Effects of irrigation methods and improvement measures on ammonia volatilization of saline soil in Hetao Irrigation Area
CHANG Fei;HONG Mei;WU Yan;LI Yan-qin;ZHAO Bayin namula;DE Hai-shan;Inner Mongolia Agricultural University;Inner Mongolia Key Laboratory of Soil Quality and Nutrient Resources;
The salinized soil in Hetao Irrigation District was taken as the research object,and the field soil ammonia volatilization in situ method(ventilation method)was used to study the effect of farmers' conventional fertilization(CK),farmers' conventional fertilization+straw returning(SR),farmers' conventional fertilization+biochar(C)on soil ammonia volatilization and sunflower yield under the flood irrigation with the Yellow River water and the underfilm drip irrigation.The results showed that:1)The ammonia volatilization rate of each treatment peaked 2 ～ 4 days after fertilization and then gradually decreased.C and SR treatment significantly reduced the cumulative loss of ammonia volatilization(P0.05).C treatment under drip irrigation and flood irrigation decreased by 57% and 44%,respectively,and SR treatment decreased by 39% and 34%. 2)The soil pH was positively correlated with the ammonia volatilization rate. The soil salinity was significantly lower than that of CK under C and SR treatment(P0.05).3)The yield increasing of C treatment was the highest under different irrigation methods,and the effect of SR on yield increasing was not obvious.4)The loss rate of ammonia volatilization under drip irrigation was 10.7% ～ 31% lower than that of flood irrigation,and the yield with C and SR treatment was 12.88% and 2.02% higher than that of flood irrigation.Analysis of variance showed that the effect of improvement measures on ammonia volatilization and yield was extremely significant(P0.01),and the effect of irrigation method was significant(P0.05).In summary,both C and SR effectively inhibited soil ammonia volatilization,and the effect was more obvious in drip irrigation mode.Considering that the yield of sunflower treated with SR is low,conventional fertilization and biochar treatment by farmers under drip irrigation are currently reasonable fertilization measures.