Abstract:
Objective To reveal the temporal and spatial variation characteristics of soil enzyme activities in silage maize field under the nitrogen (N) application, the theoretical and practical basis will be provided for high yield and efficient cultivation of silage maize in central Inner Mongolia.
Methods The “Zhongxing silage 1” was used as the experimental material, and six N treatments 0 (N0), 120 (N8), 180 (N12), 240 (N16), 300 (N20), 360 (N24) kg hm−2 were set up to systematically analyze the temporal and spatial variation characteristics of soil enzyme activities in a silage maize field at five growth stages and 0-40 cm soil layers from 2018 to 2019, and the response of silage maize yield indices to N application levels was discussed.
Results There were significant differences in soil enzyme activity in silage maize field under different N application treatments, growth period under 0-40 cm soil layer (P < 0.05 ). With the prolongation of the maize growth period, the soil enzyme activities of the silage maize field changed in a parabolic shape and the highest from the trumpet period to the tasseling stage. Compared with the 0-20 cm soil layer, the catalase (CAT) activities increased while urease (UA) activities decreased in the deeper soil layer. The activities of invertase (IA), alkaline phosphatase (APA), urease, and the yield of silage maize were increased effectively by N application, and the peak values of invertase activities and yield were concentrated when the N application rate was 240 kg ha−1 (N16). In 2018 and 2019, biomass fresh weight in N16 treatment was 8.07%-65.88% and 7.11%-59.84% higher than those of other treatments, respectively. The biological yield was 20.20%-93.97% and 5.21%-100.72% higher than those of other treatments, respectively. There was a significant positive correlation among yield indices and APA, IA, and CAT. IA and UA had higher sensitivity in reflecting soil fertility levels.
Conclusion N application affects soil fertility and yield of silage maize to a certain extent. When the N application rate is 240 kg hm−2, soil enzyme activities are effectively enhanced, soil nutrients are improved, and the yield of silage maize is increased.