Soil mineral nitrogen regulation by a novel porous material in structurally degraded soils

The availability of soil nitrogen (N) decreases as the structure of agricultural soils degrades. Traditional methods focus on organic amendments that indirectly affect the porosity and N content of soil. Due to the low efficiency of such amendments, new materials, particularly highly porous materials, are needed to improve the quality of soil, which has opened new directions.

The addition of 2 to 7 mm of porous clay ceramic (PLC) significantly increased the fresh weight of Brassica chinensis. The soil aeration porosity (>50 μm) increased by 0.69% on average in response to 1% PLC application. Soil NO₃ ^- -N, NH₄ ⁺ -N and mineral N increased by 3.3, 1.3 and 4.6 mg kg^-1 on average, respectively, following a 1% PLC application rate. The initial N content of the high PLC treatments was the lowest in the incubation experiment. The parameters of soil N mineralization, i.e. potentially mineralizable N (N₀ ), the first-order rate constant (k) and the mineralization composite index (N₀  × k), increased obviously as the amount of PLC increased. Porosities larger than 1000 μm were significantly more positively correlated with the parameters of soil N mineralization than those <500 μm. The Pearson correlation coefficients suggested that high porosity, mineral N and N₀ values had significant positive relationships with the fresh weights in double seasons.

The application of PLC increased soil aeration and enhanced the availability of soil N, which yielded large vegetable harvests in clayey soils in the short term. © 2022 Society of Chemical Industry.