The duration of intensive vegetable cultivation regulates the fates of accumulated nitrate under reductive soil disinfestation

Abstract

Purpose

Reductive soil disinfestation is an effective strategy for removing accumulated nitrate (NO₃⁻-N) from topsoil in intensive vegetable fields via elevating NO₃⁻-N consumption processes due to its water-saturated, strongly reductive, and carbon-rich characteristics. The duration of intensive vegetable cultivation may affect the relative importance of these consuming processes of NO₃⁻-N during reductive soil disinfestation treatment by altering topsoil properties. However, it remains elusive how the duration of intensive vegetable cultivation affects the fates of topsoil NO₃⁻-N during reductive soil disinfestation treatment.

Methods

Here, a soil column experiment labeled with K¹⁵NO₃ was conducted to investigate the effects of different cultivation ages (5, 10, 20 and 30 years) of intensively managed vegetable fields on the fates of topsoil NO₃⁻-N under reductive soil disinfestation treatment.

Results

The results showed that more than 91.8% of the added ¹⁵NO₃⁻-N in topsoil was removed by reductive soil disinfestation treatment, regardless of cultivation years. There was a trade-off between denitrification and NO₃⁻-N leaching into the subsoil, collectively accounting for 85.5–97.1% of the added ¹⁵NO₃⁻-N, regardless of cultivation years. The proportion of gaseous ¹⁵N loss via denitrification to added ¹⁵NO₃⁻-N (P_{denitrification}) initially increased from 5 to 10 years of cultivation, but subsequently decreased with further cultivation ages, whereas the trend was reversed for the proportion of leaching of ¹⁵NO₃⁻-N into the subsoil to added ¹⁵NO₃⁻-N (P_leaching).

Conclusion

Overall, our results highlight the critical role of using reductive soil disinfestation in removing accumulated NO₃⁻-N from the topsoil with its fates of a trade-off between P_{denitrification} and P_leaching as ages of intensive vegetable cultivation.