| Wine grape cultivar Cabernet Sauvignon as experimental materials, through field and labtorary experiments, the effects of permanent green cover in vineyard inter-row with White Clover (Trifolium repens),Perennial Ryegrass (Lolium perenne) and Alfalfa (Medicago sativa) on mineral nutrition in soil and leaf , soil moisture content, physical characteristics, vine growth and development, vineyard microclimate and leaf photosynthetic rate, quality of grape and wine were studied in Yangling, Shaanxi. With comparison of clean tillage, the results were as bellows:1 .The effect of green cover on soil in vineyardThe contents of total N and K in soil were increased whereas the total P had no significant changes. The alkaline hydrolysis N, available P and available K were decreased while the soil pH and organic matter were raised. Perennial Ryegrass reduced the alkaline hydrolysis N and available K in soil evidently by 16.68% and 11.94% compared with the other treatments. However, the soil organic matter was increased significantly with Perennial Ryegrass cover.Concerning the microelement in soil, the content of Mn was increased and Zn was decreased, the differences were significant between treatments. The contents of Cu and Fe were increased with Alfalfa cover and increased or decreased under the other two green covers. After planting grasses, soil physical characteristics were improved, soil bulk density decreased by 5.68% and soil porosity increased by 6.15%. While the soil moisture content of green cover was reduced obviously.In short, among the treatments of 3 kinds of grass, the vineyard was benefited from covering with Alfalfa and White Clover cover in N accumulating and Perennial Ryegrass in organic matter increasing. The treatment of Alfalfa increased soil nutrition significantly and affected soil moisture content less in the root system growth areas.2. The effect of green cover on vine growth and developmentThere were no significant differences in phenological phase of Cabernet Sauvignon between treatments, but the rate of bud germinating percentage, bearing shoot percentage, fruit set percentage, fruiting coefficient(bunch/shoot)of vines and yield of grape berry were reduced significantly. Growth of the vines were controlled efficiently and root densities were decreased,while the vine roots of green cover were stimulated to penetrate deep into the subsoil,it was benefit to vine roots in absorption water and mineral nutriton from soil. The contents of leaf nutrimental element, such as N,K,Ca,Mn,B, were all increased by 3 kinds of grass cover while the content of Mg was reduced. The rest measured nutrimental element were increased or decreased by different green cover. In conclusion, the most of leaf mineral nutrition has tendencies of improving by green covering. The treatment of Alfalfa was improved contents of leaf mineral nutrition evidently.3. The effect of green cover on vineyard microclimate and photosynthetic rateGreen cover in vineyard could moderate and minimize the daily fluctuation of temperature and adjust relative humidity. It declined the daily maximum temperature of soil surface 5.7～7.3℃ ,the daily range of soil surface temperature 6.7～7.6℃ in warm season, it also increased the daily range of air temperature 1.1～2.4℃, decreased the soil temperature of different depth. It was helpful to root growth and berry development. But the reduction in leaf net photosynthetic rate, stomatal conductance and transpiration rate were attributed to reduced soil moisture seriously with green cover.4. The effect of green cover on grape and wine qualityReducing sugar was higher, total acidity was lower, sugar acidity ratio was higher, in fruit from green cover compared with clean tillage, while Anthocyan, pH and tannin of wine were increased with green cover. There were no differences in duration of alcohol fermentation between treatments. The color density and tastes of wine were improved significantly under green covering.
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