Insulating Organic Material as a Protection System against Late Frost Damages on the Vine Shoots

Abstract

Late frosts are one of the major impact factors on agriculture worldwide with large economic losses for agricultural crops, with a significant impact also in wine production. Given the importance of the wine sector in the world, more and more efforts are being made to identify innovative techniques capable of creating a low-cost and effective protection for vine shoots, as well as reducing energy consumption. In a previous work, cotton candy was identified as an insulating material to solve the problems related to late frosts on vineyards and limit its damages as much as possible. From the results of the previous research, it has proved that cotton candy is an excellent thermal insulator, but it degrades quickly in windy conditions. Thus, climatic tests carried out in windy condition showed that straw can greatly slow down the degradation of cotton candy over time, giving an indirect contribution to the protective effectiveness of cotton candy. In addition, several tests were conducted with different amounts of sugar and straw without wind to evaluate whether the straw can itself make a contribution in terms of thermal insulation, as well as contribute to the protective effectiveness of cotton candy, minimizing energy use as well.

Application of a completely organic and bio-degradable sugar-based insulating coating to vine shoots, to prevent late frost damages

“…The two pairs of vine plants tested are shown in Figure 1 In both tests, for each pair of vine plants, one of them was covered by the insulating coating made of cotton candy and straw and compared to a control vine plant without insulating coating. In a previous work [16], the optimal sugar quantities, expressed as an optimum between insulating efficiency and costs, resulted equal to 33.3 g in case of a surface of 1 m 2 . Nonetheless, in these tests the quantity of sugar to be employed was equal to 20 g and 27 g in the Test 1 and 2, respectively, in order to cover the entire surface of plant with the cotton candy.…”

“…• The temperature range in which such technique may effectively be a promising opportunity, must be better define. In absence of secondary sources of heat, an external temperature about six degrees lower than the ice-point may require the usage of a higher quantity of raw material per unit of surface than that defined in [16]. Further works will be proper focused on this aspect, and direct applications of the insulating layer on vine plants will be tested for several environment temperature, in the range from 0 °C to -6 °C.…”

“…This material must meet the following requirements: nontoxic, easy to use, cheap, and completely biodegradable. In this research, the possibility to apply an innovative method, already tested in lab [15,16], in the real vine plants was investigated, allowing to detect some crucial challenges which need to be solved before to test this technology in real situations.…”

“…Nonetheless, in these tests the quantity of sugar to be employed was equal to 20 g and 27 g in the Test 1 and 2, respectively, in order to cover the entire surface of plant with the cotton candy. According to the previous work [16], the tests were carried out by keeping the ratio between the grams of sugar and the grams of straw constant. In particular, 1 g of straw is used for every 5 g of sugar.…”

“…In a subsequent work [16], the straw was added to cotton candy showing to be able to slow down the degradation of cotton candy in windy condition and thus allowing it to perform its insulating function over a longer period. A preliminary cost analysis showed that the best solution to minimize overall costs consisted in creating an insulating layer made of 33.3 g of sugar per m 2 and straw [16].…”