This experiment aimed to investigate the effect of sample pre-treatment methods and experimental conditions optimization on the NH3-N content in whole plant corn silage,providing methodological guidance for the detection of fermentation indicators in silage.20 g of whole plant corn silage samples were treated at different extraction concentrations(90,180 mL and 270 mL),extraction times(12,24 h and 48 h),and extraction temperatures(4℃,25～30℃ room temperature).Then,ammonia nitrogen was measured at different colorimetric wavelengths and color stability,and the optimal conditions were selected.The results showed that:(1)There was no significant difference in the NH3-N content of the whole plant corn silage between the extraction concentration and extraction temperature(P>0.05),but the NH3-N content was 46.2%and 53.8%higher after 24 h and 48 h of extraction compared to 12 h,respectively(P<0.01).(2)The NH3-N content significantly increased with the prolongation of the water bath color development time(P<0.01),and the color development reached stability at 30 minutes,with a maximum absorption wavelength of 630 nm;The recovery rate of NH3-N was 98.81%～104.24%(with an average of 101.2%).In concluded that 20 g of whole plant corn silage could be extracted in 180 mL of distilled water for 24 h at 4℃ to produce an extraction solution.After color development in a 37℃ water bath for 30 minutes,the determination could be carried out at a wavelength of 630 nm.
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