Abstract:

【Objective】 This study was conducted to determine the effect of inter-row cover crops in vineyard on main nitrogen compounds in grape berry (skin, pulp and seed) and wine from Cabernet Sauvignon. 【Method】 Compared with soil tillage (control), three cover crops, white clover, alfalfa and tall fescue were sown in vineyard. The main nitrogen compounds (total nitrogen, soluble protein and free amino acid) of mature grape berry (skin, pulp and seed) and wines vinified under the same conditions were extracted and analyzed with micro-kjeldahl method and full- automatic biochemical analyzer. 【Result】 The protein content in seed of alfalfa treatment was higher significantly than that of the soil tillage, and the total N and protein contents in skins, pulps and seeds decreased by different cover crops treatments. The total N content in seeds was the highest, which was 41.6% of the total N content in the whole berries, total N in pulps and skins accounted for 33.9% and 24.50% of the whole berries, respectively. While 46.0% of total nitrogen compounds in berries were proteins, the protein contents in seeds, pulps and skins were 50.9%, 33.9% and 15.2% of the total proteins, respectively. No significant difference was noticed among different treatments in total N content and protein content in wines. Compared to soil tillage, the alfalfa and tall fescue sward treatments increased the total amino acid contents of grape berry but the white clover treatment decreased them, and there was no significant difference between cover crop treatments and the control. Proline was the most abundant amino acid in grape berry in four treatments, which accounted for 45.9% to 56.9% of the total amino content, next in abundance was arginine and lysine, which accounted for 16.4% to 24.2% of the total amino acid content. The sward treatments showed a higher content of amino acid contents in wines, and there were significant differences (P＜0.05) between two cover crop treatments (tall fescue, alfalfa) and soil tillage. Praline was also the most abundant amino acid in wine, which accounted for 90.11% to 92.45% of the total amino acid content. 【Conclusion】 Cover crops in vineyard increased total free amino acid content of grape and wine, although decreased total N and protein content of grape berry. The conclusion is that the cover crops may improve the quality of wine.

Key words: vineyard, cover crops inter-row, grape berry, wine, nitrogen compound