Molecular Soil Biology 2025, Vol.16, No.4, 199-213 http://bioscipublisher.com/index.php/msb 2 06 8 Case Study Analysis 8.1 Case 1: high input conventional corn system - impact and lessons learned The high input conventional corn system is characterized by deep plowing, monoculture, high-dose fertilizers and pesticides, and is widely distributed on large farms in Europe, America, Southeast Asia and other regions. This type of system can achieve high yields in the short term, but it puts multiple pressures on soil health. Long term monoculture and high-intensity tillage lead to a decrease in soil organic matter, destruction of aggregates, increase in bulk density, and decrease in porosity, which in turn affect water retention and root growth (Bruun et al., 2017; Nyéki et al., 2022; Smith and Boardman, 2025). The excessive use of fertilizers and pesticides can also lead to soil acidification, imbalance of trace elements, and decreased microbial diversity, increasing the risk of pests and diseases (Bruun et al., 2017; Afata et al., 2024; Mukhametov et al., 2024). In cases such as Thailand and Hungary, intensive corn cultivation led to a significant decrease in quality indicators such as soil oxidizable carbon (Pox-C), and soil quality was negatively correlated with planting intensity (Bruun et al., 2017; Nyéki et al., 2022). High input systems are also prone to soil erosion and sediment loss, especially in slopes and areas with concentrated rainfall. The case of East Devon, England, shows that soil compaction and bare land exposure during corn harvesting and planting are very likely to cause muddy water flooding and serious erosion after rainstorm, threatening farmland and surrounding environment (Ruf et al., 2021; Smith and Boardman, 2025) (Figure 2). These issues suggest that relying solely on high input and mechanized conventional corn systems can increase yields in the short term, but in the long run, it will incur the cost of soil degradation and ecological risks, and there is an urgent need for management optimization and sustainable transformation. 8.2 Case 2: conservation tillage maize system - impacts and outcomes Long term field trials in China, the United States, Brazil, and other regions have shown that conservation tillage can significantly enhance soil organic carbon, aggregate stability, and microbial diversity, improve soil structure and water retention capacity (Ablimit et al., 2022; Da Silva et al., 2022; Li et al., 2023; Flynn et al., 2024). In the intercropping system of green manure maize in northwest China, ten years of conservation tillage increased soil pH, nutrient content, and enzyme activity, reduced pathogen abundance, promoted the enrichment of beneficial microorganisms, and resulted in better soil health and yield than monoculture systems (Ablimit et al., 2022). Intercropping and covering crops can increase the diversity of soil animals (such as nematodes and earthworms) and microorganisms, enhance the complexity of food webs and nutrient cycling efficiency (Da Silva et al., 2022; Liang et al., 2024). In the tropical regions of Brazil, maize grass rotation and no till management significantly improved soil organic matter and aggregate stability, as well as soil structure and erosion resistance (Da Silva et al., 2022). 8.3 Comparative analysis of cases: soil health indicators There are significant differences in soil health indicators between high input conventional systems and conservation tillage systems. Under high input conventional systems, soil organic matter, aggregate stability, microbial diversity, and enzyme activity all show a decreasing trend. Soil structure deteriorates, bulk density increases, porosity decreases, water retention capacity weakens, and erosion and nutrient loss are prone to occur (Bruun et al., 2017; Nyéki et al., 2022; Mukhametov et al., 2024; Smith and Boardman, 2025). Conservation tillage systems can significantly enhance organic carbon, aggregate stability, and microbial diversity, improve soil structure and water regulation capacity, and reduce erosion risk (Ablimit et al., 2022; Da Silva et al., 2022; Li et al., 2023; Flynn et al., 2024; Liang et al., 2024). In terms of biological indicators, soil microorganisms and animal communities under conservation tillage systems are more abundant, food web complexity and ecological functions are stronger, enzyme activity and nutrient cycling efficiency are higher (Ablimit et al., 2022; Da Silva et al., 2022; Liang et al., 2024). Chemical indicators such as pH, nutrient content, and organic matter levels are also superior to high input systems.
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