisture (Serdinescu et al. 2014).

Minimum tillage increases significantly the humus amount in soil by 0.8–22.1% especially on vertic preluvosoil. Hydro-stability of macroaggregates and organic carbon is positively influenced by minimum tillage from 1.3 to 13.6% in the first 30 cm of soil compared with the conventional tillage. Both humus amount and soil structure contribute to increasing soil fertility and have positive influence on soil permeability and water storage in soil as groundwater storage (Duda et al. 2014). Similar results have been observed on Somes Plateau argic faeoziom soils (north-west of Romania), when no-tillage, minimum tillage and conventional tillage were compared for soil respiration. In no-tillage system, the lowest soil respiration (315–1914 mmol m−2 s−1) was found. CO2 release from soil in minimum tillage was (318–2395 mmol m−2 s−1), while in conventional tillage, production of CO2 was the highest (321–2480 mmol m−2 s−1). The CO2 production was maximum in autumn (2141–2350 mmol m−2 s−1) and in late spring (1383–2480 mmol m−2 s−1). After 3 years, humus amount in soil increased by 0.64% when no-tillage was applied, followed by minimum tillage system with 0.41% humus level in soil (Rusu et al. 2016).

4.4.1.1 Grass Strips Alleyways

Soil is subjected to various degradation processes. Some of these are specific to viticulture: water and wind erosion or soil tillage; compaction; decreasing the amount of organic carbon in soil and soil biodiversity; soil salinisation and sodification; soil contamination with heavy metals and pesticides or excessive amounts of nitrates and phosphates. On clay soils, repeated tractors passing decreases soil porosity in the vine root area from middle rows. The fine soil particles by leaching agglomerate the deep layer resulting in a long-lasting compacting with adverse consequences on the vine vigour and productivity. Symptoms are yellowing or redness of the leaves associated with abnormal deformation of the leaves of vines (Valenti et al. 2002).

Grass strip alleyways and bare soil under-vines in vineyards are a common soil management system and are efficient in areas with more than 600 mm annual rainfall. Weed control on vine row is done by manual hoeing or by repeated application of residual or foliar herbicides; this system is recommended for increasing land slope stability (Murisier and Sbeuret 1986). The advantages of this system application are: reduction of erosion on sloping lands; avoiding hardpan formation; increasing the input of organic matter in the soil; improving soil structure and porosity; avoiding nitrogen runoff and leaching throughout the year; better water infiltration (Colungati and Cattarossi 2013).

Constant tillage exposes the soil to erosion as many of the vineyards are located on slopes with mild or medium slopes. On these lands, the main problem is not the landslides, but the gradual and constant transfer soil which decreases its fertility, causing a “slip” of the roots that are thus forced to expand around to find the necessary nutrients and water in the soil (Kaspar et al. 2001). Grass strips are an alternative for vineyards’ middle row soil protection. In organic viticulture, this is the first choice in vineyards floor management for increasing soil fertility and for restoration of degraded or weed-infested soil. Water and wind erode the soil by about 2.5 cm per year (Goulet et al. 2004). Grass strips protect the soil by avoiding leaching, compaction and erosion due to tractors and other equipment traffic (middle rows grass strips favour iron and phosphorus absorption, contribute to less mobile minerals alteration, reduce the rot attacks, make easier the access to the vines, and reduce the maintenance costs (Eynard and Dalmasso 2004).

Grass strips in the middle rows contribute to the improvement of grape quality, by increasing the amount of sugars in berries, vine vigour and grape yield. This system of floor management in vineyards mainly protects the soil from erosion (Goulet et al. 2004). For example, in the Rheingau (Germany) wine-growing region, on slopes ranging from 10 to 32%, grass strips reduced water running after heavy rains up to 1.8% from rainfall volume compared to 50% on the bare soil (Krull et al. 2001). The amount of soil lost by erosion in vineyards with grass strips is insignificant (3.1 kg/ ha), while on bare soil it is between 30 and 100 t/ha, depending on the degree of slope (Emde 1990). Grass strips enhance soil aggregates stability in the first 10–15 cm (Condei and Ciolacu 1991). In vineyards from many countries (Austria, Germany, Switzerland, Italy, France, Romania, etc.), middle rows are covered with mixtures of plant species. This floor management system is recommended in regions with annual rainfall of 600–700 mm, of which at least 250 mm occur between May and August (Valenti et al. 2002).

Well-structured soils store a lot of water, air, heat and nutrients, ensuring favourable conditions for vine growing and fruit set. Vineyards’ middle raw soil maintenance with permanent grass cover crops improves the structure and physical properties of the soil due to the organic matter addition and increasing microbial biomass through the biological activity (Bandici 2011; Dobrei et al. 2016).

Under high or too low soil moisture, tractors’ passing has negative impact on soil physical and chemical properties (Dobrei et al. 2008). Besides financial advantages, the permanent grass strips also provide advantages such as protection against soil erosion and degradation, allowing phytosanitary treatments in favourable stages, reduced water loss. (Dobrei et al. 2009).

The extended grass roots contribute to the soil loosening by adding organic matter transformed into humus that contributes to the activation of microbial life. Both the root mass and the above-ground plant contribute to humus restoration, the beneficial effect of dead plants being influenced by their chemical composition and diffusion in the soil (Bernaz and Dejeu 1999).

Grasses’ extent root system prevents soil erosion on sloping lands and is exposed to wind damage. Perennial plants can absorb nitrogen from the soil, but unlike legumes can only contribute to soil improvement by supplying biomass. Annual grasses such as rye, oats, barley or triticale sown in autumn are mowed or buried in spring to protect against frost. Therefore, the soil absorbs more heat over the day and releases it at night. Stubble left after mowing competes with weeds and contributes to decrease dust level and soil compaction after multiple tractors passages (Christensen 1971). However, besides advantages, natural vegetation or seeded plants can become competing for water and nutrients with vines. This competitiveness depends on the climatic conditions (especially the rainfall amount), grapevine requirements for water, the water absorption capacity of the cover crops species and the type of soil (Sicher et al. 1993). The disadvantage of natural vegetation is also derived from slowly and unevenly growing and clear space for weeds (Sicher and Dorigoni 1994).

4.4.1.1.1 Alternate Clean Cultivated and Grass (Legumes) Strips Alleyways

Floors managed with alternate clean cultivated and grass (and legumes) strips alleyways are recommended in vineyards with at least 350 mm rainfall during summer season (April–October) (Piţuc 1989). This system limits water runoff, soil erosion, increases the input of organic matter into the soil, allows tractors passing on wet weather, and reduces fuel consumption and the manual work (Condei and Ciolacu 1991). Usually after spring tillage, short species such as lawn grass (Lolium perenne—12–14 kg/ha), white clover (Trifolium repens) or species with spread roots like oilseed radish (R. sativus var. oleiferus or Raphanus sativus) are seeded. These plants can improve the soil structure, water drainage and fast root development (Bernaz and Dejeu 1999).

Grass mowed during the growing season is left on the ground as mulch. After 8–9 years, the grass strips are dissolved by tillage and the alleyways are changed with bare soil. Growing grass between vine rows for long period is not advisable because the soil becomes compacted, as emphasized by multiple tractor passing which increases soil stress. Therefore, the soil is loosened and reseeding is recommended every 4 or 5 years (Bernaz and Dejeu 1999). Once the symbiosis process of the legume plants starts, elements like nitrogen, phosphorus, potassium, iron and other minerals are released and absorbed by the soil. The vigorous root system that can reach 2–3 m underground helps to loosen soil, soil oxygenation and drainage of excess water resulting from heavy rains, snow melting, etc. Under dry and high temperature period, the well-developed leaves protect the soil from the sunburn, thus avoiding dehydration.

Plant species sown as cover crops are different for each viticultural region, climate and slope. For example, in vineyards from the Galati region (south-east of Romania), on dry and medium humidity areas with slope ≤10%, alleyways were covered with green manure (mixture of common vetch—Vicia sativa (120 kg/ha) and oat (60 kg/ha)) alternate with clean cultivation alleyways. In the same vineyard have been tested alternate alleyways of green manure (grass and legumes mixture) alternate with natural vegetation (Enache 2007).

Smooth brome (Bromus inermis Leyss.) strips, 1.2-m wide, were tested in sloping vineyards from the Moldavia region for water runoff and soil erosion control. The amount of soil loss during 1 year was estimated at 1.2 m3/ha, which is considered tolerance value. The fibrous root system contributes to reduce soil erosion and remove excess nitrogen from the soil (Enache 2007).

Peas (150–200 kg/ha), lupine bean (150–200 kg/ha), broad bean (150–200 kg/ha), soybean (150–200 kg/ha), grass legumes mixture (60 kg oat/ha + 120 kg peas/ha), rye (80–100 kg/ ha), vetch (120 kg/ha) are recommended as green manure (Enache 2007). They are fast-growing crops, with the possibility of atmospheric nitrogen fixation. Green manure is recommended in vineyards with annual rainfall over 600 mm, as well as in irrigated vineyards with large middle rows (3.0–3.6 m). Because of this, the soil is enriched in organic matter and nutrient mobility increases; excess moisture is taken by plants during the first stage of growing, and soil erosion reduces by using green mulch (Duda et al. 2014). Green manure is recommended for sandy soils. Mustard or rape on clay soils is recommended and peas on acidic soils. Lupine and clover are suggested as green manure on sandy soils. Debris is added by tillage into first 10–20 cm on sandy soils in early spring and 5–10 cm on clay soils depending on the soil type, moisture and amount of biomass. It is not advisable to incorporate green manure into the soil shortly after rain (Dobrei et al. 2016). Organic manure increases the biological activity in soil and, therefore, the fertility. About 3–50 tons/ha manure or grape pomace compost is recommended for optimum plant nutrition, yield and production after decomposition and transformation in humus by microorganisms (Vătămanu 2012).

Benefits for soil are different depending on the C/N ratio and the burring stage (young, mature, or old plants). Young plants with a low C/N ratio produce a small amount of organic matter but significantly stimulate soil biological activity (as source of minerals for microorganisms found near roots). However, mature or old plants with a high C/N ratio give an increased contribution of organic matter in soil (Moraru et al. 2015).

In vineyards from Danube terraces with rainfall over 600 mm, annually the green manure alleyways are recommended, for proper soil water balance and less soil erosion, with positive influence on organic matter in soil and less fuel consumption of 20–24 l/ha/year. Similar results have been observed on Somes Plateau argic faeoziom soils (north-west of Romania), when no-tillage, minimum tillage and conventional tillage were compared for soil respiration.

4.4.1.1.2 Fuel Consumption

In wine industry, fuel consumption is one of the major sources of GHG emissions. It is already known that fuel consumption represents among 25–40% from total energy input in a crop. Floor management in both alleyway and under-vines requires a lot of fossil fuel and contributes to the exposure of organic matter to microbial decomposition and consequently to the CO2 release (Carlisle et al. 2009). Less soil tillage contributes not only to the reduction of fossil fuel consumption but also to soil erosion and to the increase in carbon, nitrogen oxide and water supply into the soil.

Most vineyards are found on hillside lands with gentle slopes (always slopes to the south are preferred), sheltered from winds and warm in the growing season (April–October) (Gasso et al. 2014). Fuel consumption is different depending on the region, size of vineyard, tillage system, soil type, strength and moisture, land slope or altitude (Sørensen et al. 2014). Fuel consumption was variable on different soil types from Apahida, Cluj County (Stănilă 2014). On the same soils, depending on slope deep, fuel consumption is higher up to 21% on 9 to 14° slopes compared with flat land fuel consumption (Stănilă 2014).

Soil tillage by mouldboard plough at depth between 18 and 35 cm consumes fuel from 14.61 to 20.67 l/ha (Moitzi et al. 2014). By machinery traffic control in the vineyard, and suitable tillage method, total emissions of GHG are reduced, and soil compaction and runoff decrease. Therefore, in conventional tillage fuel consumption can be decreased by less soil tillage depth or by substitute conventional with minimum or no-tillage systems. Comparing conventional tillage with minimum tillage system, fuel consumption can be decreased from 72.93 to 48.26 l/ha (Stănilă et al. 2013). Performing two or three tasks in the same pass increases efficiency and decreases fuel consumption.

4.5 Conclusions

Nowadays, the effects of climate change and especially of climatic variability are becoming obvious with disastrous consequences, mainly as a result of anthropogenic actions. The wine industry generates GHG, especially during the winemaking, bottling, preservation and transport to consumers. Fortunately, viticulturists have begun to look for solutions to reduce energy and fuel consumption, which are major causes of environmental pollution. In many vineyards, manual work is still being used for pruning and canopy maintenance over the year, but also for row under-vine tillage. In many wine-growing regions, cover crops, grass alleys or other environmentally friendly methods to increase soil fertility and provide natural fertilizers have been adopted. Night-time cooling tanks, windows and large doors, underground cellars that keep constant temperature throughout the year without energy consumption, heating and cooling done with heat pumps, energy consumption provided by solar panels, deep wells for water required in the wineries, are some of the solutions already applied in few wineries from Romania. In the recent years, bag-in-box wine and wine bottled in plastic (PET) bottle are beginning to be used on a small scale to assess consumer preferences. Manual labour is still being used in vineyards for tillage, pruning or harvest; the use of agricultural machinery is still limited, thus reducing the use of chemicals and fossil fuels. These are some of the factors that render Romania a country with the lowest GHG emissions from agriculture in the EU.