Genomics and Applied Biology 2026, Vol.17, No.1, 26-36 http://bioscipublisher.com/index.php/gab 28 Research in the Yellow-Huai-Hai region has found that covering with plastic film on the basis of a ridge height of about 30 cm can increase the temperature of the 5-10 cm soil layer by 6.0%-6.4%, and simultaneously increase LAI and tuber yield (23.8%-33.8%), indicating that the water and heat conditions of the ridge can be regulated through "ridge height × covering or drip irrigation". For ridge farming systems with irrigation conditions, there are also studies proposing to control the ridge height to increase the distance between the water level surface and the soil surface, stabilizing the soil moisture content at 10%-15%, and reducing CO₂ accumulation in the root zone, demonstrating the amplification effect of ridge height in water management (Zhang et al., 2021). 2.3 Changes in the rhizosphere microenvironment under ridge cultivation and their effects on root formation Whether root formation can proceed smoothly is not merely a matter of whether there is sufficient water and nutrients; the condition of the rhizosphere being “well-ventilated” is equally crucial. In the forced aeration experiment, a phenomenon was quite obvious: when the CO₂ level in the root zone of the ridge was high, the net photosynthetic rate of the leaves and the stomatal conductance would decrease (Bhattarai et al., 2017); when the CO₂ was reduced to 0.1%-0.2%, the fresh weight and dry weight of the roots could increase to 1.18-1.19 times that of the control, and further increasing the aeration volume could even increase the dry weight by 19%-26%. It is not difficult to understand this in the field context. If the ridge body is low and the drainage is slow in fields with heavy rain and clayey soil or after rice cultivation, the accumulation of CO₂ and the risk of hypoxia in the rhizosphere are prone to occur, and the initiation and early expansion of the roots are often hindered; conversely, if the ridge body is moderately raised, the gas renewal is faster after rain, and the microenvironment is more stable. At the same time, the soil becomes looser and has better aeration, which will also increase the ATP supply and aerobic respiration efficiency of the roots, promoting starch synthesis. Two-season field experiments showed that the yield of sandy loam soil with better aeration conditions was 13.94%-32.91% higher than that of loam soil, and the peak of root expansion was more concentrated (Jin et al., 2020). Although the ridge height was not directly compared, this mechanism supports the judgment that ridge cultivation promotes root expansion by improving aeration. 3 The Effect of Ridge Height on the Growth Characteristics of Sweet Potato Aboveground Parts 3.1 Sweet potato stem and vine growth and leaf area changes at different ridge heights The impact of ridge formation on aboveground growth is often not immediately apparent, but rather changes the environment before affecting the population. When the ridge height is appropriate and the drainage and ventilation conditions are good, the slow seedlings are often faster, the root system is more stable, and the leaf area index is more likely to form an advantage; On the other hand, when encountering waterlogging damage after rain, low ridges often have yellow leaves, weak seedlings, and uneven populations. It is also difficult to make up for the gap that was widened earlier by applying fertilizer later on. In field experiments, in the Huang Huai Hai region, under the condition of about 30 cm ridge formation and film mulching, ridge formation can increase soil temperature and LAI by about 5.6%-6.4% compared to bare land (Liu et al., 2018). This indicates that the improvement of ridge water and heat directly reflects on leaf area expansion. However, stem length does not necessarily mean high yield. Comparing different ridge heights of 30, 40, and 50 cm abroad, it was found that low ridges are more likely to grow vines, while medium ridge heights are more conducive to increasing root yield, indicating that ridge height can reshape the distribution relationship between nutrient growth and root tuber enlargement (Villordon et al., 2019). So when evaluating ridge height, we cannot only focus on whether the ridge is sealed quickly, but also on whether the assimilates flow smoothly into the “reservoir” of root tubers after the ridge is sealed. 3.2 The impact of ridge height on photosynthetic capacity and material accumulation Whether photosynthesis is strong or not is not only related to the structure of the canopy, but also affected by the underground environment. In the forced aeration experiment, when the CO₂ level in the root zone rose to 1%-2%, the net photosynthetic rate and leaf conductance dropped to 0.8 and 0.7 times that of the control, respectively
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