Biochar partially offset the increased ammonia volatilization from salt-affected soil

摘要

ABSTRACT Ammonia (NH3) volatilization is one of the major forms of nitrogen (N) losses from soil after N fertilization, especially in salt-affected soil, which leads to low N use efficiency. To evaluate the effect of biochar on NH3 volatilization from salt-affected soil with two different N fertilizers (urea and ammonium sulfate (AS)), experiments were conducted with two salt-affected soils (electrical conductivity EC1:5 of 1.0 and 5.0 ds m−1, namely S1 and S2) and non-saline soil as control (S0, EC1:5 < 0.3 ds m−1). Biochar was applied to S1 and S2 at the dosage of 20 t ha−1. Results showed that increasing soil salinity significantly promoted NH3 volatilization by 38.7–76.8 than control and AS treatments recorded higher NH3 volatilization than urea in all salinity levels. The addition of biochar decreased NH3 volatilization by 10.8–20.9. The proportion of cumulative NH3 volatilization in the first week to the whole experimental period was significantly higher in S1, and biochar addition can reduce the percentages of gaseous N losses. This study unravels the immense capability of salt-affected soil to aggravate N losses in the form of NH3 volatilization, and biochar can be used as a potential soil amendment in decreasing NH3 volatilization in salt-affected soil.