Molecular Soil Biology 2026, Vol.17, No.1, 38-50 http://bioscipublisher.com/index.php/msb 39 Investigating the interactions between soil microbes and environmental factors provides insights into the mechanisms underlying continuous cropping obstacles. Moreover, manipulating microbial communities through practices like crop rotation, residue incorporation, or biochar amendment offers promising avenues to restore soil health and enhance cucumber yield sustainability in greenhouse systems (Zhao et al., 2020; Chen et al., 2022). 2 Soil Ecological Characteristics under Continuous Cropping of Greenhouse Cucumbers 2.1 Changes in soil physicochemical properties under continuous cropping conditions Continuous cucumber cropping in greenhouse systems often leads to significant alterations in soil physicochemical properties, which can negatively impact soil health and crop productivity. Studies have shown that prolonged monoculture results in decreased soil pH, increased electrical conductivity (EC), and accumulation of total salts, indicating soil acidification and salinization trends that are detrimental to plant growth. For example, research along the Yellow River irrigation area demonstrated a consistent decline in pH and rise in total salt content with increasing years of continuous cucumber cultivation, alongside increases in organic matter and available nutrients such as nitrogen, phosphorus, and potassium during the early years of cropping (Huang et al., 2023). Similarly, long-term monocropping has been associated with elevated concentrations of organic matter and nutrients but also with adverse changes like soil acidification and nutrient imbalances that challenge sustainable production (Zhao et al., 2020). Different cultivation patterns can modulate these physicochemical changes by influencing microbial communities and nutrient dynamics. Rotation systems such as paddy upland or garlic rotations have been found to mitigate soil acidification by maintaining higher pH levels compared to continuous cucumber monocropping. These rotations also promote beneficial shifts in microbial populations that contribute to improved soil quality. For instance, a study comparing six cultivation patterns over nine years found that rotation practices significantly altered bacterial and fungal community structures while alleviating the trend toward acidification seen under continuous cucumber cropping (Zhang et al., 2023). Such findings highlight the importance of diversified cropping systems for maintaining favorable soil physicochemical conditions in greenhouse cucumber production (Figure 1). Figure 1 Conceptual illustration of how continuous cucumber monocropping in greenhouse systems alters soil physicochemical properties, including pH decline, salt accumulation, and nutrient imbalance, which ultimately influence cucumber root systems and plant growth performance 2.2 Effects of continuous cropping on soil nutrient cycling Continuous cucumber cropping disrupts normal nutrient cycling processes within the soil ecosystem, often leading to nutrient accumulation or depletion that affects plant nutrition and microbial activity. While some nutrients like organic carbon, total nitrogen, available phosphorus, and potassium tend to increase initially due to fertilizer inputs and residue accumulation, their bioavailability may decline over time due to imbalances caused by monoculture practices. For example, studies have reported increased nutrient contents after several years of
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