Soil improvement is a critical technical component in horticultural engineering, addressing issues such as compaction, poor drainage, and nutrient deficiency to create optimal growing environments. Advanced techniques combine soil physics, chemistry, and biology to enhance soil health, directly impacting root development, nutrient uptake, and overall plant vitality. In degraded urban soils, these methods have been shown to increase organic matter content from 1–2% to 5–8% within 12 months, significantly improving soil structure.
Mechanical aeration techniques, such as core aeration and subsoiling, alleviate compaction in the root zone (0–30 cm depth). Core aerators remove 1–2 inch diameter plugs at 3–4 inch intervals, creating channels for air, water, and root penetration. For severe compaction (bulk density >1.6 g/cm³), subsoiling with tines reaching 40–60 cm depth breaks up hardpans without inverting the soil profile, reducing bulk density by 15–20%. These mechanical interventions are often followed by the incorporation of organic amendments, such as composted green waste (C/N ratio 20:1–30:1) applied at 5–10 cm depth, which improves soil aggregation and water-holding capacity by 30–40%.
