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

Abstract

BACKGROUND: 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.RESULTS: 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 ∼m) increased by 0.69% on average in response to 1% PLC application. Soil NO 3 − -N, NH 4 + -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 (N 0 ), the first-order rate constant (k) and the mineralization composite index (N 0 × k), increased obviously as the amount of PLC increased. Porosities larger than 1000 ∼m were significantly more positively correlated with the parameters of soil N mineralization than those <500 ∼m. The Pearson correlation coefficients suggested that high porosity, mineral N and N 0 values had significant positive relationships with the fresh weights in double seasons.CONCLUSION: 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.