Weeds in the vineyard? The geese take care of it

Here are the results of the multi-year survey conducted in the vineyard of an organic company

In tree plants, the control of weeds and the annual fertilization of production are operations that if carried out incorrectly can cause problems both in economic terms, due to the high costs to be incurred, and in terms of environmental impact. An alternative solution to the classic techniques that can be used can be the use of herbivores inside the vineyards, which with their grazing and release activities, contribute to the control of the herbs and to the fertilization of the vineyard. Furthermore, depending on the herbivorous species used, additional income can be obtained from animal products. In light of the growing populousness of the planet, from the current 7 billion people to about 9-10 expected by 2050, and the demand for food, including meat, as well as the need to conserve soils and the environment, it is unlikely that arable land will be increased.; perennial tree crops, which occupy over 150 million hectares in the world, can therefore offer abundant grazing, avoiding the use of new land.

The goose is a herbivorous animal, an excellent grazer and is used as a “natural herbicide” in various crops, including strawberries, cotton, nurseries, orchards and vineyards, particularly in the USA. In Italy, however, the use of animals for “weeding / fertilization” use is not well known. However, it should be specified that if there may be many potential advantages of this intercropping, there may also be problems, such as: potential damage in the vineyard both direct (grazing of young shoots, leaves and clusters) and indirect (if the animal load is excessive or not well distributed, they may not be effective in weeding or vice versa overgrazing and producing soil compaction).

Furthermore, in order to produce healthy and quality meats, attention must be paid to the use of plant protection products, as geese can ingest the chemicals that fall on the ground and on the pasture. Perhaps the biggest problem, however, is asking the winegrower to also become a breeder, that is, to educate himself in a new professionalism that involves not only knowing how to breed, but also knowing how to transform and sell new products. It is certainly a challenge; naturally weeded vineyards and grazing geese are products that can be exploited in a market that is increasingly sensitive to quality and respect for the environment. Below are the results of a multi-year survey aimed at highlighting the potential, the problems and the impact on the performance of a vineyard managed with a vineyard-goose association in central Italy.

Materials and methods

The study was conducted in the vineyard of an organic farm located in municipality of Cannara (Perugia) at about 250 m asl The climate of the area is continental, the average annual air temperature is 13.8 ° C and the average annual rainfall is 864 mm. The soils of the studied site derive from river and lake sediments and have a clayey-silty texture.

Vineyard

The plant used is made up of the Trebbiano Spoletino grape grafted on the Kober 5BB rootstock, trained by Guyot with planting distances of 2.80 × 0.80 m (4.460 vines / hectare), located in the municipality of Cannara, Perugia, central Italy ) of the ” Cantina Di Filippo ” company. In the 2020 harvest, i.e. after 5 years of continuous use of the geese, the unit productions, the composition of the grapes and the vigor, as well as the salient characteristics of both the soil and the goose meat were evaluated.

Farm

The geese, of the Romagnola breed , were grazed in the vineyard with a modest load, that is 120 per hectare. During the day the geese were allowed to enter the vineyard, with the rows separated by a metal mesh in order to allow grazing in one row at a time, while at night they were housed in predator-proof shelters. In the evening the geese were fed with additional feed (maize 40%, barley 30% and field beans 30%), with a controlled quantity, that is about 80% of the voluntary consumption, in order to avoid excessive consumption and favor grazing. The water was instead provided ad libitum using a tank located near the vineyard. The production performance of geese reared in the vineyard was compared with that of geese reared in the traditional way. At the end of the cycle (160 days of age for grazing geese and 130 days for intensive ones) the geese were slaughtered and the quality of the meat and the copper content in the liver (storage organ) deriving from the anti-treatment treatments were assessed. peronosporic.

RESULTS

Vineyard

With the same bunches per vine (about 9-10) the grape production was decidedly higher in the case associated with geese (+ 23%) due to the increase in the average weight of the grape (+0.21 g / grape) and of the bunch (+45 g / bunch) (Tab. 1, Fig. 1). The parameter number of berries per cluster was not influenced and therefore it is assumed that the setting had a regular course. The technological ripening of the grapes has not undergone significant changes, so much so that sugars, titratable acidity and pH of the must were rather similar, while nitrogen readily assimilable by yeasts (APA) shows significantly higher values in the thesis with the presence of geese (+ 33%).

TABLE 1 – PRODUCTION YIELDS, PRODUCTION COMPONENTS AND GRAPE COMPOSITION DURING THE HARVEST (DONE 14/09/2020) IN THE MANAGEMENT OF THE PRESENCE OF GEESE AND NOT.

* APA = nitrogen readily usable by yeasts (sum of ammonium and free amino acids net of proline).

Fig. 1 – Shape and size of the bunches produced by the vineyard managed with and without geese.

TABLE 2 – PLANT VIGOR AND VEGETABLE-PRODUCTION BALANCE INDICES (average values for the period 2018-2020).

Regarding the vigor expressed by the vines, the presence of geese caused slight increases both in the total leaf surface (+0.55 m² / vine) and in 1 year old pruned wood (+90 g / vine), while both the vegetative-productive equilibrium indexes did not show appreciable variations, since in the thesis with geese the increase of both parameters of vigor considered, an adequate increase is also paid in unit production of grapes. In both theses these indices denote a good vegetative-productive balance and / or the establishment of not too excessive nutritional competitions both between the contiguous plants and between the various organs of the vines themselves.

Soil

The grazing geese provided on average a quantity of manure of 53 kg / ha per year and therefore about 69, 82 and 44 kg / ha of N, P and K, respectively; resulting, apart from a slight deficiency of K, congruous with the needs of the crop and with the characteristics of the soil. Regarding the impact of the geese on the soil, the results did not show a total and soluble organic C (CO) enrichment in the vineyards grazed by the geese compared to the control. No differences were highlighted regarding the total N and P content available, probably following the strengthening of the re-growth of the grasses present in the lawn, on the one hand, and the greater vigor and productivity expressed by the vines, on the other. Regarding the microbial biomass, an increase in the quantity of microbial C and a certain decrease in the respiratory activity of the microorganisms in the first cm of soil of the grazed vineyards was detected compared to the control.

The load of geese per hectare was found to be suitable and did not cause damage to pasture and vegetation.

Production performance and meat quality of geese

As expected, the grazing geese, compared to those in the barn, grew more slowly both due to grazing activity, which involves a certain physical exercise and a consumption of food energy not intended for growth, and as the food was not provided ad libitum , to encourage grazing activities.

The qualitative-quantitative comparisons were made between geese of 160 days in the pasture and control geese of 130 in order to compare geese of similar weight. The feed conversion rate for grazing-raised geese was 6 kg of feed to produce 1 kg of live weight, slightly higher than for indoor animals, which was 5.3. Breast weight and storage fat were similar, while thigh and meat to bone ratio was better in vineyard geese, probably due to the increased exercise of these animals. The chemical characteristics of the meat (humidity, proteins, ashes and lipid peroxidation) did not show appreciable variations between the two groups compared to both the breast and the thigh. The only significant difference was the lower fat content of the meat of the geese in the vineyard, again due to the greater physical movement. The content of antioxidants (α-tocotrienol, α- δ- γ-tocopherol and retinol) was higher in the animals reared in the vineyard, while with regard to the acidic profile of the meat, grazing resulted in a greater presence of polyunsaturated acids (especially linolenic a detriment of linoleic) and a lower presence of monounsaturated. From a nutritional point of view this is important as it improves the availability for human nutrition of one of the n-3 fatty acids considered relevant in the prevention of cardiovascular diseases. The only drawback is the increase in copper in the goose liver reared in the vineyard (151 vs. 92 ppm) which is still significantly below the toxicity thresholds, but which must be carefully monitored.

Conclusions and application considerations

In animal production, the safety and quality of products, animal welfare and environmental sustainability are extremely topical due to the considerable attention of both governments and public opinion. All this increases the interest in extensive farming systems that are more attentive to animal welfare and environmental impact. The final report of the EU “Consumer concerns about animal welfare and the impact of food choices “(EU FAIR CT98-3678), underlines how animal welfare can be considered as an index of the safety, quality and healthiness of products of animal origin. To solve these problems, the Community directives have turned to the concept of the multifunctionality of the agricultural enterprise, to the enhancement of biodiversity that allows animals to adapt to environmental conditions, to the quality of production and to marketing through short supply chains. The characterizing element of extensive animal production (organic and free range) is the availability of grass which positively influences the behavior, the quality of the products and the state of health of the animals.

The presence of the vines implies an improvement in the farming conditions not only compared to the intensive one, but even compared to a grassy pasture breeding , as the vines create shade, useful for geese especially in summer which otherwise suffer from the heat and graze and grow less.

The results of this survey indicate that geese, if well managed with a rotating pasture and with the right load, carry out a good control of weeds, without causing damage to the vineyard and the soil, eliminate the need for additional fertilizers and improve the yields and some parameters of grape quality, for example the nitrogen readily usable by the yeasts during fermentation. The latter is of fundamental importance, since it controls the fermentation speed and positively influences the aromatic fraction of the future wine. However, it will be necessary to evaluate in the long term the possibility that a substitute flora may be formed, not appetite for geese, and which will therefore require an occasional passage with mechanical means. The possibility of increasing corporate income from the sale of products (meat, eggs, liver) generated by the association of geese should not be underestimated.

The breeding of the goose in the vineyard can therefore represent an example of economic-ecological reconciliation, which allows to combine a higher productivity per hectare with a lower environmental impact. The increasing willingness that consumers have shown in recent years to purchase products with low environmental impact and the increasing costs due to unsustainable practices, create the opportunity to develop alternative production systems. Goose and wine, therefore, could be an excellent match, not only at the table.

Alberto Palliotti, Cesare Castellini

Department of Agriculture, Food and Environmental Sciences – University of Perugia, Italy

Read the articles by prof. Palliotti here

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