To investigate the long-term effects of organic manure on soil macro-porosity and nutrient stoichiometry in greenhouse production, we studied the physical and chemical properties of soils under different vegetable systems in Jiangsu Province. These systems included organic greenhouse vegetable (OGV), organic open-field vegetable (OFV), conventional greenhouse vegetable (CGV), and conventional open-field vegetable (CFV), with rice–wheat rotation (RWR) soils used as a reference.The results showed that, compared to conventional systems, organic vegetable production increased soil macro-porosity, soil organic carbon (SOC), and total nitrogen (TN) content, as well as C:N, C:P, and N:P, particularly in the tilled layer. SOC, TN, and total phosphorus (TP) levels increased rapidly during the first 14 years of OGV cultivation, followed by a decline. SOC, TN, and stoichiometric ratios were significantly positively correlated with soil macro-porosity. The study suggests that converting RWR to OGV does not degrade soil aeration, and long-term application of organic manure positively impacts nutrient retention in the tilled layer, although the effects are time- and depth-dependent. The study highlights the potential of long-term organic manure application to improve soil aeration and nutrient balance in OGV, underscoring the importance of optimizing fertilizer management in intensive agriculture to enhance soil quality and crop yield.

Urea supplements, such as humic acids, could enhance fertilizer nitrogen use effectiveness. Melting is superior to mixing for humate urea application; however, the effects of diverse humate ureas from various coal sources on soil N supply remain unclear. This study compared the properties of two humic acids from different coal sources (HA1, weathered coal; HA2, lignite coal), and their impact on soil mineral N supply and the nitrate–ammonium ratio under flooded and 60% water-filled pore space (WFPS) over a 14-day incubation. Humate ureas stimulated soil mineral N accumulation and balanced the soil nitrate–ammonium ratio at 1:1; however, no significant difference existed between the two humate ureas under 60% WFPS. Humate urea enhanced soil ammonium nitrogen (NH₄⁺-N) retention and delayed nitrate nitrogen (NH₄⁻-N) release, leading to soil mineral N retention, especially in lignite humic acid urea (H2AU) treatments from lignite under flooding. Structural equation modeling (SEM) and linear regression revealed that humic acids elevated soil redox potential (Eh) and electrical conductivity (EC), stimulating soil N mineralization and adjusting the optimal nitrate–ammonium ratio. Humate urea improved soil mineral N supply compared to traditional urea treatments, and humic acids from lignite were more beneficial for crop cultivation from a mineral soil N supply perspective. These findings enhance our understanding of humate urea benefits and aid in optimizing humic acids application for N management.