Plant Gene and Trait 2025, Vol.16, No.3, 113-122 http://genbreedpublisher.com/index.php/pgt 119 tend to use high-density methods, while large enterprises mostly adopt standard density. The design of row spacing and plant spacing for high-density planting is mainly to make more full use of the land and facilitate the use of small mechanical equipment. 8.2 Implementation of mechanized harvest with high-density rows In the high-density system, the vineyard uses small machinery suitable for narrow row spacing for management and harvesting. Because it is planted relatively compactly, this structure can enhance the efficiency of mechanized operations and reduce manual intervention. Mechanical harvesting is not only fast, but also more consistent and efficient (Irish-Brown et al., 2022). The compact line spacing also makes it easier for the machine to pass through and operate, further enhancing the operational efficiency (Irish-Brown et al., 2022). 8.3 Observed changes in productivity, quality, and labor efficiency High-density planting significantly increased the yield per hectare, with an increase ranging from 26.8% to 32.5%, and the yield-increasing effects varied among different varieties. For instance, the Aromatnyi variety yields an average of 2.5 tons per hectare, while Zahrei yields 4.0 tons per hectare more. However, high density also brings some problems, such as the rising demand for labor. The costs of labor and drivers increased by 63.1% and 50.2% respectively, and the labor intensity per unit of product also rose by 11.3% to 13.7%. Fortunately, through mechanized operations, the problem of insufficient labor has been partially alleviated, and the harvesting efficiency has also been improved (Irish-Brown et al., 2022). In terms of fruit quality, high-density planting helps improve light conditions and space utilization, which can enhance the consistency and overall quality of the fruits (Irish-Brown et al., 2022; Manju et al., 2025). However, if the density is too high, the canopy may be overly dense, affecting the microclimate conditions around the fruit, and may even lead to problems such as fewer fruit clusters and a decrease in the number of fruit grains (Keller and Mills, 2021). Therefore, to increase both output and ensure quality, the key lies in designing a reasonable high-density system and combining it with mechanization for management (Keller and Mills, 2021; Irish-Brown et al., 2022; Manju et al., 2025). 9 Challenges and Research Gaps 9.1 Limitations in existing varieties for dense systems High-density planting has put forward higher requirements for the adaptability of grape varieties. Some studies have found that the yield of some existing varieties decreases and the fruit quality deteriorates under dense planting conditions (for example, with a plant spacing of only 0.91 meters). Because the vines grew too vigorously and the canopy was too dense, the microclimate in the orchard became worse, eventually resulting in fewer fruit clusters, fewer fruit grains, and more prone fruit stems to damage (Keller and Mills, 2021). In addition, the economic performance of some new varieties varies at different densities. It is still necessary to continue screening out specialized varieties that are more suitable for high-density mechanized planting (Di Lorenzo et al., 2022). 9.2 Equipment compatibility in sloped or non-uniform terrain Mechanical harvesting equipment performs well in flat vineyards, but it encounters difficulties on sloping land or in areas with irregular terrain. In emerging grape-producing areas like China, due to the complex terrain, along with the variety of equipment types and inconsistent standards, mechanical harvesting cannot be widely implemented in many places (Yang et al., 2025). Moreover, there is no clear conclusion yet on whether it is cost-effective and useful for small vineyards to use small equipment under high-density planting conditions. In orchards with complex terrain, machine operations may also make the soil more compact, affecting the long-term health of the vineyard. 9.3 Long-term effects on vineyard longevity and soil health High-density planting combined with frequent mechanical operations may also have an impact on soil health and the sustainable development of orchards. Long-term dense planting will cause the nutrients in the soil to be consumed more quickly, the organic matter to decrease, the soil may become acidic, and salinization problems
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